FLIR Systems FLIRE49001 Infrared Camera User Manual
FLIR Systems AB Infrared Camera
User manual
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| Document ID | 1642630 |
| Application ID | GiOEdKZNPKEF7SmZpCdKTQ== |
| Document Description | User manual |
| Short Term Confidential | No |
| Permanent Confidential | No |
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| Document Type | User Manual |
| Display Format | Adobe Acrobat PDF - pdf |
| Filesize | 177.74kB (2221719 bits) |
| Date Submitted | 2012-02-24 00:00:00 |
| Date Available | 2012-02-24 00:00:00 |
| Creation Date | 2011-09-27 12:03:17 |
| Producing Software | XEP 4.8 build 20061128 |
| Document Lastmod | 2011-09-27 11:50:52 |
| Document Title | Untitled |
| Document Creator | Unknown |
| Document Author: | Unknown |
User’s manual FLIR Exx series Publ. No. Revision Language Issue date T559597 a554 English (EN) September 27, 2011 User’s manual Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 Legal disclaimer All products manufactured by FLIR Systems are warranted against defective materials and workmanship for a period of one (1) year from the delivery date of the original purchase, provided such products have been under normal storage, use and service, and in accordance with FLIR Systems instruction. Products which are not manufactured by FLIR Systems but included in systems delivered by FLIR Systems to the original purchaser, carry the warranty, if any, of the particular supplier only. FLIR Systems has no responsibility whatsoever for such products. The warranty extends only to the original purchaser and is not transferable. It is not applicable to any product which has been subjected to misuse, neglect, accident or abnormal conditions of operation. Expendable parts are excluded from the warranty. In the case of a defect in a product covered by this warranty the product must not be further used in order to prevent additional damage. The purchaser shall promptly report any defect to FLIR Systems or this warranty will not apply. FLIR Systems will, at its option, repair or replace any such defective product free of charge if, upon inspection, it proves to be defective in material or workmanship and provided that it is returned to FLIR Systems within the said one-year period. FLIR Systems has no other obligation or liability for defects than those set forth above. No other warranty is expressed or implied. FLIR Systems specifically disclaims the implied warranties of merchantability and fitness for a particular purpose. FLIR Systems shall not be liable for any direct, indirect, special, incidental or consequential loss or damage, whether based on contract, tort or any other legal theory. This warranty shall be governed by Swedish law. Any dispute, controversy or claim arising out of or in connection with this warranty, shall be finally settled by arbitration in accordance with the Rules of the Arbitration Institute of the Stockholm Chamber of Commerce. The place of arbitration shall be Stockholm. The language to be used in the arbitral proceedings shall be English. U.S. Government Regulations ■ The products described in the user documentation may require government authorization for export/re-export, or transfer. Contact FLIR Systems for details. ■ Depending on license and export procedures, lenses may be permanently fixed to cameras shipped to customers outside United States. Interchangeable lenses fall under U.S. Department of State jurisdiction. Copyright © 2011, FLIR Systems. All rights reserved worldwide. No parts of the software including source code may be reproduced, transmitted, transcribed or translated into any language or computer language in any form or by any means, electronic, magnetic, optical, manual or otherwise, without the prior written permission of FLIR Systems. This documentation must not, in whole or part, be copied, photocopied, reproduced, translated or transmitted to any electronic medium or machine readable form without prior consent, in writing, from FLIR Systems. Names and marks appearing on the products herein are either registered trademarks or trademarks of FLIR Systems and/or its subsidiaries. All other trademarks, trade names or company names referenced herein are used for identification only and are the property of their respective owners. Quality assurance The Quality Management System under which these products are developed and manufactured has been certified in accordance with the ISO 9001 standard. FLIR Systems is committed to a policy of continuous development; therefore we reserve the right to make changes and improvements on any of the products described in this manual without prior notice. Patents One or several of the following patents or design patents apply to the products and/or features described in this manual: 0002258-2; 000279476-0001; 000439161; 000499579-0001; 000653423; 000726344; 000859020; 000889290; 001106306-0001; 001707738; 001707746; 001707787; 001776519; 0101577-5; 0102150-0; 0200629-4; 0300911-5; 0302837-0; 1144833; 1182246; 1182620; 1188086; 1285345; 1287138; 1299699; 1325808; 1336775; 1365299; 1402918; 1404291; 1678485; 1732314; 200530018812.0; 200830143636.7; 2106017; 235308; 3006596; 3006597; 466540; 483782; 484155; 518836; 60004227.8; 60122153.2; 602004011681.5-08; 6707044; 68657; 7034300; 7110035; 7154093; 7157705; 7237946; 7312822; 7332716; 7336823; 7544944; 75530; 7667198; 7809258; 7826736; D540838; D549758; D579475; D584755; D599,392; DI6702302-9; DI6703574-4; DI6803572-1; DI6803853-4; DI6903617-9; DM/057692; DM/061609; ZL00809178.1; ZL01823221.3; ZL01823226.4; ZL02331553.9; ZL02331554.7; ZL200480034894.0; ZL200530120994.2; ZL200630130114.4; ZL200730151141.4; ZL200730339504.7; ZL200830128581.2. EULA Terms ■ iv You have acquired a device (“INFRARED CAMERA”) that includes software licensed by FLIR Systems AB from Microsoft Licensing, GP or its affiliates (“MS”). Those installed software products of MS origin, as well as associated media, printed materials, and “online” or electronic documentation (“SOFTWARE”) are protected by international intellectual property laws and treaties. The SOFTWARE is licensed, not sold. All rights reserved. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 ■ IF YOU DO NOT AGREE TO THIS END USER LICENSE AGREEMENT (“EULA”), DO NOT USE THE DEVICE OR COPY THE SOFTWARE. INSTEAD, PROMPTLY CONTACT FLIR Systems AB FOR INSTRUCTIONS ON RETURN OF THE UNUSED DEVICE(S) FOR A REFUND. ANY USE OF THE SOFTWARE, INCLUDING BUT NOT LIMITED TO USE ON THE DEVICE, WILL CONSTITUTE YOUR AGREEMENT TO THIS EULA (OR RATIFICATION OF ANY PREVIOUS CONSENT). ■ GRANT OF SOFTWARE LICENSE. This EULA grants you the following license: ■ You may use the SOFTWARE only on the DEVICE. ■ NOT FAULT TOLERANT. THE SOFTWARE IS NOT FAULT TOLERANT. FLIR Systems AB HAS INDEPENDENTLY DETERMINED HOW TO USE THE SOFTWARE IN THE DEVICE, AND MS HAS RELIED UPON FLIR Systems AB TO CONDUCT SUFFICIENT TESTING TO DETERMINE THAT THE SOFTWARE IS SUITABLE FOR SUCH USE. ■ NO WARRANTIES FOR THE SOFTWARE. THE SOFTWARE is provided “AS IS” and with all faults. THE ENTIRE RISK AS TO SATISFACTORY QUALITY, PERFORMANCE, ACCURACY, AND EFFORT (INCLUDING LACK OF NEGLIGENCE) IS WITH YOU. ALSO, THERE IS NO WARRANTY AGAINST INTERFERENCE WITH YOUR ENJOYMENT OF THE SOFTWARE OR AGAINST INFRINGEMENT. IF YOU HAVE RECEIVED ANY WARRANTIES REGARDING THE DEVICE OR THE SOFTWARE, THOSE WARRANTIES DO NOT ORIGINATE FROM, AND ARE NOT BINDING ON, MS. ■ No Liability for Certain Damages. EXCEPT AS PROHIBITED BY LAW, MS SHALL HAVE NO LIABILITY FOR ANY INDIRECT, SPECIAL, CONSEQUENTIAL OR INCIDENTAL DAMAGES ARISING FROM OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THE SOFTWARE. THIS LIMITATION SHALL APPLY EVEN IF ANY REMEDY FAILS OF ITS ESSENTIAL PURPOSE. IN NO EVENT SHALL MS BE LIABLE FOR ANY AMOUNT IN EXCESS OF U.S. TWO HUNDRED FIFTY DOLLARS (U.S.$250.00). ■ Limitations on Reverse Engineering, Decompilation, and Disassembly. You may not reverse engineer, decompile, or disassemble the SOFTWARE, except and only to the extent that such activity is expressly permitted by applicable law notwithstanding this limitation. ■ SOFTWARE TRANSFER ALLOWED BUT WITH RESTRICTIONS. You may permanently transfer rights under this EULA only as part of a permanent sale or transfer of the Device, and only if the recipient agrees to this EULA. If the SOFTWARE is an upgrade, any transfer must also include all prior versions of the SOFTWARE. ■ EXPORT RESTRICTIONS. You acknowledge that SOFTWARE is subject to U.S. export jurisdiction. You agree to comply with all applicable international and national laws that apply to the SOFTWARE, including the U.S. Export Administration Regulations, as well as end-user, end-use and destination restrictions issued by U.S. and other governments. For additional information see http://www.microsoft.com/exporting/. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 vi Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 Table of contents Warnings & Cautions ..................................................................................................................... Notice to user .................................................................................................................................. Customer help ................................................................................................................................ Documentation updates ................................................................................................................. Important note about this manual ................................................................................................. Parts lists ......................................................................................................................................... 6.1 Scope of delivery .................................................................................................................. 6.2 List of accessories and services ........................................................................................... Quick Start Guide ........................................................................................................................... 10 Camera parts ................................................................................................................................... 8.1 View from the right ................................................................................................................ 8.2 View from the left .................................................................................................................. 8.3 Keypad .................................................................................................................................. 8.4 View from the bottom ........................................................................................................... 8.5 Battery condition LED indicator ............................................................................................ 8.6 Power LED indicator ............................................................................................................. 8.7 Laser pointer ......................................................................................................................... Screen elements ............................................................................................................................. 20 11 11 12 13 15 16 17 18 10 Navigating the menu system ......................................................................................................... 21 11 Connecting external devices and storage media ....................................................................... 22 12 Pairing Bluetooth devices .............................................................................................................. 24 13 Configuring Wi-Fi ............................................................................................................................ 25 14 Handling the camera ...................................................................................................................... 14.1 Turning on the camera ......................................................................................................... 14.2 Turning off the camera .......................................................................................................... 14.3 Adjusting the infrared camera focus manually .................................................................... 14.4 Operating the laser pointer ................................................................................................... 27 27 27 28 29 15 Working with images ...................................................................................................................... 15.1 Previewing an image ............................................................................................................ 15.2 Saving an image ................................................................................................................... 15.3 Opening an image ................................................................................................................ 15.4 Adjusting an image ............................................................................................................... 15.5 Changing the palette ............................................................................................................ 15.6 Deleting an image ................................................................................................................. 15.7 Deleting all images ............................................................................................................... 15.8 Creating a PDF report in the camera ................................................................................... 30 30 31 32 33 36 37 38 39 16 Working with thermal fusion and picture-in-picture image modes ........................................... 40 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 vii 17 Working with measurement tools ................................................................................................. 17.1 Laying out measurement tools: spots, areas, etc. ............................................................... 17.2 Laying out measurement tool: isotherms ............................................................................ 17.3 Moving or resizing a measurement tool ............................................................................... 17.4 Creating and setting up a difference calculation ................................................................. 17.5 Changing object parameters ................................................................................................ 44 44 45 46 47 48 18 Fetching data from external Extech meters ................................................................................. 50 18.1 Typical moisture measurement and documentation procedure .......................................... 52 19 Working with isotherms ................................................................................................................. 53 19.1 Building isotherms ................................................................................................................ 53 20 Annotating images .......................................................................................................................... 20.1 Taking a digital photo ........................................................................................................... 20.2 Creating a voice annotation ................................................................................................. 20.3 Creating a text annotation .................................................................................................... 54 55 56 57 21 Recording video clips .................................................................................................................... 59 22 Changing settings .......................................................................................................................... 60 23 Cleaning the camera ...................................................................................................................... 23.1 Camera housing, cables, and other items ........................................................................... 23.2 Infrared lens .......................................................................................................................... 23.3 Infrared detector ................................................................................................................... 61 61 62 63 24 Technical data ................................................................................................................................. 64 25 Dimensional drawings ................................................................................................................... 25.1 Camera dimensions, front view (1) ...................................................................................... 25.2 Camera dimensions, front view (2) ...................................................................................... 25.3 Camera dimensions, side view (1) ....................................................................................... 25.4 Camera dimensions, side view (2) ....................................................................................... 25.5 Camera dimensions, side view (3) ....................................................................................... 25.6 Infrared lens (30 mm/15°) ..................................................................................................... 25.7 Infrared lens (10 mm/45°) ..................................................................................................... 25.8 Battery (1) ............................................................................................................................. 25.9 Battery (2) ............................................................................................................................. 25.10 Battery (3) ............................................................................................................................. 25.11 Battery charger (1) ................................................................................................................ 25.12 Battery charger (2) ................................................................................................................ 25.13 Battery charger (3) ................................................................................................................ 25.14 Battery charger (4) ................................................................................................................ 65 65 66 67 68 69 70 71 72 73 74 75 76 77 78 26 Application examples ..................................................................................................................... 26.1 Moisture & water damage .................................................................................................... 26.2 Faulty contact in socket ........................................................................................................ 26.3 Oxidized socket .................................................................................................................... 26.4 Insulation deficiencies .......................................................................................................... 26.5 Draft ...................................................................................................................................... 79 79 80 81 82 83 27 Introduction to building thermography ........................................................................................ 84 27.1 Disclaimer ............................................................................................................................. 84 viii Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27.2 27.3 27.4 27.1.1 Copyright notice ................................................................................................... 84 27.1.2 Training & certification .......................................................................................... 84 27.1.3 National or regional building codes ..................................................................... 84 Important note ...................................................................................................................... 84 Typical field investigations .................................................................................................... 85 27.3.1 Guidelines ............................................................................................................. 85 27.3.1.1 General guidelines ............................................................................ 85 27.3.1.2 Guidelines for moisture detection, mold detection & detection of water damages .................................................................................. 85 27.3.1.3 Guidelines for detection of air infiltration & insulation deficiencies ... 86 27.3.2 About moisture detection ..................................................................................... 87 27.3.3 Moisture detection (1): Low-slope commercial roofs .......................................... 87 27.3.3.1 General information ........................................................................... 87 27.3.3.2 Safety precautions ............................................................................ 88 27.3.3.3 Commented building structures ....................................................... 89 27.3.3.4 Commented infrared images ............................................................ 90 27.3.4 Moisture detection (2): Commercial & residential façades .................................. 92 27.3.4.1 General information ........................................................................... 92 27.3.4.2 Commented building structures ....................................................... 92 27.3.4.3 Commented infrared images ............................................................ 94 27.3.5 Moisture detection (3): Decks & balconies .......................................................... 94 27.3.5.1 General information ........................................................................... 94 27.3.5.2 Commented building structures ....................................................... 95 27.3.5.3 Commented infrared images ............................................................ 97 27.3.6 Moisture detection (4): Plumbing breaks & leaks ................................................ 97 27.3.6.1 General information ........................................................................... 97 27.3.6.2 Commented infrared images ............................................................ 98 27.3.7 Air infiltration ......................................................................................................... 100 27.3.7.1 General information ........................................................................... 100 27.3.7.2 Commented building structures ....................................................... 100 27.3.7.3 Commented infrared images ............................................................ 102 27.3.8 Insulation deficiencies .......................................................................................... 103 27.3.8.1 General information ........................................................................... 103 27.3.8.2 Commented building structures ....................................................... 103 27.3.8.3 Commented infrared images ............................................................ 105 Theory of building science ................................................................................................... 107 27.4.1 General information .............................................................................................. 107 27.4.2 The effects of testing and checking ..................................................................... 108 27.4.3 Sources of disruption in thermography ................................................................ 109 27.4.4 Surface temperature and air leaks ....................................................................... 111 27.4.4.1 Pressure conditions in a building ..................................................... 111 27.4.5 Measuring conditions & measuring season ......................................................... 117 27.4.6 Interpretation of infrared images .......................................................................... 117 27.4.7 Humidity & dew point ........................................................................................... 119 27.4.7.1 Relative & absolute humidity ............................................................ 119 27.4.7.2 Definition of dew point ...................................................................... 119 27.4.8 Excerpt from Technical Note ‘Assessing thermal bridging and insulation continuity’ (UK example) ...................................................................................... 119 27.4.8.1 Credits ............................................................................................... 119 27.4.8.2 Introduction ....................................................................................... 120 27.4.8.3 Background information ................................................................... 120 27.4.8.4 Quantitative appraisal of thermal anomalies .................................... 121 27.4.8.5 Conditions and equipment ............................................................... 124 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 ix 27.4.8.6 27.4.8.7 Survey and analysis .......................................................................... 125 Reporting ........................................................................................... 126 28 Introduction to thermographic inspections of electrical installations ...................................... 128 28.1 Important note ...................................................................................................................... 128 28.2 General information .............................................................................................................. 128 28.2.1 Introduction ........................................................................................................... 128 28.2.2 General equipment data ....................................................................................... 129 28.2.3 Inspection ............................................................................................................. 130 28.2.4 Classification & reporting ...................................................................................... 130 28.2.5 Priority ................................................................................................................... 131 28.2.6 Repair .................................................................................................................... 131 28.2.7 Control .................................................................................................................. 132 28.3 Measurement technique for thermographic inspection of electrical installations ............... 133 28.3.1 How to correctly set the equipment ..................................................................... 133 28.3.2 Temperature measurement ................................................................................... 133 28.3.3 Comparative measurement .................................................................................. 135 28.3.4 Normal operating temperature ............................................................................. 136 28.3.5 Classification of faults ........................................................................................... 137 28.4 Reporting .............................................................................................................................. 139 28.5 Different types of hot spots in electrical installations ........................................................... 141 28.5.1 Reflections ............................................................................................................ 141 28.5.2 Solar heating ......................................................................................................... 141 28.5.3 Inductive heating ................................................................................................... 142 28.5.4 Load variations ...................................................................................................... 142 28.5.5 Varying cooling conditions ................................................................................... 143 28.5.6 Resistance variations ............................................................................................ 144 28.5.7 Overheating in one part as a result of a fault in another ...................................... 144 28.6 Disturbance factors at thermographic inspection of electrical installations ........................ 146 28.6.1 Wind ...................................................................................................................... 146 28.6.2 Rain and snow ...................................................................................................... 146 28.6.3 Distance to object ................................................................................................. 147 28.6.4 Object size ............................................................................................................ 148 28.7 Practical advice for the thermographer ................................................................................ 150 28.7.1 From cold to hot ................................................................................................... 150 28.7.2 Rain showers ........................................................................................................ 150 28.7.3 Emissivity .............................................................................................................. 150 28.7.4 Reflected apparent temperature ........................................................................... 151 28.7.5 Object too far away ............................................................................................... 151 29 About FLIR Systems ....................................................................................................................... 152 29.1 More than just an infrared camera ....................................................................................... 153 29.2 Sharing our knowledge ........................................................................................................ 154 29.3 Supporting our customers ................................................................................................... 154 29.4 A few images from our facilities ........................................................................................... 154 30 Glossary ........................................................................................................................................... 156 31 Thermographic measurement techniques ................................................................................... 160 31.1 Introduction .......................................................................................................................... 160 31.2 Emissivity .............................................................................................................................. 160 31.2.1 Finding the emissivity of a sample ....................................................................... 161 31.2.1.1 Step 1: Determining reflected apparent temperature ....................... 161 31.2.1.2 Step 2: Determining the emissivity ................................................... 163 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 31.3 31.4 31.5 31.6 Reflected apparent temperature .......................................................................................... 164 Distance ................................................................................................................................ 164 Relative humidity .................................................................................................................. 164 Other parameters .................................................................................................................. 164 32 History of infrared technology ...................................................................................................... 165 33 Theory of thermography ................................................................................................................ 169 33.1 Introduction ........................................................................................................................... 169 33.2 The electromagnetic spectrum ............................................................................................ 169 33.3 Blackbody radiation .............................................................................................................. 170 33.3.1 Planck’s law .......................................................................................................... 171 33.3.2 Wien’s displacement law ...................................................................................... 172 33.3.3 Stefan-Boltzmann's law ......................................................................................... 174 33.3.4 Non-blackbody emitters ....................................................................................... 175 33.4 Infrared semi-transparent materials ..................................................................................... 177 34 The measurement formula ............................................................................................................. 179 35 Emissivity tables ............................................................................................................................. 185 35.1 References ............................................................................................................................ 185 35.2 Important note about the emissivity tables .......................................................................... 185 35.3 Tables .................................................................................................................................... 186 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 xi xii Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 1 Warnings & Cautions WARNING ■ ■ (Applies only to Class A digital devices.) This equipment generates, uses, and can radiate radio frequency energy and if not installed and used in accordance with the instruction manual, may cause interference to radio communications. It has been tested and found to comply with the limits for a Class A computing device pursuant to Subpart J of Part 15 of FCC Rules, which are designed to provide reasonable protection against such interference when operated in a commercial environment. Operation of this equipment in a residential area is likely to cause interference in which case the user at his own expense will be required to take whatever measures may be required to correct the interference. (Applies only to Class B digital devices.) This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: ■ ■ ■ ■ ■ Reorient or relocate the receiving antenna. Increase the separation between the equipment and receiver. Connect the equipment into an outlet on a circuit different from that to which the receiver is connected. Consult the dealer or an experienced radio/TV technician for help. (Applies only to digital devices subject to 15.19/RSS-210.) NOTICE: This device complies with Part 15 of the FCC Rules and with RSS-210 of Industry Canada. Operation is subject to the following two conditions: 1 this device may not cause harmful interference, and 2 this device must accept any interference received, including interference that may cause undesired operation. ■ ■ ■ ■ (Applies only to digital devices subject to 15.21.) NOTICE: Changes or modifications made to this equipment not expressly approved by (manufacturer name) may void the FCC authorization to operate this equipment. (Applies only to digital devices subject to 2.1091/2.1093/OET Bulletin 65.) Radiofrequency radiation exposure Information: The radiated output power of the device is far below the FCC radio frequency exposure limits. Nevertheless, the device shall be used in such a manner that the potential for human contact during normal operation is minimized. (Applies only to cameras with laser pointer:) Do not look directly into the laser beam. The laser beam can cause eye irritation. Applies only to cameras with battery: ■ Do not disassemble or do a modification to the battery. The battery contains safety and protection devices which, if they become damaged, can cause the battery to become hot, or cause an explosion or an ignition. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 1 – Warnings & Cautions ■ ■ ■ CAUTION ■ Make sure that you read all applicable MSDS (Material Safety Data Sheets) and warning labels on containers before you use a liquid: the liquids can be dangerous. ■ Do not point the infrared camera (with or without the lens cover) at intensive energy sources, for example devices that emit laser radiation, or the sun. This can have an unwanted effect on the accuracy of the camera. It can also cause damage to the detector in the camera. Do not use the camera in a temperature higher than +50°C (+122°F), unless specified otherwise in the user documentation. High temperatures can cause damage to the camera. (Applies only to cameras with laser pointer:) Protect the laser pointer with the protective cap when you do not operate the laser pointer. Applies only to cameras with battery: ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ If there is a leak from the battery and the fluid gets into your eyes, do not rub your eyes. Flush well with water and immediately get medical care. The battery fluid can cause injury to your eyes if you do not do this. Do not continue to charge the battery if it does not become charged in the specified charging time. If you continue to charge the battery, it can become hot and cause an explosion or ignition. Only use the correct equipment to discharge the battery. If you do not use the correct equipment, you can decrease the performance or the life cycle of the battery. If you do not use the correct equipment, an incorrect flow of current to the battery can occur. This can cause the battery to become hot, or cause an explosion and injury to persons. Do not attach the batteries directly to a car’s cigarette lighter socket, unless a specific adapter for connecting the batteries to a cigarette lighter socket is provided by FLIR Systems. Do not connect the positive terminal and the negative terminal of the battery to each other with a metal object (such as wire). Do not get water or salt water on the battery, or permit the battery to get wet. Do not make holes in the battery with objects. Do not hit the battery with a hammer. Do not step on the battery, or apply strong impacts or shocks to it. Do not put the batteries in or near a fire, or into direct sunlight. When the battery becomes hot, the built-in safety equipment becomes energized and can stop the battery charging process. If the battery becomes hot, damage can occur to the safety equipment and this can cause more heat, damage or ignition of the battery. Do not put the battery on a fire or increase the temperature of the battery with heat. Do not put the battery on or near fires, stoves, or other high-temperature locations. Do not solder directly onto the battery. Do not use the battery if, when you use, charge, or store the battery, there is an unusual smell from the battery, the battery feels hot, changes color, changes shape, or is in an unusual condition. Contact your sales office if one or more of these problems occurs. Only use a specified battery charger when you charge the battery. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 1 – Warnings & Cautions ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The temperature range through which you can charge the battery is ±0°C to +45°C (+32°F to +113°F), unless specified otherwise in the user documentation. If you charge the battery at temperatures out of this range, it can cause the battery to become hot or to break. It can also decrease the performance or the life cycle of the battery. The temperature range through which you can discharge the battery is −15°C to +50°C (+5°F to +122°F), unless specified otherwise in the user documentation. Use of the battery out of this temperature range can decrease the performance or the life cycle of the battery. When the battery is worn, apply insulation to the terminals with adhesive tape or similar materials before you discard it. Remove any water or moisture on the battery before you install it. Do not apply solvents or similar liquids to the camera, the cables, or other items. This can cause damage. Be careful when you clean the infrared lens. The lens has a delicate anti-reflective coating. Do not clean the infrared lens too vigorously. This can damage the anti-reflective coating. In furnace and other high-temperature applications, you must mount a heatshield on the camera. Using the camera in furnace and other high-temperature applications without a heatshield can cause damage to the camera. (Applies only to cameras with an automatic shutter that can be disabled.) Do not disable the automatic shutter in the camera for a prolonged time period (typically max. 30 minutes). Disabling the shutter for a longer time period may harm, or irreparably damage, the detector. The encapsulation rating is valid only when all openings on the camera are sealed with their designated covers, hatches, or caps. This includes, but is not limited to, compartments for data storage, batteries, and connectors. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 2 Notice to user Typographical conventions This manual uses the following typographical conventions: ■ ■ ■ ■ User-to-user forums Semibold is used for menu names, menu commands and labels, and buttons in dialog boxes. Italic is used for important information. Monospace is used for code samples. UPPER CASE is used for names on keys and buttons. Exchange ideas, problems, and infrared solutions with fellow thermographers around the world in our user-to-user forums. To go to the forums, visit: http://www.infraredtraining.com/community/boards/ Calibration (This notice only applies to cameras with measurement capabilities.) We recommend that you send in the camera for calibration once a year. Contact your local sales office for instructions on where to send the camera. Accuracy (This notice only applies to cameras with measurement capabilities.) For very accurate results, we recommend that you wait 5 minutes after you have started the camera before measuring a temperature. For cameras where the detector is cooled by a mechanical cooler, this time period excludes the time it takes to cool down the detector. Disposal of electronic waste 10742803;a1 As with most electronic products, this equipment must be disposed of in an environmentally friendly way, and in accordance with existing regulations for electronic waste. Please contact your FLIR Systems representative for more details. Training To read about infrared training, visit: ■ ■ ■ http://www.infraredtraining.com http://www.irtraining.com http://www.irtraining.eu Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 3 Customer help General For customer help, visit: http://support.flir.com Submitting a question To submit a question to the customer help team, you must be a registered user. It only takes a few minutes to register online. If you only want to search the knowledgebase for existing questions and answers, you do not need to be a registered user. When you want to submit a question, make sure that you have the following information to hand: ■ ■ ■ ■ ■ ■ Downloads The camera model The camera serial number The communication protocol, or method, between the camera and your PC (for example, HDMI, Ethernet, USB™, or FireWire™) Operating system on your PC Microsoft® Office version Full name, publication number, and revision number of the manual On the customer help site you can also download the following: ■ ■ ■ ■ ■ Firmware updates for your infrared camera Program updates for your PC software User documentation Application stories Technical publications Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 4 Documentation updates General Our manuals are updated several times per year, and we also issue product-critical notifications of changes on a regular basis. To access the latest manuals and notifications, go to the Download tab at: http://support.flir.com It only takes a few minutes to register online. In the download area you will also find the latest releases of manuals for our other products, as well as manuals for our historical and obsolete products. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 5 Important note about this manual General FLIR Systems issues generic manuals that cover several cameras within a model line. This means that this manual may contain descriptions and explanations that do not apply to your particular camera model. NOTE FLIR Systems reserves the right to discontinue models, software, parts or accessories, and other items, or to change specifications and/or functionality at any time without prior notice. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 6 Parts lists 6.1 Scope of delivery Contents ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Infrared camera with lens Hard transport case Battery (2*) Bluetooth headset* Calibration certificate FLIR Tools PC software CD-ROM Handstrap Lens cap Memory card Power supply, including multi-plugs Printed Getting Started Guide Printed Important Information Guide USB cable User documentation CD-ROM Video cable Warranty extension card or Registration card * Dependent on the camera model/customer configuration. NOTE FLIR Systems reserves the right to discontinue models, parts or accessories, and other items, or to change specifications at any time without prior notice. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 6 – Parts lists 6.2 List of accessories and services General This section contains a list of accessories and services that you can purchase for your camera. Accessories and services ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ NOTE 1196497 Cigarette lighter adapter kit, 12 VDC, 1.2 m/3.9 ft. 1196960 IR lens f = 10 mm, 45° including case 1196961 IR lens f = 30 mm, 15° including case 1910423 USB cable Std A to Mini-B 1910582 Video cable ITC-ADV-3011 ITC Advanced Building—attendance 1 person ITC-ADV-3019 ITC Advanced Building—group of 10 persons ITC-ADV-3021 ITC Advanced General Thermography Course—attendance, 1 person ITC-ADV-3029 ITC Advanced General Thermography Course—group of 10 persons ITC-CER-5101 ITC Level 1 Thermography Course—attendance, 1 person ITC-CER-5109 ITC Level 1 Thermography Course—group of 10 persons ITC-CER-5201 ITC Level 2 Thermography Course—attendance, 1 person ITC-CER-5209 ITC Level 2 Thermography Course—group of 10 persons T197453 FLIR ResearchIR 1.2 T197453L10 FLIR ResearchIR 1.2, 10 user licenses T197453L5 FLIR ResearchIR 1.2, 5 user licenses T197454 FLIR QuickPlot 1.2 T197454L10 FLIR QuickPlot 1.2, 10 user licenses T197454L5 FLIR QuickPlot 1.2, 5 user licenses T197717 FLIR Reporter 8.5 SP2, Professional T197717L10 FLIR Reporter 8.5 SP2, Professional, 10 user licenses T197717L5 FLIR Reporter 8.5 SP2, Professional, 5 user licenses T197771 Bluetooth headset T197778 FLIR BuildIR 2.1 T197778L10 FLIR BuildIR 2.1, 10 user licenses T197778L5 FLIR BuildIR 2.1, 5 user licenses T910737 Memory card micro-SD with adapters T910972 EX845: Clamp meter + IR therm TRMS 1000A AC/DC T910973 MO297: Moisture meter, pinless with memory FLIR Systems reserves the right to discontinue models, parts or accessories, and other items, or to change specifications at any time without prior notice. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 7 Quick Start Guide Procedure Follow this procedure to get started right away: Put a battery into the battery compartment. Charge the battery for 4 hours before starting the camera for the first time, or until the green battery condition LED glows continuously. Insert a memory card into a card slot. Push the Aim the camera towards the object of interest. Focus the camera by rotating the focus ring. Pull and hold the trigger for more than 1 second to save an image directly. Move the image to a computer by doing one of the following: ■ ■ NOTE 10 button to turn on the camera. Remove the memory card and insert it in a card reader connected to a computer. Connect a computer to the camera using a USB mini-B cable. Move the image from the card or camera, using a drag-and-drop operation. You can also move the images to the computer using FLIR Tools, which comes with your camera. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 8 Camera parts 8.1 View from the right Figure T638786;a1 Explanation This table explains the figure above: Cover for the right-hand connectors compartment: ■ ■ ■ USB-A. USB mini-B. Power. Trigger to preview/save images. Tripod mount. Requires an adapter (extra accessory). Focus ring. Infrared lens. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 11 8 – Camera parts 8.2 View from the left Figure T638790;a1 Explanation This table explains the figure above: Laser pointer. Lamp for the digital camera. Digital camera. Cover for connectors and storage media: ■ ■ 12 Memory card. Video out. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 8 – Camera parts 8.3 Keypad Figure T638787;a2 Explanation This table explains the figure above: Touch-screen LCD. Navigation pad. ■ ■ Button to confirm choice. Button to switch between automatic and manual adjustment modes. Image archive. Button to operate the laser pointer. Power indicator. On/off button. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 13 8 – Camera parts ■ ■ 14 Button to display the menu system. Back button. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 8 – Camera parts 8.4 View from the bottom Figure T638785;a3 Explanation This table explains the figure above: Latch to open the cover for the battery compartment. Push to open. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 15 8 – Camera parts 8.5 Battery condition LED indicator Figure T638791;a1 Explanation This table explains the battery condition LED indicator: 16 Type of signal Explanation The green LED flashes two times per second. The battery is being charged. The green LED glows continuously. The battery is fully charged. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 8 – Camera parts 8.6 Power LED indicator Figure T638781;a1 Explanation This table explains the power LED indicator: Type of signal Explanation The LED is off. The camera is off. The LED is blue. The camera is on. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 17 8 – Camera parts 8.7 Laser pointer General The camera has a laser pointer. When the laser pointer is on, you can see a laser dot above the target. Figure This figure shows the difference in position between the laser pointer and the optical center of the infrared lens: T638771;a1 WARNING Do not look directly into the laser beam. The laser beam can cause eye irritation. NOTE ■ ■ Laser warning label 18 The symbol is displayed on the screen when the laser pointer is on. The laser pointer may not be enabled in all markets. A laser warning label with the following information is attached to the camera: 10743603;a2 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 8 – Camera parts Laser rules and regulations Wavelength: 635 nm. Maximum output power: 1 mW. This product complies with 21 CFR 1040.10 and 1040.11 except for deviations pursuant to Laser Notice No. 50, dated June 24, 2007. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 19 9 Screen elements Figure T638713;a3 Explanation This table explains the figure above: 20 Measurement result table. Measurement tools (e.g., spotmeter). Status and mode icons. Temperature scale. Setup mode. Video mode recording. Camera mode/live image mode. View mode (infrared camera, digital camera, thermal fusion, picture-in-picture). Measurement tools. 10 Color palettes. 11 Measurement parameters. 12 Zoom. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 10 Navigating the menu system Figure T638777;a1 Explanation The figure above shows the two ways to navigate the menu system in the camera: ■ ■ T638780;a1 Using the index finger to navigate the menu system (left). Using the navigation pad to navigate the menu system (right). Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 21 11 Connecting external devices and storage media Figure T638789;a4 Explanation This table explains the figure above: 22 Indicator showing that the memory card is busy. Note: Do not remove the memory card when this indicator is glowing. Memory card. Headset cable. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 11 – Connecting external devices and storage media Figure T638788;a1 Explanation This table explains the figure above: Power cable. USB mini-B cable (to connect the camera to a PC). USB-A cable (to connect the camera to an external device, e.g., a USB memory stick). Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 23 12 Pairing Bluetooth devices General Before you can use a Bluetooth device with the camera, you need to pair the devices. Procedure Follow this procedure: Go to (Settings). Go to the Connectivity tab. Activate Bluetooth. Note: You also need to activate Bluetooth connectivity on the external device. NOTE ■ ■ ■ ■ ■ 24 Select Add Bluetooth device. Select Scan for Bluetooth device, and wait until a list of available devices is displayed. This will take about 15 seconds. When a Bluetooth device is found, select the device to add it. The device is now ready to be used. You can add several devices. You can remove an added device by selecting the device and and then selecting Remove. After adding a MeterLink device, such as the Extech MO297 or EX845, the result from the meter will be visible in the measurement result table. After adding a Bluetooth-enabled headset, it is ready to be used in camera preview mode. It is also possible to add live snapshot values in preview mode. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 13 Configuring Wi-Fi General Depending on your camera configuration, you can connect the camera to a wireless local area network (WLAN) using Wi-Fi, or let the camera provide Wi-Fi access to another device. You can connect the camera in two different ways: ■ ■ Setting up a peer-to-peer connection (most common use) Most common use: Setting up a peer-to-peer connection (also called ad hoc or P2P connection). This method is primarily used with other devices, e.g., an iPhone or iPad. Less common use: Connecting the camera to a WLAN. Follow this procedure: Go to (Settings) . Go to the Connectivity tab. Under Wi-Fi, select Connect device. Select Wi-Fi settings. Enter values for the following parameters: ■ ■ ■ ■ ■ ■ SSID (the name of the network). Channel (the channel that the other device is broadcasting on). Encryption (the encryption algorithm, e.g., TKIP or AES). Key (the access key to the network). Address (the IP address for the network). Gateway (the gateway IP address for the network). Note: These parameters are set for your camera's network. They will be used by the external device to connect that device to the network. Push Connecting the camera to a wireless local area network (less common use) to confirm the choice. Follow this procedure: Go to (Settings) . Go to the Connectivity tab. Under Wi-Fi, select Connect to WLAN. Select Wi-Fi settings. Select one of the available networks. Password-protected networks are indicated with a padlock icon, and for these you will need to enter an access key. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 25 13 – Configuring Wi-Fi Push NOTE 26 to confirm the choice. Some networks do not broadcast their existence. To connect to such a network, select Add manually and set all parameters manually according to that network. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 14 Handling the camera 14.1 Turning on the camera Procedure 14.2 Procedure To turn on the camera, push and release the button. Turning off the camera To turn off the camera, push and hold the Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 button for more than 0.2 second. 27 14 – Handling the camera 14.3 Adjusting the infrared camera focus manually NOTE ■ ■ Do not touch the lens surface when you adjust the infrared camera focus manually. If this happens, clean the lens according to the instructions in section 23.2 – Infrared lens on page 62. The focus ring can be rotated infinitely, but only a certain amount of rotation is needed when focusing. Figure T638779;a1 Procedure Do one of the following: ■ ■ 28 For far focus, rotate the focus ring counter-clockwise (looking at the touch-screen LCD side). For near focus, rotate the focus ring clockwise (looking at the touch-screen LCD side). Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 14 – Handling the camera 14.4 Operating the laser pointer Figure T638778;a1 Procedure Follow this procedure to operate the laser pointer: NOTE ■ ■ To turn on the laser pointer, push and hold the laser button. To turn off the laser pointer, release the laser button. A warning indicator is displayed on the screen when the laser pointer is turned on. The position of the laser dot is indicated on the infrared image (depending on the camera model). Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 29 15 Working with images 15.1 Previewing an image General You can preview an infrared image or a digital photo before you save it to a memory card. This enables you to see if the image or photo contains the information you want before you save it. In preview mode, you can also manipulate the image before you save it, and add annotations. Procedure NOTE To preview an image, briefly pull and release the trigger. You can change the function of the trigger under be set to one of the following: ■ ■ ■ 30 (Settings). The function can Preview/Save. Save directly. Always preview. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 15 – Working with images 15.2 Saving an image General You can save an image directly, without previewing the image first. Image capacity This table gives information on the approximate number of infrared (IR) and digital camera (DC) images that can be saved on memory cards: Card size IR only IR + DC IR + DC + 30 seconds voice annotation 1 GB 5500 850 600 2 GB 11 000 1700 1200 Naming convention The naming convention for images is IR_xxxx.jpg, where xxxx is a unique counter. Procedure To save an image directly, pull and hold down the trigger for more than 1 second. NOTE You can change the function of the trigger in the Settings menus. The function can be set to one of the following: ■ ■ ■ Preview/Save. Save directly. Always preview. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 31 15 – Working with images 15.3 Opening an image General When you save an image, the image is stored on a memory card. To display the image again, open it from the memory card. Procedure Follow this procedure to open an image: Push Push the navigation pad up/down or left/right to select the image you want to view. Push . This will display the image at full size. To edit the opened image, push the menu. 32 button, which will bring up a Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 15 – Working with images 15.4 General Example 1 Adjusting an image An image can be adjusted automatically or manually. You use the button to switch between these two modes. Note that this only works in live mode and not in preview/archive mode. This figure shows two infrared images of cable connection points. In the left image a correct analysis of the left cable is difficult to do if you only auto-adjust the image. You can analyze the left cable in more detail if you ■ ■ change the temperature scale level change the temperature scale span. The image on the left has been auto-adjusted. In the right image the maximum and minimum temperature levels have been changed to temperature levels near the object. On the temperature scale to the right of each image you can see how the temperature levels were changed. 10577503;a2 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 33 15 – Working with images Example 2 This figure shows two infrared images of an isolator in a power line. In the image on the left the cold sky and the power line structure have been recorded at a minimum temperature of –26.0°C (–14.8°F). In the right image the maximum and minimum temperature levels have been changed to temperature levels near the isolator. This makes it easier to analyze the temperature variations in the isolator. 10742503;a3 34 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 15 – Working with images Changing the temperature scale level Follow this procedure to change the temperature scale level: Push Use the navigation pad to select Changing the temperature scale span (Manual). To change the scale level, push the navigation pad up/down. Follow this procedure to change the temperature scale span: Push Use the navigation pad to select NOTE (Manual). To change the scale span, push the navigation pad left/right. These procedures only apply to live image mode. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 35 15 – Working with images 15.5 Changing the palette General You can change the color palette that the camera uses to display different temperatures. A different palette can make it easier to analyze an image. Procedure Follow this procedure to change the palette: Push to display the menu system. Use the navigation pad to go to Push to display a submenu. Use the navigation pad to select a different palette. Push 36 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 15 – Working with images 15.6 Deleting an image General You can delete one or more images in a folder. Procedure Follow this procedure to delete an image: Push Push the navigation pad up/down or left/right to select the image you want to delete. Push to display the image. Push to display a menu. NOTE On the menu, select Delete and confirm the choice. Note that all images in the same group will be deleted at the same time, e.g., digital photos. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 37 15 – Working with images 15.7 Deleting all images General You can delete all images in a folder. Procedure Follow this procedure to delete an image: Push Push the navigation pad up/down or left/right to select any image. Push to display the image. Push to display a menu. 38 On the menu, select Delete all and confirm the choice. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 15 – Working with images 15.8 Creating a PDF report in the camera General You can create a PDF report in the camera. You can then transfer the PDF report to a computer, iPhone, or iPad using the FLIR Viewer app, and send the report to a customer. Procedure Follow this procedure to create a PDF report: Push Push the navigation pad up/down or left/right to select an image. Push to display the image. Push to display a menu. On the menu, select Create report. This will display a menu where you can change the following: ■ ■ ■ Header. Footer. Logo. (The location of the logo should be /report/logo/ and the file format *.jpg.) On the menu, select Create report. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 39 16 Working with thermal fusion and picture-in-picture image modes What is thermal fusion? Thermal fusion is a function that lets you display part of a digital photo as an infrared image. For example, you can set the camera to display all areas of an image that have a certain temperature in infrared, with all other areas displayed as a digital photo. What is picture-inpicture? Picture-in-picture is similar to thermal fusion in that it lets you display part of a digital photo as an infrared image. However, picture-in-picture displays an infrared image frame on top of a digital photo. Types Depending on the camera model, up to four different types are available. These are: ■ ■ ■ ■ Image examples Above: All areas in the digital photo with a temperature above the specified temperature level are displayed in infrared. Below: All areas in the digital photo with a temperature below the specified temperature level are displayed in infrared. Interval: All areas in the digital photo with a temperature between two specified temperature levels are displayed in infrared. Picture-in-Picture: An infrared image frame is displayed on top of the digital photo. This table explains the four different types: Fusion type Image Above Below 40 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 16 – Working with thermal fusion and picture-in-picture image modes Fusion type Image Interval Picture-in-Picture Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 41 16 – Working with thermal fusion and picture-in-picture image modes Procedure to set up thermal fusion Follow this procedure: Push to display the menu system. In the menu system, select . This will display a submenu. In the submenu, select Thermal fusion. Push 42 To change the portion of infrared in the image, do one of the following: ■ Push the joystick left/right to select , then push the joystick up/down to change the bottom temperature level. ■ Push the joystick left/right to select to change the top temperature level. ■ Push the joystick left/right to select , then push the joystick up/down to change the top and bottom temperature level at the same time, and left/right to change the temperature span. , then push the joystick up/down Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 16 – Working with thermal fusion and picture-in-picture image modes Procedure to set up picture-in-picture Follow this procedure: Push to display the menu system. In the menu system, select . This will display a submenu. In the submenu, select Picture-in-Picture. This will display an infrared image frame on top of a digital photo. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 43 17 Working with measurement tools 17.1 Laying out measurement tools: spots, areas, etc. General To measure a temperature, you use one or more measurement tools, e.g., a spotmeter or a box. Procedure Follow this procedure to lay out a measurement tool: Push to display the menu system. Use the navigation pad to go to Push to display a submenu. Use the navigation pad to go to a measurement tool. Push 44 . This will display the measurement tool on the screen. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 17 – Working with measurement tools 17.2 Laying out measurement tool: isotherms General The isotherm command applies a contrasting color to all pixels with a temperature above, below, or between one or more set temperature levels. Using isotherms is a good method to easily discover anomalies in an infrared image. Procedure Follow this procedure to lay out an isotherm: Push to display the menu system. Use the navigation pad to go to Push to display a submenu. Use the navigation pad to go to Push . This will display a submenu. In the submenu, select one of the following: ■ ■ ■ ■ ■ Above. This will apply a contrasting color to all pixels with a temperature above one or more set temperature levels. Below. This will apply a contrasting color to all pixels with a temperature below one or more set temperature levels. Interval. This will apply a contrasting color to all pixels with a temperature between two or more set temperature levels. Humidity. This will apply a contrasting color to all pixels with a temperature below a threshold calculated by humidity parameters. Insulation. This will apply a contrasting color to all pixels with a temperature below a threshold calculated by insulation parameters. This will display a flag in the temperature scale. To change the temperature level, tap and drag the flag up or down. See the image below. T639069;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 45 17 – Working with measurement tools 17.3 Moving or resizing a measurement tool General You can move and resize a measurement tool. NOTE ■ ■ Procedure This procedure assumes that you have previously laid out a measurement tool on the screen. You can also move and resize the measurement tool using your finger. Follow this procedure to move or resize a measurement tool: Push to display the menu system. Use the navigation pad to go to (Tools). Push to display a submenu. Use the navigation pad to go to (Adjust tools). Push resize. 46 and select the measurement tool that you want to move or Use the navigation pad to move or resize the measurement tool. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 17 – Working with measurement tools 17.4 Creating and setting up a difference calculation General A difference calculation gives the difference between the values of two known measurement results. NOTE This procedure assumes that you have previously laid out at least two measurement tools on the screen. Procedure Follow this procedure to create and set up a difference calculation: Push to display the menu system. Use the navigation pad to go to (Tools). Push to display a submenu. Use the navigation pad to select (Add difference). Push . This will display a dialog box where you can select the measurement tools that you want to use in the difference calculation. Push . The result of the difference calculation is now displayed in the result table. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 47 17 – Working with measurement tools 17.5 Changing object parameters General For accurate measurements, you must set the object parameters. Types of parameters The camera can use these object parameters: ■ ■ ■ ■ ■ ■ Recommended values 48 Emissivity, i.e., how much radiation an object emits, compared with the radiation of a theoretical reference object of the same temperature (called a “blackbody”). The opposite of emissivity is reflectivity. The emissivity determines how much of the radiation originates from the object as opposed to being reflected by it. Reflected apparent temperature, which is used when compensating for the radiation from the surroundings reflected by the object into the camera. This property of the object is called reflectivity. Object distance, i.e., the distance between the camera and the object of interest. Atmospheric temperature, i.e., the temperature of the air between the camera and the object of interest. Relative humidity, i.e., the relative humidity of the air between the camera and the object of interest. External IR window compensation, i.e., the temperature of any protective windows, etc., that are set up between the camera and the object of interest. If no protective window or protective shield is used, this value is irrelevant and should be left inactive. If you are unsure about the values, the following are recommended: Atmospheric temperature +20°C (+69°F) Emissivity 0.95 Object distance 1.0 m (3.3 ft.) Reflected apparent temperature +20°C (+69°F) Relative humidity 50% Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 17 – Working with measurement tools Procedure Follow this procedure to change the object parameters: Push to display the menu system. Use the navigation pad to go to Push to display a dialog box. Use the navigation pad to select and change an object parameter. Push . This will close the dialog box. NOTE Of the parameters above, emissivity and reflected apparent temperature are the two most important to set correctly in the camera. Related topics For in-depth information about parameters, and how to correctly set the emissivity and reflected apparent temperature, see section 31 – Thermographic measurement techniques on page 160. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 49 18 Fetching data from external Extech meters General You can fetch data from an external Extech meter and merge this data into the result table in the infrared image. Figure T638370;a1 Supported Extech meters ■ Technical support for Extech meters support@extech.com NOTE ■ ■ This support is for Extech meters only. For technical support for infrared cameras, go to http://support.flir.com. ■ Procedure 50 Extech Moisture Meter MO297 Extech Clamp Meter EX845 This procedure assumes that you have paired the Bluetooth devices. For more information about products from Extech Instruments, go to http://www.extech.com/instruments/. Follow this procedure: Turn on the camera. Turn on the Extech meter. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 18 – Fetching data from external Extech meters On the meter, enable Bluetooth mode. Refer to the user documentation for the meter for information on how to do this. On the meter, choose the quantity that you want to use (voltage, current, resistance, etc.). Refer to the user documentation for the meter for information on how to do this. Results from the meter will now automatically be displayed in the result table in the top left corner of the infrared camera screen. Do one of the following: ■ ■ ■ To preview an image, push the Preview/Save button. At this stage, you can add additional values. To do so, take a new measurement with the meter and select Add on the infrared camera screen. To save an image without previewing, push and hold down the Preview/Save button. (Dependent on camera model) To add a value to a recalled image, turn on the meter after you have recalled the image, then select Add on the infrared camera screen. A maximum of eight values can be added, but note that some values are broken into two lines. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 51 18 – Fetching data from external Extech meters 18.1 Typical moisture measurement and documentation procedure General The following procedure can form the basis for other procedures using Extech meters and infrared cameras. Procedure Follow this procedure: 52 Use the infrared camera to identify any potential damp areas behind walls and ceilings. Use the moisture meter to measure the moisture levels at various suspect locations that may have been found. When a spot of particular interest is located, store the moisture reading in the moisture meter’s memory and identify the measurement spot with a handprint or other thermal identifying marker. Recall the reading from the meter memory. The moisture meter will now continuously transmit this reading to the infrared camera. Use the camera to take a thermal image of the area with the identifying marker. The stored data from the moisture meter will also be saved on the image. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 19 Working with isotherms 19.1 Building isotherms General The camera features isotherm types that are specific to the building trade. You can make the camera trigger the following types of isotherms: ■ ■ Humidity: Triggers when a measurement tool detects a surface where the relative humidity exceeds a preset value. Insulation: Triggers when there is an insulation deficiency in a wall. About the Humidity isotherm To detect areas where the relative humidity is less than 100% you can use the Humidity isotherm, where you can set the relative humidity above which the isotherm will colorize the image. About the Insulation isotherm The Insulation isotherm can detect areas where there may be an insulation deficiency in the building. It will trigger when the insulation level falls below a preset value of the energy leakage through a wall. Different building codes recommend different values, but typical values for the insulation level are 0.6–0.8 for new buildings. Refer to your national building code for recommendations. Procedure Follow this procedure to set up an isotherm: Push to display the menu system. Use the navigation pad to go to Push to display a submenu. Use the navigation pad to go to Push . This will display a submenu. In the submenu, select Humidity or Insulation. This will display a dialog box where you can set the necessary parameters. Push The setup is now complete, and an isotherm will be displayed when the parameters are met. NOTE For this isotherm to be meaningful, the parameters must be set with some care. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 53 20 Annotating images General This section describes how to save additional information in an infrared image by using annotations. Using annotations makes reporting and post-processing more efficient by providing essential information about the image, e.g., conditions, photos, and information about where an image is taken. You can set the camera to automatically add an annotation to your images. 54 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 20 – Annotating images 20.1 Taking a digital photo General When you save an infrared image you can also take a digital photo of the object of interest. This digital photo will automatically be grouped together with the infrared image, which will simplify post-processing and reporting. NOTE This procedure assumes that you have not set the camera to automatically add a digital photo. Procedure Follow this procedure to take a digital photo: To preview an infrared image, briefly pull and release the trigger. Use the navigation pad to select Push to display a submenu. Use the navigation pad to select Digital camera photo. Push to take the digital photo. The digital photo will now be added to to what is called an “group,” and will be grouped together with the infrared image in the image archive, and also when moving files from the camera to reporting software on the computer. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 55 20 – Annotating images 20.2 Creating a voice annotation General A voice annotation is an audio recording that is stored in an infrared image file. The voice annotation is recorded using a Bluetooth headset. The recording can be played back in the camera, and in image analysis and reporting software from FLIR Systems. Procedure Follow this procedure to create a voice annotation: To preview an image, pull the trigger. Use the navigation pad to select 56 Do one or more of the following, and push the joystick to confirm each choice. Some buttons have more than one function. ■ To start a recording, select ■ To pause/resume a recording, select ■ To stop a recording, select ■ To listen to a recording, select ■ To pause a voice annotation that you are listening to, select ■ ■ To go to the beginning of a recording, select To delete a recording, move the joystick left/right or up/down and select ■ To save a recording, select Save. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 20 – Annotating images 20.3 Creating a text annotation General A text annotation is grouped with an image file. Using this feature, you can annotate images. This text can be revised later. This feature is very efficient when saving information on an image when you are inspecting a large number of similar objects. Using text annotations avoids filling out forms or inspection protocols manually. NOTE This procedure assumes that you have not set the camera to automatically add a text annotation. Procedure Follow this procedure to create a text annotation: To preview an image, pull the trigger. Use the navigation pad to select Push to display a dialog box. T639064;a1 In this dialog box you can do one of the following: ■ ■ ■ Use an existing text annotation template, or create a new template. Create new fields. Enter new text values for the fields. The text annotation will now be added to to what is called a group, and will be grouped together with the infrared image in the image archive, and also when moving files from the camera to reporting software on the computer. (Step 5–8 describes how to add values to existing labels.) Use the navigation pad to select a label in the list, e.g., Location or Object. Push to display a dialog box. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 57 20 – Annotating images In this dialog, do one of the following: ■ ■ 58 Select one of the predefined descrptions, e.g., engine or vent. Click Keyboard and type in a new description. Click OK. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 21 Recording video clips General You can record non-radiometric infrared or visual video clips. In this mode, the camera can be regarded as an ordinary digital video camera. The video clips can be played back in Microsoft Windows Media Player, but it will not be possible to retrieve radiometric information from the video clips. Procedure Follow this procedure to record infrared or visual non-radiometric video clips: Push to display the menu system. Use the joystick to go to Do the following: ■ ■ To start a recording, briefly push and release the Preview/Save button. To stop a recording, briefly push and release the Preview/Save button. When you have stopped the recording, a toolbar will be presented where you can do one or more of the following: ■ ■ ■ ■ ■ Save the recording. Cancel the recording. Play back the recording. Add a text annotation. Add a sketch. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 59 22 Changing settings General You can change a variety of settings for the camera: ■ ■ ■ ■ Camera settings, e.g., the display intensity, power management, touch-screen calibration, and default settings. Preferences, e.g., settings for annotations and overlay. Connectivity, e.g., settings for Wi-Fi and Bluetooth. Regional settings, e.g., the language, date and time, date and time format, and temperature and distance units. This area also contains uneditable camera information, e.g., the serial number, firmware version, and battery level. Procedure Follow this procedure to change settings: Push to display the menu system. Use the navigation pad to go to (Settings) . Push 60 . This will display a dialog box. Do the following: ■ Use the navigation pad to go between tabs and up/down on tabs. ■ Use the button to edit the currently selected setting. ■ Use the button to confirm choices. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 23 Cleaning the camera 23.1 Camera housing, cables, and other items Liquids Use one of these liquids: ■ ■ Warm water A weak detergent solution Equipment A soft cloth Procedure Follow this procedure: CAUTION Soak the cloth in the liquid. Twist the cloth to remove excess liquid. Clean the part with the cloth. Do not apply solvents or similar liquids to the camera, the cables, or other items. This can cause damage. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 61 23 – Cleaning the camera 23.2 Infrared lens Liquids Use one of these liquids: ■ ■ 96% isopropyl alcohol. A commercial lens cleaning liquid with more than 30% isopropyl alcohol. Equipment Cotton wool Procedure Follow this procedure: Soak the cotton wool in the liquid. Twist the cotton wool to remove excess liquid. Clean the lens one time only and discard the cotton wool. WARNING Make sure that you read all applicable MSDS (Material Safety Data Sheets) and warning labels on containers before you use a liquid: the liquids can be dangerous. CAUTION ■ ■ 62 Be careful when you clean the infrared lens. The lens has a delicate anti-reflective coating. Do not clean the infrared lens too vigorously. This can damage the anti-reflective coating. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 23 – Cleaning the camera 23.3 Infrared detector General Even small amounts of dust on the infrared detector can result in major blemishes in the image. To remove any dust from the detector, follow the procedure below. NOTE ■ ■ This section only applies to cameras where removing the lens exposes the infrared detector. In some cases the dust cannot be removed by following this procedure: the infrared detector must be cleaned mechanically. This mechanical cleaning must be carried out by an authorized service partner. CAUTION In Step 2 below, do not use pressurized air from pneumatic air circuits in a workshop, etc., as this air usually contains oil mist to lubricate pneumatic tools. Procedure Follow this procedure: Remove the lens from the camera. Use pressurized air from a compressed air canister to blow off the dust. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 63 24 Technical data For technical data, refer to the datasheets on the user documentation CD-ROM that comes with the camera. Technical data is also available at http://support.flir.com. 64 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 25 Dimensional drawings 25.1 Camera dimensions, front view (1) Figure T638765;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 65 25 – Dimensional drawings 25.2 Figure 66 Camera dimensions, front view (2) T638766;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 25 – Dimensional drawings 25.3 Figure Camera dimensions, side view (1) T638772;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 67 25 – Dimensional drawings 25.4 Figure 68 Camera dimensions, side view (2) T638773;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 25 – Dimensional drawings 25.5 Figure Camera dimensions, side view (3) T638774;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 69 25 – Dimensional drawings 25.6 Figure 70 Infrared lens (30 mm/15°) 10762503;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 25 – Dimensional drawings 25.7 Figure Infrared lens (10 mm/45°) 10762403;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 71 25 – Dimensional drawings 25.8 Battery (1) Figure T638782;a1 NOTE Use a clean, dry cloth to remove any water or moisture on the battery before you install it. 72 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 25 – Dimensional drawings 25.9 Battery (2) Figure T638783;a1 NOTE Use a clean, dry cloth to remove any water or moisture on the battery before you install it. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 73 25 – Dimensional drawings 25.10 Battery (3) Figure T638784;a1 NOTE Use a clean, dry cloth to remove any water or moisture on the battery before you install it. 74 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 25 – Dimensional drawings 25.11 Battery charger (1) Figure T638767;a1 NOTE Use a clean, dry cloth to remove any water or moisture on the battery before you put it in the battery charger. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 75 25 – Dimensional drawings 25.12 Battery charger (2) Figure T638768;a1 NOTE Use a clean, dry cloth to remove any water or moisture on the battery before you put it in the battery charger. 76 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 25 – Dimensional drawings 25.13 Battery charger (3) Figure T638769;a1 NOTE Use a clean, dry cloth to remove any water or moisture on the battery before you put it in the battery charger. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 77 25 – Dimensional drawings 25.14 Battery charger (4) Figure T638770;a1 NOTE Use a clean, dry cloth to remove any water or moisture on the battery before you put it in the battery charger. 78 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 26 Application examples 26.1 Moisture & water damage General It is often possible to detect moisture and water damage in a house by using an infrared camera. This is partly because the damaged area has a different heat conduction property and partly because it has a different thermal capacity to store heat than the surrounding material. NOTE Many factors can come into play as to how moisture or water damage will appear in an infrared image. For example, heating and cooling of these parts takes place at different rates depending on the material and the time of day. For this reason, it is important that other methods are used as well to check for moisture or water damage. Figure The image below shows extensive water damage on an external wall where the water has penetrated the outer facing because of an incorrectly installed window ledge. 10739503;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 79 26 – Application examples 26.2 Faulty contact in socket General Depending on the type of connection a socket has, an improperly connected wire can result in local temperature increase. This temperature increase is caused by the reduced contact area between the connection point of the incoming wire and the socket , and can result in an electrical fire. NOTE A socket’s construction may differ dramatically from one manufacturer to another. For this reason, different faults in a socket can lead to the same typical appearance in an infrared image. Local temperature increase can also result from improper contact between wire and socket, or from difference in load. Figure The image below shows a connection of a cable to a socket where improper contact in the connection has resulted in local temperature increase. 10739603;a1 80 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 26 – Application examples 26.3 Oxidized socket General Depending on the type of socket and the environment in which the socket is installed, oxides may occur on the socket's contact surfaces. These oxides can lead to locally increased resistance when the socket is loaded, which can be seen in an infrared image as local temperature increase. NOTE A socket’s construction may differ dramatically from one manufacturer to another. For this reason, different faults in a socket can lead to the same typical appearance in an infrared image. Local temperature increase can also result from improper contact between a wire and socket, or from difference in load. Figure The image below shows a series of fuses where one fuse has a raised temperature on the contact surfaces against the fuse holder. Because of the fuse holder’s blank metal, the temperature increase is not visible there, while it is visible on the fuse’s ceramic material. 10739703;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 81 26 – Application examples 26.4 Insulation deficiencies General Insulation deficiencies may result from insulation losing volume over the course of time and thereby not entirely filling the cavity in a frame wall. An infrared camera allows you to see these insulation deficiencies because they either have a different heat conduction property than sections with correctly installed insulation, and/or show the area where air is penetrating the frame of the building. NOTE When you are inspecting a building, the temperature difference between the inside and outside should be at least 10°C (18°F). Studs, water pipes, concrete columns, and similar components may resemble an insulation deficiency in an infrared image. Minor differences may also occur naturally. Figure In the image below, insulation in the roof framing is lacking.. Due to the absence of insulation, air has forced its way into the roof structure, which thus takes on a different characteristic appearance in the infrared image. 10739803;a1 82 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 26 – Application examples 26.5 Draft General Draft can be found under baseboards, around door and window casings, and above ceiling trim. This type of draft is often possible to see with an infrared camera, as a cooler airstream cools down the surrounding surface. NOTE When you are investigating draft in a house, there should be sub-atmospheric pressure in the house. Close all doors, windows, and ventilation ducts, and allow the kitchen fan to run for a while before you take the infrared images. An infrared image of draft often shows a typical stream pattern. You can see this stream pattern clearly in the picture below. Also keep in mind that drafts can be concealed by heat from floor heating circuits. Figure The image below shows a ceiling hatch where faulty installation has resulted in a strong draft. 10739903;a1 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 83 27 Introduction to building thermography 27.1 Disclaimer 27.1.1 Copyright notice Some sections and/or images appearing in this chapter are copyrighted to the following organizations and companies: ■ ■ ■ ■ ■ FORMAS—The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning, Stockholm, Sweden ITC—Infrared Training Center, Boston, MA, United States Stockton Infrared Thermographic Services, Inc., Randleman, NC, United States Professional Investigative Engineers, Westminster, CO, United States United Kingdom Thermography Association (UKTA) 27.1.2 Training & certification Carrying out building thermography inspections requires substantial training and experience, and may require certification from a national or regional standardization body. This section is provided only as an introduction to building thermography. The user is strongly recommended to attend relevant training courses. For more information about infrared training, visit the following website: http://www.infraredtraining.com 27.1.3 National or regional building codes The commented building structures in this chapter may differ in construction from country to country. For more information about construction details and standards of procedure, always consult national or regional building codes. 27.2 Important note All camera functions and features that are described in this section may not be supported by your particular camera configuration. 84 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 27.3 Typical field investigations 27.3.1 Guidelines As will be noted in subsequent sections there are a number of general guidelines the user should take heed of when carrying out building thermography inspection. This section gives a summary of these guidelines. 27.3.1.1 ■ ■ ■ General guidelines The emissivity of the majority of building materials fall between 0.85 and 0.95. Setting the emissivity value in the camera to 0.90 can be regarded as a good starting point. An infrared inspection alone should never be used as a decision point for further actions. Always verify suspicions and findings using other methods, such as construction drawings, moisture meters, humidity & temperature datalogging, tracer gas testing etc. Change level and span to thermally tune the infrared image and reveal more details. The figure below shows the difference between a thermally untuned and a thermally tuned infrared image. 10552103;a2 Figure 27.1 LEFT: A thermally untuned infrared image; RIGHT: A thermally tuned infrared image, after having changed level and span. 27.3.1.2 ■ ■ Guidelines for moisture detection, mold detection & detection of water damages Building defects related to moisture and water damages may only show up when heat has been applied to the surface, e.g. from the sun. The presence of water changes the thermal conductivity and the thermal mass of the building material. It may also change the surface temperature of building material due to evaporative cooling. Thermal conductivity is a material’s ability to conduct heat, while thermal mass is its ability to store heat. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 85 27 – Introduction to building thermography ■ Infrared inspection does not directly detect the presence of mold, rather it may be used to find moisture where mold may develop or has already developed. Mold requires temperatures between +4°C to +38°C (+40°F to +100°F), nutrients and moisture to grow. Humidity levels above 50% can provide sufficient moisture to enable mold to grow. 10556003;a1 Figure 27.2 Microscopic view of mold spore 27.3.1.3 ■ ■ ■ ■ Guidelines for detection of air infiltration & insulation deficiencies For very accurate camera measurements, take measurements of the temperature and enter this value in the camera. It is recommended that there is a difference in pressure between the outside and the inside of the building structure. This facilitates the analysis of the infrared images and reveals deficiencies that would not be visible otherwise. Although a negative pressure of between 10 and 50 Pa is recommended, carrying out the inspection at a lower negative pressure may be acceptable. To do this, close all windows, doors and ventilation ducts and then run the kitchen exhaust fan for some time to reach a negative pressure of 5–10 Pa (applies to residential houses only). A difference in temperature between the inside and the outside of 10–15°C (18–27°F) is recommended. Inspections can be carried out at a lower temperature difference, but will make the analysis of the infrared images somewhat more difficult. Avoid direct sunlight on a part of a building structure—e.g. a façade—that is to be inspected from the inside. The sunlight will heat the façade which will equalize the temperature differences on the inside and mask deficiencies in the building structure. Spring seasons with low nighttime temperatures (±0°C (+32°F)) and high daytime temperatures (+14°C (+57°F)) are especially risky. 86 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 27.3.2 About moisture detection Moisture in a building structure can originate from several different sources, e.g.: External leaks, such as floods, leaking fire hydrants etc. Internal leaks, such as freshwater piping, waste water piping etc. Condensation, which is humidity in the air falling out as liquid water due to condensation on cold surfaces. Building moisture, which is any moisture in the building material prior to erecting the building structure. Water remaining from firefighting. ■ ■ ■ ■ ■ As a non-destructive detection method, using an infrared camera has a number of advantages over other methods, and a few disadvantages: Advantage ■ ■ ■ ■ ■ Disadvantage The method is quick. The method is a non-intrusive means of investigation. The method does not require relocation of the occupants. The method features an illustrative visual presentation of findings. The method confirms failure points and moisture migration paths. ■ ■ The method only detects surface temperature differentials and can not see through walls. The method can not detect subsurface damage, i.e. mold or structural damage. 27.3.3 Moisture detection (1): Low-slope commercial roofs 27.3.3.1 General information Low-slope commercial roofing is one of the most common roof types for industrial building, such as warehouses, industrial plants, machinery shops etc. Its major advantages over a pitched roof is the lower cost in material and building. However, due to its design where snow and ice will not fall off by itself—as is the case for the majority of pitched roofs—it must be strongly built to support the accumulated weight of both roof structure and any snow, ice and rain. Although a basic understanding of the construction of low-slope commercial roofs is desirable when carrying out a roof thermography inspection, expert knowledge is not necessary. There is a large number of different design principles for low-slope commercial roofs—both when it comes to material and design—and it would be impossible for the infrared inspection person to know them all. If additional information about a certain roof is needed, the architect or contractor of the building can usually supply the relevant information. Common causes of roof failure are outlined in the table below (from SPIE Thermosense Proceedings Vol. 371 (1982), p. 177). Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 87 27 – Introduction to building thermography Cause Poor workmanship 47.6 Roof traffic 2.6 Poor design 16.7 Trapped moisture 7.8 Materials 8.0 Age & weathering 8.4 Potential leak locations include the following: ■ ■ ■ ■ ■ Flashing Drains Penetrations Seams Blisters 27.3.3.2 ■ ■ ■ ■ ■ Safety precautions Recommend a minimum of two people on a roof, preferably three or more. Inspect the underside of the roof for structural integrity prior to walking on it. Avoid stepping on blisters that are common on built up bitumen and gravel roofs. Have a cell phone or radio available in case of emergency. Inform local police and plant security prior to doing nighttime roof survey. 88 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 27.3.3.3 Commented building structures This section includes a few typical examples of moisture problems on low-slope commercial roofs. Structural drawing Comment 10553603;a2 Inadequate sealing of roof membrane around conduit and ventilation ducts leading to local leakage around the conduit or duct. 10553703;a2 Roof membrane inadequately sealed around roof access hatch. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 89 27 – Introduction to building thermography Structural drawing Comment 10553803;a2 Drainage channels located too high and with too low an inclination. Some water will remain in the drainage channel after rain, which may lead to local leakage around the channel. 10553903;a2 Inadequate sealing between roof membrane and roof outlet leading to local leakage around the roof outlet. 27.3.3.4 Commented infrared images How do you find wet insulation below the surface of the roof? When the surface itself is dry, including any gravel or ballast, a sunny day will warm the entire roof. Early in the evening, if the sky is clear, the roof will begin to cool down by radiation. Because of its higher thermal capacity the wet insulation will stay warmer longer than the dry and will be visible in the infrared camera (see photos below). The technique is particularly effective on roofs having absorbent insulation—such as wood fiber, fiberglass, and perlite—where thermal patterns correlate almost perfectly with moisture. 90 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography Infrared inspections of roofs with nonabsorbent insulations, common in many singleply systems, are more difficult to diagnose because patterns are more diffuse. This section includes a few typical infrared images of moisture problems on low-slope commercial roofs: Infrared image Comment 10554003;a1 Moisture detection on a roof, recorded during the evening. Since the building material affected by moisture has a higher thermal mass, its temperature decreases slower than surrounding areas. 10554103;a1 Water-damaged roofing components and insulation identified from infrared scan from the underside of the built-up roof on a structural concrete tee deck. Affected areas are cooler than the surrounding sound areas, due to conductive and/or thermal capacitive effect. 10554203;a1 Daytime survey of built-up low-slope commercial roof. Affected areas are cooler than the surrounding dry areas, due to conductive and/or thermal capacitive effect. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 91 27 – Introduction to building thermography 27.3.4 Moisture detection (2): Commercial & residential façades 27.3.4.1 General information Thermography has proven to be invaluable in the assessment of moisture infiltration into commercial and residential façades. Being able to provide a physical illustration of the moisture migration paths is more conclusive than extrapolating moisture meter probe locations and more cost-effective than large intrusive test cuts. 27.3.4.2 Commented building structures This section includes a few typical examples of moisture problems on commercial and residential façades. Structural drawing Comment 10554303;a2 Pelting rain penetrates the façade due to badly executed bed joints. Moisture builds up in the masonry above the window. 10554403;a2 Pelting rain hits the window at an angle. Most of the rain runs off the window edge flashing but some finds its way into the masonry where the plaster meets the underside of the flashing. 92 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography Structural drawing Comment 10554503;a2 Rain hits the façade at an angle and penetrates the plaster through cracks. The water then follows the inside of the plaster and leads to frost erosion. 10554603;a2 Rain splashes on the façade and penetrates the plaster and masonry by absorption, which eventually leads to frost erosion. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 93 27 – Introduction to building thermography 27.3.4.3 Commented infrared images This section includes a few typical infrared images of moisture problems on commercial & residential façades. Infrared image Comment 10554703;a1 Improperly terminated and sealed stone veneer to window frame and missing flashings has resulted in moisture infiltration into the wall cavity and interior living space. 10554803;a1 Moisture migration into drywall from capillary drive and interior finish components from inadequate clearance and slope of grade from vinyl siding façade on an apartment complex. 27.3.5 Moisture detection (3): Decks & balconies 27.3.5.1 General information Although there are differences in design, materials and construction, decks—plaza decks, courtyard decks etc—suffer from the same moisture and leaking problems as low-slope commercial roofs. Improper flashing, inadequately sealed membranes, and insufficient drainage may lead to substantial damage in the building structures below. Balconies, although smaller in size, require the same care in design, choice of material, and workmanship as any other building structure. Since balconies are usually supported on one side only, moisture leading to corrosion of struts and concrete reinforcement can cause problems and lead to hazardous situations. 94 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 27.3.5.2 Commented building structures This section includes a few typical examples of moisture problems on decks and balconies. Structural drawing Comment 10555203;a2 Improper sealing of paving and membrane to roof outlet, leading to leakage during rain. 10555103;a2 No flashing at deck-to-wall connection, leading to rain penetrating the concrete and insulation. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 95 27 – Introduction to building thermography Structural drawing Comment 10555003;a2 Water has penetrated the concrete due to inadequately sized drop apron and has led to concrete disintegration and corrosion of reinforcement. SECURITY RISK! 10554903;a2 Water has penetrated the plaster and underlying masonry at the point where the handrail is fastened to the wall. SECURITY RISK! 96 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 27.3.5.3 Commented infrared images This section includes a few typical infrared images of moisture problems on decks and balconies. Infrared image Comment 10555303;a1 Improper flashing at balcony-to-wall connections and missing perimeter drainage system resulted in moisture intrusion into the wood framing support structure of the exterior walkway balcony of a loft complex. 10555403;a1 A missing composite drainage plane or medium on a below-grade parking garage plaza deck structure resulted in standing water between the structural concrete deck and the plaza wearing surface. 27.3.6 Moisture detection (4): Plumbing breaks & leaks 27.3.6.1 General information Water from plumbing leaks can often lead to severe damage on a building structure. Small leaks may be difficult to detect, but can—over the years—penetrate structural walls and foundations to a degree where the building structure is beyond repair. Using building thermography at an early stage when plumbing breaks and leaks are suspected can lead to substantial savings on material and labor. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 97 27 – Introduction to building thermography 27.3.6.2 Commented infrared images This section includes a few typical infrared images of plumbing breaks & leaks. Infrared image Comment 10555503;a1 Moisture migration tracking along steel joist channels inside ceiling of a single family home where a plumbing line had ruptured. 10555603;a1 Water from plumbing leak was found to have migrated farther than originally anticipated by the contractor during remediation techniques of cutting back carpet and installing dehumidifiers. 98 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography Infrared image Comment 10555703;a1 The infrared image of this vinyl-sided 3-floor apartment house clearly shows the path of a serious leak from a washing machine on the third floor, which is completely hidden within the wall. 10555803;a1 Water leak due to improper sealing between floor drain and tiles. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 99 27 – Introduction to building thermography 27.3.7 Air infiltration 27.3.7.1 General information Due to the wind pressure on a building, temperature differences between the inside and the outside of the building, and the fact that most buildings use exhaust air terminal devices to extract used air from the building, a negative pressure of 2–5 Pa can be expected. When this negative pressure leads to cold air entering the building structure due to deficiencies in building insulation and/or building sealing, we have what is called air infiltration. Air infiltration can be expected at joints and seams in the building structure. Due to the fact that air infiltration creates an air flow of cool air into e.g. a room, it can lead to substantial deterioration of the indoor climate. Air flows as small as 0.15 m/s (0.49 ft./s) are usually noticed by inhabitants, although these air flows may be difficult to detect using ordinary measurement devices. On an infrared image air infiltration can be identified by its typical ray pattern, which emanates from the point of exit in the building structure—e.g. from behind a skirting strip. Furthermore, areas of air infiltration typically have a lower detected temperature than areas where there is only an insulation deficiency. This is due to the chill factor of the air flow. 27.3.7.2 Commented building structures This section includes a few typical examples of details of building structures where air infiltration may occur. Structural drawing Comment 10552503;a2 Insulation deficiencies at the eaves of a brickwall house due to improperly installed fiberglass insulation batts. The air infiltration enters the room from behind the cornice. 100 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography Structural drawing Comment 10552303;a2 Insulation deficiencies in an intermediate flow due to improperly installed fiberglass insulation batts. The air infiltration enters the room from behind the cornice. 10552603;a2 Air infiltration in a concrete floor-over-crawl-space due to cracks in the brick wall façade. The air infiltration enters the room beneath the skirting strip. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 101 27 – Introduction to building thermography 27.3.7.3 Commented infrared images This section includes a few typical infrared images of details of building structures where air infiltration has occurred. Infrared image Comment 10552703;a1 Air infiltration from behind a skirting strip. Note the typical ray pattern. 10552803;a1 Air infiltration from behind a skirting strip. Note the typical ray pattern. The white area to the left is a radiator. 10552903;a1 102 Air infiltration from behind a skirting strip. Note the typical ray pattern. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 27.3.8 Insulation deficiencies 27.3.8.1 General information Insulation deficiencies do not necessarily lead to air infiltration. If fiberglass insulation batts are improperly installed air pockets will form in the building structure. Since these air pockets have a different thermal conductivity than areas where the insulation batts are properly installed, the air pockets can be detected during a building thermography inspection. As a rule of thumb, areas with insulation deficiencies typically have higher temperatures than where there is only an air infiltration. When carrying out building thermography inspections aimed at detecting insulation deficiencies, be aware of the following parts in a building structure, which may look like insulation deficiencies on the infrared image: ■ ■ ■ ■ ■ ■ Wooden joists, studs, rafter, beams Steel girders and steel beams Water piping inside walls, ceilings, floors Electrical installations inside walls, ceilings, floors—such as trunking, piping etc. Concrete columns inside timber framed walls Ventilation ducts & air ducts 27.3.8.2 Commented building structures This section includes a few typical examples of details of building structures with insulation deficiencies: Structural drawing Comment 10553203;a2 Insulation deficiencies (and air infiltration) due to improper installation of insulation batts around an electrical mains supply. This kind of insulation deficiency will show up as dark areas on an infrared image. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 103 27 – Introduction to building thermography Structural drawing Comment 10553103;a2 Insulation deficiencies due to improper installation of insulation batts around an attic floor beam. Cool air infiltrates the structure and cools down the inside of the ceiling. This kind of insulation deficiency will show up as dark areas on an infrared image. 10553003;a2 Insulation deficiencies due to improper installation of insulation batts creating an air pocket on the outside of an inclined ceiling. This kind of insulation deficiency will show up as dark areas on an infrared image. 104 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 27.3.8.3 Commented infrared images This section includes a few typical infrared images of insulation deficiencies. Infrared image Comment 10553303;a1 Insulation deficiencies in an intermediate floor structure. The deficiency may be due to either missing insulation batts or improperly installed insulations batts (air pockets). 10553403;a1 Improperly installed fiberglass batts in a suspended ceiling. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 105 27 – Introduction to building thermography Infrared image Comment 10553503;a1 Insulation deficiencies in an intermediate floor structure. The deficiency may be due to either missing insulation batts or improperly installed insulations batts (air pockets). 106 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 27.4 Theory of building science 27.4.1 General information The demand for energy-efficient constructions has increased significantly in recent times. Developments in the field of energy, together with the demand for pleasant indoor environments, have resulted in ever-greater significance having to be attached to both the function of a building’s thermal insulation and airtightness and the efficiency of its heating and ventilation systems. Defective insulation and tightness in highly insulated and airtight structures can have a great impact on energy losses. Defects in a building’s thermal insulation and airtightness do not merely entail risk of excessive heating and maintenance costs, they also create the conditions for a poor indoor climate. A building’s degree of insulation is often stated in the form of a thermal resistance or a coefficient of thermal transmittance (U value) for the various parts of the building. However, the stated thermal resistance values rarely provide a measure of the actual energy losses in a building. Air leakage from joints and connections that are not airtight and insufficiently filled with insulation often gives rise to considerable deviations from the designed and expected values. Verification that individual materials and building elements have the promised properties is provided by means of laboratory tests. Completed buildings have to be checked and inspected in order to ensure that their intended insulation and airtightness functions are actually achieved. In its structural engineering application, thermography is used to study temperature variations over the surfaces of a structure. Variations in the structure’s thermal resistance can, under certain conditions, produce temperature variations on its surfaces. Leakage of cold (or warm) air through the structure also affects the variation in surface temperature. This means that insulation defects, thermal bridges and air leaks in a building’s enclosing structural components can be located and surveyed. Thermography itself does not directly show the structure’s thermal resistance or airtightness. Where quantification of thermal resistance or airtightness is required, additional measurements have also to be taken. Thermographic analysis of buildings relies on certain prerequisites in terms of temperature and pressure conditions across the structure. Details, shapes and contrasts in the thermal image can vary quite clearly with changes in any of these parameters. The in-depth analysis and interpretation of thermal images therefore requires thorough knowledge of such aspects as material and structural properties, the effects of climate and the latest measuring techniques. For assessing Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 107 27 – Introduction to building thermography the results of measurements, there are special requirements in terms of the skills and experience of those taking the measurements, e.g. by means of authorization by a national or regional standardization body. 27.4.2 The effects of testing and checking It can be difficult to anticipate how well the thermal insulation and airtightness of a completed building will work. There are certain factors involved in assembling the various components and building elements that can have a considerable impact on the final result. The effects of transport, handling and storage at the site and the way the work is done cannot be calculated in advance. To ensure that the intended function is actually achieved, verification by testing and checking the completed building is required. Modern insulation technology has reduced the theoretical heat requirement. This does mean, however, that defects that are relatively minor, but at important locations, e.g. leaking joints or incorrectly installed insulation, can have considerable consequences in terms both of heat and comfort. Verification tests, e.g. by means of thermography, have proved their value, from the point of view both of the designer and the contractor and of the developer, the property manager and the user. ■ ■ ■ For the designer, the important thing is to find out about the function of various types of structures, so that they can be designed to take into account both working methods and functional requirements. The designer must also know how different materials and combinations of materials function in practice. Effective testing and checking, as well as experiential feedback, can be used to achieve the required development in this area. The contractor is keen on more testing and inspection in order to ensure that the structures keep to an expected function that corresponds to established requirements in the regulations issued by authorities and in contractual documents. The contractor wants to know at an early stage of construction about any changes that may be necessary so that systematic defects can be prevented. During construction, a check should therefore be carried out on the first apartments completed in a mass production project. Similar checking then follows as production continues. In this way systematic defects can be prevented and unnecessary costs and future problems can be avoided. This check is of benefit both to manufacturers and to users. For the developer and the property manager it is essential that buildings are checked with reference to heat economy, maintenance (damage from moisture or moisture infiltration) and comfort for the occupants (e.g. cooled surfaces and air movements in occupied zones). 108 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography ■ For the user the important thing is that the finished product fulfills the promised requirements in terms of the building’s thermal insulation and airtightness. For the individual, buying a house involves a considerable financial commitment, and the purchaser therefore wants to know that any defects in the construction will not involve serious financial consequences or hygiene problems. The effects of testing and checking a building’s insulation and airtightness are partly physiological and partly financial. The physiological experience of an indoor climatic environment is very subjective, varying according to the particular human body’s heat balance and the way the individual experiences temperature. The experience of climate depends on both the indoor air temperature and that of the surrounding surfaces. The speed of movement and moisture content of indoor air are also of some significance. Physiologically, a draft produces the sensation of local cooling of the body’s surface caused by ■ ■ ■ excessive air movements in the occupied zone with normal air temperature; normal air movements in the occupied zone but a room temperature that is too low; substantial radiated heat exchange with a cold surface. It is difficult to assess the quantitative effects of testing and checking a building’s thermal insulation. Investigations have shown that defects found in the thermal insulation and airtightness of buildings cause heat losses that are about 20–30% more than was expected. Monitoring energy consumption before and after remedial measures in relatively large complexes of small houses and in multi-dwelling blocks has also demonstrated this. The figures quoted are probably not representative of buildings in general, since the investigation data cannot be said to be significant for the entire building stock. A cautious assessment however would be that effectively testing and checking a building’s thermal insulation and airtightness can result in a reduction in energy consumption of about 10%. Research has also shown that increased energy consumption associated with defects is often caused by occupants increasing the indoor temperature by one or a few degrees above normal to compensate for the effect of annoying thermal radiation towards cooled surfaces or a sensation of disturbing air movements in a room. 27.4.3 Sources of disruption in thermography During a thermographic survey, the risk of confusing temperature variations caused by insulation defects with those associated with the natural variation in U values along warm surfaces of a structure is considered slight under normal conditions. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 109 27 – Introduction to building thermography The temperature changes associated with variations in the U value are generally gradual and symmetrically distributed across the surface. Variations of this kind do of course occur at the angles formed by roofs and floors and at the corners of walls. Temperature changes associated with air leaks or insulation defects are in most cases more evident with characteristically shaped sharp contours. The temperature pattern is usually asymmetrical. During thermography and when interpreting an infrared image, comparison infrared images can provide valuable information for assessment. The sources of disruption in thermography that occur most commonly in practice are ■ ■ ■ ■ ■ the effect of the sun on the surface being thermographed (sunlight shining in through a window); hot radiators with pipes; lights directed at, or placed near, the surface being measured; air flows (e.g. from air intakes) directed at the surface; the effect of moisture deposits on the surface. Surfaces on which the sun is shining should not be subjected to thermography. If there is a risk of an effect by sunlight, windows should be covered up (closing Venetian blinds). However, be aware that there are building defects or problems (typically moisture problems) that only show up when heat has been applied to the surface, e.g. from the sun. For more information about moisture detection, see section 27.3.2 – About moisture detection on page 87. A hot radiator appears as a bright light surface in an infrared image. The surface temperature of a wall next to a radiator is raised, which may conceal any defects present. For maximum prevention of disruptive effects from hot radiators, these may be shut off a short while before the measurement is taken. However, depending on the construction of the building (low or high mass), these may need to be shut off several hours before a thermographic survey. The room air temperature must not fall so much as to affect the surface temperature distribution on the structure’s surfaces. There is little timelag with electric radiators, so they cool down relatively quickly once they have been switched off (20–30 minutes). Lights placed against walls should be switched off when the infrared image is taken. During a thermographic survey there should not be any disruptive air flows (e.g. open windows, open valves, fans directed at the surface being measured) that could affect the surfaces being thermographed. 110 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography Any wet surfaces, e.g. as a result of surface condensation, have a definite effect on heat transfer at the surface and the surface temperature. Where there is moisture on a surface, there is usually some evaporation which draws off heat, thus lowering the temperature of the surface by several degrees. There is risk of surface condensation at major thermal bridges and insulation defects. Significant disruptions of the kind described here can normally be detected and eliminated before measuring. If during thermography it is not possible to shield surfaces being measured from disruptive factors, these must be taken into account when interpreting and evaluating the results. The conditions in which the thermography was carried out should be recorded in detail when each measurement is taken. 27.4.4 Surface temperature and air leaks Defects in building airtightness due to small gaps in the structure can be detected by measuring the surface temperature. If there is a negative pressure in the building under investigation, air flows into the space through leaks in the building. Cold air flowing in through small gaps in a wall usually lowers the temperature in adjacent areas of the wall. The result is that a cooled surface area with a characteristic shape develops on the inside surface of the wall. Thermography can be used to detect cooled surface areas. Air movements at the wall surface can be measured using an air velocity indicator. If there is a positive pressure inside the building being investigated, warm room air will leak out through gaps in the wall, resulting in locally warm surface areas around the locations of the leaks. The amount of leakage depends partly on gaps and partly on the differential pressure across the structure. 27.4.4.1 Pressure conditions in a building The most important causes of differential pressure across a structural element in a building are ■ ■ ■ wind conditions around the building; the effects of the ventilation system; temperature differences between air inside and outside (thermal differential pressure). The actual pressure conditions inside a building are usually caused by a combination of these factors. The resultant pressure gradient across the various structural elements can be illustrated by the figure on page 113. The irregular effects of wind on a building means that in practice the pressure conditions may be relatively variable and complicated. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 111 27 – Introduction to building thermography In a steady wind flow, Bernoulli’s Law applies: where: ρ Air density in kg/m3 Wind velocity in m/s Static pressure in Pa and where: denotes the dynamic pressure and p the static pressure. The total of these pressures gives the total pressure. Wind load against a surface makes the dynamic pressure become a static pressure against the surface. The magnitude of this static pressure is determined by, amongst other things, the shape of the surface and its angle to the wind direction. The portion of the dynamic pressure that becomes a static pressure on the surface (pstat) is determined by what is known as a stress concentration factor: If ρ is 1.23 kg/m3 (density of air at +15°C (+59°F)), this gives the following local pressures in the wind flow: 112 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 10551803;a1 Figure 27.3 Distribution of resultant pressures on a building’s enclosing surfaces depending on wind effects, ventilation and internal/external temperature difference. 1: Wind direction; Tu: Thermodynamic air temperature outdoors in K; Ti: Thermodynamic air temperature indoors in K. If the whole of the dynamic pressure becomes static pressure, then C = 1. Examples of stress concentration factor distributions for a building with various wind directions are shown in the figure on page 114. The wind therefore causes an internal negative pressure on the windward side and an internal positive pressure on the leeward side. The air pressure indoors depends on the wind conditions, leaks in the building and how these are distributed in relation to the wind direction. If the leaks in the building are evenly distributed, the internal pressure may vary by ±0.2 pstat. If most of the leaks are on the windward side, the internal pressure increases somewhat. In the opposite case, with most of the leaks on the leeward side, the internal pressure falls. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 113 27 – Introduction to building thermography 10551903;a1 Figure 27.4 Stress concentration factor (C) distributions for various wind directions and wind velocities (v) relative to a building. Wind conditions can vary substantially over time and between relatively closely situated locations. In thermography, such variations can have a clear effect on the measurement results. It has been demonstrated experimentally that the differential pressure on a façade exposed to an average wind force of about 5 m/s (16.3 ft/s) will be about 10 Pa. Mechanical ventilation results in a constant internal negative or positive pressure (depending on the direction of the ventilation). Research has showed that the negative pressure caused by mechanical extraction (kitchen fans) in small houses is usually between 5 and 10 Pa. Where there is mechanical extraction of ventilation air, e.g. in multi-dwelling blocks, the negative pressure is somewhat greater, 10–50 Pa. Where there is so-called balanced ventilation (mechanically controlled supply and extract air), this is normally adjusted to produce a slight negative pressure inside (3–5 Pa). The differential pressure caused by temperature differences, the so-called chimney effect (airtightness differences of air at different temperatures) means that there is a negative pressure in the building’s lower part and a positive pressure in the upper 114 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography part. At a certain height there is a neutral zone where the pressures on the inside and outside are the same, see the figure on page 116. This differential pressure may be described by the relationship: Δp Air pressure differential within the structure in Pa 9.81 m/s2 ρu Air density in kg/m3 Tu Thermodynamic air temperature outdoors in K Ti Thermodynamic air temperature indoors in K Distance from the neutral zone in meters If ρu = 1.29 kg/m3 (density of air at a temperature of 273 K and ≈100 kPa), this produces: With a difference of +25°C (+77°F) between the ambient internal and external temperatures, the result is a differential pressure difference within the structure of about 1 Pa/m difference in height (= 3.28 Pa/ft.). Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 115 27 – Introduction to building thermography 10552003;a1 Figure 27.5 Distribution of pressures on a building with two openings and where the external temperature is lower than the internal temperature. 1: Neutral zone; 2: Positive pressure; 3: Negative pressure; h: Distance from the neutral zone in meters. The position of the neutral zone may vary, depending on any leaks in the building. If the leaks are evenly distributed vertically, this zone will be about halfway up the building. If more of the leaks are in the lower part of the building, the neutral zone will move downwards. If more of the leaks are in the upper part, it will move upwards. Where a chimney opens above the roof, this has a considerable effect on the position of the neutral zone, and the result may be a negative pressure throughout the building. This situation most commonly occurs in small buildings. In a larger building, such as a tall industrial building, with leaks at doors and any windows in the lower part of the building, the neutral zone is about one-third of the way up the building. 116 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography 27.4.5 Measuring conditions & measuring season The foregoing may be summarized as follows as to the requirements with regard to measuring conditions when carrying out thermographic imaging of buildings. Thermographic imaging is done in such a way that the disruptive influence from external climatic factors is as slight as possible. The imaging process is therefore carried out indoors, i.e. where a building is heated, the structure’s warm surfaces are examined. Outdoor thermography is only used to obtain reference measurements of larger façade surfaces. In certain cases, e.g. where the thermal insulation is very bad or where there is an internal positive pressure, outdoor measurements may be useful. Even when investigating the effects of installations located within the building’s climatic envelope, there may be justification for thermographic imaging from outside the building. The following conditions are recommended: ■ ■ ■ ■ The air temperature difference within the relevant part of the building must be at least +10°C (+18°F) for a number of hours before thermographic imaging and for as long as the procedure takes. For the same period, the ambient temperature difference must not vary by more than ±30% of the difference when the thermographic imaging starts. During the thermographic imaging, the indoor ambient temperature should not change by more than ±2°C (±3.6°F). For a number of hours prior before thermographic imaging and as long as it continues, no influencing sunlight may fall upon the relevant part of the building. Negative pressure within the structure ≈ 10–50 Pa. When conducting thermographic imaging in order to locate only air leaks in the building’s enclosing sections, the requirements in terms of measuring conditions may be lower. A difference of 5°C (9°F) between the inside and outside ambient temperatures ought to be sufficient for detecting such defects. To be able to detect air leaks, certain requirements must however be made with regard to the differential pressure; about 10 Pa should be sufficient. 27.4.6 Interpretation of infrared images The main purpose of thermography is to locate faults and defects in thermal insulation in exterior walls and floor structures and to determine their nature and extent. The measuring task can also be formulated in such a way that the aim of the thermography is to confirm whether or not the wall examined has the promised insulation and airtightness characteristics. The ‘promised thermal insulation characteristics’ for the wall according to the design can be converted into an expected surface temperature distribution for the surface under investigation if the measuring conditions at the time when the measurements are taken are known. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 117 27 – Introduction to building thermography In practice the method involves the following: Laboratory or field tests are used to produce an expected temperature distribution in the form of typical or comparative infrared images for common wall structures, comprising both defect-free structures and structures with in-built defects. Examples of typical infrared images are shown in section 27.3 – Typical field investigations on page 85. If infrared images of structural sections taken during field measurements are intended for use as comparison infrared images, then the structure’s composition, the way it was built, and the measurement conditions at the time the infrared image was taken must be known in detail and documented. In order, during thermography, to be able to comment on the causes of deviations from the expected results, the physical, metrological and structural engineering prerequisites must be known. The interpretation of infrared images taken during field measurements may be described in brief as follows: A comparison infrared image for a defect-free structure is selected on the basis of the wall structure under investigation and the conditions under which the field measurement was taken. An infrared image of the building element under investigation is then compared with the selected infrared image. Any deviation that cannot be explained by the design of the structure or the measurement conditions is noted as a suspected insulation defect. The nature and extent of the defect is normally determined using comparison infrared images showing various defects. If no suitable comparison infrared image is available, evaluation and assessment are done on the basis of experience. This requires more precise reasoning during the analysis. When assessing an infrared image, the following should be looked at: ■ ■ ■ ■ ■ Uniformity of brightness in infrared images of surface areas where there are no thermal bridges Regularity and occurrence of cooled surface areas, e.g. at studding and corners Contours and characteristic shapes in the cooled surface area Measured temperature differences between the structure’s normal surface temperature and the selected cooled surface area Continuity and uniformity of the isotherm curve on the surface of the structure. In the camera software the isotherm function is called Isotherm or Color alarm, depending on camera model. 118 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography Deviations and irregularities in the appearance of the infrared image often indicate insulation defects. There may obviously be considerable variations in the appearance of infrared images of structures with insulation defects. Certain types of insulation defects have a characteristic shape on the infrared image. Section 27.3 – Typical field investigations on page 85 shows examples of interpretations of infrared images. When taking infrared images of the same building, the infrared images from different areas should be taken with the same settings on the infrared camera, as this makes comparison of the various surface areas easier. 27.4.7 Humidity & dew point 27.4.7.1 Relative & absolute humidity Humidity can be expressed in two different ways—either as relative humidity or as absolute humidity. Relative humidity is expressed in percent of how much water a certain volume of air can hold at a certain temperature, while absolute humidity is expressed in percent water by weight of material. The latter way to express humidity is common when measuring humidity in wood and other building materials. The higher the temperature of air, the larger the amount of water this certain volume of air can hold. 27.4.7.2 Definition of dew point Dew point is the temperature at which the humidity in a certain volume of air will condense as liquid water. 27.4.8 Excerpt from Technical Note ‘Assessing thermal bridging and insulation continuity’ (UK example) 27.4.8.1 Credits This Technical Note was produced by a working group including expert thermographers, and research consultants. Additional consultation with other persons and organisations results in this document being widely accepted by all sides of industries. The contents of this Technical Note is reproduced with kind permission from, and fully copyrighted to, United Kingdom Thermography Association (UKTA). UK Thermography Association c/o British Institute of Nondestructive Testing 1 Spencer Parade Northampton NN1 5AA United Kingdom Tel: +44 (0)1604 630124 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 119 27 – Introduction to building thermography Fax: +44 (0)1604 231489 27.4.8.2 Introduction Over the last few years the equipment, applications, software, and understanding connected with thermography have all developed at an astonishing rate. As the technology has gradually become integrated into mainstream practises, a corresponding demand for application guides, standards and thermography training has arisen. The UKTA is publishing this technical note in order to establish a consistent approach to quantifying the results for a ‘Continuity of Thermal Insulation’ examination. It is intended that specifiers should refer to this document as a guide to satisfying the requirement in the Building Regulations, therefore enabling the qualified thermographer to issue a pass or fail report. 27.4.8.3 Background information Thermography can detect surface temperature variations as small as 0.1 K and graphic images can be produced that visibly illustrate the distribution of temperature on building surfaces. Variations in the thermal properties of building structures, such as poorly fitted or missing sections of insulation, cause variations in surface temperature on both sides of the structure. They are therefore visible to the thermographer. However, many other factors such as local heat sources, reflections and air leakage can also cause surface temperature variations. The professional judgement of the thermographer is usually required to differentiate between real faults and other sources of temperature variation. Increasingly, thermographers are asked to justify their assessment of building structures and, in the absence of adequate guidance, it can be difficult to set definite levels for acceptable or unacceptable variation in temperature. The current Standard for thermal iamging of building fabric in the UK is BS EN 13187:1999 (BS EN 13187:1999, Thermal Performance of Buildings—Qualitative detection of thermal properties in building envelopes—Infrared method (ISO 6781:1983 modified). However, this leaves interpretation of the thermal image to the professional expertise of of the thermographer and provides little guidance on the demarcation between acceptable and unacceptable variations. Guidance on the appearance of a range of thermal anomalies can be found in BINDT Guides to thermal imaging (Infrared Thermography Handbook; Volume 1, Principles and Practise, Norman Walker, ISBN 0903132338, Volume 2, Applications, A. N. Nowicki, ISBN 090313232X, BINDT, 2005). 27.4.8.3.1 Requirements A thermographic survey to demonstrate continuity of insulation, areas of thermal bridging and compliance with Building Regulations should include the following: 120 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography ■ ■ ■ ■ Thermal anomalies. Differentiate between real thermal anomalies, where temperature differences are caused by deficiencies in thermal insulation, and those that occur through confounding factors such as localised differences in air movement, reflection and emissivity. Quantify affected areas in relation to the total insulated areas. State whether the anomalies and the building thermal insulation as a whole are acceptable. 27.4.8.4 Quantitative appraisal of thermal anomalies A thermographic survey will show differences in apparent temperature of areas within the field of view. To be useful, however, it must systematically detect all the apparent defects; assess them against a predetermined set of criteria; reliably discount those anomalies that are not real defects; evaluate those that are real defects, and report the results to the client. 27.4.8.4.1 Selection of critical temperature parameter The BRE information Paper IP17/01 (Information Paper IP17/01, Assessing the Effects of Thermal Bridging at Junctions and Around Openings. Tim Ward, BRE, 2001) provides useful guidance on minimum acceptable internal surface temperatures and appropriate values of Critical Surface Temperature Factor, fCRsi. The use of a surface temperature factor allows surveys under any thermal conditions to show areas that are at risk of condensation or mould growth under design conditions. The actual surface temperature will depend greatly on the temperatures inside and outside at the time of the survey, but a ‘Surface Temperature Factor’ (fRsi) has been devised that is independent of the absolute conditions. It is a ratio of temperature drop across the building fabric to the total temperature drop between inside and outside air. For internal surveys: fRsi = (Tsi – Te)/(Ti – Te) Tsi = internal surface temperature Ti = internal air temperature Te = external air temperature A value for fCRsi of 0.75 is considered appropriate across new building as the upper end usage is not a factor considered in testing for ‘Continuity of Insulation’, or ‘Thermal Bridging’. However, when considering refurbished or extended buildings, for example swimming pools, internal surveys may need to account for unusal circumstances. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 121 27 – Introduction to building thermography 27.4.8.4.2 Alternative method using only surface temperatures There are strong arguments for basing thermographic surveys on surface temperatures alone, with no need to measure air temperature. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Stratification inside the building makes reference to air internal temperatures very difficult. Is it mean air temperature, low level, high level or temperature at the level of the anomaly and how far from the wall should it be measured? Radiation effects, such as radiation to the night sky, make use of of external air temperature difficult. It is not unusual for the outside surface of building fabric to be below air temperature because of radiation to the sky which may be as low as –50℃ (–58℉). This can be seen with the naked eye by the fact that dew and frost often appear on building surfaces even when the air temperature does not drop below the dewpoint. It should be noted that the concept of U values is based on ‘environmental temperatures’ on each side of the structure. This is neglected by many inexperienced analysts. The two temperatures that are firmly related to the transfer of heat through building fabric (and any solid) are the surface temperatures on each side. Therefore, by referring to surface temperatures the survey is more repeatable. The surface temperatures used are the averages of surface temperatures on the same material in an area near the anomaly on the inside and the outside of the fabric. Together with the temperature of the anomaly, a threshold level can be set dependent on these temperatures using the critical surface temperature factor. These arguments do not obviate the need for the thermographer to beware of reflections of objects at unusual temperatures in the background facing the building fabric surfaces. The thermographer should also use a comparison between external faces facing different directions to determine whether there is residual heat from solar gain affecting the external surfaces. External surveys should not be conducted on a surface where Tsi – Tso on the face is more than 10% greater than Tsi – Tso on the north or nearest to north face. For a defect that causes a failure under the 0.75 condition of IP17/01 the critical surface factors are 0.78 on the inside surface and 0.93 on the outside surface. The table below shows the internal and external surface temperatures at an anomaly which would lead to failure under IP17/01. It also shows the deterioration in thermal insulation that is necessary to cause this. Example for lightweight built-up cladding with defective insulation Good area Failing area Outside temperature in ℃ Inside surface temperature in ℃ 19.1 15.0 122 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography Example for lightweight built-up cladding with defective insulation Good area Failing area Outside surface temperature in ℃ 0.3 1.5 Surface factor from IP17/01 0.95 0.75 Critical external surface temperature factor, after IP17/01 Insulation thickness to give this level of performance, mm Local U value W/m2K 0.92 80 5.1 0.35 1.92 UKTA TN1 surface factor 0.78 UKTA TN1 surface factor outside 0.93 Notes to the table 1 Values of surface resistances taken from ADL2 2001, are: ■ ■ Inside surface 0.13 m2K/W Outside surface 0.04 m2K/W These originate from BS EN ISO 6946 (BN EN ISO 6946:1997 Building components and building elements - Thermal resistance and thermal transmittance - Calculation method). Thermal insulation used here is assumed to have a conductivity of 0.03 W/m K. The difference in temperature between an anomaly and the good areas is 1.2 degrees on the outside and 4.1 degrees on the inside. The UKTA TN1 surface temperature factor for internal surveys is: Fsi = (Tsia – Tso)/(Tsi – Tso) where: Tsia = internal surface temperature at anomaly Tso = external surface temperature (good area) Tsi = internal surface temperature (good area) The UKTA TN1 surface temperature factor for external surveys is: Fso = (Tsoa – Tsi)/(Tso – Tsi) where Tsoa = external surface temperature at anomaly 27.4.8.4.3 Selecting maximum acceptable defect area The allowable area of defect is a quality control issue. It can be argued that there should be no area on which condensation, mould growth or defective insulation will occur and any such anomalies should be included in the report. However, a commonly used value of 0.1% of the building exposed surface area is generally accepted as the maximum combined defect area allowable to comply with the Building Regulations. This represents one square metre in every thousand. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 123 27 – Introduction to building thermography 27.4.8.4.4 Measuring surface temperature Measurement of surface temperature is the function of the infrared imaging system. The trained thermographer will recognise, account for and report on the variation of emissivity and reflectivity of the surfaces under consideration. 27.4.8.4.5 Measuring area of the defects Measurement of defect area can be performed by pixel counting in the thermal analysis software or most spreadhseet packages provided that: ■ ■ ■ the distance from camera to object is accurately measured probably using a laser measurement system, the target distance should take into account the IFOV of the imaging system, any angular change between the camera and the object surface from the perpendicular is accounted for. Buildings consist of numerous construction features that are not conducive to quantitative surveys including windows, roof lights, luminaries, heat emitters, cooling equipment, service pipes and electrical conductors. However, the joints and connections between these objects and the building envelope should be considered as part of the survey. 27.4.8.5 Conditions and equipment To achieve best results from a thermal insulation survey it is important to consider the environmental conditions and to use the most appropriate thermographic technique for the task. Thermal anomalies will only present themselves to the thermographer where temperature differences exist and environmental phenomena are accounted for. As a minimum, the following conditions should be complied with: ■ ■ ■ ■ Temperature differences across the building fabric to be greater than 10℃ (18℉). Internal air to ambient air temperature difference to be greater than 5℃ (9℉) for the last twentyfour hours before survey. External air temperature to be within ±3℃ (±5.4℉) for duration of survey and for the previous hour. External air temperature to be within ±10℃ (±18℉) for the preceding twentyfour hours. In addition, external surveys should also comply with the following: ■ ■ ■ Necessary surfaces free from direct solar radiation and the residual effects of past solar radiation. This can be checked by comparing the surface temperatures of opposite sides of the building. No precipitation either just prior to or during the survey. Ensure all building surfaces to be inspected are dry. 124 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography ■ Wind speed to be less than 10 metres / second (19.5 kn.). As well as temperature, there are other environmental conditions that should also be taken into account when planning a thermographic building survey. External inspections, for example, may be influenced by radiation emissions and reflections from adjacent buildings or a cold clear sky, and even more significantly the heating effect that the sun may have on surface. Additionally, where background temperatures differ from air temperatures either internally or externally by more than 5 K, then background temperatures should be measured on all effected surfaces to allow surface temperature to be measured with sufficient accuracy. 27.4.8.6 Survey and analysis The following provides some operational guidance to the thermographic operator. The survey must collect sufficient thermographic information to demonstrate that all surfaces have been inspected in order that all thermal anomalies are reported and evaluated. Initially, environmental data must be collected, as with any thermographic survey including: ■ ■ ■ ■ ■ Internal temperature in the region of the anomaly. External temperature in the region of the anomaly. Emissivity of the surface. Background temperature. Distance from the surface. By interpolation, determine the threshold temperature to be used. ■ ■ For internal surveys the threshold surface temperature (Tsia) is Tsia = fsi(Tsi – Tso) + Tso. The thermographer will be looking for evidence of surface temperature below this threshold. For external surveys the threshold temperature (Tsoa) is Tsoa = fso(Tso – Tsi) + Tsi. The thermographer will be looking for evidence of surface temperature above this threshold. Images of anomalies must be captured in such a way that they are suitable for analysis: ■ ■ The image is square to any features of the wall or roof. The viewing angle is nearly perpendicular to the surface being imaged. Interfering sources of infrared radiation such as lights, heat emitters, electric conductors, reflective elements are minimised. The method of analysis will depend somewhat on analysis software used, but the key stages are as follows: Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 125 27 – Introduction to building thermography Produce an image of each anomaly or cluster of anomalies. ■ ■ ■ ■ ■ ■ Use a software analysis tool to enclose the anomalous area within the image, taking care not to include construction details that are to be excluded. Calculate the area below the threshold temperature for internal surveys or above the threshold temperature for external surveys. This is the defect area. Some anomalies that appeared to be defects at the time of the survey may not show defect areas at this stage. Add the defect areas from all the images ∑Ad. Calculate the total area of exposed building fabric. This is the surface area of all the walls and roof. It is conventional to use the external surface area. For a simple shape building this is calculated from overall width, length and height. At = (2h(L + w)) + (Lw) Identify the critical defect area Ac. Provisionally this is set at one thousandth or 0.1% of the total surface area. Ac = At/1000 If ∑Ad < Ac the building as a whole can be considered to have ‘reasonably continuous’ insulation. 27.4.8.7 Reporting Reports should certificate a pass/fail result, comply with customers requirements and as a minimum include the information required by BSEN 13187. The following data is normally required so that survey can be repeated following remedial action. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Background to the objective and principles of the test. Location, orientation, date and time of survey. A unique identifying reference. Thermographer’s name and qualifications. Type of construction. Weather conditions, wind speed and direction, last precipitation, sunshine, degree of cloud cover. Ambient temperatures inside and outside before, at the beginning of survey and the time of each image. Air temperature and radiant temperature should be recorded. Statement of any deviation from relevant test requirements. Equipment used, last calibration date, any knows defects. Name, affiliation and qualifications of tester. Type, extent and position of each observed defect. Results of any supplementary measurements and investigations. Reports should be indexed and archived by thermographers. 27.4.8.7.1 Considerations and limitations The choice between internal and external surveys will depend on: 126 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 27 – Introduction to building thermography ■ ■ ■ ■ ■ ■ Access to the surface. Buildings where both the internal and the external surfaces are obscured, e.g., by false ceilings racking or materials stacked against walls may not be amenable to this type of survey. Location of the thermal insulation. Surveys are usually more effective from the side nearest to the thermal insulation. Location of heavyweight materials. Surveys are usually less effective from the side nearest to the heavyweight material. The purpose of the survey. If the survey aims to show risk of condensation and mould growth it should be internal. Location of glass, bare metal or other materials that may be highly reflective. Surveys are usually less effective on highly reflective surfaces. A defect will usually produce a smaller temperature difference on the outside of a wall exposed to external air movement. However, missing or defective insulation near the external surface can often be more readily indentified externally. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 127 28 Introduction to thermographic inspections of electrical installations 28.1 Important note All camera functions and features that are described in this section may not be supported by your particular camera configuration. Electrical regulations differ from country to country. For that reason, the electrical procedures described in this section may not be the standard of procedure in your particular country. Also, in many countries carrying out electrical inspections requires formal qualification. Always consult national or regional electrical regulations. 28.2 General information 28.2.1 Introduction Today, thermography is a well-established technique for the inspection of electrical installations. This was the first and still is the largest. the largest application of thermography. The infrared camera itself has gone through an explosive development and we can say that today, the 8th generation of thermographic systems is available. It all began in 1964, more than 40 years ago. The technique is now established throughout the whole world. Industrialized countries as well as developing countries have adopted this technique. Thermography, in conjunction with vibration analysis, has over the latest decades been the main method for fault diagnostics in the industry as a part of the preventive maintenance program. The great advantage with these methods is that it is not only possible to carry out the inspection on installations in operation; normal working condition is in fact a prerequisite for a correct measurement result, so the ongoing production process is not disturbed. Thermographic inspection of electrical installations are used in three main areas: ■ ■ ■ Power generation Power transmission Power distribution, that is, industrial use of electrical energy. The fact that these controls are carried out under normal operation conditions has created a natural division between these groups. The power generation companies measure during the periods of high load. These periods vary from country to country 128 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations and for the climatic zones. The measurement periods may also differ depending on the type of plant to be inspected, whether they are hydroelectric, nuclear, coal-based or oil-based plants. In the industry the inspections are—at least in Nordic countries with clear seasonal differences—carried out during spring or autumn or before longer stops in the operation. Thus, repairs are made when the operation is stopped anyway. However, this seems to be the rule less and less, which has led to inspections of the plants under varying load and operating conditions. 28.2.2 General equipment data The equipment to be inspected has a certain temperature behavior that should be known to the thermographer before the inspection takes place. In the case of electrical equipment, the physical principle of why faults show a different temperature pattern because of increased resistance or increased electrical current is well known. However, it is useful to remember that, in some cases, for example solenoids, ‘overheating’ is natural and does not correspond to a developing defect. In other cases, like the connections in electrical motors, the overheating might depend on the fact that the healthy part is taking the entire load and therefore becomes overheated. A similar example is shown in section 28.5.7 – Overheating in one part as a result of a fault in another on page 144. Defective parts of electrical equipment can therefore both indicate overheating and be cooler than the normal ‘healthy’ components. It is necessary to be aware of what to expect by getting as much information as possible about the equipment before it is inspected. The general rule is, however, that a hot spot is caused by a probable defect. The temperature and the load of that specific component at the moment of inspection will give an indication of how serious the fault is and can become in other conditions. Correct assessment in each specific case demands detailed information about the thermal behavior of the components, that is, we need to know the maximum allowed temperature of the materials involved and the role the component plays in the system. Cable insulations, for example, lose their insulation properties above a certain temperature, which increases the risk of fire. In the case of breakers, where the temperature is too high, parts can melt and make it impossible to open the breaker, thereby destroying its functionality. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 129 28 – Introduction to thermographic inspections of electrical installations The more the IR camera operator knows about the equipment that he or she is about to inspect, the higher the quality of the inspection. But it is virtually impossible for an IR thermographer to have detailed knowledge about all the different types of equipment that can be controlled. It is therefore common practice that a person responsible for the equipment is present during the inspection. 28.2.3 Inspection The preparation of the inspection should include the choice of the right type of report. It is often necessary to use complementary equipment such as ampere meters in order to measure the current in the circuits where defects were found. An anemometer is necessary if you want to measure the wind speed at inspection of outdoor equipment. Automatic functions help the IR operator to visualize an IR image of the components with the right contrast to allow easy identification of a fault or a hot spot. It is almost impossible to miss a hot spot on a scanned component. A measurement function will also automatically display the hottest spot within an area in the image or the difference between the maximum temperature in the chosen area and a reference, which can be chosen by the operator, for example the ambient temperature. 10712703;a3 Figure 28.1 An infrared and a visual image of a power line isolator When the fault is clearly identified and the IR thermographer has made sure that it is not a reflection or a naturally occurring hot spot, the collection of the data starts, which will allow the correct reporting of the fault. The emissivity, the identification of the component, and the actual working conditions, together with the measured temperature, will be used in the report. In order to make it easy to identify the component a visual photo of the defect is often taken. 28.2.4 Classification & reporting Reporting has traditionally been the most time-consuming part of the IR survey. A one-day inspection could result in one or two days’ work to report and classify the found defects. This is still the case for many thermographers, who have chosen not to use the advantages that computers and modern reporting software have brought to IR condition monitoring. 130 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations The classification of the defects gives a more detailed meaning that not only takes into account the situation at the time of inspection (which is certainly of great importance), but also the possibility to normalize the over-temperature to standard load and ambient temperature conditions. An over-temperature of +30°C (+86°F) is certainly a significant fault. But if that overtemperature is valid for one component working at 100% load and for another at 50% load, it is obvious that the latter will reach a much higher temperature should its load increase from 50% to 100%. Such a standard can be chosen by the plant’s circumstances. Very often, however, temperatures are predicted for 100% load. A standard makes it easier to compare the faults over time and thus to make a more complete classification. 28.2.5 Priority Based on the classification of the defects, the maintenance manager gives the defects a repair priority. Very often, the information gathered during the infrared survey is put together with complementary information on the equipment collected by other means such as vibration monitoring, ultrasound or the preventive maintenance scheduled. Even if the IR inspection is quickly becoming the most used method of collecting information about electrical components safely with the equipment under normal operating conditions, there are many other sources of information the maintenance or the production manager has to consider. The priority of repair should therefore not be a task for the IR camera operator in the normal case. If a critical situation is detected during the inspection or during the classification of the defects, the attention of the maintenance manager should of course be drawn to it, but the responsibility for determining the urgency of the repair should be his. 28.2.6 Repair To repair the known defects is the most important function of preventive maintenance. However, to assure production at the right time or at the right cost can also be important goals for a maintenance group. The information provided by the infrared survey can be used to improve the repair efficiency as well as to reach the other goals with a calculated risk. To monitor the temperature of a known defect that can not be repaired immediately for instance because spare parts are not available, can often pay for the cost of inspection a thousandfold and sometimes even for the IR camera. To decide not to repair known defects to save on maintenance costs and avoid unnecessary downtime is also another way of using the information from the IR survey in a productive way. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 131 28 – Introduction to thermographic inspections of electrical installations However, the most common result of the identification and classification of the detected faults is a recommendation to repair immediately or as soon as it is practically possible. It is important that the repair crew is aware of the physical principles for the identification of defects. If a defect shows a high temperature and is in a critical situation, it is very common that the repair personnel expect to find a highly corroded component. It should also come as no surprise to the repair crew that a connection, which is usually healthy, can give the same high temperatures as a corroded one if it has come loose. These misinterpretations are quite common and risk putting in doubt the reliability of the infrared survey. 28.2.7 Control A repaired component should be controlled as soon as possible after the repair. It is not efficient to wait for the next scheduled IR survey in order to combine a new inspection with the control of the repaired defects. The statistics on the effect of the repair show that up to a third of the repaired defects still show overheating. That is the same as saying that those defects present a potential risk of failure. To wait until the next scheduled IR survey represents an unnecessary risk for the plant. Besides increasing the efficiency of the maintenance cycle (measured in terms of lower risk for the plant) the immediate control of the repair work brings other advantages to the performance of the repair crew itself. When a defect still shows overheating after the repair, the determination of the cause of overheating improves the repair procedure, helps choose the best component suppliers and detect design shortcomings on the electrical installation. The crew rapidly sees the effect of the work and can learn quickly both from successful repairs and from mistakes. Another reason to provide the repair crew with an IR instrument is that many of the defects detected during the IR survey are of low gravity. Instead of repairing them, which consumes maintenance and production time, it can be decided to keep these defects under control. Therefore the maintenance personnel should have access to their own IR equipment. It is common to note on the report form the type of fault observed during the repair as well as the action taken. These observations make an important source of experience that can be used to reduce stock, choose the best suppliers or to train new maintenance personnel. 132 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations 28.3 Measurement technique for thermographic inspection of electrical installations 28.3.1 How to correctly set the equipment A thermal image may show high temperature variations: 10712803;a4 Figure 28.2 Temperature variations in a fusebox In the images above, the fuse to the right has a maximum temperature of +61°C (+142°F), whereas the one to the left is maximum +32°C (+90°F) and the one in the middle somewhere in between. The three images are different inasmuch as the temperature scale enhances only one fuse in each image. However, it is the same image and all the information about all three fuses is there. It is only a matter of setting the temperature scale values. 28.3.2 Temperature measurement Some cameras today can automatically find the highest temperature in the image. The image below shows how it looks to the operator. 10712903;a3 Figure 28.3 An infrared image of a fusebox where the maximum temperature is displayed The maximum temperature in the area is +62.2°C (+144.0°F). The spot meter shows the exact location of the hot spot. The image can easily be stored in the camera memory. The correct temperature measurement depends, however, not only on the function of the evaluation software or the camera. It may happen that the actual fault is, for example, a connection, which is hidden from the camera in the position it happens Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 133 28 – Introduction to thermographic inspections of electrical installations to be in for the moment. It might be so that you measure heat, which has been conducted over some distance, whereas the ‘real’ hot spot is hidden from you. An example is shown in the image below. 10717603;a3 Figure 28.4 A hidden hot spot inside a box Try to choose different angles and make sure that the hot area is seen in its full size, that is, that it is not disappearing behind something that might hide the hottest spot. In this image, the hottest spot of what the camera can ‘see’, is +83°C (+181°F), where the operating temperature on the cables below the box is +60°C (+140°F). However, the real hot spot is most probably hidden inside the box, see the in yellow encircled area. This fault is reported as a +23.0°C (+41.4°F) excess temperature, but the real problem is probably essentially hotter. Another reason for underestimating the temperature of an object is bad focusing. It is very important that the hot spot found is in focus. See the example below. 10717403;a2 Figure 28.5 LEFT: A hot spot in focus; RIGHT: A hot spot out of focus In the left image, the lamp is in focus. Its average temperature is +64°C (+147°F). In the right image, the lamp is out of focus, which will result in only +51°C (+124°F) as the average temperature. 134 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations 28.3.3 Comparative measurement For thermographic inspections of electrical installations a special method is used, which is based on comparison of different objects, so-called measurement with a reference. This simply means that you compare the three phases with each other. This method needs systematic scanning of the three phases in parallel in order to assess whether a point differs from the normal temperature pattern. A normal temperature pattern means that current carrying components have a given operation temperature shown in a certain color (or gray tone) on the display, which is usually identical for all three phases under symmetrical load. Minor differences in the color might occur in the current path, for example, at the junction of two different materials, at increasing or decreasing conductor areas or on circuit breakers where the current path is encapsulated. The image below shows three fuses, the temperatures of which are very close to each other. The inserted isotherm actually shows less than +2°C (+3.6°F) temperature difference between the phases. Different colors are usually the result if the phases are carrying an unsymmetrical load. This difference in colors does not represent any overheating since this does not occur locally but is spread along the whole phase. 10713203;a3 Figure 28.6 An isotherm in an infrared image of a fusebox A ‘real’ hot spot, on the other hand, shows a rising temperature as you look closer to the source of the heat. See the image below, where the profile (line) shows a steadily increasing temperature up to about +93°C (+199°F) at the hot spot. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 135 28 – Introduction to thermographic inspections of electrical installations 10713303;a4 Figure 28.7 A profile (line) in an infrared image and a graph displaying the increasing temperature 28.3.4 Normal operating temperature Temperature measurement with thermography usually gives the absolute temperature of the object. In order to correctly assess whether the component is too hot, it is necessary to know its operating temperature, that is, its normal temperature if we consider the load and the temperature of its environment. As the direct measurement will give the absolute temperature—which must be considered as well (as most components have an upper limit to their absolute temperatures)—it is necessary to calculate the expected operating temperature given the load and the ambient temperature. Consider the following definitions: ■ ■ Operating temperature: the absolute temperature of the component. It depends on the current load and the ambient temperature. It is always higher than the ambient temperature. Excess temperature (overheating): the temperature difference between a properly working component and a faulty one. The excess temperature is found as the difference between the temperature of a ‘normal’ component and the temperature of its neighbor. It is important to compare the same points on the different phases with each other. As an example, see the following image taken from indoor equipment: 10713403;a4 Figure 28.8 An infrared image of indoor electrical equipment (1). 136 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations The two left phases are considered as normal, whereas the right phase shows a very clear excess temperature. Actually, the operating temperature of the left phase is +68°C (+154°F), that is, quite a substantial temperature, whereas the faulty phase to the right shows a temperature of +86°C (+187°F). This means an excess temperature of +18°C (+33°F), that is, a fault that has to be attended to quickly. For practical reasons, the (normal, expected) operating temperature of a component is taken as the temperature of the components in at least two out of three phases, provided that you consider them to be working normally.. The ‘most normal’ case is of course that all three phases have the same or at least almost the same temperature. The operating temperature of outdoor components in substations or power lines is usually only 1°C or 2°C above the air temperature (1.8°F or 3.6°F). In indoor substations, the operating temperatures vary a lot more. This fact is clearly shown by the image below as well. Here the left phase is the one, which shows an excess temperature. The operating temperature, taken from the two ‘cold’ phases, is +66°C (+151°F). The faulty phase shows a temperature of +127°C (+261°F), which has to be attended to without delay. 10713503;a5 Figure 28.9 An infrared image of indoor electrical equipment (2). 28.3.5 Classification of faults Once a faulty connection is detected, corrective measures may be necessary—or may not be necessary for the time being. In order to recommend the most appropriate action the following criteria should be evaluated: ■ ■ ■ ■ ■ Load during the measurement Even or varying load Position of the faulty part in the electrical installation Expected future load situation Is the excess temperature measured directly on the faulty spot or indirectly through conducted heat caused by some fault inside the apparatus? Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 137 28 – Introduction to thermographic inspections of electrical installations Excess temperatures measured directly on the faulty part are usually divided into three categories relating to 100% of the maximum load. < 5°C (9°F) The start of the overheat condition. This must be carefully monitored. II 5–30°C (9–54°F) Developed overheating. It must be repaired as soon as possible (but think about the load situation before a decision is made). III >30°C (54°F) Acute overheating. Must be repaired immediately (but think about the load situation before a decision is made). 138 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations 28.4 Reporting Nowadays, thermographic inspections of electrical installations are probably, without exception, documented and reported by the use of a report program. These programs, which differ from one manufacturer to another, are usually directly adapted to the cameras and will thus make reporting very quick and easy. The program, which has been used for creating the report page shown below, is called FLIR Reporter. It is adapted to several types of infrared cameras from FLIR Systems. A professional report is often divided into two sections: ■ Front pages, with facts about the inspection, such as: ■ ■ ■ ■ ■ ■ ■ ■ Who the client is, for example, customer’s company name and contact person Location of the inspection: site address, city, and so on Date of inspection Date of report Name of thermographer Signature of thermographer Summary or table of contents Inspection pages containing IR images to document and analyze thermal properties or anomalies. ■ Identification of the inspected object: ■ ■ ■ IR image. When collecting IR images there are some details to consider: ■ ■ ■ ■ What is the object: designation, name, number, and so on Photo Optical focus Thermal adjustment of the scene or the problem (level & span) Composition: proper observation distance and viewing angle. Comment ■ ■ ■ Is there an anomaly or not? Is there a reflection or not? Use a measurement tool—spot, area or isotherm—to quantify the problem. Use the simplest tool possible; a profile graph is almost never needed in electrical reports. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 139 28 – Introduction to thermographic inspections of electrical installations 10713603;a3 Figure 28.10 A report example 140 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations 28.5 Different types of hot spots in electrical installations 28.5.1 Reflections The thermographic camera sees any radiation that enters the lens, not only originating from the object that you are looking at, but also radiation that comes from other sources and has been reflected by the target. Most of the time, electrical components are like mirrors to the infrared radiation, even if it is not obvious to the eye. Bare metal parts are particularly shiny, whereas painted, plastic or rubber insulated parts are mostly not. In the image below, you can clearly see a reflection from the thermographer. This is of course not a hot spot on the object. A good way to find out if what you see is a reflection or not, is for you to move. Look at the target from a different angle and watch the ‘hot spot.’ If it moves when you do, it is a reflection. Measuring temperature of mirror like details is not possible. The object in the images below has painted areas which are well suited for temperature measurement. The material is copper, which is a very good heat conductor. This means that temperature variation over the surface is small. 10717503;a2 Figure 28.11 Reflections in an object 28.5.2 Solar heating The surface of a component with a high emissivity, for example, a breaker, can on a hot summer day be heated up to quite considerable temperatures by irradiation from the sun. The image shows a circuit breaker, which has been heated by the sun. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 141 28 – Introduction to thermographic inspections of electrical installations 10713803;a3 Figure 28.12 An infrared image of a circuit breaker 28.5.3 Inductive heating 10713903;a3 Figure 28.13 An infrared image of hot stabilizing weights Eddy currents can cause a hot spot in the current path. In cases of very high currents and close proximity of other metals, this has in some cases caused serious fires. This type of heating occurs in magnetic material around the current path, such as metallic bottom plates for bushing insulators. In the image above, there are stabilizing weights, through which a high current is running. These metal weights, which are made of a slightly magnetic material, will not conduct any current but are exposed to the alternating magnetic fields, which will eventually heat up the weight. The overheating in the image is less than +5°C (+9°F). This, however, need not necessarily always be the case. 28.5.4 Load variations 3-phase systems are the norm in electric utilities. When looking for overheated places, it is easy to compare the three phases directly with each other, for example, cables, breakers, insulators. An even load per phase should result in a uniform temperature pattern for all three phases. A fault may be suspected in cases where the temperature of one phase differs considerably from the remaining two. However, you should always make sure that the load is indeed evenly distributed. Looking at fixed ampere meters or using a clip-on ampere meter (up to 600 A) will tell you. 142 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations 10714003;a3 Figure 28.14 Examples of infrared images of load variations The image to the left shows three cables next to each other. They are so far apart that they can be regarded as thermally insulated from each other. The one in the middle is colder than the others. Unless two phases are faulty and overheated, this is a typical example of a very unsymmetrical load. The temperature spreads evenly along the cables, which indicates a load-dependent temperature increase rather than a faulty connection. The image to the right shows two bundles with very different loads. In fact, the bundle to the right carries next to no load. Those which carry a considerable current load, are about 5°C (9°F) hotter than those which do not. No fault to be reported in these examples. 28.5.5 Varying cooling conditions 10714103;a3 Figure 28.15 An infrared image of bundled cables When, for example, a number of cables are bundled together it can happen that the resulting poor cooling of the cables in the middle can lead to them reaching very high temperatures. See the image above. The cables to the right in the image do not show any overheating close to the bolts. In the vertical part of the bundle, however, the cables are held together very tightly, the cooling of the cables is poor, the convection can not take the heat away, and the cables are notably hotter, actually about 5°C (9°F) above the temperature of the better cooled part of the cables. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 143 28 – Introduction to thermographic inspections of electrical installations 28.5.6 Resistance variations Overheating can have many origins. Some common reasons are described below. Low contact pressure can occur when mounting a joint, or through wear of the material, for example, decreasing spring tension, worn threads in nuts and bolts, even too much force applied at mounting. With increasing loads and temperatures, the yield point of the material is exceeded and the tension weakens. The image to the left below shows a bad contact due to a loose bolt. Since the bad contact is of very limited dimensions, it causes overheating only in a very small spot from which the heat is spread evenly along the connecting cable. Note the lower emissivity of the screw itself, which makes it look slightly colder than the insulated—and thereby it has a high emissivity—cable insulation. The image to the right shows another overheating situation, this time again due to a loose connection. It is an outdoor connection, hence it is exposed to the cooling effect of the wind and it is likely that the overheating would have shown a higher temperature, if mounted indoors. 10714203;a3 Figure 28.16 LEFT: An infrared image showing bad contact due to a loose bolt; RIGHT: A loose outdoor connection, exposed to the wind cooling effect. 28.5.7 Overheating in one part as a result of a fault in another Sometimes, overheating can appear in a component although that component is OK. The reason is that two conductors share the load. One of the conductors has an increased resistance, but the other is OK. Thus, the faulty component carries a lower load, whereas the fresh one has to take a higher load, which may be too high and which causes the increased temperature. See the image. 144 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations 10714303;a3 Figure 28.17 Overheating in a circuit breaker The overheating of this circuit breaker is most probably caused by bad contact in the near finger of the contactor. Thus, the far finger carries more current and gets hotter. The component in the infrared image and in the photo is not the same, however, it is similar). Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 145 28 – Introduction to thermographic inspections of electrical installations 28.6 Disturbance factors at thermographic inspection of electrical installations During thermographic inspections of different types of electrical installations, disturbance factors such as wind, distance to object, rain or snow often influence the measurement result. 28.6.1 Wind During outdoor inspection, the cooling effect of the wind should be taken into account. An overheating measured at a wind velocity of 5 m/s (10 knots) will be approximately twice as high at 1 m/s (2 knots). An excess temperature measured at 8 m/s (16 knots) will be 2.5 times as high at 1 m/s (2 knots). This correction factor, which is based on empirical measurements, is usually applicable up to 8 m/s (16 knots). There are, however, cases when you have to inspect even if the wind is stronger than 8 m/s (16 knots). There are many windy places in the world, islands, mountains, and so on but it is important to know that overheated components found would have shown a considerably higher temperature at a lower wind speed. The empirical correction factor can be listed. Wind speed (m/s) Wind speed (knots) Correction factor 1.36 1.64 1.86 10 2.06 12 2.23 14 2.40 16 2.54 The measured overheating multiplied by the correction factor gives the excess temperature with no wind, that is, at 1 m/s (2 knots). 28.6.2 Rain and snow Rain and snow also have a cooling effect on electrical equipment. Thermographic measurement can still be conducted with satisfactory results during light snowfall with dry snow and light drizzle, respectively. The image quality will deteriorate in heavy 146 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations snow or rain and reliable measurement is no longer possible. This is mainly because a heavy snowfall as well as heavy rain is impenetrable to infrared radiation and it is rather the temperature of the snowflakes or raindrops that will be measured. 28.6.3 Distance to object This image is taken from a helicopter 20 meters (66 ft.) away from this faulty connection. The distance was incorrectly set to 1 meter (3 ft.) and the temperature was measured to +37.9°C (+100.2°F). The measurement value after changing the distance to 20 meters (66 ft.), which was done afterwards, is shown in the image to the right, where the corrected temperature is +38.8°C (+101.8°F). The difference is not too crucial, but may take the fault into a higher class of seriousness. So the distance setting must definitely not be neglected. 10714403;a3 Figure 28.18 LEFT: Incorrect distance setting; RIGHT: Correct distance setting The images below show the temperature readings from a blackbody at +85°C (+185°F) at increasing distances. 10714503;a3 Figure 28.19 Temperature readings from a blackbody at +85°C (+185°F) at increasing distances Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 147 28 – Introduction to thermographic inspections of electrical installations The measured average temperatures are, from left to right, +85.3°C (+185.5°F),+85.3°C (+185.5°F), +84.8°C (+184.6°F), +84.8°C (+184.6°F), +84.8°C (+184.6°F) and +84.3°C (+183.7°F) from a blackbody at +85°C (+185°F). The thermograms are taken with a 12° lens. The distances are 1, 2, 3, 4, 5 and 10 meters (3, 7, 10, 13, 16 and 33 ft.). The correction for the distance has been meticulously set and works, because the object is big enough for correct measurement. 28.6.4 Object size The second series of images below shows the same but with the normal 24° lens. Here, the measured average temperatures of the blackbody at +85°C (+185°F) are: +84.2°C (+183.6°F), +83.7°C (+182.7°F), +83.3°C (+181.9°F), +83.3°C (+181.9°F), +83.4°C (+181.1°F) and +78.4°C (+173.1°F). The last value, (+78.4°C (+173.1°F)), is the maximum temperature as it was not possible to place a circle inside the now very small blackbody image. Obviously, it is not possible to measure correct values if the object is too small. Distance was properly set to 10 meters (33 ft.). 10714603;a3 Figure 28.20 Temperature readings from a blackbody at +85°C (+185°F) at increasing distances (24° lens) The reason for this effect is that there is a smallest object size, which gives correct temperature measurement. This smallest size is indicated to the user in all FLIR Systems cameras. The image below shows what you see in the viewfinder of camera model 695. The spot meter has an opening in its middle, more easily seen in the detail to the right. The size of the object has to be bigger than that opening or some radiation from its closest neighbors, which are much colder, will come into the measurement 148 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations as well, strongly lowering the reading. In the above case, where we have a pointshaped object, which is much hotter than the surroundings, the temperature reading will be too low. 10714703;a3 Figure 28.21 Image from the viewfinder of a ThermaCAM 695 This effect is due to imperfections in the optics and to the size of the detector elements. It is typical for all infrared cameras and can not be avoided. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 149 28 – Introduction to thermographic inspections of electrical installations 28.7 Practical advice for the thermographer Working in a practical way with a camera, you will discover small things that make your job easier. Here are five of them to start with. 28.7.1 From cold to hot You have been out with the camera at +5°C (+41°F). To continue your work, you now have to perform the inspection indoors. If you wear glasses, you are used to having to wipe off condensed water, or you will not be able to see anything. The same thing happens with the camera. To measure correctly, you should wait until the camera has become warm enough for the condensation to evaporate. This will also allow for the internal temperature compensation system to adjust to the changed condition. 28.7.2 Rain showers If it starts raining you should not perform the inspection because the water will drastically change the surface temperature of the object that you are measuring. Nevertheless, sometimes you need to use the camera even under rain showers or splashes. Protect your camera with a simple transparent polyethylene plastic bag. Correction for the attenuation which is caused by the plastic bag can be made by adjusting the object distance until the temperature reading is the same as without the plastic cover. Some camera models have a separate External optics transmission entry. 28.7.3 Emissivity You have to determine the emissivity for the material, which you are measuring. Mostly, you will not find the value in tables. Use optical black paint, that is, Nextel Black Velvet. Paint a small piece of the material you are working with. The emissivity of the optical paint is normally 0.94. Remember that the object has to have a temperature, which is different—usually higher—than the ambient temperature. The larger the difference the better the accuracy in the emissivity calculation. The difference should be at least 20°C (36°F). Remember that there are other paints that support very high temperatures up to +800°C (+1472°F). The emissivity may, however, be lower than that of optical black. Sometimes you can not paint the object that you are measuring. In this case you can use a tape. A thin tape for which you have previously determined the emissivity will work in most cases and you can remove it afterwards without damaging the object of your study. Pay attention to the fact that some tapes are semi-transparent and thus are not very good for this purpose. One of the best tapes for this purpose is Scotch electrical tape for outdoor and sub-zero conditions. 150 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 28 – Introduction to thermographic inspections of electrical installations 28.7.4 Reflected apparent temperature You are in a measurement situation where there are several hot sources that influence your measurement. You need to have the right value for the reflected apparent temperature to input into the camera and thus get the best possible correction. Do it in this way: set the emissivity to 1.0. Adjust the camera lens to near focus and, looking in the opposite direction away from the object, save one image. With the area or the isotherm, determine the most probable value of the average of the image and use that value for your input of reflected apparent temperature. 28.7.5 Object too far away Are you in doubt that the camera you have is measuring correctly at the actual distance? A rule of thumb for your lens is to multiply the IFOV by 3. (IFOV is the detail of the object seen by one single element of the detector). Example: 25 degrees correspond to about 437 mrad. If your camera has a 120 × 120 pixel image, IFOV becomes 437/120 = 3.6 mrad (3.6 mm/m) and your spot size ratio is about 1000/(3 × 3.6)=92:1. This means that at a distance of 9.2 meters (30.2 ft.), your target has to be at least about 0.1 meter or 100 mm wide (3.9"). Try to work on the safe side by coming closer than 9 meters (30 ft.). At 7–8 meters (23–26 ft.), your measurement should be correct. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 151 29 About FLIR Systems FLIR Systems was established in 1978 to pioneer the development of high-performance infrared imaging systems, and is the world leader in the design, manufacture, and marketing of thermal imaging systems for a wide variety of commercial, industrial, and government applications. Today, FLIR Systems embraces five major companies with outstanding achievements in infrared technology since 1958—the Swedish AGEMA Infrared Systems (formerly AGA Infrared Systems), the three United States companies Indigo Systems, FSI, and Inframetrics, and the French company Cedip. In November 2007, Extech Instruments was acquired by FLIR Systems. T638608;a1 Figure 29.1 Patent documents from the early 1960s The company has sold more than 140,000 infrared cameras worldwide for applications such as predictive maintenance, R & D, non-destructive testing, process control and automation, and machine vision, among many others. FLIR Systems has three manufacturing plants in the United States (Portland, OR, Boston, MA, Santa Barbara, CA) and one in Sweden (Stockholm). Since 2007 there is also a manufacturing plant in Tallinn, Estonia. Direct sales offices in Belgium, Brazil, 152 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 29 – About FLIR Systems China, France, Germany, Great Britain, Hong Kong, Italy, Japan, Korea, Sweden, and the USA—together with a worldwide network of agents and distributors—support our international customer base. FLIR Systems is at the forefront of innovation in the infrared camera industry. We anticipate market demand by constantly improving our existing cameras and developing new ones. The company has set milestones in product design and development such as the introduction of the first battery-operated portable camera for industrial inspections, and the first uncooled infrared camera, to mention just two innovations. 10722703;a2 Figure 29.2 LEFT: Thermovision® Model 661 from 1969. The camera weighed approximately 25 kg (55 lb.), the oscilloscope 20 kg (44 lb.), and the tripod 15 kg (33 lb.). The operator also needed a 220 VAC generator set, and a 10 L (2.6 US gallon) jar with liquid nitrogen. To the left of the oscilloscope the Polaroid attachment (6 kg/13 lb.) can be seen. RIGHT: FLIR i7 from 2009. Weight: 0.34 kg (0.75 lb.), including the battery. FLIR Systems manufactures all vital mechanical and electronic components of the camera systems itself. From detector design and manufacturing, to lenses and system electronics, to final testing and calibration, all production steps are carried out and supervised by our own engineers. The in-depth expertise of these infrared specialists ensures the accuracy and reliability of all vital components that are assembled into your infrared camera. 29.1 More than just an infrared camera At FLIR Systems we recognize that our job is to go beyond just producing the best infrared camera systems. We are committed to enabling all users of our infrared camera systems to work more productively by providing them with the most powerful Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 153 29 – About FLIR Systems camera–software combination. Especially tailored software for predictive maintenance, R & D, and process monitoring is developed in-house. Most software is available in a wide variety of languages. We support all our infrared cameras with a wide variety of accessories to adapt your equipment to the most demanding infrared applications. 29.2 Sharing our knowledge Although our cameras are designed to be very user-friendly, there is a lot more to thermography than just knowing how to handle a camera. Therefore, FLIR Systems has founded the Infrared Training Center (ITC), a separate business unit, that provides certified training courses. Attending one of the ITC courses will give you a truly handson learning experience. The staff of the ITC are also there to provide you with any application support you may need in putting infrared theory into practice. 29.3 Supporting our customers FLIR Systems operates a worldwide service network to keep your camera running at all times. If you discover a problem with your camera, local service centers have all the equipment and expertise to solve it within the shortest possible time. Therefore, there is no need to send your camera to the other side of the world or to talk to someone who does not speak your language. 29.4 A few images from our facilities 10401303;a1 Figure 29.3 LEFT: Development of system electronics; RIGHT: Testing of an FPA detector 154 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 29 – About FLIR Systems 10401403;a1 Figure 29.4 LEFT: Diamond turning machine; RIGHT: Lens polishing 10401503;a1 Figure 29.5 LEFT: Testing of infrared cameras in the climatic chamber; RIGHT: Robot used for camera testing and calibration Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 155 30 Glossary Term or expression Explanation absorption (absorption factor) The amount of radiation absorbed by an object relative to the received radiation. A number between 0 and 1. atmosphere The gases between the object being measured and the camera, normally air. autoadjust A function making a camera perform an internal image correction. autopalette The IR image is shown with an uneven spread of colors, displaying cold objects as well as hot ones at the same time. blackbody Totally non-reflective object. All its radiation is due to its own temperature. blackbody radiator An IR radiating equipment with blackbody properties used to calibrate IR cameras. calculated atmospheric transmission A transmission value computed from the temperature, the relative humidity of air and the distance to the object. cavity radiator A bottle shaped radiator with an absorbing inside, viewed through the bottleneck. color temperature The temperature for which the color of a blackbody matches a specific color. conduction The process that makes heat diffuse into a material. continuous adjust A function that adjusts the image. The function works all the time, continuously adjusting brightness and contrast according to the image content. convection Convection is a heat transfer mode where a fluid is brought into motion, either by gravity or another force, thereby transferring heat from one place to another. dual isotherm An isotherm with two color bands, instead of one. emissivity (emissivity factor) The amount of radiation coming from an object, compared to that of a blackbody. A number between 0 and 1. emittance Amount of energy emitted from an object per unit of time and area (W/m2) environment Objects and gases that emit radiation towards the object being measured. estimated atmospheric transmission A transmission value, supplied by a user, replacing a calculated one 156 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 30 – Glossary Term or expression Explanation external optics Extra lenses, filters, heat shields etc. that can be put between the camera and the object being measured. filter A material transparent only to some of the infrared wavelengths. FOV Field of view: The horizontal angle that can be viewed through an IR lens. FPA Focal plane array: A type of IR detector. graybody An object that emits a fixed fraction of the amount of energy of a blackbody for each wavelength. IFOV Instantaneous field of view: A measure of the geometrical resolution of an IR camera. image correction (internal or external) A way of compensating for sensitivity differences in various parts of live images and also of stabilizing the camera. infrared Non-visible radiation, having a wavelength from about 2–13 μm. IR infrared isotherm A function highlighting those parts of an image that fall above, below or between one or more temperature intervals. isothermal cavity A bottle-shaped radiator with a uniform temperature viewed through the bottleneck. Laser LocatIR An electrically powered light source on the camera that emits laser radiation in a thin, concentrated beam to point at certain parts of the object in front of the camera. laser pointer An electrically powered light source on the camera that emits laser radiation in a thin, concentrated beam to point at certain parts of the object in front of the camera. level The center value of the temperature scale, usually expressed as a signal value. manual adjust A way to adjust the image by manually changing certain parameters. NETD Noise equivalent temperature difference. A measure of the image noise level of an IR camera. noise Undesired small disturbance in the infrared image object parameters A set of values describing the circumstances under which the measurement of an object was made, and the object itself (such as emissivity, reflected apparent temperature, distance etc.) object signal A non-calibrated value related to the amount of radiation received by the camera from the object. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 157 30 – Glossary Term or expression Explanation palette The set of colors used to display an IR image. pixel Stands for picture element. One single spot in an image. radiance Amount of energy emitted from an object per unit of time, area and angle (W/m2/sr) radiant power Amount of energy emitted from an object per unit of time (W) radiation The process by which electromagnetic energy, is emitted by an object or a gas. radiator A piece of IR radiating equipment. range The current overall temperature measurement limitation of an IR camera. Cameras can have several ranges. Expressed as two blackbody temperatures that limit the current calibration. reference temperature A temperature which the ordinary measured values can be compared with. reflection The amount of radiation reflected by an object relative to the received radiation. A number between 0 and 1. relative humidity Relative humidity represents the ratio between the current water vapour mass in the air and the maximum it may contain in saturation conditions. saturation color The areas that contain temperatures outside the present level/span settings are colored with the saturation colors. The saturation colors contain an ‘overflow’ color and an ‘underflow’ color. There is also a third red saturation color that marks everything saturated by the detector indicating that the range should probably be changed. span The interval of the temperature scale, usually expressed as a signal value. spectral (radiant) emittance Amount of energy emitted from an object per unit of time, area and wavelength (W/m2/μm) temperature difference, or difference of temperature. A value which is the result of a subtraction between two temperature values. temperature range The current overall temperature measurement limitation of an IR camera. Cameras can have several ranges. Expressed as two blackbody temperatures that limit the current calibration. temperature scale The way in which an IR image currently is displayed. Expressed as two temperature values limiting the colors. thermogram infrared image 158 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 30 – Glossary Term or expression Explanation transmission (or transmittance) factor Gases and materials can be more or less transparent. Transmission is the amount of IR radiation passing through them. A number between 0 and 1. transparent isotherm An isotherm showing a linear spread of colors, instead of covering the highlighted parts of the image. visual Refers to the video mode of a IR camera, as opposed to the normal, thermographic mode. When a camera is in video mode it captures ordinary video images, while thermographic images are captured when the camera is in IR mode. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 159 31 Thermographic measurement techniques 31.1 Introduction An infrared camera measures and images the emitted infrared radiation from an object. The fact that radiation is a function of object surface temperature makes it possible for the camera to calculate and display this temperature. However, the radiation measured by the camera does not only depend on the temperature of the object but is also a function of the emissivity. Radiation also originates from the surroundings and is reflected in the object. The radiation from the object and the reflected radiation will also be influenced by the absorption of the atmosphere. To measure temperature accurately, it is therefore necessary to compensate for the effects of a number of different radiation sources. This is done on-line automatically by the camera. The following object parameters must, however, be supplied for the camera: ■ ■ ■ ■ ■ The emissivity of the object The reflected apparent temperature The distance between the object and the camera The relative humidity Temperature of the atmosphere 31.2 Emissivity The most important object parameter to set correctly is the emissivity which, in short, is a measure of how much radiation is emitted from the object, compared to that from a perfect blackbody of the same temperature. Normally, object materials and surface treatments exhibit emissivity ranging from approximately 0.1 to 0.95. A highly polished (mirror) surface falls below 0.1, while an oxidized or painted surface has a higher emissivity. Oil-based paint, regardless of color in the visible spectrum, has an emissivity over 0.9 in the infrared. Human skin exhibits an emissivity 0.97 to 0.98. Non-oxidized metals represent an extreme case of perfect opacity and high reflexivity, which does not vary greatly with wavelength. Consequently, the emissivity of metals is low – only increasing with temperature. For non-metals, emissivity tends to be high, and decreases with temperature. 160 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 31 – Thermographic measurement techniques 31.2.1 Finding the emissivity of a sample 31.2.1.1 Step 1: Determining reflected apparent temperature Use one of the following two methods to determine reflected apparent temperature: 31.2.1.1.1 Method 1: Direct method Look for possible reflection sources, considering that the incident angle = reflection angle (a = b). 10588903;a1 Figure 31.1 1 = Reflection source If the reflection source is a spot source, modify the source by obstructing it using a piece if cardboard. 10589103;a2 Figure 31.2 1 = Reflection source Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 161 31 – Thermographic measurement techniques Measure the radiation intensity (= apparent temperature) from the reflecting source using the following settings: ■ ■ Emissivity: 1.0 Dobj: 0 You can measure the radiation intensity using one of the following two methods: 10589003;a2 Figure 31.3 1 = Reflection source Note: Using a thermocouple to measure reflected apparent temperature is not recommended for two important reasons: ■ ■ A thermocouple does not measure radiation intensity A thermocouple requires a very good thermal contact to the surface, usually by gluing and covering the sensor by a thermal isolator. 31.2.1.1.2 Method 2: Reflector method Crumble up a large piece of aluminum foil. Uncrumble the aluminum foil and attach it to a piece of cardboard of the same size. Put the piece of cardboard in front of the object you want to measure. Make sure that the side with aluminum foil points to the camera. Set the emissivity to 1.0. 162 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 31 – Thermographic measurement techniques Measure the apparent temperature of the aluminum foil and write it down. 10727003;a2 Figure 31.4 Measuring the apparent temperature of the aluminum foil 31.2.1.2 Step 2: Determining the emissivity Select a place to put the sample. Determine and set reflected apparent temperature according to the previous procedure. Put a piece of electrical tape with known high emissivity on the sample. Heat the sample at least 20 K above room temperature. Heating must be reasonably even. Focus and auto-adjust the camera, and freeze the image. Adjust Level and Span for best image brightness and contrast. Set emissivity to that of the tape (usually 0.97). Measure the temperature of the tape using one of the following measurement functions: ■ ■ ■ Isotherm (helps you to determine both the temperature and how evenly you have heated the sample) Spot (simpler) Box Avg (good for surfaces with varying emissivity). Write down the temperature. 10 Move your measurement function to the sample surface. 11 Change the emissivity setting until you read the same temperature as your previous measurement. 12 Write down the emissivity. Note: Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 163 31 – Thermographic measurement techniques ■ ■ ■ ■ Avoid forced convection Look for a thermally stable surrounding that will not generate spot reflections Use high quality tape that you know is not transparent, and has a high emissivity you are certain of This method assumes that the temperature of your tape and the sample surface are the same. If they are not, your emissivity measurement will be wrong. 31.3 Reflected apparent temperature This parameter is used to compensate for the radiation reflected in the object. If the emissivity is low and the object temperature relatively far from that of the reflected it will be important to set and compensate for the reflected apparent temperature correctly. 31.4 Distance The distance is the distance between the object and the front lens of the camera. This parameter is used to compensate for the following two facts: ■ ■ That radiation from the target is absorbed by the athmosphere between the object and the camera. That radiation from the atmosphere itself is detected by the camera. 31.5 Relative humidity The camera can also compensate for the fact that the transmittance is also dependent on the relative humidity of the atmosphere. To do this set the relative humidity to the correct value. For short distances and normal humidity the relative humidity can normally be left at a default value of 50%. 31.6 Other parameters In addition, some cameras and analysis programs from FLIR Systems allow you to compensate for the following parameters: ■ ■ ■ Atmospheric temperature – i.e. the temperature of the atmosphere between the camera and the target External optics temperature – i.e. the temperature of any external lenses or windows used in front of the camera External optics transmittance – i.e. the transmission of any external lenses or windows used in front of the camera 164 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 32 History of infrared technology Before the year 1800, the existence of the infrared portion of the electromagnetic spectrum wasn't even suspected. The original significance of the infrared spectrum, or simply ‘the infrared’ as it is often called, as a form of heat radiation is perhaps less obvious today than it was at the time of its discovery by Herschel in 1800. 10398703;a1 Figure 32.1 Sir William Herschel (1738–1822) The discovery was made accidentally during the search for a new optical material. Sir William Herschel – Royal Astronomer to King George III of England, and already famous for his discovery of the planet Uranus – was searching for an optical filter material to reduce the brightness of the sun’s image in telescopes during solar observations. While testing different samples of colored glass which gave similar reductions in brightness he was intrigued to find that some of the samples passed very little of the sun’s heat, while others passed so much heat that he risked eye damage after only a few seconds’ observation. Herschel was soon convinced of the necessity of setting up a systematic experiment, with the objective of finding a single material that would give the desired reduction in brightness as well as the maximum reduction in heat. He began the experiment by actually repeating Newton’s prism experiment, but looking for the heating effect rather than the visual distribution of intensity in the spectrum. He first blackened the bulb of a sensitive mercury-in-glass thermometer with ink, and with this as his radiation detector he proceeded to test the heating effect of the various colors of the spectrum formed on the top of a table by passing sunlight through a glass prism. Other thermometers, placed outside the sun’s rays, served as controls. As the blackened thermometer was moved slowly along the colors of the spectrum, the temperature readings showed a steady increase from the violet end to the red end. This was not entirely unexpected, since the Italian researcher, Landriani, in a similar experiment in 1777 had observed much the same effect. It was Herschel, Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 165 32 – History of infrared technology however, who was the first to recognize that there must be a point where the heating effect reaches a maximum, and that measurements confined to the visible portion of the spectrum failed to locate this point. 10398903;a1 Figure 32.2 Marsilio Landriani (1746–1815) Moving the thermometer into the dark region beyond the red end of the spectrum, Herschel confirmed that the heating continued to increase. The maximum point, when he found it, lay well beyond the red end – in what is known today as the ‘infrared wavelengths’. When Herschel revealed his discovery, he referred to this new portion of the electromagnetic spectrum as the ‘thermometrical spectrum’. The radiation itself he sometimes referred to as ‘dark heat’, or simply ‘the invisible rays’. Ironically, and contrary to popular opinion, it wasn't Herschel who originated the term ‘infrared’. The word only began to appear in print around 75 years later, and it is still unclear who should receive credit as the originator. Herschel’s use of glass in the prism of his original experiment led to some early controversies with his contemporaries about the actual existence of the infrared wavelengths. Different investigators, in attempting to confirm his work, used various types of glass indiscriminately, having different transparencies in the infrared. Through his later experiments, Herschel was aware of the limited transparency of glass to the newly-discovered thermal radiation, and he was forced to conclude that optics for the infrared would probably be doomed to the use of reflective elements exclusively (i.e. plane and curved mirrors). Fortunately, this proved to be true only until 1830, when the Italian investigator, Melloni, made his great discovery that naturally occurring rock salt (NaCl) – which was available in large enough natural crystals to be made into lenses and prisms – is remarkably transparent to the infrared. The result was that rock salt became the principal infrared optical material, and remained so for the next hundred years, until the art of synthetic crystal growing was mastered in the 1930’s. 166 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 32 – History of infrared technology 10399103;a1 Figure 32.3 Macedonio Melloni (1798–1854) Thermometers, as radiation detectors, remained unchallenged until 1829, the year Nobili invented the thermocouple. (Herschel’s own thermometer could be read to 0.2 °C (0.036 °F), and later models were able to be read to 0.05 °C (0.09 °F)). Then a breakthrough occurred; Melloni connected a number of thermocouples in series to form the first thermopile. The new device was at least 40 times as sensitive as the best thermometer of the day for detecting heat radiation – capable of detecting the heat from a person standing three meters away. The first so-called ‘heat-picture’ became possible in 1840, the result of work by Sir John Herschel, son of the discoverer of the infrared and a famous astronomer in his own right. Based upon the differential evaporation of a thin film of oil when exposed to a heat pattern focused upon it, the thermal image could be seen by reflected light where the interference effects of the oil film made the image visible to the eye. Sir John also managed to obtain a primitive record of the thermal image on paper, which he called a ‘thermograph’. 10399003;a2 Figure 32.4 Samuel P. Langley (1834–1906) Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 167 32 – History of infrared technology The improvement of infrared-detector sensitivity progressed slowly. Another major breakthrough, made by Langley in 1880, was the invention of the bolometer. This consisted of a thin blackened strip of platinum connected in one arm of a Wheatstone bridge circuit upon which the infrared radiation was focused and to which a sensitive galvanometer responded. This instrument is said to have been able to detect the heat from a cow at a distance of 400 meters. An English scientist, Sir James Dewar, first introduced the use of liquefied gases as cooling agents (such as liquid nitrogen with a temperature of -196 °C (-320.8 °F)) in low temperature research. In 1892 he invented a unique vacuum insulating container in which it is possible to store liquefied gases for entire days. The common ‘thermos bottle’, used for storing hot and cold drinks, is based upon his invention. Between the years 1900 and 1920, the inventors of the world ‘discovered’ the infrared. Many patents were issued for devices to detect personnel, artillery, aircraft, ships – and even icebergs. The first operating systems, in the modern sense, began to be developed during the 1914–18 war, when both sides had research programs devoted to the military exploitation of the infrared. These programs included experimental systems for enemy intrusion/detection, remote temperature sensing, secure communications, and ‘flying torpedo’ guidance. An infrared search system tested during this period was able to detect an approaching airplane at a distance of 1.5 km (0.94 miles), or a person more than 300 meters (984 ft.) away. The most sensitive systems up to this time were all based upon variations of the bolometer idea, but the period between the two wars saw the development of two revolutionary new infrared detectors: the image converter and the photon detector. At first, the image converter received the greatest attention by the military, because it enabled an observer for the first time in history to literally ‘see in the dark’. However, the sensitivity of the image converter was limited to the near infrared wavelengths, and the most interesting military targets (i.e. enemy soldiers) had to be illuminated by infrared search beams. Since this involved the risk of giving away the observer’s position to a similarly-equipped enemy observer, it is understandable that military interest in the image converter eventually faded. The tactical military disadvantages of so-called 'active’ (i.e. search beam-equipped) thermal imaging systems provided impetus following the 1939–45 war for extensive secret military infrared-research programs into the possibilities of developing ‘passive’ (no search beam) systems around the extremely sensitive photon detector. During this period, military secrecy regulations completely prevented disclosure of the status of infrared-imaging technology. This secrecy only began to be lifted in the middle of the 1950’s, and from that time adequate thermal-imaging devices finally began to be available to civilian science and industry. 168 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 33 Theory of thermography 33.1 Introduction The subjects of infrared radiation and the related technique of thermography are still new to many who will use an infrared camera. In this section the theory behind thermography will be given. 33.2 The electromagnetic spectrum The electromagnetic spectrum is divided arbitrarily into a number of wavelength regions, called bands, distinguished by the methods used to produce and detect the radiation. There is no fundamental difference between radiation in the different bands of the electromagnetic spectrum. They are all governed by the same laws and the only differences are those due to differences in wavelength. 10067803;a1 Figure 33.1 The electromagnetic spectrum. 1: X-ray; 2: UV; 3: Visible; 4: IR; 5: Microwaves; 6: Radiowaves. Thermography makes use of the infrared spectral band. At the short-wavelength end the boundary lies at the limit of visual perception, in the deep red. At the long-wavelength end it merges with the microwave radio wavelengths, in the millimeter range. The infrared band is often further subdivided into four smaller bands, the boundaries of which are also arbitrarily chosen. They include: the near infrared (0.75–3 μm), the middle infrared (3–6 μm), the far infrared (6–15 μm) and the extreme infrared (15–100 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 169 33 – Theory of thermography μm). Although the wavelengths are given in μm (micrometers), other units are often still used to measure wavelength in this spectral region, e.g. nanometer (nm) and Ångström (Å). The relationships between the different wavelength measurements is: 33.3 Blackbody radiation A blackbody is defined as an object which absorbs all radiation that impinges on it at any wavelength. The apparent misnomer black relating to an object emitting radiation is explained by Kirchhoff’s Law (after Gustav Robert Kirchhoff, 1824–1887), which states that a body capable of absorbing all radiation at any wavelength is equally capable in the emission of radiation. 10398803;a1 Figure 33.2 Gustav Robert Kirchhoff (1824–1887) The construction of a blackbody source is, in principle, very simple. The radiation characteristics of an aperture in an isotherm cavity made of an opaque absorbing material represents almost exactly the properties of a blackbody. A practical application of the principle to the construction of a perfect absorber of radiation consists of a box that is light tight except for an aperture in one of the sides. Any radiation which then enters the hole is scattered and absorbed by repeated reflections so only an infinitesimal fraction can possibly escape. The blackness which is obtained at the aperture is nearly equal to a blackbody and almost perfect for all wavelengths. By providing such an isothermal cavity with a suitable heater it becomes what is termed a cavity radiator. An isothermal cavity heated to a uniform temperature generates blackbody radiation, the characteristics of which are determined solely by the temperature of the cavity. Such cavity radiators are commonly used as sources of radiation in temperature reference standards in the laboratory for calibrating thermographic instruments, such as a FLIR Systems camera for example. 170 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 33 – Theory of thermography If the temperature of blackbody radiation increases to more than 525°C (977°F), the source begins to be visible so that it appears to the eye no longer black. This is the incipient red heat temperature of the radiator, which then becomes orange or yellow as the temperature increases further. In fact, the definition of the so-called color temperature of an object is the temperature to which a blackbody would have to be heated to have the same appearance. Now consider three expressions that describe the radiation emitted from a blackbody. 33.3.1 Planck’s law 10399203;a1 Figure 33.3 Max Planck (1858–1947) Max Planck (1858–1947) was able to describe the spectral distribution of the radiation from a blackbody by means of the following formula: where: Wλb Blackbody spectral radiant emittance at wavelength λ. Velocity of light = 3 × 108 m/s Planck’s constant = 6.6 × 10-34 Joule sec. Boltzmann’s constant = 1.4 × 10-23 Joule/K. Absolute temperature (K) of a blackbody. λ Wavelength (μm). Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 171 33 – Theory of thermography ➲ The factor 10-6 is used since spectral emittance in the curves is expressed in Watt/m2, μm. Planck’s formula, when plotted graphically for various temperatures, produces a family of curves. Following any particular Planck curve, the spectral emittance is zero at λ = 0, then increases rapidly to a maximum at a wavelength λmax and after passing it approaches zero again at very long wavelengths. The higher the temperature, the shorter the wavelength at which maximum occurs. 10327103;a4 Figure 33.4 Blackbody spectral radiant emittance according to Planck’s law, plotted for various absolute temperatures. 1: Spectral radiant emittance (W/cm2 × 103(μm)); 2: Wavelength (μm) 33.3.2 Wien’s displacement law By differentiating Planck’s formula with respect to λ, and finding the maximum, we have: This is Wien’s formula (after Wilhelm Wien, 1864–1928), which expresses mathematically the common observation that colors vary from red to orange or yellow as the temperature of a thermal radiator increases. The wavelength of the color is the same as the wavelength calculated for λmax. A good approximation of the value of λmax for a given blackbody temperature is obtained by applying the rule-of-thumb 3 000/T 172 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 33 – Theory of thermography μm. Thus, a very hot star such as Sirius (11 000 K), emitting bluish-white light, radiates with the peak of spectral radiant emittance occurring within the invisible ultraviolet spectrum, at wavelength 0.27 μm. 10399403;a1 Figure 33.5 Wilhelm Wien (1864–1928) The sun (approx. 6 000 K) emits yellow light, peaking at about 0.5 μm in the middle of the visible light spectrum. At room temperature (300 K) the peak of radiant emittance lies at 9.7 μm, in the far infrared, while at the temperature of liquid nitrogen (77 K) the maximum of the almost insignificant amount of radiant emittance occurs at 38 μm, in the extreme infrared wavelengths. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 173 33 – Theory of thermography 10327203;a4 Figure 33.6 Planckian curves plotted on semi-log scales from 100 K to 1000 K. The dotted line represents the locus of maximum radiant emittance at each temperature as described by Wien's displacement law. 1: Spectral radiant emittance (W/cm2 (μm)); 2: Wavelength (μm). 33.3.3 Stefan-Boltzmann's law By integrating Planck’s formula from λ = 0 to λ = ∞, we obtain the total radiant emittance (Wb) of a blackbody: This is the Stefan-Boltzmann formula (after Josef Stefan, 1835–1893, and Ludwig Boltzmann, 1844–1906), which states that the total emissive power of a blackbody is proportional to the fourth power of its absolute temperature. Graphically, Wb represents the area below the Planck curve for a particular temperature. It can be shown that the radiant emittance in the interval λ = 0 to λmax is only 25% of the total, which represents about the amount of the sun’s radiation which lies inside the visible light spectrum. 174 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 33 – Theory of thermography 10399303;a1 Figure 33.7 Josef Stefan (1835–1893), and Ludwig Boltzmann (1844–1906) Using the Stefan-Boltzmann formula to calculate the power radiated by the human body, at a temperature of 300 K and an external surface area of approx. 2 m2, we obtain 1 kW. This power loss could not be sustained if it were not for the compensating absorption of radiation from surrounding surfaces, at room temperatures which do not vary too drastically from the temperature of the body – or, of course, the addition of clothing. 33.3.4 Non-blackbody emitters So far, only blackbody radiators and blackbody radiation have been discussed. However, real objects almost never comply with these laws over an extended wavelength region – although they may approach the blackbody behavior in certain spectral intervals. For example, a certain type of white paint may appear perfectly white in the visible light spectrum, but becomes distinctly gray at about 2 μm, and beyond 3 μm it is almost black. There are three processes which can occur that prevent a real object from acting like a blackbody: a fraction of the incident radiation α may be absorbed, a fraction ρ may be reflected, and a fraction τ may be transmitted. Since all of these factors are more or less wavelength dependent, the subscript λ is used to imply the spectral dependence of their definitions. Thus: ■ ■ ■ The spectral absorptance αλ= the ratio of the spectral radiant power absorbed by an object to that incident upon it. The spectral reflectance ρλ = the ratio of the spectral radiant power reflected by an object to that incident upon it. The spectral transmittance τλ = the ratio of the spectral radiant power transmitted through an object to that incident upon it. The sum of these three factors must always add up to the whole at any wavelength, so we have the relation: Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 175 33 – Theory of thermography For opaque materials τλ = 0 and the relation simplifies to: Another factor, called the emissivity, is required to describe the fraction ε of the radiant emittance of a blackbody produced by an object at a specific temperature. Thus, we have the definition: The spectral emissivity ελ= the ratio of the spectral radiant power from an object to that from a blackbody at the same temperature and wavelength. Expressed mathematically, this can be written as the ratio of the spectral emittance of the object to that of a blackbody as follows: Generally speaking, there are three types of radiation source, distinguished by the ways in which the spectral emittance of each varies with wavelength. ■ ■ ■ A blackbody, for which ελ = ε = 1 A graybody, for which ελ = ε = constant less than 1 A selective radiator, for which ε varies with wavelength According to Kirchhoff’s law, for any material the spectral emissivity and spectral absorptance of a body are equal at any specified temperature and wavelength. That is: From this we obtain, for an opaque material (since αλ + ρλ = 1): For highly polished materials ελ approaches zero, so that for a perfectly reflecting material (i.e. a perfect mirror) we have: For a graybody radiator, the Stefan-Boltzmann formula becomes: This states that the total emissive power of a graybody is the same as a blackbody at the same temperature reduced in proportion to the value of ε from the graybody. 176 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 33 – Theory of thermography 10401203;a2 Figure 33.8 Spectral radiant emittance of three types of radiators. 1: Spectral radiant emittance; 2: Wavelength; 3: Blackbody; 4: Selective radiator; 5: Graybody. 10327303;a4 Figure 33.9 Spectral emissivity of three types of radiators. 1: Spectral emissivity; 2: Wavelength; 3: Blackbody; 4: Graybody; 5: Selective radiator. 33.4 Infrared semi-transparent materials Consider now a non-metallic, semi-transparent body – let us say, in the form of a thick flat plate of plastic material. When the plate is heated, radiation generated within its volume must work its way toward the surfaces through the material in which it is partially absorbed. Moreover, when it arrives at the surface, some of it is reflected back into the interior. The back-reflected radiation is again partially absorbed, but Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 177 33 – Theory of thermography some of it arrives at the other surface, through which most of it escapes; part of it is reflected back again. Although the progressive reflections become weaker and weaker they must all be added up when the total emittance of the plate is sought. When the resulting geometrical series is summed, the effective emissivity of a semitransparent plate is obtained as: When the plate becomes opaque this formula is reduced to the single formula: This last relation is a particularly convenient one, because it is often easier to measure reflectance than to measure emissivity directly. 178 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 34 The measurement formula As already mentioned, when viewing an object, the camera receives radiation not only from the object itself. It also collects radiation from the surroundings reflected via the object surface. Both these radiation contributions become attenuated to some extent by the atmosphere in the measurement path. To this comes a third radiation contribution from the atmosphere itself. This description of the measurement situation, as illustrated in the figure below, is so far a fairly true description of the real conditions. What has been neglected could for instance be sun light scattering in the atmosphere or stray radiation from intense radiation sources outside the field of view. Such disturbances are difficult to quantify, however, in most cases they are fortunately small enough to be neglected. In case they are not negligible, the measurement configuration is likely to be such that the risk for disturbance is obvious, at least to a trained operator. It is then his responsibility to modify the measurement situation to avoid the disturbance e.g. by changing the viewing direction, shielding off intense radiation sources etc. Accepting the description above, we can use the figure below to derive a formula for the calculation of the object temperature from the calibrated camera output. 10400503;a1 Figure 34.1 A schematic representation of the general thermographic measurement situation.1: Surroundings; 2: Object; 3: Atmosphere; 4: Camera Assume that the received radiation power W from a blackbody source of temperature Tsource on short distance generates a camera output signal Usource that is proportional to the power input (power linear camera). We can then write (Equation 1): Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 179 34 – The measurement formula or, with simplified notation: where C is a constant. Should the source be a graybody with emittance ε, the received radiation would consequently be εWsource. We are now ready to write the three collected radiation power terms: 1 – Emission from the object = ετWobj, where ε is the emittance of the object and τ is the transmittance of the atmosphere. The object temperature is Tobj. 2 – Reflected emission from ambient sources = (1 – ε)τWrefl, where (1 – ε) is the reflectance of the object. The ambient sources have the temperature Trefl. It has here been assumed that the temperature Trefl is the same for all emitting surfaces within the halfsphere seen from a point on the object surface. This is of course sometimes a simplification of the true situation. It is, however, a necessary simplification in order to derive a workable formula, and Trefl can – at least theoretically – be given a value that represents an efficient temperature of a complex surrounding. Note also that we have assumed that the emittance for the surroundings = 1. This is correct in accordance with Kirchhoff’s law: All radiation impinging on the surrounding surfaces will eventually be absorbed by the same surfaces. Thus the emittance = 1. (Note though that the latest discussion requires the complete sphere around the object to be considered.) 3 – Emission from the atmosphere = (1 – τ)τWatm, where (1 – τ) is the emittance of the atmosphere. The temperature of the atmosphere is Tatm. The total received radiation power can now be written (Equation 2): We multiply each term by the constant C of Equation 1 and replace the CW products by the corresponding U according to the same equation, and get (Equation 3): Solve Equation 3 for Uobj (Equation 4): 180 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 34 – The measurement formula This is the general measurement formula used in all the FLIR Systems thermographic equipment. The voltages of the formula are: Figure 34.2 Voltages Uobj Calculated camera output voltage for a blackbody of temperature Tobj i.e. a voltage that can be directly converted into true requested object temperature. Utot Measured camera output voltage for the actual case. Urefl Theoretical camera output voltage for a blackbody of temperature Trefl according to the calibration. Uatm Theoretical camera output voltage for a blackbody of temperature Tatm according to the calibration. The operator has to supply a number of parameter values for the calculation: ■ ■ ■ ■ ■ ■ the object emittance ε, the relative humidity, Tatm object distance (Dobj) the (effective) temperature of the object surroundings, or the reflected ambient temperature Trefl, and the temperature of the atmosphere Tatm This task could sometimes be a heavy burden for the operator since there are normally no easy ways to find accurate values of emittance and atmospheric transmittance for the actual case. The two temperatures are normally less of a problem provided the surroundings do not contain large and intense radiation sources. A natural question in this connection is: How important is it to know the right values of these parameters? It could though be of interest to get a feeling for this problem already here by looking into some different measurement cases and compare the relative magnitudes of the three radiation terms. This will give indications about when it is important to use correct values of which parameters. The figures below illustrates the relative magnitudes of the three radiation contributions for three different object temperatures, two emittances, and two spectral ranges: SW and LW. Remaining parameters have the following fixed values: ■ ■ ■ τ = 0.88 Trefl = +20°C (+68°F) Tatm = +20°C (+68°F) Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 181 34 – The measurement formula It is obvious that measurement of low object temperatures are more critical than measuring high temperatures since the ‘disturbing’ radiation sources are relatively much stronger in the first case. Should also the object emittance be low, the situation would be still more difficult. We have finally to answer a question about the importance of being allowed to use the calibration curve above the highest calibration point, what we call extrapolation. Imagine that we in a certain case measure Utot = 4.5 volts. The highest calibration point for the camera was in the order of 4.1 volts, a value unknown to the operator. Thus, even if the object happened to be a blackbody, i.e. Uobj = Utot, we are actually performing extrapolation of the calibration curve when converting 4.5 volts into temperature. Let us now assume that the object is not black, it has an emittance of 0.75, and the transmittance is 0.92. We also assume that the two second terms of Equation 4 amount to 0.5 volts together. Computation of Uobj by means of Equation 4 then results in Uobj = 4.5 / 0.75 / 0.92 – 0.5 = 6.0. This is a rather extreme extrapolation, particularly when considering that the video amplifier might limit the output to 5 volts! Note, though, that the application of the calibration curve is a theoretical procedure where no electronic or other limitations exist. We trust that if there had been no signal limitations in the camera, and if it had been calibrated far beyond 5 volts, the resulting curve would have been very much the same as our real curve extrapolated beyond 4.1 volts, provided the calibration algorithm is based on radiation physics, like the FLIR Systems algorithm. Of course there must be a limit to such extrapolations. 182 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 34 – The measurement formula 10400603;a2 Figure 34.3 Relative magnitudes of radiation sources under varying measurement conditions (SW camera). 1: Object temperature; 2: Emittance; Obj: Object radiation; Refl: Reflected radiation; Atm: atmosphere radiation. Fixed parameters: τ = 0.88; Trefl = 20°C (+68°F); Tatm = 20°C (+68°F). Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 183 34 – The measurement formula 10400703;a2 Figure 34.4 Relative magnitudes of radiation sources under varying measurement conditions (LW camera). 1: Object temperature; 2: Emittance; Obj: Object radiation; Refl: Reflected radiation; Atm: atmosphere radiation. Fixed parameters: τ = 0.88; Trefl = 20°C (+68°F); Tatm = 20°C (+68°F). 184 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 35 Emissivity tables This section presents a compilation of emissivity data from the infrared literature and measurements made by FLIR Systems. 35.1 References Mikaél A. Bramson: Infrared Radiation, A Handbook for Applications, Plenum press, N.Y. William L. Wolfe, George J. Zissis: The Infrared Handbook, Office of Naval Research, Department of Navy, Washington, D.C. Madding, R. P.: Thermographic Instruments and systems. Madison, Wisconsin: University of Wisconsin – Extension, Department of Engineering and Applied Science. William L. Wolfe: Handbook of Military Infrared Technology, Office of Naval Research, Department of Navy, Washington, D.C. Jones, Smith, Probert: External thermography of buildings..., Proc. of the Society of Photo-Optical Instrumentation Engineers, vol.110, Industrial and Civil Applications of Infrared Technology, June 1977 London. Paljak, Pettersson: Thermography of Buildings, Swedish Building Research Institute, Stockholm 1972. Vlcek, J: Determination of emissivity with imaging radiometers and some emissivities at λ = 5 µm. Photogrammetric Engineering and Remote Sensing. Kern: Evaluation of infrared emission of clouds and ground as measured by weather satellites, Defence Documentation Center, AD 617 417. Öhman, Claes: Emittansmätningar med AGEMA E-Box. Teknisk rapport, AGEMA 1999. (Emittance measurements using AGEMA E-Box. Technical report, AGEMA 1999.) 10 Matteï, S., Tang-Kwor, E: Emissivity measurements for Nextel Velvet coating 811-21 between –36°C AND 82°C. 11 Lohrengel & Todtenhaupt (1996) 12 ITC Technical publication 32. 13 ITC Technical publication 29. 35.2 Important note about the emissivity tables The emissivity values in the table below are recorded using a shortwave (SW) camera. The values should be regarded as recommendations only and used with caution. Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 185 35 – Emissivity tables 35.3 Tables Figure 35.1 T: Total spectrum; SW: 2–5 µm; LW: 8–14 µm, LLW: 6.5–20 µm; 1: Material; 2: Specification; 3: Temperature in °C; 4: Spectrum; 5: Emissivity: 6: Reference 3M type 35 Vinyl electrical tape (several colors) < 80 LW Ca. 0.96 13 3M type 88 Black vinyl electrical tape < 105 LW Ca. 0.96 13 3M type 88 Black vinyl electrical tape < 105 MW < 0.96 13 3M type Super 33+ Black vinyl electrical tape < 80 LW Ca. 0.96 13 Aluminum anodized, black, dull 70 LW 0.95 Aluminum anodized, black, dull 70 SW 0.67 Aluminum anodized, light gray, dull 70 LW 0.97 Aluminum anodized, light gray, dull 70 SW 0.61 Aluminum anodized sheet 100 0.55 Aluminum as received, plate 100 0.09 Aluminum as received, sheet 100 0.09 Aluminum cast, blast cleaned 70 LW 0.46 Aluminum cast, blast cleaned 70 SW 0.47 Aluminum dipped in HNO3, plate 100 0.05 Aluminum foil 27 3 µm 0.09 Aluminum foil 27 10 µm 0.04 Aluminum oxidized, strongly 50–500 0.2–0.3 Aluminum polished 50–100 0.04–0.06 Aluminum polished, sheet 100 0.05 Aluminum polished plate 100 0.05 186 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 35 – Emissivity tables Aluminum roughened 27 3 µm 0.28 Aluminum roughened 27 10 µm 0.18 Aluminum rough surface 20–50 0.06–0.07 Aluminum sheet, 4 samples differently scratched 70 LW 0.03–0.06 Aluminum sheet, 4 samples differently scratched 70 SW 0.05–0.08 Aluminum vacuum deposited 20 0.04 Aluminum weathered, heavily 17 SW 0.83–0.94 20 0.60 Aluminum bronze Aluminum hydroxide powder 0.28 Aluminum oxide activated, powder 0.46 Aluminum oxide pure, powder (alumina) 0.16 Asbestos board 0.96 Asbestos fabric 0.78 Asbestos floor tile 35 SW 0.94 Asbestos paper 40–400 0.93–0.95 Asbestos powder 0.40–0.60 Asbestos slate 20 0.96 LLW 0.967 Asphalt paving 20 Brass dull, tarnished 20–350 0.22 Brass oxidized 70 SW 0.04–0.09 Brass oxidized 70 LW 0.03–0.07 Brass oxidized 100 0.61 Brass oxidized at 600°C 200–600 0.59–0.61 Brass polished 200 0.03 Brass polished, highly 100 0.03 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 187 35 – Emissivity tables Brass rubbed with 80grit emery 20 0.20 Brass sheet, rolled 20 0.06 Brass sheet, worked with emery 20 0.2 Brick alumina 17 SW 0.68 Brick common 17 SW 0.86–0.81 Brick Dinas silica, glazed, rough 1100 0.85 Brick Dinas silica, refractory 1000 0.66 Brick Dinas silica, unglazed, rough 1000 0.80 Brick firebrick 17 SW 0.68 Brick fireclay 20 0.85 Brick fireclay 1000 0.75 Brick fireclay 1200 0.59 Brick masonry 35 SW 0.94 Brick masonry, plastered 20 0.94 Brick red, common 20 0.93 Brick red, rough 20 0.88–0.93 Brick refractory, corundum 1000 0.46 Brick refractory, magnesite 1000–1300 0.38 Brick refractory, strongly radiating 500–1000 0.8–0.9 Brick refractory, weakly radiating 500–1000 0.65–0.75 Brick silica, 95% SiO2 1230 0.66 Brick sillimanite, 33% SiO2, 64% Al2O3 1500 0.29 188 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 35 – Emissivity tables Brick waterproof 17 SW 0.87 Bronze phosphor bronze 70 LW 0.06 Bronze phosphor bronze 70 SW 0.08 Bronze polished 50 0.1 Bronze porous, rough 50–150 0.55 Bronze powder 0.76–0.80 Carbon candle soot 0.95 Carbon charcoal powder 0.96 Carbon graphite, filed surface 0.98 Carbon graphite powder 0.97 Carbon lampblack 20–400 0.95–0.97 Chipboard untreated 20 SW 0.90 Chromium polished 50 0.10 Chromium polished 500–1000 0.28–0.38 Clay fired 70 0.91 Cloth black 20 0.98 20 0.92 Concrete 20 20 Concrete dry 36 SW 0.95 Concrete rough 17 SW 0.97 Concrete walkway LLW 0.974 Copper commercial, burnished 20 0.07 Copper electrolytic, carefully polished 80 0.018 Copper electrolytic, polished –34 0.006 Copper molten 1100–1300 0.13–0.15 Copper oxidized 50 0.6–0.7 Copper oxidized, black 27 0.78 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 189 35 – Emissivity tables Copper oxidized, heavily 20 0.78 Copper oxidized to blackness 0.88 Copper polished 50–100 0.02 Copper polished 100 0.03 Copper polished, commercial 27 0.03 Copper polished, mechanical 22 0.015 Copper pure, carefully prepared surface 22 0.008 Copper scraped 27 0.07 Copper dioxide powder 0.84 Copper oxide red, powder 0.70 0.89 80 0.85 20 0.9 Ebonite Emery coarse Enamel Enamel lacquer 20 0.85–0.95 Fiber board hard, untreated 20 SW 0.85 Fiber board masonite 70 LW 0.88 Fiber board masonite 70 SW 0.75 Fiber board particle board 70 LW 0.89 Fiber board particle board 70 SW 0.77 Fiber board porous, untreated 20 SW 0.85 Gold polished 130 0.018 Gold polished, carefully 200–600 0.02–0.03 Gold polished, highly 100 0.02 Granite polished 20 LLW 0.849 Granite rough 21 LLW 0.879 Granite rough, 4 different samples 70 LW 0.77–0.87 190 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 35 – Emissivity tables Granite rough, 4 different samples 70 SW 0.95–0.97 20 0.8–0.9 Gypsum Ice: See Water Iron, cast casting 50 0.81 Iron, cast ingots 1000 0.95 Iron, cast liquid 1300 0.28 Iron, cast machined 800–1000 0.60–0.70 Iron, cast oxidized 38 0.63 Iron, cast oxidized 100 0.64 Iron, cast oxidized 260 0.66 Iron, cast oxidized 538 0.76 Iron, cast oxidized at 600°C 200–600 0.64–0.78 Iron, cast polished 38 0.21 Iron, cast polished 40 0.21 Iron, cast polished 200 0.21 Iron, cast unworked 900–1100 0.87–0.95 Iron and steel cold rolled 70 LW 0.09 Iron and steel cold rolled 70 SW 0.20 Iron and steel covered with red rust 20 0.61–0.85 Iron and steel electrolytic 22 0.05 Iron and steel electrolytic 100 0.05 Iron and steel electrolytic 260 0.07 Iron and steel electrolytic, carefully polished 175–225 0.05–0.06 Iron and steel freshly worked with emery 20 0.24 Iron and steel ground sheet 950–1100 0.55–0.61 Iron and steel heavily rusted sheet 20 0.69 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 191 35 – Emissivity tables Iron and steel hot rolled 20 0.77 Iron and steel hot rolled 130 0.60 Iron and steel oxidized 100 0.74 Iron and steel oxidized 100 0.74 Iron and steel oxidized 125–525 0.78–0.82 Iron and steel oxidized 200 0.79 Iron and steel oxidized 1227 0.89 Iron and steel oxidized 200–600 0.80 Iron and steel oxidized strongly 50 0.88 Iron and steel oxidized strongly 500 0.98 Iron and steel polished 100 0.07 Iron and steel polished 400–1000 0.14–0.38 Iron and steel polished sheet 750–1050 0.52–0.56 Iron and steel rolled, freshly 20 0.24 Iron and steel rolled sheet 50 0.56 Iron and steel rough, plane surface 50 0.95–0.98 Iron and steel rusted, heavily 17 SW 0.96 Iron and steel rusted red, sheet 22 0.69 Iron and steel rusty, red 20 0.69 Iron and steel shiny, etched 150 0.16 Iron and steel shiny oxide layer, sheet, 20 0.82 Iron and steel wrought, carefully polished 40–250 0.28 Iron galvanized heavily oxidized 70 LW 0.85 Iron galvanized heavily oxidized 70 SW 0.64 Iron galvanized sheet 92 0.07 Iron galvanized sheet, burnished 30 0.23 Iron galvanized sheet, oxidized 20 0.28 192 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 35 – Emissivity tables Iron tinned sheet 24 0.064 Krylon Ultra-flat black 1602 Flat black Room temperature up to 175 LW Ca. 0.96 12 Krylon Ultra-flat black 1602 Flat black Room temperature up to 175 MW Ca. 0.97 12 Lacquer 3 colors sprayed on Aluminum 70 LW 0.92–0.94 Lacquer 3 colors sprayed on Aluminum 70 SW 0.50–0.53 Lacquer Aluminum on rough surface 20 0.4 Lacquer bakelite 80 0.83 Lacquer black, dull 40–100 0.96–0.98 Lacquer black, matte 100 0.97 Lacquer black, shiny, sprayed on iron 20 0.87 Lacquer heat–resistant 100 0.92 Lacquer white 40–100 0.8–0.95 Lacquer white 100 0.92 Lead oxidized, gray 20 0.28 Lead oxidized, gray 22 0.28 Lead oxidized at 200°C 200 0.63 Lead shiny 250 0.08 Lead unoxidized, polished 100 0.05 Lead red 100 0.93 Lead red, powder 100 0.93 0.75–0.80 0.3–0.4 Leather tanned Lime Magnesium 22 0.07 Magnesium 260 0.13 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 193 35 – Emissivity tables Magnesium Magnesium polished 538 0.18 20 0.07 0.86 Magnesium powder Molybdenum 600–1000 0.08–0.13 Molybdenum 1500–2200 0.19–0.26 700–2500 0.1–0.3 17 SW 0.87 Molybdenum filament Mortar Mortar dry 36 SW 0.94 Nextel Velvet 81121 Black Flat black –60–150 LW > 0.97 10 and 11 Nichrome rolled 700 0.25 Nichrome sandblasted 700 0.70 Nichrome wire, clean 50 0.65 Nichrome wire, clean 500–1000 0.71–0.79 Nichrome wire, oxidized 50–500 0.95–0.98 Nickel bright matte 122 0.041 Nickel commercially pure, polished 100 0.045 Nickel commercially pure, polished 200–400 0.07–0.09 Nickel electrolytic 22 0.04 Nickel electrolytic 38 0.06 Nickel electrolytic 260 0.07 Nickel electrolytic 538 0.10 Nickel electroplated, polished 20 0.05 Nickel electroplated on iron, polished 22 0.045 Nickel electroplated on iron, unpolished 20 0.11–0.40 194 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 35 – Emissivity tables Nickel electroplated on iron, unpolished 22 0.11 Nickel oxidized 200 0.37 Nickel oxidized 227 0.37 Nickel oxidized 1227 0.85 Nickel oxidized at 600°C 200–600 0.37–0.48 Nickel polished 122 0.045 Nickel wire 200–1000 0.1–0.2 Nickel oxide 500–650 0.52–0.59 Nickel oxide 1000–1250 0.75–0.86 Oil, lubricating 0.025 mm film 20 0.27 Oil, lubricating 0.050 mm film 20 0.46 Oil, lubricating 0.125 mm film 20 0.72 Oil, lubricating film on Ni base: Ni base only 20 0.05 Oil, lubricating thick coating 20 0.82 Paint 8 different colors and qualities 70 LW 0.92–0.94 Paint 8 different colors and qualities 70 SW 0.88–0.96 Paint Aluminum, various ages 50–100 0.27–0.67 Paint cadmium yellow 0.28–0.33 Paint chrome green 0.65–0.70 Paint cobalt blue 0.7–0.8 Paint oil 17 SW 0.87 Paint oil, black flat 20 SW 0.94 Paint oil, black gloss 20 SW 0.92 Paint oil, gray flat 20 SW 0.97 Paint oil, gray gloss 20 SW 0.96 Paint oil, various colors 100 0.92–0.96 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 195 35 – Emissivity tables Paint oil based, average of 16 colors 100 0.94 Paint plastic, black 20 SW 0.95 Paint plastic, white 20 SW 0.84 Paper 4 different colors 70 LW 0.92–0.94 Paper 4 different colors 70 SW 0.68–0.74 Paper black 0.90 Paper black, dull 0.94 Paper black, dull 70 LW 0.89 Paper black, dull 70 SW 0.86 Paper blue, dark 0.84 Paper coated with black lacquer 0.93 Paper green 0.85 Paper red 0.76 Paper white 20 0.7–0.9 Paper white, 3 different glosses 70 LW 0.88–0.90 Paper white, 3 different glosses 70 SW 0.76–0.78 Paper white bond 20 0.93 Paper yellow 0.72 17 SW 0.86 Plaster Plaster plasterboard, untreated 20 SW 0.90 Plaster rough coat 20 0.91 Plastic glass fibre laminate (printed circ. board) 70 LW 0.91 Plastic glass fibre laminate (printed circ. board) 70 SW 0.94 196 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 35 – Emissivity tables Plastic polyurethane isolation board 70 LW 0.55 Plastic polyurethane isolation board 70 SW 0.29 Plastic PVC, plastic floor, dull, structured 70 LW 0.93 Plastic PVC, plastic floor, dull, structured 70 SW 0.94 Platinum 17 0.016 Platinum 22 0.03 Platinum 100 0.05 Platinum 260 0.06 Platinum 538 0.10 Platinum 1000–1500 0.14–0.18 Platinum 1094 0.18 Platinum pure, polished 200–600 0.05–0.10 Platinum ribbon 900–1100 0.12–0.17 Platinum wire 50–200 0.06–0.07 Platinum wire 500–1000 0.10–0.16 Platinum wire 1400 0.18 Porcelain glazed 20 0.92 Porcelain white, shiny 0.70–0.75 Rubber hard 20 0.95 Rubber soft, gray, rough 20 0.95 0.60 20 0.90 Sand Sand Sandstone polished 19 LLW 0.909 Sandstone rough 19 LLW 0.935 Silver polished 100 0.03 Silver pure, polished 200–600 0.02–0.03 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 197 35 – Emissivity tables Skin human 32 0.98 Slag boiler 0–100 0.97–0.93 Slag boiler 200–500 0.89–0.78 Slag boiler 600–1200 0.76–0.70 Slag boiler 1400–1800 0.69–0.67 Soil dry 20 0.92 Soil saturated with water 20 0.95 Stainless steel alloy, 8% Ni, 18% Cr 500 0.35 Stainless steel rolled 700 0.45 Stainless steel sandblasted 700 0.70 Stainless steel sheet, polished 70 LW 0.14 Stainless steel sheet, polished 70 SW 0.18 Stainless steel sheet, untreated, somewhat scratched 70 LW 0.28 Stainless steel sheet, untreated, somewhat scratched 70 SW 0.30 Stainless steel type 18-8, buffed 20 0.16 Stainless steel type 18-8, oxidized at 800°C 60 0.85 Stucco rough, lime 10–90 0.91 Styrofoam insulation 37 SW 0.60 0.79–0.84 Snow: See Water Tar Tar paper 20 0.91–0.93 Tile glazed 17 SW 0.94 Tin burnished 20–50 0.04–0.06 Tin tin–plated sheet iron 100 0.07 198 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 35 – Emissivity tables Titanium oxidized at 540°C 200 0.40 Titanium oxidized at 540°C 500 0.50 Titanium oxidized at 540°C 1000 0.60 Titanium polished 200 0.15 Titanium polished 500 0.20 Titanium polished 1000 0.36 Tungsten 200 0.05 Tungsten 600–1000 0.1–0.16 Tungsten 1500–2200 0.24–0.31 Tungsten filament 3300 0.39 Varnish flat 20 SW 0.93 Varnish on oak parquet floor 70 LW 0.90–0.93 Varnish on oak parquet floor 70 SW 0.90 Wallpaper slight pattern, light gray 20 SW 0.85 Wallpaper slight pattern, red 20 SW 0.90 Water distilled 20 0.96 Water frost crystals –10 0.98 Water ice, covered with heavy frost 0.98 Water ice, smooth –10 0.96 Water ice, smooth 0.97 Water layer >0.1 mm thick 0–100 0.95–0.98 Water snow 0.8 Water snow –10 0.85 Wood 17 SW 0.98 Wood 19 LLW 0.962 0.5–0.7 Wood ground Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 199 35 – Emissivity tables Wood pine, 4 different samples 70 LW 0.81–0.89 Wood pine, 4 different samples 70 SW 0.67–0.75 Wood planed 20 0.8–0.9 Wood planed oak 20 0.90 Wood planed oak 70 LW 0.88 Wood planed oak 70 SW 0.77 Wood plywood, smooth, dry 36 SW 0.82 Wood plywood, untreated 20 SW 0.83 Wood white, damp 20 0.7–0.8 Zinc oxidized at 400°C 400 0.11 Zinc oxidized surface 1000–1200 0.50–0.60 Zinc polished 200–300 0.04–0.05 Zinc sheet 50 0.20 200 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 A note on the technical production of this publication This publication was produced using XML—the eXtensible Markup Language. For more information about XML, please visit http://www.w3.org/XML/ A note on the typeface used in this publication This publication was typeset using Swiss 721, which is Bitstream’s pan-European version of the Helvetica™ typeface. Helvetica™ was designed by Max Miedinger (1910–1980). 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