Standard Specifications And Details For Construction 2012 404 Std Specs Dtls

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Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
_________________________________________________________________________________________________
_________________________________________________________________________________________________
December 2012
i
New in the Standard Specifications and Details for Construction 2012
The Pima County Regional Wastewater Reclamation Department’s Standard Specifications and Details for Construction 2012
is a major revision of the sanitary sewer-related material provided in the 2003 Edition of the City of Tucson and Pima County
Standard Specifications and Details for Public Improvements, and all subsequent updates (Engineering Directives) issued
prior to December 2012. Although the notable changes are mentioned below, the users of this document are strongly
encouraged to read through its entirety and get familiar with how it has been reorganized and formatted.
New Specifications and Details:
Subsection 1.4: General provisions for contractors, include licensing requirements and standards for as-built plans
Subsection 3.2.2(F): Fiberglass reinforced pipe (FRP)
Subsection 3.4.4: All manufactured products and trademark names intentionally removed from the specifications and
details and referenced to the Departments List of Approved Products
RWRD-100: Casing for sewer lines
RWRD-112: Sewer easements in environmentally sensitive areas
RWRD-113: Scour protection for sewer lines
RWRD-200: Precast manhole base
RWRD-202: Manhole flow channels
RWRD-210: Manhole steps configuration
RWRD-211: Concrete collar for paved areas
RWRD-229 & -230: Low drop and high drop manhole connections
RWRD-302: Raise existing bench for existing manholes
RWRD-403: Internal drop manhole for HCS connection
RWRD-404: Types of cleanouts for HCS
Specifications and Details with major updates:
Subsection 2: Standards and guidelines for wastewater flow management
Subsection 3.2.2(G): Removed PVC lining for RCP and refer to the Departments List of Approved Products
Subsection 3.2.3(B): Installation of various pipe materials now reference appropriate pipe installation publications
Subsection 3.3.3(B)(viii)(5): 3 year warranty for interior manhole coatings (previously 5 years)
RWRD-104: Rigid and flexible pipe trench details combined into a single detail
RWRD-108, RWRD-109, RWRD-110, RWRD-111, RWRD-201, RWRD-208, RWRD-209, RWRD-212, RWRD-225,
RWRD-228, RWRD-300, RWRD-301, RWRD-304, RWRD-305, RWRD-500, RWRD-501, RWRD-502, RWRD-503 and
RWRD-504: Miscellaneous drafting improvements and clarification
RWRD-203: Traditional “block-out” concept removed
RWRD-205 & -206: Flat-top manholes incorporated into both details (previously WWM-208 through -211)
RWRD-207: Varying diameters of shallow manholes provided (30”, 48” and 60”)
RWRD-300 & -301: Clarifies connections into precast risers and concrete bases
RWRD-402: Provides HCS connections to manholes in cul-de-sacs and knuckle intersections
Specifications and Details with minor updates:
Section 4: Standard details requiring special approval are identified as “special standard details” (S.S.D.)
RWRD-208, RWRD-209, RWRD-214, RWRD-215, RWRD-216, RWRD-217, RWRD-218, RWRD-223, RWRD-224,
RWRD-226, RWRD-228, RWRD-300, RWRD-306, RWRD-400, RWRD-500, RWRD-501, RWRD-502 and RWRD-503
RWRD-504: Re-numbered details (see bottom-left corner of detail for old WWM number)
Specifications and Details that have been deleted:
WWM-A-1 through WWM-A-5: Information has been updated and incorporated into the Design Standards 2012
WWM-106: General sewer notes will be provided in the Sewer Improvement Plan Checklist
WWM-202: Bases for manhole diameters greater than 60” in diameter are a structural submittal
WWM-204: New brick manhole construction
WWM-213.0: Manhole specifications (redundant with Subsection 3.3.2)
WWM-216 through -218: Manhole steps to be included in the Department’s List of Approved Products
WWM-224: Sewer marker posts
WWM-225: Concrete collar for dual manholes (second manhole deleted from RWRD-225)
WWM-509: Air injection panel
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
_________________________________________________________________________________________________
_________________________________________________________________________________________________
December 2012
ii
00 GENERAL CONTENTS
New in the Standard Specifications and Details for Construction 2012 ..................... i
General Contents ............................................................................................................ ii
Acronyms and Abbreviations ....................................................................................... iii
01 GENERAL PROVISIONS FOR PUBLIC SEWER
CONSTRUCTION
Table of Contents
1.1 Introduction
1.2 Definitions and Terms
1.3 Revisions to the Standard Specifications and Details
1.4 General Provisions
1.5 Work in Public Sewer Easements
02
WASTEWATER FLOW MANAGEMENT
Table of Contents
2.1 Introduction
2.2 Planning for Wastewater Flow Management
2.3 FMP Approval Process for Construction
2.4 Determining Wastewater Flow Rates for Existing Sewers
2.5 Design Flows for Flow Management Measures
2.6 Standards Measures for Wastewater Flow Management
2.7 Formatting Requirements for Flow Management Plans
2.8 Customer Notifications for Service Interruptions
03
STANDARD SPECIFICATIONS
Table of Contents
3.1 Earthwork
3.2 Sanitary Sewer Pipe
3.3 Sanitary Sewer Manholes
3.4 Other Sanitary Sewer Appurtenances
04
STANDARD DETAILS
Sheet Index
Standard Details
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
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December 2012
iii
Acronyms and Abbreviations
Wherever the following abbreviations are used in this document, they are construed to be the
same as the respective expressions represented;
Term Description
AAC Arizona Administrative Code
AASHTO American Association of State Highway and Transportation Officials
AC Alternating Current
ACH Air Changes Per Hour
ACI American Concrete Institute
ACP Asbestos Cement Pipe
ACPA American Concrete Pipe Association
ADEQ Arizona Department of Environmental Quality
ADOT Arizona Department of Transportation
ADWF Average Dry Weather Flow
ANSI American National Standards Institute
APP Aquifer Protection Permit
ARS Arizona Revised Statutes
ARV Air Relief Valve
ASTM American Society for Testing and Materials
AWWA American Water Works Association
AZPDES Arizona Pollutant Discharge Elimination System
BADCT Best Available Demonstrated Control Technology
BCS Building Connection Sewer
BMPs Best Management Practices
CA Construction Authorization per R18-9-E301 – 4.01 General Permit
CCFRPM Centrifugally Cast Fiberglass Reinforced Polymer Mortar
CCTV Closed Circuit Television
cfs Cubic Feet Per Second
CIP Capital Improvement Program
CIPP Cured in Place Pipe
CLSM Controlled Low Strength Material
CMP Corrugated Metal Pipe
Code Pima County, Arizona, Code of Ordinances, specifically Title 13 – Public Services,
Division II – Sewers
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
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December 2012
iv
COT City of Tucson
DA Discharge Authorization per R18-9-E301 – 4.01 General Permit
dB Decibels
Design
Standards The Pima County Regional Wastewater Reclamation Department’s Planning and
Engineering Design Standards 2012
dia Diameter
DIP Ductile Iron Pipe
DIPRA Ductile Iron Pipe Research Association
DR Dimension Ratio
DSD Development Services Department
ECC Engineer’s Certificate of Completion
EPA Environmental Protection Agency
EPDM Ethylene Propylene Diene Monomer (rubber)
FCR Final Compaction Report
FE Field Engineering
Fed Spec Federal Specifications
FEMA Federal Emergency Management Agency
FMP Flow Management Plan
ft Feet
GFCI Ground-Fault Circuit Interrupter
GIS Geographical Information System
gpad Gallons Per Acre per Day
gpd Gallons Per Day
gpm Gallons Per Minute
HAZMAT Hazardous Material
HCS House Connection Sewer
HDPE High Density Polyethylene
HMI Human Machine Interface
HOA Home Owners Association
Hz Hertz
IBC International Building Code
IMS Infrastructure Management System (Hansen Asset Management Program)
in Inch or Inches
IPC International Plumbing Code
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
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December 2012
v
I&I Infiltration and Inflow
LF Linear Foot
max Maximum
mgd Million Gallons Per Day
MH Manhole
min Minimum
mil 1/1,000 of an Inch
mV Millivolt
N/A Not Applicable
NASSCO National Association of Sewer Service Companies
NCPI National Clay Pipe Institute
NEC National Electric Code
NEMA National Electrical Manufacturers Association
NFPA National Fire Protection Association
NPSHA Net Positive Suction Head Available
NPSHR Net Positive Suction Head Required
O&M Operation and Maintenance
OEM Original Equipment Manufacturer
ORP Oxidation/Reduction Potential
OSHA Occupational Safety and Health Administration
PAG Pima Association of Governments
PAG
Standard
Specifications
The 2003 Edition of the City of Tucson and Pima County Standard Specifications
and Details for Public Improvements or latest revision
PCDSD Pima County Development Services Department
PCRWRD Pima County Regional Wastewater Reclamation Department
PDEQ Pima County Department of Environmental Quality
PDWF Peak Dry Weather Flow
P.E. Professional Engineer
PE/FBE Polyethylene (PE) Fusion Bonded Epoxy (FBE)
PF Peaking Factor
PMOC Point and Method of Connection
PPI Plastics Pipe Institute
psi Pounds Per Square Inch
PUE Public Utilities Easement
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
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December 2012
vi
PVC Polyvinyl Chloride
PVCPA The PVC Pipe Association
PWWF Peak Wet Weather Flow
RAP Recycled Asphalt Product
RCP Reinforced Concrete Pipe
rpm Revolutions Per Minute
RTU Remote Terminal Unit
SCADA Supervisory Control and Data Acquisition
SDR Standard Dimension Ratio
S.D. Standard Detail
S.S.D. Special Standard Detail
S.S. Stainless Steel
sf Square Foot
SPCS State Plane Coordinate System
SSO Sanitary Sewer Overflow
Standard
Specifications
and Details
The Pima County Regional Wastewater Reclamation Department’s Standard
Specifications and Details 2012
SWPPP Storm Water Pollution Prevention Plan
TDH Total Dynamic Head
UC Utility Coordination
UBC Uniform Building Code
v Velocity
VCP Vitrified Clay Pipe
WSS Welded Steel Sewer
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intentionally
left blank
Pima County
Regional Wastewater Reclamation Department
SECTION 1
GENERAL PROVISIONS FOR
PUBLIC SEWER CONSTRUCTION
Standard Specifications and Details for Construction
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-i General Provisions for
Public Sewer Construction
TABLE OF CONTENTS
SECTION PAGE
1.1Introduction .............................................................................................. 1
1.2Definitions and Terms.............................................................................. 1
1.2.1Interpretation of Terms .................................................................................... 6
1.2.2Titles and Headings ......................................................................................... 6
1.2.3Capitalization of Defined Terms ...................................................................... 6
1.3Revisions to the Standard Specifications and Details .......................... 6
1.4General Provisions .................................................................................. 7
1.4.1Permits and Fees ............................................................................................ 7
1.4.2License Requirements for Contractors ............................................................ 7
1.4.3Pre-Construction Meeting ................................................................................ 7
1.4.4Inspection of Work ........................................................................................... 8
1.4.5Field Changes ................................................................................................. 8
1.4.6Storage of Construction Materials near a Public Sewer Manhole ................... 8
1.4.7As-Built Plans .................................................................................................. 9
1.4.8Construction Acceptance .............................................................................. 10
1.5Work in Public Sewer Easements ......................................................... 11
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-1 General Provisions for
Public Sewer Construction
General Provisions for Public Sewer Construction
1.1 Introduction
It is the policy of the Department that all Public Sewers be constructed in
accordance with accepted construction standards. The purpose of the Standard
Specifications and Details is to establish the minimum acceptable standards by
which certain new Public Sewers, or modifications to existing Public Sewers, are
to be constructed in Pima County. Public Sewers and related appurtenances
shall be constructed in full accordance with the Standard Specifications and
Details unless otherwise Approved in the Sewer Plans or in writing by the
Sanitary Engineering Manager.
1.2 Definitions and Terms
Whenever the following terms are used in this document, the intent and meaning
shall be interpreted as described in this subsection. Where there is a conflict
between these definitions and those in the AAC and ARS, the AAC and ARS
definitions shall apply for persons seeking a Discharge Authorization under a
Type 4.01 General Permit.
100-Year Flood – A flood event that statistically has a 1 out of 100 (or one percent)
chance of being equaled or exceeded on a specific watercourse in any given year.
Accept or Acceptance – Written notice from the Director or his/her authorized
representative agreeing to the concept presented in the plans, studies or reports, and
required as part of a review process.
Affidavit of Cost – Documentation of final construction costs.
Agency – The jurisdictional body for whom the construction is being done, either by
Permit or Contract.
Aggregate – Inert material such as sand, gravel, broken stone, crushed stone, or a
combination thereof.
Applicant – The owner or a representative of the owner of the property or unit
requesting connection to the Public Sewer.
Approve or Approval – Written authorization from the Department for a submittal when
it has been determined that it meets a County standard.
As-Built Plans or As-Builts – An annotated copy of the Sewer Plans providing the
exact final location and layout of Public Sewer facilities, their positional verification and
records that include deviations to the design.
Section
1
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-2 General Provisions for
Public Sewer Construction
Augmentation – The construction of sanitary sewer facilities adjacent to or in
replacement of existing Public Sewer facilities for the purpose of increasing flow
capacity.
Backfill – The material used to fill a trench from the top of shading to subgrade or
finished grade.
Bedding – The material placed at the bottom of a trench and used to support the pipe
prior to the placement of Shading and Backfill.
Bill of Sale – A written instrument showing the voluntary transfer of a right, interest, or
title to personal property, either by way of security or absolutely, from one person to
another without the actual physical possession of the property leaving the owner or
being delivered to the other party.
Building Connection Sewer (BCS) – The private sanitary sewer line between the
commercial or industrial building and its connection to the Collection Sewer.
Calendar Day – Any day shown on the calendar, beginning at midnight, extending for a
24 hour period, and ending at midnight.
Cathodic Protection – A method for protecting metallic materials from damage caused
by corrosive soils.
Code – Pima County, Arizona, Code of Ordinances; more specifically, Title 13 – Public
Services, Division II – Sewers that includes ordinances governing wastewater
management.
Collector or Collection Sewer – A sanitary sewer line that receives Wastewater from
two or more Service Laterals.
Construction Acceptance – The Acceptance, by the Department, for the transfer of
newly constructed or modified sanitary sewer assets to the Department.
Construction Permit – Written authorization from the Department to allow construction,
modification or connection to Public Sewer facilities in accordance with the Sewer Plans.
Also see Observation Permit.
Contractor – The individual, partnership, firm, corporation, or any acceptable
combination thereof that is responsible for the construction of the Project in accordance
with the Sewer Plans and Construction Permit.
Cover – The vertical distance from the top of a buried pipe to finished grade.
Crown – In a transverse cross section of pipe, the highest point of elevation on the
interior surface.
d/D – Ratio of flow depth (d) to pipe diameter (D).
Day – Unless otherwise designated, day shall be understood to mean a Calendar Day.
Deficiency – Departure from, or noncompliance with, specified criteria.
Department – The Pima County Regional Wastewater Reclamation Department.
Design Drawings – The Sewer Plans prior to their Acceptance by the Department. Also
see Sewer Plans.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-3 General Provisions for
Public Sewer Construction
Design Engineer – The Professional Engineer sealing the Design Drawings for a
Project or design staff performing duties under his/her direct supervision.
Developer – One or more individuals or incorporated entities that desires to convert land
from its present use to another.
Development – Any man-made improvement (change) to real property including but not
limited to: buildings or structures, fencing, paving, grading, filling, excavation, trenching
dredging mining, drilling, or storage of equipment or materials.
Director – The Director of the Department or his/her designated representative.
Engineering Directive – The process used by the Department to clarify and improve
the design and construction standards and details for Public Sewer facilities.
Excavation – Any man-made cut, cavity, trench, or depression in the earth’s surface
formed by earth removal.
Field Engineer – The Sanitary Engineering Manager’s authorized representative
assigned to make detailed inspections for the construction or modification of Public
Sewer facilities.
Flow Through –That part of a Public Sewer intended for receiving existing or future
Wastewater originating from outside a development or municipality and not from inside a
development or municipality.
Force Main – A pressurized sanitary sewer discharge line extending from a Pump
Station having a horizontal length greater than 10-feet.
Full Flow – A ratio of 1.0 d/D, where d is the hydraulic grade line of Wastewater flow in
the pipe and D is the inside diameter of the pipe.
Geotechnical Engineer – An Arizona-Registered Professional Engineer (Civil)
responsible for Project soils characterization and construction backfill compaction quality
control testing and certifications.
Grey Water – Residential wastewater collected separately that originates from clothes
washers, bathtubs, showers and sinks. Grey water excludes wastewater from kitchen
sinks, dishwashers and toilets.
Haunch – That portion of a pipe barrel extending from the bottom to the springline.
Holiday – (1) A legal holiday pursuant to A.R.S. 1-301, as amended. (2) Microscopic
holes in liners and coatings detected by a Holiday Test.
Holiday Test – Electrical testing used to determine the presence and number of
discontinuities in a coating film performed on a nonconductive coating applied to an
electrically conductive surface in accordance with ASTM D5162 standards.
House Connection Sewer (HCS) – The private sanitary sewer line between the
residence or building connection and its connection to the Collection Sewer.
Inspector – See Field Engineer.
Interceptor Sewer – A sanitary sewer line that receives Wastewater from a number of
collector and trunk sewers.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-4 General Provisions for
Public Sewer Construction
Invert – In a transverse cross section of pipe, the lowest point of elevation on the interior
surface.
Jetting – A soil compaction technique that forces pressurized water into the bedding or
backfill material in order to saturate it and force the air out. Also referred to as flooding.
Lift Station – A sanitary sewer facility that pumps Wastewater to a higher elevation
without the need for a Force Main. Also see Pump Station.
Observation Permit – Written authorization from the Department to allow access into
Public Sewer manholes. Also see Construction Permit.
Over-sizing – The increase in capacity of sanitary sewer facilities to provide capacity for
future flow from within or beyond the proposed design boundaries of a Project.
PAG Standard Specifications – The 2003 Edition of the City of Tucson and Pima
County Standard Specifications for Public Improvements or latest revision.
Permit – See Construction Permit and Observation Permit.
Pressure Sewer – See Force Main.
Project – The specific, coordinated design, construction or similar undertaking identified
by a single Project number.
Public Sewer – The sanitary sewer assets of Pima County, specifically for the
conveyance of Wastewater.
Pump Station – A sanitary sewer facility that pumps Wastewater to a higher elevation
and requires the use of a Force Main. Also see Lift Station.
Reach – A single gravity sewer line connecting into a manhole at both ends.
Record Drawings – See As-Built Plans.
Residual Capacity – The difference between the predicted PDWF from the
development constructing the sanitary sewer line and the theoretical flow in the sanitary
sewer line at 0.75 d/D (where d is the depth of flow and D is the inside diameter of the
pipe) based on the Manning Equation using an “n” value of 0.013 at any given point in
the Sanitary Sewer.
Right-of-Way – A general term, denoting a strip of land, property or interest therein,
acquired for or devoted to transportation and other public works purposes.
Sanitary Sewage – See Wastewater.
Scour – A computed value for the potential depth that material, from the bed and banks
of a Wash, will be removed due to the flow of water during a 100-year flood event.
Service Lateral – The private sanitary sewer line between a residential, commercial, or
industrial building and its connection to the Collection Sewer. Also see House
Connection Sewer and Building Connection Sewer.
Sewer Basin – All portions of the sanitary sewer collection system tributary to an
interceptor sewer or pump station. Generally, the sewers within a Sewer Basin are
hydraulically linked.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-5 General Provisions for
Public Sewer Construction
Sewer Plans – The Project’s official construction documents, or reproductions thereof,
Accepted by the Department, that show the location, character, dimensions and details
for the extension, augmentation or modification of Public Sewers. Also see Design
Drawings.
Shading – The material that extends from the top of the Bedding to one foot (typically)
above the top of pipe.
Siphon – A sanitary sewer conveyance facility used to convey Wastewater underneath
an obstruction, such as a Wash or drainage culvert, without pumping.
Special Approval – Written authorization from the Department to proceed with the
design of a specific concept for Public Sewers that is typically not Accepted by the
Department.
Special Provisions – Additions and revisions to the Standard Specifications and
Details, specifically Section 3, covering conditions and requirements peculiar to on
individual Project.
Springline – In a transverse cross section of pipe, the line of maximum horizontal
dimension.
Storm Drain – A conduit or system of conduits that convey stormwater runoff, street
drainage, and other wash waters or drainage but excludes Wastewater.
Stub-Out – An upstream length of pipe installed at a sanitary sewer manhole that is
intended for future connection.
Trench – A narrow excavation for the installation of sanitary sewer facilities or other
utilities.
Trunk Sewer – A sanitary sewer line that receives Wastewater from many Collector
Sewers.
Variance – A waiver, issued in writing by the Department, granting a one-time deviation
from a specific design or construction standard for unique circumstances where full
compliance is not realistically feasible.
Wash – A dry creek bed or gulch that temporarily fills with water after a heavy rain; an
arroyo or an alluvial watercourse.
Wastewater – The wastes from toilets, baths, sinks, lavatories, laundries, drains, and
other plumbing fixtures in residences, mobile homes, institutions, public and business
buildings, industrial wastewaters and other places of human habitation, employment, or
recreation.
Work – All labor, materials, equipment, and other incidentals necessary or convenient to
the successful completion of Public Sewer construction and the carrying out of all the
duties and obligations required by the Sewer Plans.
Working Day – Any Day, other than Saturday, Sunday or a Holiday, on which legal
business can be conducted by Pima County.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-6 General Provisions for
Public Sewer Construction
1.2.1 Interpretation of Terms
When not inconsistent with the context, words used in the present tense include
the future, words in the singular number include the plural, and words in the
plural number include the singular.
1.2.2 Titles and Headings
The titles or headings of sections and subsections are intended for convenience
of reference and shall not be considered as having any bearing on their
interpretation.
1.2.3 Capitalization of Defined Terms
Defined terms within this document that are intended to be capitalized. The
Director reserves the right to interpret words or phrases listed in Subsection 1.2 -
Definitions and Terms, where the context warrants.
1.3 Revisions to the Standard Specifications and Details
The Sanitary Engineering Manager will be responsible for monitoring revisions to
the Standard Specifications and Details to ensure that the standards:
Are consistent with current and accepted engineering practices;
Do not impose extraordinary burdens for typical development and
improvement projects; and
Do not conflict with Code, AAC or the public’s interest.
When a specific standard requires immediate attention for clarification or
improvement, the Sanitary Engineering Manager will make a request to the
Standards Committee for review and Approval of an Engineering Directive. An
Engineering Directive is a separate document that describes new standards, or
modifications, until such revisions can be incorporated in the Standard
Specifications and Details. Any errors to the current standards should be brought
to the attention of the Sanitary Engineering Manager, in writing.
The Department will keep users of the Standard Specifications and Details
informed of future updates through its website. Hard copy (printed) revisions will
not be distributed. It is the holder’s responsibility to keep the document current by
periodically checking the Department’s website for updates.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-7 General Provisions for
Public Sewer Construction
1.4 General Provisions
1.4.1 Permits and Fees
A Construction Permit shall be obtained from the Department at least 72 hours
prior to accessing the Public Sewer or commencing work for any Project that
proposes:
New Public Sewers;
Modifications to existing Public Sewers;
New service connections to Public Sewers; or
Modifications to existing maintenance access to Public Sewer manholes.
Pursuant to Code, specifically 13.20.045, all applicable permit and connection
fees shall be paid prior to issuance of the Construction Permit. A Construction
Permit cannot be issued until the Sewer Plans are Accepted by the Department.
1.4.2 License Requirements for Contractors
The Contractor responsible for the construction of, modification or connection to
Public Sewers, shall be an Arizona Registered Contractor with an A, A-12, AE or
K-80 type license, as applicable per the Arizona Registrar of Contractors. The
Contractor shall be responsible for performing all required actions that will allow
completion of Public Sewer construction.
1.4.3 Pre-Construction Meeting
The Contractor shall schedule a pre-construction meeting with the Field Engineer
after the Construction Permit is obtained and the FMP Approved (see Subsection
2.3). The construction of Public Sewers shall not commence until a written notice
to proceed is issued by Field Engineering. Any Public Sewer construction done
prior to the notice to proceed shall be removed at the sole expense of the
Contractor.
The purpose of the preconstruction meeting is for the Contractor and the Field
Engineer to review any special inspections requirements and items peculiar to
Public Sewer construction. It is also intended to get personnel together to
become familiar with the Project and each other. Prior to this meeting the
Contractor, Field Engineer and all other key personnel should study the Sewer
Plans and become familiar with the Project site to be well informed as to the
requirements and existing conditions.
At a minimum, the Contractor shall furnish the following documentation to the
Field Engineer at the pre-construction meeting:
Survey cut sheets per Subsection 3.2.3(A)(i);
Certification documents and batch numbers for DIP interior linings per
Subsection 3.2.2(D);
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-8 General Provisions for
Public Sewer Construction
Certification documents for all materials testing (e.g. sieve analysis) per
Subsection 3.1.2; and
Shop drawings for manufactured assemblies, if applicable.
1.4.4 Inspection of Work
All Work done to or within an existing Public Sewer manhole, in order to install a
new connection, shall be inspected and Approved by the Field Engineer prior to
approval of private sewer construction by the Agency having jurisdiction over the
building and plumbing codes.
If a new Public Sewer manhole is constructed on the existing Public Sewer line in
order to install a private connection, the new manhole shall be inspected and
Approved by the Field Engineer prior to approval of private sewer construction by
the Agency having jurisdiction over the building and plumbing codes.
1.4.5 Field Changes
The Contractor shall notify the Field Engineer of any field change prior to
proceeding with construction. The Field Engineer will determine whether the field
change is de minimus or reportable. For a de minimus field change, sewer
construction may continue and the field change shall be annotated on the As-
Built Plans per Subsection 1.4.5. For a reportable field change, construction shall
not proceed on the affected areas or upstream of the affected areas until the
Sewer Plans are revised and Accepted by the Department.
1.4.6 Storage of Construction Materials near a Public Sewer Manhole
Construction materials shall not be stored within 10 feet of any existing Public
Sewer manhole. The contractor must contact the Department’s Conveyance
Division at least 48 hours in advance to request permission to temporarily block
or restrict access to an existing Public Sewer manhole. The Contractor shall
indicate the nature of the planned activity and length of time that access will be
blocked or restricted.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-9 General Provisions for
Public Sewer Construction
1.4.7 As-Built Plans
Pursuant to AAC R18-5-508 and Code, specifically 13.20.030(E), the As-Built
Plans for the construction of new Public Sewers or for the repair, replacement or
rehabilitation of existing Public Sewers, shall be submitted to ADEQ and the
Department for review and Approval, prior to Construction Acceptance (see
Subsection 1.4.8). Emergency repairs are exempt from the prior Approval
requirement but not from the requirement to submit As-built Plans.
The Contractor shall be responsible for retaining an Arizona Registered Land
Surveyor to provide the exact final location and layout of Public Sewers, and
preparing the sewer As-Built Plans in accordance with the following
requirements:
As-Built Plans shall be certified by an Arizona Registered Land Surveyor or
an Arizona Registered P.E. (Civil). The following certification shall appear
on each sheet of the As-Built Plans: a seal per AAC R4-30-304, the label
“AS-BUILT” and the contact information of the certifier’s employer. The
cover sheet shall also include the following certification statement: “I
HEREBY CERTIFY THAT THE AS-BUILT ANNOTATIONS PROVIDED ON
THIS DRAWING WERE BASED ON AN AS-BUILT SURVEY CONDUCTED
UNDER MY SUPERVISION AND ACCURATELY DEPICTS EXISTING
FIELD CONDITIONS TO THE BEST OF MY KNOWLEDGE AND BELIEF”.
The party responsible for annotating the As-Built Plans shall obtain from the
Design Engineer, either a full-size copy or an electronic copy of the original
and complete Sewer Plans, with all seals, acceptance signatures and design
revisions. The quality of the hard copy shall be equivalent to the original
Sewer Plans. The quality of the electronic copy shall have a minimum
resolution of 200 x 200 dpi.
The As-Built Plan submittal shall include a complete and full-size set of the
Sewer Plans. If a complete set of plans includes sheets that are not related
to Public Sewer construction, the Field Engineer may allow these sheets to
be excluded from the As-Built Plans.
The As-Built Plan submittal shall be of a quality that ensures clear
reproduction through electronic scanning and microfilming. The quality of
these copies shall conform in appearance, scale, resolution and accuracy to
the original Sewer Plans. All design information and annotations shown on
the As-Built Plans shall be clear and legible.
For deviated design values, As-Built annotations shall add a strikethrough of
the design value with the measured value shown next to it. For non-deviated
design values, As-Built annotations shall add the letters “AB” next to the
design value to indicate that it was verified with the As-Built survey and is
accurate.
As-Built annotations shall verify or update the horizontal control data for
each new manhole, at the center of its base (e.g. station and offset). This
may also be accomplished by providing a separate tabular report with the
manhole number, and the ‘X’ and ‘Y’ coordinates based on SPCS (NAD83).
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-10 General Provisions for
Public Sewer Construction
As-Built annotations shall verify or update all pipe invert elevations and the
rim elevations for new or modified manholes. Elevation data shall be
consistent with the vertical datum used in the Sewer Plans.
As-Built annotations shall verify the nominal diameter, slope, length and pipe
material for each reach of new sewer line. The As-Built slopes for each
reach shall be calculated based on the horizontal reach length between the
interior walls of each manhole and the invert of the sewer line at these
locations.
As-Built annotations shall verify or update the layout of new service laterals
(HCS/BCS) in plan view. In addition, the As-Built Plans shall provide a
separate tabular report with the lot number, ‘X’ and ‘Y’ coordinates of the
private cleanout riser based on SPCS (NAD83), the distance from the
HCS/BCS at the sewer line connection to the nearest downstream manhole,
and the station of the HCS/BCS sewer line connection.
Pursuant to Arizona Blue Stake law (ARS 40-360.21 to 40-360.32) the
Department is responsible for locating service laterals (HCS/BCS) installed
after December 31, 2005. Where service laterals are damaged due to
inaccurate As-Built annotations, the registrant and the firm certifying the As-
Built Plans may be held accountable for the cost of repair.
The use of non-transparent blocks, masking, or the pasting of information
onto the Sewer Plans that would cover any language, design data or line
work shown on the original Sewer Plans is not allowed. If additional room is
required for annotations, an additional sheet shall be added to the As-Built
Plans.
The As-Built Plans shall include any construction variances or design
revisions that occurred during the progress of construction.
For new force mains, annotations shall additionally verify or update the
horizontal alignment of the force main and the location of any bends.
Three full-size copies of the As-Built Plans shall be submitted to the Field
Engineer, within 30-days of the completion of all sewer construction. The
submittal will be reviewed for conformance. Incomplete or non-conforming
submittals will be returned for revisions. The As-Built Plans must be Approved by
the Department prior to completion and processing of the ECC.
1.4.8 Construction Acceptance
Upon written notice from the Contractor of completion of the Work, the Field
Engineer will conduct a final inspection. If all construction is complete and in
accordance with the Sewer Plans and the Standard Specifications and Details,
the Field Engineer will process the Engineer’s Certificate of Completion (ECC)
per AAC R18-9-E301(E).
If, however, the final inspection discloses any Work, in whole or in part, as being
unsatisfactory or not complete, the Field Engineer will notify the Contractor and
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-11 General Provisions for
Public Sewer Construction
he shall immediately correct such deficiencies. Upon completion and correction
of the Work, another final inspection will be required to verify the Work has been
satisfactorily completed.
The Contractor shall provide the following documentation to the Field Engineer
before the ECC is processed by the Department:
As-Built Plans conforming to the requirements of Subsection 1.4.7;
Materials testing documentation per Subsection 3.1.2 and 3.3.2;
Pipe installation testing documentation per Subsection 3.2.3(D);
Manhole installation testing documentation per 3.3.3(C);
Backfill density testing documentation per Subsection 3.1.3(F); and
If applicable, a Memorandum of Understanding per for Type III buried
cleanouts per 3.2.3(C).
The Applicant shall provide the following documentation to the Permitting group
of the Department before the Discharge Authorization (DA) request is processed:
A Notarized Bill of Sale;
An Affidavit of Cost for Public Sewers; and
A check made payable to “ADEQ” for review fees.
The Department will issue a letter of acceptance and release of assurances to
the Applicant upon receipt of the DA from ADEQ, as required to obtain a
certificate of occupancy.
1.5 Work in Public Sewer Easements
The Department has the right to install anywhere within a Public Sewer
easement temporary or permanent underground or above ground facilities that
may be required to monitor, operate, maintain, repair or replace Public Sewers,
or under emergency conditions, pump or otherwise convey wastewater.
The Department assumes no liability for damage to or removal of any vegetation,
above ground or below ground facilities, surface treatments, materials,
equipment or structures placed within a Public Sewer easement or within 20 feet
above its surface by anyone other than the Department.
The property owner shall be liable for injury to personnel and/or damage to
maintenance vehicles or construction equipment that result from contact with any
prohibited encroachments anywhere within the full width of the Public Sewer
easement or within 20 feet above its surface, or from any actions necessary to
remove such encroachments from the easement. Liability for injury or damage
includes personnel and equipment of the Department.
The Department will endeavor to provide advance notice to the property owner of
the need to utilize/access Public Sewer easements and/or Public Sewers.
However, the Department has no obligation to provide such advance notice and
shall not provide notice under emergency conditions.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 1
December 2012 1-12 General Provisions for
Public Sewer Construction
Temporary storage of vehicles, equipment, or materials by the property owner is
not allowed within the Public Sewer easement without the prior written
permission of the Department.
Pima County
Regional Wastewater Reclamation Department
SECTION 2
WASTEWATER FLOW
MANAGEMENT
Standard Specifications and Details for Construction
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-i Wastewater Flow Management
TABLE OF CONTENTS
SECTION PAGE
2.1Introduction .............................................................................................. 1
2.2Planning for Wastewater Flow Management ......................................... 1
2.2.1Conditions that Require an FMP ..................................................................... 1
2.2.2Preparing the Flow Management Plan ............................................................ 2
2.2.3Flow Management Data .................................................................................. 2
2.2.4Formats of the Flow Management Plan .......................................................... 2
2.3FMP Approval Process for Construction ............................................... 3
2.4Determining Wastewater Flow Rates for Existing Sewers ................... 4
2.4.1Flow Metering Method ..................................................................................... 4
2.4.2Assumed Depth Method .................................................................................. 5
2.4.3ADEQ Design Method ..................................................................................... 6
2.5Design Flows for Flow Management Measures ..................................... 6
2.6Standard Measures for Wastewater Flow Management ........................ 7
2.6.1Phasing ........................................................................................................... 7
2.6.2Pumping Systems ........................................................................................... 7
2.6.3Manholes for Pumping or Gravity Bypass ....................................................... 9
2.6.4Plugs ............................................................................................................. 10
2.6.5Gravity Bypass Measures ............................................................................. 10
2.6.6Odor Control .................................................................................................. 10
2.6.7Daily Inspection Logs .................................................................................... 11
2.6.8Direct Connections to Existing Sewer Lines .................................................. 11
2.6.9New Manholes on Existing Sewer Lines ....................................................... 12
2.6.10New Sewer Line Connections to Existing Terminal Manholes ...................... 13
2.6.11New Lateral Sewer Line Connections to Existing Manholes ......................... 13
2.6.12Sewer Line Repairs and Pipe Section Replacements ................................... 14
2.6.13Manhole Adjustments .................................................................................... 14
2.7Formatting Requirements for Flow Management Plans ..................... 14
2.7.1Simple Format FMP ...................................................................................... 14
2.7.2Detailed Format FMP .................................................................................... 16
2.7.3Wastewater Flow Data .................................................................................. 17
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-ii Wastewater Flow Management
2.7.4Map of Flow Management Measures ............................................................ 18
2.7.5Sanitary Sewer Overflow Spill Prevention Plan ............................................. 18
2.8Customer Notifications for Service Interruptions ............................... 19
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-1 Wastewater Flow Management
Wastewater Flow Management
2.1 Introduction
When a modification or connection is proposed to a live Public Sewer line, the
Contractor shall:
Develop a written Flow Management Plan (FMP) and submit to the Field
Engineering section for Approval prior to construction;
Furnish, operate and maintain all equipment necessary to provide
continuous sewer service to customers tributary;
Manage wastewater flows in a planned and proactive manner to prevent
any sanitary sewer overflow (SSO); and
Conform to all applicable environmental and regulatory requirements.
These are the primary goals that shall be reflected in an FMP and closely
adhered to by the Contractor.
2.2 Planning for Wastewater Flow Management
2.2.1 Conditions that Require an FMP
An FMP shall be required for any proposed construction that encroaches into the
impact zone of existing Public Sewers (see Figure 2-1). Proposed construction
includes, but is not limited to, any type of connection to, or modification of, a
Public Sewer line or manhole, as well as any proposed excavation with the
potential to undermine, or cause the collapse of, any such asset.
Figure 2-1: Impact Zone for Existing Sewer Lines
Section
2
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-2 Wastewater Flow Management
2.2.2 Preparing the Flow Management Plan
For Projects that require wastewater flow management measures, an FMP shall
be prepared by the Design Engineer during the design stage of a Project. The
FMP is a “living” document and may be updated by the Contractor for site-
specific conditions during construction. The FMP may be shown either as part of
the Sewer Plans or as a separate and stand-alone document.
2.2.3 Flow Management Data
At a minimum, the FMP shall include the following data:
A note that the Contractor shall adhere to the Department’s flow
management standards, more specifically Section 2 of the Standard
Specifications and Details;
Wastewater flow rates, either:
o Metered with the time and date at each existing manhole; or
o Estimated, showing the method of calculation (e.g. ½ flow, full flow,
etc.) and the results;
The nearest upstream and downstream manholes including the following
information:
o Manhole diameters and materials;
o Pipe diameters, materials and inverts; and
A description of the available flow management options and constraints.
2.2.4 Formats of the Flow Management Plan
The criteria for determining the format of the FMP as well as the content shall
depend on the diameter of existing Public Sewer lines to be impacted.
A. Small Lines
For proposed construction impacting existing Public Sewers having pipe sizes
equal to or less than 12 inches in diameter (i.e. small lines), the Sewer Plans
may also serve as the FMP if flow management data per Subsection 2.2.3 is
incorporated into the Sewer Plans. A separate and stand-alone FMP may be
provided; however, it is not required.
B. Large Lines
For proposed construction impacting existing Public Sewers having pipe sizes
greater than 12 inches in diameter (i.e. large lines), a separate and stand-alone
FMP shall be prepared. Under this format, the FMP shall be sealed by an
Arizona Registered P.E. and include the following information:
Flow management data, per Subsection 2.2.3;
A plan view of the proposed flow management bypass layout;
Pump calculations for total dynamic head, flow rates and head losses;
Sizing of bypass pumping units and setup;
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-3 Wastewater Flow Management
Temporary wet wells, if necessary;
Discharge piping materials, lengths and diameters;
A list of necessary standby equipment and any equipment checks required
before placing into bypass service;
A list of required equipment submittals (e.g. pump specifications, etc.);
If a gravity bypass system is proposed, sheets showing a plan and profile
of the system, along with supporting hydraulic calculations; and
Any additional information necessary for the Contractor to quickly
implement the recommended bypass activities.
If low-flow conditions exist, the FMP format for existing small lines per
Subsection 2.2.4(A) may be permitted with Approval by the Field Engineering
manager.
2.3 FMP Approval Process for Construction
The Contractor shall ultimately be responsible for providing an Approved FMP
that is appropriate to Project-specific conditions. The Contractor has the option to
either resubmit the FMP originally developed by the Design Engineer or develop
a new FMP. If the Contractor elects to use the original FMP, the Contractor shall
field-verify all field conditions and flow rates before it is submitted for Approval to
the Field Engineering section.
The pre-construction meeting shall not be scheduled until the FMP is Approved
by the Field Engineering section. It is recommended that the Contractor submit
the FMP at least 4 weeks prior to the anticipated pre-construction meeting date.
The Field Engineering section will complete the FMP review within 10 business
days, in order to accommodate a second review if needed.
The Contractor shall submit one original and two copies of the FMP to:
Field Engineering Manager
PCRWRD Field Engineering Section
1313 S. Mission Rd.
Tucson, AZ 85713-1398
With prior Approval from the Field Engineering manager, the FMP may be
submitted electronically as a color portable document file (PDF). A cover letter
shall also be included with any submittal and signed by the Contractor.
The Contractor shall, at his expense, obtain all permits necessary for the
installation and operation of flow management measures. The Contractor shall
also notify the assigned Field Engineer at least 72 hours in advance of
commencing either Public Sewer construction or flow management measures.
Where indicated in the Sewer Plans, the Contractor may also be required to
provide at least 72 hours advance notice to the designated community relations
representative of the Department.
Any questions or concerns regarding the development of the FMP should be
directed to the Field Engineering manager. The Field Engineering manager
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-4 Wastewater Flow Management
reserves the right to allow or modify the requirements specified on a case-by-
case basis.
In cases where there are no wastewater flows in an existing sewer, the
Contractor may request, in writing, a waiver of the FMP requirements. In most
cases, the Field Engineering manager will verify the absence of flows before
granting this waiver.
2.4 Determining Wastewater Flow Rates for Existing Sewers
The Department recognizes specific methods for determining the actual
wastewater flow rates in existing sewers for flow management. The Field
Engineering manager may allow the modification of a selected method for
determining the actual wastewater flow rates or may consider alternatives for
unique field conditions. Such conditions may include existing sewer lines with
reaches having significant slope variations or unique channel configurations
within existing manholes.
2.4.1 Flow Metering Method
The most accurate method for determining wastewater flow rates is flow
metering. This method may require the cleaning and flushing of existing sewers
prior to the installation of metering equipment. Metering equipment will typically
remain installed in the existing manhole for a period of 1 to 2 weeks prior to
removal. Flow metering data shall expire 18 months from the date it was
obtained. After 18 months, the data must be re-verified prior to commencing flow
management measures. The flow results obtained by the flow metering method
shall be represented as peak dry weather flow and used as the basis for flow
management planning.
The effectiveness of this method is limited to ideal field conditions, as described
in the following:
Manholes and pipes should be silt-free;
Flow depths should range between 2.5 inches and 0.60 [d/D], at all times;
Flow velocities should range between 2 fps and 6 fps, at all times;
Force main discharge should not be immediately upstream;
Nearest adjacent manhole should be at least 60 pipe diameters away;
Flow channel should be straight and without lateral connections; and
Flow channel should conform in shape to the bottom half of the pipe.
If a recorded precipitation event occurs during the metering period, which results
in increased flows from inflow and infiltration (I/I), the Field Engineering manager
may allow the increase in flow rates to be ignored. This decision shall only be
made after consultation with the Flow Metering group.
The Flow Metering group of the Department may provide flow metering services
after a Temporary Flow Metering Request form is submitted. For a copy of the
current form, contact the Department’s Flow Metering group or check the
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-5 Wastewater Flow Management
Department’s website. This submittal should occur at least 9 weeks prior to the
date that flow data is needed (4 weeks for scheduling, 3 weeks for data collection
and 2 weeks for data analysis). Flow metering requests will be reviewed and
scheduled on a first-come, first-served basis.
When the proposed sewer construction involves an existing small Public Sewer
line (pipe sizes of 12 inches in diameter or less), the flow metering request shall
include the following:
Temporary Flow Metering Request Form (for a blank copy of this form,
contact the Field Engineering section or check the engineering forms page
on the Department’s website);
A plan depicting the current sewer basin area and all contributing sewer
lines to the point of proposed bypass (MapGuide map is acceptable);
Construction schedule (additional pump capacity may be required for rainy
months); and
A review of the potential for flow surges caused by industrial dischargers
(e.g. pool draining, laundromat operations, etc.)
When proposed sewer construction involves an existing large Public Sewer line
(pipe sizes greater than 12 inches in diameter), the flow metering request shall
include the following:
The design requirements for an existing small line (described in
Subsection 2.2.2);
Review and condition assessment of the impacted manholes;
A list of all seasonal flow contributors identified within the sewer basin (i.e.
schools, RV parks, etc.); and
A preliminary version of the flow management design being developed.
The Flow Metering group will review these requests and notify the applicant, as
soon as possible, if the flow metering request cannot be met. When existing field
conditions are not ideal for reasonable flow metering or the task cannot be
performed by the Department for other reasons, the Flow Metering group will
recommend other methods for estimating current wastewater flow rates.
If the Flow Metering group cannot provide services within a reasonable amount
of time or within the frame that was requested, the following methods for
estimating wastewater flows may be used for flow management planning, when
authorized by the Field Engineering manager:
At their own expense, the property owner or the Developer may hire an
Approved third-party flow metering service; or
The Assumed Depth Method per Subsection 2.4.2.
2.4.2 Assumed Depth Method
Where metering does not yield reliable results or cannot be performed, flows may
be estimated based on an assumed depth calculation method. This method is
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-6 Wastewater Flow Management
subject to approval after the Field Engineering section has verified such depth
conditions during the flow management review process. For low depths of flow
(less than 2.5 inches), the existing pipe shall be assumed to be flowing half-full.
For high depths of flow (0.60D < d < 1.0D), the existing pipe shall be assumed to
be flowing full. The Manning’s formula shall be used to estimate wastewater
flows. The flow results obtained by the Assumed Depth Method shall be
represented as peak dry weather flow and used as the basis for flow
management planning.
2.4.3 ADEQ Design Method
Where accurate flow data is not needed, existing wastewater flow rates may be
estimated in accordance with the method required for sewer design by ADEQ for
calculating peak dry weather flows. These method is more specifically described
in AAC R18-9-E301(D) – Type 4 General Permits and R18-9-Table 1 - Unit
Design Flows. This method may be more practical for flow management planning
purposes in the early stages of a project and may be superseded later by a more
precise method, such as flow metering, if elected by the Contractor.
2.5 Design Flows for Flow Management Measures
The Contractor shall be responsible for providing wastewater flow management
measures that are capable of conveying the existing wastewater flows in all
conditions, including wet weather. All peak dry weather flows shall be multiplied
by a factor of 1.5 to obtain the design flow for flow management measures, such
as pumping or gravity bypass systems. A factor of 1.5 shall be used to
accommodate most variations in flow and wet weather conditions, unless
otherwise specified by the Field Engineering Manager.
Example 2.1 – Calculate Bypass Pumping Flow Rate:
The Flow Metering group provides the PDWF for an incoming sewer line at
manhole number MH-5462 as 1.17 mgd. Determine the required design flow to
properly specify the pumps to be used in bypass pumping measures.
Solution:
  1.5
Where:

PumpingDesignFlow
   1.17 1.5 1.755
  1.755
1,440/ 1.75510/
1,440/   1,218.75
Rounduptothenearest5gpm;therefore:
1,220gpm
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-7 Wastewater Flow Management
2.6 Standard Measures for Wastewater Flow Management
The following are standard measures intended for typical small Public Sewer line
construction and may not be applicable in all cases, as actual site conditions may
vary. For large Public Sewer line construction, the Field Engineering manager
should be contacted early in the flow management planning stage to identify
project-specific requirements.
The bypass method, either pumping or gravity, will consider project-specific
conditions and the Contractor’s level of expertise. Bypass pumping is more
appropriate for short durations of construction or restricted areas; whereas
gravity bypass measures is more appropriate for long durations of construction,
for large sewer lines, or for open, undeveloped areas. The Contractor shall be
responsible for determining the most appropriate method for Approval by the
Field Engineering section.
2.6.1 Phasing
For some projects, it is more cost-effective to phase flow management measures
simultaneously with regulatory approvals. The Contractor shall be responsible for
proposing any such phasing in the FMP. The FMP shall clearly identify the
phasing of flow management measures, the wastewater flows associated with
each phase, the details for flow management measures, and any special
construction.
2.6.2 Pumping Systems
Flow management pumping measures may require a pump truck or a stationary
bypass pumping system. The type of pumping measure will depend on the flow
rate in the existing sewer line, the duration of Public Sewer construction and site-
specific conditions. With Approval of the Field Engineering section, the
Contractor can determine the best type of pumping measure to be used on a
project-specific basis.
A. Pump Trucks
The use of a pump truck for flow management measures is most suitable for low
flow rates and short durations of construction.
B. Stationary Bypass Pumping Systems
The use of stationary bypass pumping systems for flow management measures
are more suitable for high flow rates, long durations of construction and
inaccessible site conditions for a pump truck.
Fuel storage shall be provided for stationary pumping measures, sufficient for 24
hours of operation. Stationary pumping units shall be quiet during operation. If
necessary, the Contractor shall provide noise suppressing systems, such as
sound boards, barriers or mufflers. The Contractor shall also adhere to any noise
abatement requirements of the local jurisdictional agency.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-8 Wastewater Flow Management
For standby stationary pumping measures, pumping equipment shall be tested
with clean water and located in a nearby staging area.
When stationary bypass pumping measures are used, the Contractor shall be
responsible for providing spare pumps in case maintenance or repair is
necessary. The required number of spare pumps shall be determined by
multiplying the total number of pumps required for the design flow by a factor of
0.50 and rounding up to the nearest integer.
Example 2.2 – Calculate the Required Number of Spare Pumps:
The Contractor specifies 3 pumps, each at 410 gpm, for a PDWF flow of 1,220
gpm, obtained from flow metering results. Determine total number of pumps
required for stationary bypass pumping measures.
Solution:
 #  0.5
  3 0.5  1.5
1.5  2
#  3 2  
Suction piping shall be steel-reinforced pipe or other Approved material.
Separate suction pipes shall be used for each pump; manifolds shall not be
permitted. Spacing between suction pipes shall be sufficient to prevent
interference and swirling. Each suction pipe shall be installed without provisions
for debris control (e.g. screens). If debris is a problem, the Contractor shall
consult with the Field Engineering manager for appropriate countermeasures.
Two pumping discharge lines shall be required for redundancy. Discharge lines
shall be butt-fused HDPE (SDR 11), with a minimum nominal inside diameter of 3
inches. Structural calculations may be required for some installations as
determined by the Field Engineering manager. Where air relief valves are
required, a redundant valve shall be installed. Vertical bends shall be installed at
the discharge manhole as needed to direct flows into the outgoing sewer line
without splashing and excessive scour affects. Where applicable, the Contractor
shall install measures for protecting the discharge lines from vandalism.
Where discharge lines will cross paved roads, the Contractor shall provide
measures as needed for protecting the lines from vehicular damage, and for the
safe and efficient flow of traffic. Approved measures for road crossings include
the use of pre-fabricated pipe ramps or cutting pavement and burying the line
with an approved minimum cover. Such crossings shall be capable of handling
H-20 truck loadings and shall not be susceptible to damage by vehicles with low
height clearances (e.g. fire trucks).
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-9 Wastewater Flow Management
The Contractor shall maintain daily inspection logs per Subsection 2.6.7 for
recording pump/motor operational data and the condition of discharge lines at
maximum time intervals of ½ hour throughout the duration of pumping.
2.6.3 Manholes for Pumping or Gravity Bypass
New manholes for pumping or gravity bypass measures shall be sized to provide
for the expeditious installation and removal of plugs with the use of isolation
gates per S.D. RWRD-228 or as Approved by the Field Engineering manager.
Isolation gates shall be oriented in such a way not to interfere with any such flow
management measures.
Where the surcharging of wastewater is required above the bench of an existing
manhole that will be used for pumping, the interior walls of the manhole shall be
sealed with an Approved coating product prior to pumping. This coating shall be
applied to the manhole walls, from the bench to at least 1 foot above the required
surcharging elevation. In no case shall the surcharging of wastewater rise above
the required surcharging elevation. If the Department determines that an existing
manhole requires rehabilitation or reconstruction, it shall be considered incidental
to the Project and the responsibility of the Contractor.
A level-monitoring system that is capable of notifying the Contractor by pager or
cell phone during high-water levels shall be installed at the suction and the
discharge manholes. The level-monitoring system shall be tested prior to actual
startup of bypass flow measures.
Once field conditions have been verified, the Contractor shall submit a written
procedure and schematic for any planned cuts into the tops of pipes and for the
safe removal of, and preservation of, coupons. Pipe coupons shall be cut at an
angle to prevent it from falling into the existing pipe. In the case that a coupon is
damaged, is destroyed, or is otherwise unable to be replaced intact onto the cut
pipe, the Contractor shall have a plan in place to fabricate a coupon of similar
material, or material Approved by the Department, that can be attached to the cut
pipe in a manner acceptable to the Department.
At the conclusion of pumping or gravity bypass measures, pipe coupons shall be
reinstalled using a high-strength, moisture-insensitive, structural epoxy paste
adhesive. All temporary piping shall be removed and flow channels filled with
concrete or grout to form a smooth surface. For temporary manholes, the coupon
area of the pipe and bench shall be capped with concrete the manhole
abandoned per Subsection 3.3.3(E). The precise location of abandoned
temporary manholes shall be annotated on the As-Built Plans and abandonment
monuments installed per S.D. RWRD-503.
The Contractor shall maintain daily inspection logs for recording depth of water in
pumping or diversion manholes at maximum time intervals of ½ hour per
Subsection 2.6.7.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-10 Wastewater Flow Management
2.6.4 Plugs
The installation of plugs shall only occur during low-flow conditions. Sewer plugs
for flow management measures shall be approved pneumatic pipe plugs with
permanent tags to identify the Contractor. Plugs shall be installed in the sewer
line and secured to an affixed object with a chain or steel cable. As a secondary
safety measure for sewer lines that extend to daylight, a second plug shall also
be installed in the opposite end of the same sewer line. The installation of plugs
shall conform to the manufacturer and OSHA requirements.
Prior to installing a pneumatic plug, the Contractor shall inspect the host pipe for
imperfections that could cause damage to the plug or the pipe during inflation.
The results of this inspection may require an alternate installation location for the
plug. The Contractor shall ensure that the pneumatic plug is properly positioned
in the pipe and closely monitor the air pressure gage during inflation. The
Contractor shall also verify that air lines are not compromised by tension, friction
or other conditions that could cause damage or failure. The Contractor shall
install plugs and isolation gates only during low-flow conditions. The Contractor
shall maintain daily inspection logs per Subsection 2.6.7 for recording the air
pressure of pneumatic pipe plugs at maximum time intervals of ½ hour.
Where an isolation gate is located immediately downstream of an installed plug,
it may be used for supporting the plug in place.
After the plug is removed, the Contractor shall remove all debris within the
manhole flow channels and bench.
2.6.5 Gravity Bypass Measures
Temporary gravity bypass measures shall be designed for flows per Subsection
2.5. These measures shall use pipes that are equivalent in size and slope to the
existing system, unless otherwise approved by the Field Engineering manager.
The FMP submittal (See Subsection 2.2.4(B)) for gravity bypass measures shall
also include a hydraulic analysis proving that the proposed gravity bypass
system will be adequate for conveying the design flows. Materials for gravity
bypass pipes shall be adequate for Public Sewer applications and Approved by
the Field Engineering manager. The use of corrugated metal pipe or other storm
drain piping materials is not permitted.
Prior to excavation, the Contractor shall be responsible for accurately locating all
existing utilities. For gravity bypass measures utilizing pipe sizes that are greater
than 12 inches in diameter, the Contractor should locate these utilities by method
of potholing.
2.6.6 Odor Control
The Contractor shall provide measures for minimizing odors and preventing their
migration to populated areas. Approved odor control measures may include lids,
shroud covers or chemical agents. In cases where odors are excessive, the
Department may require that an Approved odor control unit be installed onsite.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-11 Wastewater Flow Management
2.6.7 Daily Inspection Logs
The Contractor shall ensure that all bypass measures are working correctly and
not leaking with regular frequent inspections. The Contractor shall have on-site
and qualified personnel monitoring flow management measures at all times
during bypass operations (24 hours per day, 7 days per week). High level alarm
notifications to pagers or cell phones shall not eliminate this requirement.
The Contractor shall also maintain daily inspection logs, for specific flow
management measures. For typical inspection log forms, contact the Field
Engineering section. The Contractor shall keep all flow management inspection
logs at the site and shall have them available for review by the Department at all
times. At the conclusion of the project, a copy of all inspection logs shall be
provided to Field Engineering section prior to Construction Acceptance.
2.6.8 Direct Connections to Existing Sewer Lines
When a new service lateral (HCS/ BCS) will be connected directly to an existing
Public Sewer line, the best management practice for flow management will
depend on the depth of flow in the pipe during the time of the connection. The
connection may occur during at low flow periods or when the depth of flow is less
than half the pipe. However, when the depth of flow is equal to or greater than
half the pipe diameter, standby pumping measures or other considerations will be
required.
Figure 2-2: Direct Connection to Existing Sewer Lines
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-12 Wastewater Flow Management
2.6.9 New Manholes on Existing Sewer Lines
When a new manhole will be constructed on an existing Public Sewer line, the
best management practice for flow management will depend on the depth of flow
in the pipe during the time of the connection.
Figure 2-3: New Manhole on an Existing Sewer Line
A. Low and Moderate Depths of Flow
When the depth of flow in an existing pipe is moderate (2.5 inches to 0.60 [d/D]),
two best management practices will be available, depending on the material of
the existing pipe. When the existing pipe is a flexible material, such as PVC or
DIP, the construction of a poured base per RWRD 303 may be permitted without
standby pumping measures and with the existing pipe fully intact. However, when
the existing pipe is a rigid material, such as VCP or ACP, the upstream pipe(s)
shall be plugged at the nearest upstream manhole(s) and monitored with standby
pumping measures.
The Field Engineering manager may waive the need for standby pumping
measures if the depth of flow is low (less than 2.5 inches) and the Contractor has
demonstrated substantial experience with the construction of manholes in
accordance with S.D. RWRD-303.
B. High Depths of Flow
When the depth of flow in an existing pipe is high (greater than 0.60 [d/D]), the
best management practices will be limited to standby pumping at the nearest
upstream manhole(s).
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-13 Wastewater Flow Management
2.6.10 New Sewer Line Connections to Existing Terminal Manholes
When a new sewer line will be connected to an existing terminal manhole, the
downstream sewer line shall be plugged to prevent construction debris from
being flushed downstream and also to protect the work area from an
unanticipated backwater surcharge. After all work within the manhole is
completed and all debris removed, the plug shall be moved to the new line.
Figure 2-4: New Sewer Line Connection to Existing Manhole
2.6.11 New Lateral Sewer Line Connections to Existing Manholes
When a new lateral sewer line will be connected to an existing manhole, as
shown in Figure 2-5, the flow in the existing manhole governs the flow
management options. Connections to an existing manhole are made either by
using a block-out or by coring the manhole barrel above the base.
Figure 2-5: New Lateral Sewer Line Connection to Existing Manhole
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-14 Wastewater Flow Management
A. Low Depths of Flow
When the depth of flow in the existing sewer line is low (less than 2.5 inches), a
flow-through plug may be installed inside the upstream line and the upstream
manhole(s) shall be monitored.
B. Moderate and Low Depths of Flow
When the depth of flow in the existing sewer line is moderate (2.5 inches to 60%
depth of flow), a flow-through plug may be installed during the connection and
during construction. A second available option is to install a plug inside the
upstream existing sewer line with pumping at the upstream manhole(s). The
pumping measures may be reduced to monitoring with a standby pumping setup
for low depths of flow (less than 2.5 inches).
C. High Depths of Flow
When the depth of flow in the existing sewer line is high (greater than 60% depth
of flow), flow management options are limited to pump bypass measures at the
upstream manhole(s).
2.6.12 Sewer Line Repairs and Pipe Section Replacements
With the exception of a dry sewer line, any sewer line repair or the replacement
of an existing pipe section (e.g. DIP replacements) shall require a plug to be
installed in the upstream sewer line at the upstream manhole for pumping
measures. A plug shall also be installed in the downstream pipe at the
downstream manhole to protect the existing sewer system from receiving
construction debris.
2.6.13 Manhole Adjustments
The Contractor shall install a flow channel cover per S.D. RWRD-306 on the
bench of a manhole that will have its rim adjusted or any other type of
construction having the potential for debris or equipment to fall into the manhole.
The Contractor shall comply with any request by the Field Engineering section to
install a flow channel cover.
2.7 Formatting Requirements for Flow Management Plans
2.7.1 Simple Format FMP
For relatively simple construction activities involving an existing small line, the
FMP may be presented in a simple letter-format consisting of a cover letter with
attached documents. The cover letter should meet the following requirements:
A. Use the letterhead of the Contractor responsible for wastewater flow
management (add contact information if not included in letterhead);
B. Identify the project name, plan number (e.g. G#, etc.), project owner,
location and brief description of sewer-related construction;
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-15 Wastewater Flow Management
C. Identify the Department’s unique manhole identification number for
manholes impacted by, or located immediately upstream and downstream
of, sewer-related construction;
D. Include a detailed description of the proposed measures for wastewater
flow management and phasing, if applicable;
E. Identify the estimated flows in the existing sewer line, the method of how
these flows were estimated, and the dates and times of metering or
observation;
F. Identify the calculated design flows that the proposed measures were
based on;
G. Specify the type of disinfectant and required volume for incidental releases;
H. Provide a schedule for sewer-related construction activities (e.g. dates and
times for start, completion, normal working hours and variations for sewer-
related construction);
I. Include the following standard note to the Contractor: “Machine excavation
shall not be conducted within 2 feet of the top of sewer. Excavation within 2
feet of the top of sewer shall be conducted by hand digging only. Any
manhole frame and cover adjustments shall be conducted only after a flow
channel cover per Detail No. RWRD 306 has been properly installed to
protect existing Public Sewers from receiving construction debris.”;
J. Include the name, signature, title and contact information of the person
responsible for implementing the FMP; and
K. Include a contractor’s certification statement such as: “We have read,
understand and will adhere to Section 2 of the Pima County RWRD
Standard Specifications and Details for Construction 2012 for the
preparation of Flow Management Plans”.
For a boiler-plate example of this cover letter, contact the Field Engineering
section. Where applicable, the simple-letter format FMP should also meet the
following requirements:
L. Include a map per Subsection 2.7.4;
M. Include spare pump calculations per Subsection 2.6.2;
N. Include photos of existing manholes that are impacted by flow management
activities. Photos shall be taken looking down into the manhole, clearly
showing the flow channels and with the north pointing to the top. For each
photo, provide the date, time and the Department’s unique manhole
identification number;
O. Provide flow metering documents and calculations showing how existing
flows and design flows were obtained;
P. Include a customer notification plan in accordance with Subsection 2.8;
Q. Include cut sheets for flow management equipment;
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-16 Wastewater Flow Management
R. Include a list of emergency contact numbers for Contractor’s staff
responsible for maintaining wastewater flow management (i.e. project
owner, superintendent, etc.); and
S. Include a list of emergency contact numbers for Department staff (for
verification and to be returned to Contractor).
2.7.2 Detailed Format FMP
For larger sewer construction activities that will involve existing large lines, the
FMP shall be presented in a plan format and shall meet the following
requirements:
A. Submit plans on sheets, 24” x 36” in size;
B. Provide a simple-format FMP cover letter per Subsection 2.7.1;
C. If phasing is proposed, provide a complete and detailed description of the
flow management procedures and their order of phasing;
D. Specify the required procedures for sealing and testing the proposed
pumping or gravity bypass system to prevent leakage;
E. If either pumping or gravity bypass measures are proposed, use a
minimum scale of 1” = 40’ (plan) and 1” = 4’ (profile) on all sheets;
F. If pumping bypass measures are proposed, include detailed information for
bypass piping (e.g. stationing, offsets, elevations, size, material, suction
and discharge points, air relief valves, discharge manifold, etc.);
G. If gravity bypass measures are proposed, include all existing utilities in the
vicinity of excavation on all plan sheets;
H. Include a Map of Flow Management Measures per Subsection 2.7.4;
I. Provide a separate detail for temporary pumping and diversion manholes;
detail should emphasize the piping cutout location and dimensions,
isolation gates and spacing between suction lines;
The specifications for a FMP shall meet the following requirements:
J. Provide in an 8.5” x 11” bound format;
K. Include all required attachments for a simple format FMP, with the
exception of the map requirements per Subsection 2.7.4;
L. If isolation gates will be used, include structural calculations sealed by an
Arizona Registered P.E.;
M. If pumping measures will be used, include calculations for the minimum
required sump depth in the manhole and sealed by an Arizona Registered
P.E.;
N. Include pump performance curves with system curve and duty points
shown;
O. Show that NPSHA substantially exceeds the NPSHR to avoid cavitation;
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-17 Wastewater Flow Management
P. If gravity bypass measures will be used, include a hydraulic analysis for
these measures and sealed by an Arizona Registered P.E.;
Q. If pumping or gravity bypass measures will be used, include a capacity
analysis, sealed by an Arizona Registered P.E., of the existing sewer lines
that will receive additional flows and include the maximum flow depths that
will occur in existing sewer lines, manhole flow channels and service
laterals (HCS/BCS);
R. If odor control measures will be used, include a detailed description of this
requirement and specifications;
S. Include a list of equipment and identify the primary and backup equipment
that will be kept onsite;
T. Include an equipment maintenance and inspection plan with sample
inspection logs for the required daily inspections of installed flow
management facilities;
U. Provide provisions to ensure pneumatic pipe plugs will be closely
monitored;
V. Include a description of the security measures for personnel and equipment
during flow management measures and outside standard work hours, as
applicable;
W. Include a description of the proposed measures for keeping local residents
and businesses informed of service interruptions and the status of
construction. For certain projects, the Contractor may be required to
coordinate with the Departments public relations group, for customer
notifications;
X. Include a Sanitary Sewer Overflow Spill Prevention Plan per Subsection
2.7.5.
2.7.3 Wastewater Flow Data
The FMP shall provide the following information in either a table or at each
manhole:
A. For metered flows, show the peak dry weather flows, dates of metering,
and note any wet weather conditions, if applicable;
B. For instantaneous flow observations, show the estimated peak dry weather
flow with the assumed pipe depth (e.g. half-flow or full-flow) and note any
wet weather conditions, if applicable; and
C. Show the available flow capacity of the downstream sewer lines that will
convey bypass flows during sewer construction.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-18 Wastewater Flow Management
2.7.4 Map of Flow Management Measures
The FMP shall include a map that clearly depicts of the area of sewer-related
construction, along with the proposed layout for flow management measures.
This map shall clearly and legibly show the following information:
A. Existing Public Sewers in the vicinity of flow management activities;
B. The type of plugs required and the locations they are to be installed; and
C. Street address and location of service laterals (HCS/BCS) that will be
affected by construction.
In some cases, a copy of the Pima County MapGuide with clear and legible
hand-written annotations may be acceptable.
2.7.5 Sanitary Sewer Overflow Spill Prevention Plan
The Contractor shall be responsible for insuring there will be no unauthorized
discharges or spills of raw sewage during construction. For construction that will
impact large sewer lines, the Contractor shall also prepare a Spill Prevention
Plan in the event of a flow management failure and a sanitary sewer overflow
(SSO). The SSO Spill Prevention Plan shall be included with the submittal of the
FMP for review and approval by the Department.
The Contractor shall install containment measures for incidental spills at pumps,
valves and manifolds. These measures may be accomplished by constructing
earthen berms along the perimeter of the equipment’s staging area and lining
that area with a single sheet of polyethylene plastic sheeting or other approved
material. Berms shall be a minimum height of 6-inches and the sheeting material
shall have a minimum thickness of 35 mils. The use of a portable spill
containment setup may also be permitted when Approved by the Field
Engineering manager.
The Contractor shall store 12.5% sodium hypochlorite solution (NaOCl) near
each pumping setup for the disinfection and cleanup of incidental spills. For
sewer lines 12 inches in diameter or less, the minimum required volume of
NaOCl shall be 6 gallons. For sewer lines greater than 12 inches in diameter, the
minimum volume shall be 50 gallons. Storage containers for this solution shall be
sealed securely at all times to prevent off-gassing. Unsealed containers shall be
replaced immediately with fresh solution. These measures are not intended for
an SSO.
In the event of an SSO, the Contractor shall immediately notify the Field
Engineer and Department’s Conveyance Division. For weekends, Holidays or
between 5:00 pm and 8:00 am, the Contractor shall immediately call the Pima
County Sheriff’s Communication Center and request a Department
representative to be dispatched to the site.
The Contractor shall take immediate action to prevent or contain an SSO. The
Contractor shall be responsible for all costs to repair the system, for all expenses
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-19 Wastewater Flow Management
to mitigate the release and to disinfect the release areas, and for any regulatory
penalties levied on the Department.
The Contractor shall repair all damage to the satisfaction of the Director or
his/her delegate. In cases where the Contractor is not in compliance with
mitigation efforts, any assistance provided by the Department will be billed to the
Contractor. The Contractor shall compensate the Department for the cost of any
fines levied as the result of an SSO.
2.8 Customer Notifications for Service Interruptions
The FMP shall also include a customer notification plan that shall address, at a
minimum, all of the following requirements:
Identify all customers that may experience service interruptions or any
other disturbances during construction and describe why these cannot be
avoided;
Describe how customer notifications for service interruptions or
disturbances will be carried out by the Contractor;
Describe the mitigation methods proposed by the Contractor for service
interruptions or disturbances; and
Include specific time frames for service interruptions or disturbances.
The customer notification plan shall be reviewed and approved by the
Department’s public relations group, prior to construction.
The Contractor shall be responsible for locating all service laterals (HCS/BCS)
that will be affected by construction and shall identify any services with the
potential for high flow rates or other non-typical flow characteristics. The
Contractor should contact the Department’s Maps and Records section to obtain
all available records regarding the location of existing service laterals. If location
records are not available, the Contractor shall locate existing service laterals
through such methods as CCTV, dye testing or locating private cleanouts.
The Contractor shall make every possible effort to notify, in person, all sewer
customers that will be affected by proposed construction and shall promptly
respond to any questions or concerns. The Contractor shall make arrangements
for at least 1 neighborhood meeting a minimum of 10 Calendar Days prior to
construction to address sewer-related issues. The Contractor's superintendent
and at least 1 staff member from the Field Engineering section shall attend these
meetings. The neighborhood meetings shall be a dialogue between the
Contractor, the Department and the public to cover the following items, at a
minimum:
Describe the parameters of the Project and how proposed construction will
affect service to sewer customers;
Identify any special requirements or specific needs from the public;
Exchange contact information for any questions or concerns; and
Provide an opportunity for questions and answers.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 2
December 2012 2-20 Wastewater Flow Management
At least 72 hours in advance, the Contractor shall also distribute door hanger
pamphlets to all sewer customers to be affected by proposed construction. Each
pamphlet shall be typed in both English and Spanish and shall describe the
scope of the work, methods of construction and the dates and times that any
interruptions in service may occur.
The Contractor shall also re-confirm with all customers at least 24 hours prior to
the scheduled interruption in their service. The 24 hour notification shall require
the Contractor to attempt to contact each customer verbally (i.e. by phone call or
in-person) and also distribute an "Official Notification" that has been approved by
the Department’s public relations group. The Contractor shall maintain a
customer notifications log to track the notification attempts for each customer.
This log shall include the customer names, dates and times of each attempt, and
the type of notification (e.g. verbal or door hanger pamphlet). A copy of the
customer notification log shall be submitted to the Field Engineering section prior
to the interruption in service.
For customers with interrupted sewer service, the Contractor shall provide
portable sanitary facilities during the entire period of interruption. The required
number of portable sanitary facilities shall not be less than one portable facility
per two residences and one portable facility per each business. The Contractor
shall be responsible for cleaning and maintaining these facilities. The Contractor
shall accommodate any special requirements or specific needs for these
customers (e.g. ADA compliance). If the period of any service interruption
exceeds 24 hours, the Contractor shall provide temporary bypass pumping
systems for these services.
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Pima County
Regional Wastewater Reclamation Department
SECTION 3
STANDARD SPECIFICATIONS
Standard Specifications and Details for Construction
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-i Standard Specifications
TABLE OF CONTENTS
SECTION PAGE
STANDARD SPECIFICATIONS ....................................................................................... 1
3.1Earthwork .................................................................................................. 1
3.1.1Description ...................................................................................................... 1
3.1.2Materials .......................................................................................................... 1
A.Crushed Stone ............................................................................................................. 1
B.Sand............................................................................................................................. 1
C.Excavated Native Material ........................................................................................... 2
D.Select Import Material .................................................................................................. 2
E.Controlled Low-Strength Material (CLSM) ................................................................... 2
F.Recycled Asphalt Product (RAP) and Lime ................................................................. 3
3.1.3Construction Details ........................................................................................ 3
A.Trenches and Embankments ....................................................................................... 3
B.Foundations ................................................................................................................. 3
C.Bedding ........................................................................................................................ 4
D.Haunching and Shading .............................................................................................. 4
E.Backfill ......................................................................................................................... 5
F.Backfill Density Testing Procedures ............................................................................ 5
G.Stabilized Surface Treatment for Public Sewer Easements ........................................ 8
3.2Sanitary Sewer Pipe ................................................................................. 8
3.2.1Description ...................................................................................................... 8
3.2.2Materials .......................................................................................................... 8
A.General ........................................................................................................................ 8
B.Vitrified Clay Pipe (VCP) ............................................................................................. 8
C.Polyvinyl Chloride (PVC) Pipe ..................................................................................... 8
D.Ductile Iron Pipe (DIP) ................................................................................................. 9
E.High-Density Polyethylene (HDPE) Pipe ................................................................... 10
F.Fiberglass Reinforced Pipe (FRP) ............................................................................. 11
G.Reinforced Concrete Pipe (RCP) .............................................................................. 13
3.2.3Construction Details ...................................................................................... 15
A.Survey Requirements ................................................................................................ 15
B.Installation of Pipe ..................................................................................................... 16
C.Service Lateral (HCS/BCS) Connections .................................................................. 22
D.Sewer Line Testing and Tolerances .......................................................................... 23
E.Markers and Monuments ........................................................................................... 31
F.Casing and Carrier Pipe ............................................................................................ 32
G.Modifications and Repairs ......................................................................................... 32
H.Abandonment of Pipe ................................................................................................ 32
3.3Sanitary Sewer Manholes ...................................................................... 33
3.3.1Description .................................................................................................... 33
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-ii Standard Specifications
3.3.2Materials ........................................................................................................ 33
A.Concrete .................................................................................................................... 33
B.Reinforcing Steel ....................................................................................................... 33
C.Grout and Mortar ....................................................................................................... 33
D.Water ......................................................................................................................... 33
E.Precast Concrete Manhole Sections ......................................................................... 33
F.Interior Corrosion Protection ...................................................................................... 34
G.Steps .......................................................................................................................... 34
H.Frames, Covers and Hatches .................................................................................... 34
I.Flexible Joint Gaskets ................................................................................................ 35
3.3.3Construction Details ...................................................................................... 35
A.Excavation and Backfill .............................................................................................. 35
B.Installation of Manholes ............................................................................................. 36
C.Manhole Installation Testing and Tolerances ............................................................ 41
D.Modification of Existing Manholes ............................................................................. 41
E.Abandonment of Manholes ........................................................................................ 44
3.4Other Sanitary Sewer Appurtenances .................................................. 44
3.4.1Piles ............................................................................................................... 44
3.4.2Casing Pipe ................................................................................................... 44
3.4.3List of Approved Products for Public Sewers ................................................ 45
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-1 Standard Specifications
Standard Specifications
3.1 Earthwork
3.1.1 Description
Any Work under the Standard Specifications and Details shall consist of
performing all operations necessary to excavate all materials, regardless of
character and subsurface conditions; to excavate trenches for Public Sewers; to
excavate all materials necessary for the construction of Public Sewer manholes
and other structures; to place backfill for Public Sewer lines; to backfill holes, pits
and other depressions; to remove and replace unsuitable material; and
compaction requirements. These operations shall be performed in accordance
with the lines, grades and typical sections designated in the Sewer Plans and the
Standard Specifications and Details unless otherwise approved by the Field
Engineer.
3.1.2 Materials
A. Crushed Stone
Crushed stone shall conform to the requirements of Table 1 in S.D. RWRD-104.
This material shall consist of durable particles of crushed stone free of silt, clay,
or other unsuitable material, and have a percentage of wear of not more than
40% when tested in accordance with ASTM C131 or C535. When material is
subjected to five cycles of the sodium sulfate soundness test in accordance with
ASTM C88 - Sodium Sulfate Solution, the weighted percentage of loss shall not
exceed 12%. Additional tests for pH and minimum resistivity, in accordance with
Arizona Test Method 236b, shall be required for sewer lines where ductile iron
pipe and/or ductile iron fittings are used. The value of resistivity shall not be less
than that for the existing in-place material or 2,000 ohm-cm, whichever is smaller.
Prior to the start of construction, documentation for materials testing shall be
certified for conformance and submitted to the Field Engineer. When this material
is obtained from excavation or a source selected by the Contractor, it must be
Approved by the Field Engineer and require documentation for materials testing
by a third party Geotechnical Engineer.
B. Sand
Sand shall conform to the requirements of Table 1 in S.D. RWRD-104. Additional
tests for pH and minimum resistivity, in accordance with Arizona Test Method
236b, shall be required for sewer lines where ductile iron pipe and/or ductile iron
fittings are used. The value of resistivity shall not be less than that for the existing
in-place material or 2,000 ohm-cm, whichever is smaller.
Section
3
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-2 Standard Specifications
Prior to the start of construction, documentation for materials testing shall be
certified for conformance and submitted to the Field Engineer. When this material
is obtained from excavation or a source selected by the Contractor, it must be
Approved by the Field Engineer and require documentation for materials testing
by a third party Geotechnical Engineer.
C. Excavated Native Material
Excavated native material used for backfill shall conform to the requirements of
Table 1 in S.D. RWRD-104. This material shall not contain organic material,
rubbish, debris or deleterious material. It shall not contain rocks, frozen earth or
solid material larger than 6 inches in greatest dimension. Excavated material
shall be well-graded and capable of meeting the compaction requirements of
Subsection 3.1.3(F). Additional tests for pH and minimum resistivity, in
accordance with Arizona Test Method 236b, shall be required for sewer lines
where ductile iron pipe and/or ductile iron fittings are used in conjunction with the
rigid pipe trench detail, per S.D. RWRD-104. The value of resistivity shall not be
less than that for the existing in-place material or 2,000 ohm-cm, whichever is
smaller.
Excavated material from an offsite source selected by the Contractor must be
Approved by the Field Engineer and require documentation for materials testing
certification by a third party Geotechnical Engineer.
D. Select Import Material
Select import material shall conform to the requirements of Table 1 in S.D.
RWRD-104. This material shall not contain frozen lumps, rocks larger than 3
inches in diameter, chunks of clay or other objectionable material. Additional
tests for pH and minimum resistivity, in accordance with Arizona Test Method
236b, shall be required for sewer lines where ductile iron pipe and/or ductile iron
fittings are used in conjunction with the rigid pipe trench detail per S.D. RWRD-
104. The value of resistivity shall not be less than that for the existing in-place
material or 2,000 ohm-cm, whichever is smaller.
Prior to the start of construction, documentation for materials testing shall be
certified for conformance and submitted to the Field Engineer. When this material
is obtained from excavation or a source selected by the Contractor, it must be
Approved by the Field Engineer and require documentation for materials testing
by a third party Geotechnical Engineer.
E. Controlled Low-Strength Material (CLSM)
Materials comprised of CLSM shall conform to the requirements of Section 1006
of the PAG Standard Specifications. CLSM mix designs shall conform to Section
501-2.03 Table 501-1 of the PAG Standard Specifications, unless otherwise
indicated in the Sewer Plans, or as directed by the Field Engineer.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-3 Standard Specifications
F. Recycled Asphalt Product (RAP) and Lime
The use of recycled asphalt product or lime for trench materials and other sewer
construction is prohibited.
3.1.3 Construction Details
A. Trenches and Embankments
The Contractor shall comply with all OSHA regulations pertaining to trenching
operations. When used, trench boxes shall be positioned so that the compaction
of trench material is not compromised when the box is advanced with work in
progress. The inside walls of the box should be at least two pipe diameters clear
on each side of the sewer pipe.
In regards to the completion of backfill operations prior to the end of the
Contractor’s work day, the maximum length of open trench for all installations
shall be either 500 feet, or the Contractor's daily installation length, whichever is
greater.
Trench widths for sewer lines installations shall conform to S.D. RWRD-104,
unless otherwise noted in the Sewer Plans. The completed trench bottom shall
be firm for its full length and width.
In special cases, the Sewer Plans may specify either a longitudinal camber or
longitudinal arch along the trench bottom to compensate for the anticipated
settlement of the sewer pipe. In such cases, special provisions for grade staking
and alignment verification/testing shall be included in the Sewer Plans.
In cases where groundwater is encountered, the method of dewatering shall be
determined on a case-by-case basis. In any case, the Contractor shall submit to
the Field Engineer, a dewatering plan and a Stormwater Pollution Prevention
Plan (SWPPP) for review and Approval, prior to the start of construction. Any
modification due to variable soils or groundwater encountered during
construction shall be forwarded to the Field Engineer.
If the ground surface elevation over any portion of an existing sewer line will be
reduced so that the cover is less than 4 feet, the Contractor shall replace the
reach with DIP or an Approved equal. This standard applies during construction,
where the lowest elevation attained may be less than the finish grade. It also
applies to the reconstruction of streets, the re-grading of Public Sewer
easements or any other excavation where the existing sewer line will be
subjected to additional loads by heavy trucks or compaction equipment.
B. Foundations
A modified trench foundation is required only when the native soil in the trench
bottom does not provide a firm working platform for placement of bedding
material, as described in the following cases.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-4 Standard Specifications
Where rock, hardpan or other unyielding material is encountered at the trench
bottom, such material shall be removed at least 12 inches below the trench
bottom or as directed by the Field Engineer. The width to be removed shall
conform to S.D. RWRD-104 or as indicated in the Sewer Plans, and maintained
throughout the over-excavation. The over-excavated material shall be replaced
with an Approved foundation material in accordance with S.D. RWRD-104.
Where unsuitable material is encountered that causes the trench bottom to be
unstable, the unsuitable material shall be removed to a depth as specified by a
Geotechnical Engineer. The width to be removed shall be the width of the trench,
as shown on S.D. RWRD-104 or as indicated in the Sewer Plans, and
maintained throughout the over-excavation. The over-excavated material shall be
replaced with an Approved foundation material in accordance with S.D. RWRD-
104.
Foundation material shall be compacted in layers, not exceeding 6 inches in
depth, to at least 95% of the maximum dry density and optimum moisture content
determined in accordance with the requirements of the applicable test methods
of the ADOT Materials Testing Manual or as specified by the Geotechnical
Engineer.
C. Bedding
Prior to the placement of bedding material and pipe, all trash, forms, sheeting,
bracing and loose rock or loose earth shall be removed from the trench. The
thickness of bedding material shall be in accordance with S.D. RWRD-104. Bell
holes shall be provided at each pipe joint to permit proper assembly and support
of the pipe.
D. Haunching and Shading
Haunching and shading material shall be the same material as that used for
bedding.
Haunching shall be completed as the pipe is laid and placed up to the pipe’s
Springline (50% of the pipe’s diameter). The shovel slicing technique shall be
used to ensure material is placed under the haunches of the pipe to reduce voids
and increase pipe support.
Shading material shall be placed in a manner which will prevent distortion of,
damage to, or displacement of the pipe from its horizontal and vertical
alignments. Shading material shall be placed over the haunching and pipe to a
minimum of 12 inches above the top of the pipe and extend horizontally to the
interior walls of the trench.
Haunching and shading material shall be compacted to 95% standard proctor, in
accordance with the requirements of the applicable test methods of the ADOT
Materials Testing Manual, as directed and Approved by the Field Engineer,
unless otherwise noted in the Sewer Plans. Compaction through water settling or
jetting is not permitted.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-5 Standard Specifications
E. Backfill
Prior to placement of backfill material, all trash, forms, sheeting, bracing, loose
rock or loose earth shall be removed from the trench.
Backfill material shall be compacted in lifts to attain a minimum of 95% standard
proctor, in accordance with the requirements of the applicable test methods of
the ADOT Materials Testing Manual, as directed and Approved by the Field
Engineer, unless otherwise noted in the Sewer Plans. Backfill material and
compaction shall also conform to the requirements of the Agency having
jurisdiction of the Right-of-Way in which Public Sewers are being installed.
Compaction through water settling or jetting is not permitted. Backfill shall not be
wheel loaded until 3 feet of cover is provided over the top of the pipe.
Failure of backfill compaction test results will result in rejection of that portion of
the pipe installation. Replacement of trench materials and pipe will be at the
Contractor's expense.
F. Backfill Density Testing Procedures
Additional density testing procedures for the compaction of backfill shall be
provided for sewer construction projects meeting any of the following criteria:
A cumulative total of 500 LF or more of new Public Sewer lines;
The depth of either trench excavation or cover is greater than 20 feet;
The geotechnical report, soil borings or historical records indicate a
potential for the presence of groundwater; or
The Department deems that site soil conditions warrant a geotechnical
oversight (e.g. difficult to process soil type).
Density testing services shall be provided by a Geotechnical Engineer. Contact
information for the Geotechnical Engineer and the field technicians working
under his direction, shall be provided to the Field Engineer at the pre-
construction meeting.
The Contractor shall continuously review density test results during backfill
activities. Successive lifts of backfill shall not be placed until density test results
show conformance to compaction requirements. Failure by the Contractor to
adhere to these requirements will result in suspension of inspection by the
Department and cancellation of the construction permit.
It is option of the Contractor to select either Procedure A or Procedure B for the
density testing of backfill. Each procedure is described in the following
Subsections.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-6 Standard Specifications
i. Procedure A
The Geotechnical Engineer shall prepare and seal a Geotechnical Quality
Control Plan (GQCP). The GQCP shall include the following:
Project information;
Quality Control Organization;
Resumes;
AASHTO Laboratory Certificate; and
Control Procedures (i.e. moisture and density per lift).
The GQCP shall specify the minimum frequencies of random density and
moisture tests to be performed for the Project and shall meet the minimum
testing requirements of Subsection 3.1.3(F). It shall be submitted to the Field
Engineering section for conformance review. A written notice to proceed will be
issued by the Field Engineering section when the GQCP is Approved.
The applicable density test method will be dictated by the variability of backfill
material to ensure proper compaction values are recorded.
The Contractor and the Geotechnical Engineer shall be equally responsible for
ensuring proper backfill compaction is accomplished. Daily density testing results
shall be made available upon request to the Contractor and the Field Engineer.
Density test results shall meet or exceed minimum compaction requirements and
shall be submitted to the Field Engineer on a weekly basis.
Density testing procedures shall conform to the following requirements:
(1) Perform random density and moisture tests in accordance with the GQCP
(additional tests may be performed at any given location at the discretion of
the Geotechnical Engineer).
(2) Perform a visual inspection of the trench bottom and check for unsuitable
materials. If unsuitable material is encountered, it shall be over-excavated
and replaced as directed by the Geotechnical Engineer.
(3) Trench Backfill:
Density testing of trench backfill shall commence at approximately 2 feet
above top of sewer pipe and continue to the base of the roadway
structural section, or to the base of the stabilized surface, as applicable;
and
For each sewer reach installed, a minimum of one density test shall be
taken at every vertical 2 feet of backfill between manholes, or one every
300 feet, whichever is shorter. The field technician shall conduct backfill
density tests randomly, both horizontal and vertical, in accordance with the
GQCP. These tests shall provide a representation of the compacted effort
throughout the sewer reach length.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-7 Standard Specifications
(4) Perform a visual inspection of each manhole base and check for unsuitable
materials. If unsuitable material is encountered, it shall be over-excavated
and replaced as directed by the Geotechnical Engineer. Where over-
excavation and replacement under a proposed structure base is required, a
minimum of one density test shall be taken at the approximate center of the
proposed structure, or as directed by the Geotechnical Engineer.
(5) Density testing for backfill around manholes shall consist of one test per lift,
and rotating with successive 2-foot increments at 120 degree intervals.
Density testing of backfill around formed structures shall require one test per
lift, alternating sides with successive 2-foot increments as instructed by the
Geotechnical Engineer and in accordance with the GQCP. Density tests will
be taken as close as possible to the structure to determine the representative
compaction density, but not so close as to interfere with the functioning of the
testing equipment.
Upon completion of sewer construction and prior to issuance of the ECC, the
Geotechnical Engineer shall provide the Field Engineer with a Final Compaction
Report (FCR) for review and approval. The FCR shall be certified with a cover
letter and include all test data (i.e. re-tests, calibration tests, and test methods)
and a map showing testing locations, referenced by station, depth below grade
and percent compaction achieved. The Geotechnical Engineer shall also include
a statement confirming that the FCR meets the original requirements of the
GQCP.
Under the provisions of the compaction testing requirements herein, geotechnical
oversight by the Geotechnical Engineer shall be taken to include review of the
Sewer Plans, development of the GQCP and the FCR, supervision of and
coordination with the field technician(s) performing compaction testing, and
review of test results for compliance.
ii. Procedure B
The Geotechnical Engineer shall provide a full-time field technician, working
under his/her direction, for observation and collection of the density testing
results for sewer construction.
Density testing results meeting or exceeding minimum approved Project
requirements shall be demonstrated through a Daily Observation and Testing
Report (DOTR) prepared by the field technician. The Contractor and
Geotechnical Engineer shall effectively communicate density test results to
ensure proper backfill compaction is accomplished. The DOTR shall be made
available to the Field Engineer and the Contractor by the end of each day.
Upon completion of sewer construction, the Geotechnical Engineer shall compile
all DOTRs into a complete package. This package shall also include a sealed
cover letter stating that backfill density testing procedures were adhered to in
accordance with the Department’s requirements.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-8 Standard Specifications
G. Stabilized Surface Treatment for Public Sewer Easements
Stabilized surface treatment for Public Sewer easements shall conform to S.D.
RWRD-111, unless otherwise indicated in the Sewer Plans.
3.2 Sanitary Sewer Pipe
3.2.1 Description
The work under Subsection 3.2 shall consist of furnishing and installing sanitary
sewer pipe, and all other appurtenant materials required, including excavation
and the furnishing, placing and compacting of bedding and backfill material, all in
accordance with the details shown in the Sewer Plans and the requirements of
the Standard Specifications and Details.
3.2.2 Materials
A. General
At each location where a pipe is to be installed, the pipe material, diameter and
length, along with the requirements for each approved option at that location,
such as wall thickness, coatings, lining, class and strength, shall be in
accordance with the Sewer Plans.
Certification documents from the manufacturer shall be furnished attesting that
the pipe and appurtenances (excluding linings and coatings if applied by an
independent applicator) meet the requirements set forth in the Standard
Specifications and Details. All pipe and appurtenances shall be clearly marked
with the name or trademark of the manufacturer, the batch number, and the
location of the manufacturing plant.
B. Vitrified Clay Pipe (VCP)
VCP shall be new and extra strength. All materials, manufacture and testing for
VCP shall meet the requirements of ASTM C700, C1208, ASTM C896, ASTM
C301 and ASTM C425.
C. Polyvinyl Chloride (PVC) Pipe
Except as modified herein, all materials, manufacture and testing for PVC gravity
sewer pipe and fittings shall conform to ASTM D3034 for diameters of 4 through
15 inches and ASTM F679 for diameters of 18 inches and larger. PVC gravity
sewer pipe shall be SDR 35 unless otherwise shown in the Sewer Plans.
PVC gravity sewer pipe shall have a minimum pipe stiffness of 46 psi at 5%
deflection, in accordance with ASTM D2412.
PVC gravity sewer pipe and fittings shall be made of PVC plastic having a cell
classification of 12454 or 12364, as defined in ASTM D1784. Additives and
fillers, including, but not limited, to stabilizers, antioxidants, lubricants, colorants,
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-9 Standard Specifications
etc., shall not exceed 10 parts by weight per 100 parts of PVC resin in the
compound.
PVC gravity sewer pipe joints shall be gasketed, bell-and-spigot, push-on type,
conforming to ASTM D3212. Because each pipe manufacturer has a different
design for push-on joints, gaskets shall be part of a complete pipe section and
purchased as such. Gaskets shall conform to ASTM F477 and be factory-
installed and locked-in. Lubricant shall be as recommended by the pipe
manufacturer.
Standard laying lengths for PVC gravity sewer pipe shall be 14 feet.
Service connections shall be installed with “Tee” or “Wye” fittings, gasketed “Tee”
saddles with stainless steel bands, or other tapping devices as Approved by the
Field Engineer. Solvent welded “Wye” saddles are not Approved.
All fittings shall be compatible with the pipe to which they are attached.
Pipes or fittings may be rejected by the Field Engineer for failure to comply with
the requirements herein.
D. Ductile Iron Pipe (DIP)
All materials, manufacture and testing for DIP shall be in accordance with ASTM
A746 and the latest revision of ANSI/AWWA C151/A21.51. Each pipe shall be
subjected to a hydrostatic pressure test of at least 500 psi at the point of
manufacture. DIP shall be manufactured in nominal 18 or 20-foot laying lengths.
DIP shall have standard asphaltic coating on the exterior, unless otherwise
specified in the Sewer Plans.
DIP shall have an Approved interior lining installed by the pipe manufacturer or a
third-party lining applicator. Refer to the Department’s List of Approved Products
for the recommended DIP interior lining materials.
The party responsible for applying the interior lining shall provide a certification
statement as described in the following:
ALL DIP AND FITTINGS HAVE AN INTERNAL LINING COMPRISED OF
[insert type of lining]. THE INTERNAL LINING THICKNESS IS 40 MILS
NOMINAL (35 MILS MINIMUM) IN THE BARREL AREA, 10 MILS
MINIMUM IN THE BELL AREA, AND 10 MILS MINIMUM ON THE
EXTERIOR OF THE SPIGOT END.
EACH PIECE OF PIPE AND EACH FITTING HAVE BEEN CHECKED
FOR HOLIDAYS UTILIZING A TESTING VOLTAGE OF 7,500 V WITH A
DRY CONDUCTIVE PROBE IN THE BARREL AREA AND A TESTING
VOLTAGE OF 67.5 V WITH A WET SPONGE IN BOTH THE BELL AREA
AND THE EXTERIOR OF THE SPIGOT END, AND THAT NO HOLIDAYS
WERE FOUND.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-10 Standard Specifications
THE [insert lining name] EXTENDS FROM THE BOTTOM OF THE
GASKET SOCKET IN THE BELL TO A POINT ON THE EXTERIOR OF
THE SPIGOT END OF THE PIPE WHERE THE NEXT PIPE GASKET
WOULD OVERLAP THE LINING.
THE [insert lining name] IS INCLUDED ON THE PCRWRD LIST OF
APPROVED PRODUCTS FOR DIP INTERIOR LININGS.
A MAXIMUM LINING THICKNESS OF 15 MILS HAS BEEN APPLIED TO
BOTH THE GASKET SEAT GROOVE IN THE BELL AREA AND THE
EXTERIOR OF THE SPIGOT END.
The following information shall be clearly marked on the exterior surface of each
piece of DIP:
Name or trademark of pipe manufacturer ;
Pipe material “DI” or “Ductile”;
Pressure class or thickness class;
Date and country of pipe casting;
Lot or Serial number;
Name of lining applicator;
Name of lining product;
Thickness of lining; and
Date of lining application.
All pipe shall be furnished with push-on type joints, such as Tyton® or Fastite®.
Joints shall conform to the latest revision of ANSI/AWWA C111/A21.11, and shall
be furnished complete with all required accessories. EPDM gasket material shall
be used for all DIP, unless otherwise specified in the Sewer Plans.
Fittings shall be ductile iron and shall conform to the latest revision of either
ANSI/AWWA C110/A21.10 or ANSI/AWWA C153/A21.53. Fittings and
accessories shall be furnished with either push-on or mechanical type joints in
accordance with to the latest revision of ANSI/AWWA C111/A21.11.
Polyethylene wrap in tube or sheet form for piping encasement shall be
manufactured from virgin polyethylene material and marked in accordance with
the requirements of ANSI A21.5, ASTM D4976 and AWWA C105. The minimum
thickness shall be 8 mils.
E. High-Density Polyethylene (HDPE) Pipe
HDPE pipe shall be manufactured from extra high molecular weight polyethylene
material, meeting the requirements of Type III, Class C, Category 5, Grade P34,
as defined in ASTM D1248. The pipe material shall meet the requirements of cell
classification PE345464C or PE345464E of standard polyethylene code
designation PE3408, as defined by ASTM D3350. The manufacturer shall certify
that the pipe material has been tested, in accordance with the provisions of
ASTM F1473, for greater than 100 hours without failure. The manufacturer shall
also certify that the pipe has a hydrostatic design basis of 1,600 psi at 73° F and
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-11 Standard Specifications
800 psi at 140° F, when tested in accordance with the provisions of ASTM
D2837.
HDPE pipe shall have a controlled outside diameter and manufactured to the
SDR/DR rating and inside diameter specified by the Sewer Plans. The pressure
rating of HDPE pipe shall be in accordance with ASTM D3035 and ASTM F714.
Fittings shall be manufactured using the same pressure rating as the designed
piping system. Fittings shall have a controlled outside diameter and the SDR/DR
rating for the pressure specified by the Sewer Plans. Fittings shall be specifically
manufactured to standardized dimensions noted in the Sewer Plans.
Butt fusion fittings shall be manufactured from the same material as the extruded
pipe, shall be rated for a pressure service equal to at least that for the system
pipe, and shall have outlets manufactured to the same DR as the system pipe.
Molded fittings shall be manufactured in accordance with ASTM D3261 and
socket fittings shall be manufactured in accordance with ASTM D2683.
The pipe manufacturer shall have 5 years minimum experience in producing
HDPE pipe. The pipe manufacturer shall maintain a continuous quality control
program. HDPE pipe and fittings for a project shall be manufactured from the
product of a single, approved manufacturer.
A Certificate of Compliance shall be provided by the pipe manufacturer that the
HDPE pipe and fittings conform to the requirements of Subsection 3.2.2(E).
F. Fiberglass Reinforced Pipe (FRP)
Except where modified in the Standard Specifications and Details, all materials,
manufacture and testing for FRP pipe shall conform to ASTM D3262, ASTM
D3681-01, ASTM D4161 and ASTM D2412. The minimum pipe stiffness when
tested in accordance with ASTM D2412, shall be 46 psi.
The pipe manufacturer shall maintain a continuous quality control program. FRP
pipe shall be manufactured from only polyester resin systems with a proven
history of performance in the application of gravity sewer pipe installations. The
historical data shall have been acquired from material(s) of similar construction
and composition as the proposed product.
The reinforcing glass fibers used to manufacture the components shall be of the
highest quality commercial grade E-glass filaments with binder and sizing
compatible with impregnating resins.
Sand shall be a minimum of 98% silica with a maximum moisture content of
0.2%.
When used, resin additives, such as curing agents, pigments, dyes, fillers, and
thixotropic agents shall not detrimentally affect the performance of the product.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-12 Standard Specifications
Gaskets shall be suitable for the service intended, conform to ASTM F477, and
be supplied by a qualified gasket manufacturer.
The pipe shall be manufactured using only the centrifugal-casting process, in
order to produce a dense, non-porous, corrosion-resistant, uniform structure. The
pipe shall meet the ASTM D3262 standard specification, Cell Limit Type 1, Liner
2 and Grade 3. The manufacturer of pipe and fittings must demonstrate a 10-
year history of successful installations in the United States for sanitary sewer
service.
Unless otherwise indicated in the Sewer Plans, the pipe shall be field connected
with fiberglass sleeve couplings that utilize built-in double fin elastomeric sealing
gaskets made of EPDM rubber compound as the sole means to maintain joint
water tightness. The joints must meet the performance requirements of ASTM
D4161.
For sliplining and tunnel carrier installations, joints at tie-ins, may utilize
fiberglass, gasket-sealed closure couplings.
For jacking installations, the joint shall have approximately the same outside
diameter as the pipe. When the pipes are assembled, the joints are essentially
flush with the pipe outside surface. Joints at tie-ins, may utilize fiberglass, gasket-
sealed closure couplings.
The interior surface layer or liner shall consist of a highly flexibilized nominal 40
mil thick polyester resin with a minimum elongation of 50% when tested
according to ASTM D638. Interior glass reinforced layers of pipe cannot be the
corrosion barrier or liner finish. All pipes shall be tested per ASTM D3681
corrosion test using 1 N sulfuric acid and demonstrating a 0.90% or better strain
for 100-year service life design.
Flanges, elbows, reducers, tees, wyes, laterals and other fittings, shall be
capable of withstanding all operating conditions when installed. They may be
contact molded or manufactured from mitered sections of pipe joined by glass-
fiber-reinforced overlays. Properly protected standard ductile iron, fusion-bonded
epoxy coated steel and stainless steel fittings may also be used.
Reinforced fiberglass manhole tee base fittings shall be constructed of mitered
sections of FRP connected with fiberglass reinforcement laminations. The
diameter and length of the tee base through section, and the vertical leg shall be
as shown in the Sewer Plans or as agreed between purchaser and supplier, as
Approved by the Field Engineer. Pipes used to construct the tee base shall have
the same stiffness as the line pipes, but not greater than 46 psi as a minimum
requirement. Fabricate the tee base through section with a mitered elbow
configuration to achieve the required angles shown in the Sewer Plans.
Maximum angle of each miter is 30 degrees except individual alignment changes
up to 35 degrees may be 1 miter. Construct drop configurations as shown in the
Sewer Plans. Accommodate diameter changes at manholes using a reducer on
the upstream side of the tee base. Assemble the tee base to the line pipes using
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-13 Standard Specifications
the same gasket-sealed joint as pipe-to-pipe connections or another gasket-
sealed joint as approved by the pipe manufacturer.
The actual outside diameter for pipe sizes ranging from 18-inches to 48-inches
shall be in accordance with ASTM D3262. For other pipe sizes, the outside
diameters shall be in accordance with the manufacturer’s literature.
Pipe shall be supplied in nominal lengths of 20 feet. Actual laying length shall be
nominal +1, -4 inches. At least 90% of the total footage of each size and class of
pipe, excluding special order lengths, shall be furnished in nominal length
sections.
For direct bury and sliplining installations, the minimum wall thickness shall be
the stated design thickness.
For jacking installations, the minimum wall thickness is determined from the
maximum jacking load. This thickness is measured at the bottom of the spigot
gasket groove where the wall cross-section has been reduced. The minimum
factor of safety against jacking force is 2.5, based on straight alignment.
Pipe ends shall be square to the pipe axis, with a maximum tolerance of 1/8”.
The Field Engineer shall be entitled to inspect pipes or witness the pipe
manufacturing.
Should the Field Engineer request to see specific pipes during any phase of the
manufacturing process, the manufacturer shall provide the Field Engineer with
adequate advance notice of when and where the production of those pipes will
take place.
Packaging, handling, and shipping shall be done in accordance with the
manufacturer’s instructions.
G. Reinforced Concrete Pipe (RCP)
RCP for Public Sewers shall be circular and conform to the requirements of
ASTM C76. The use of arch or elliptical RCP is not permitted. RCP shall have all
of its interior surfaces lined with an Approved lining material or as Approved in
the Sewer Plans. Refer to the Department’s List of Approved Products for the
recommended interior lining materials for RCP. RCP shall have a nominal laying
length of 8 to 20 feet, unless otherwise Approved by the Field Engineer.
The wall thickness and reinforcing steel shall conform to ASTM C76 and the
designated class of pipe as indicated in the Sewer Plans. When the designated
class of pipe is not specified in the Sewer Plans, it shall be determined in
accordance with the Concrete Pipe Design Manual by the American Concrete
Pipe Association, latest edition. All jacking pipe shall be specifically designed by
the pipe manufacturer to withstand all forces that the pipe may be subjected to
during jacking operations.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-14 Standard Specifications
All RCP shall be manufactured in accordance with ASTM C76 and C497, or as
specified in the Sewer Plans. A letter from the supplier to the Field Engineer shall
be submitted certifying that all RCP is manufactured in accordance with ASTM
C76.
The manufacturer shall specify the maximum allowable joint gaps on all conduit
sizes for the project and it shall be provided to the Field Engineer. The maximum
allowable joint gap is determined as that point where the bevel of the bell and the
shoulder of the spigot are vertically aligned and the rubber gasket has achieved
the minimum compression necessary to ensure a water tight seal.
A production schedule shall be provided to the Field Engineer at least three
Working Days in advance of when the various types of pipe will be cast, so that
the casting operation may be inspected and appropriate specimens may be
selected for testing in accordance with the Sewer Plans.
Type II Portland Cement complying with the requirements of ASTM C150 shall
be used in the production of RCP unless otherwise indicated in the Sewer Plans
or Approved by the Field Engineer.
Lifting anchors shall be used on all precast concrete pipe. Lifting holes are not
allowed. The use of other lifting mechanisms proposed for handling and
placement of RCP shall be submitted to the Field Engineer for Approval.
Details of all fittings and specials shall be submitted for Approval to the Field
Engineer prior to construction. Fittings and specials shall be made up of pipe
segments having the same structural qualities and the same interior treatment as
the adjoining pipe.
Joints shall be formed using rubber gaskets that provide a watertight seal, in
accordance with ASTM C443. Joints shall be capable of withstanding the forces
caused by the compression of the gasket when joined.
Joints shall be either bell-and-spigot or tongue-and-groove styles. The spigot or
tongue shall be grooved to properly contain and seat the rubber gasket. Joint
assemblies shall be accurately formed so that when each pipe section is forced
together in the trench, the assembled pipe shall form a continuous watertight
conduit with a smooth and uniform interior surface. Joints shall provide for slight
movement of any piece of the pipeline caused by expansion, contraction,
settlement or lateral displacement. The gasket shall be the sole element of the
joint providing water tightness. The ends of the pipe shall be perpendicular to the
longitudinal centerline of the pipe, except where bevel-end pipe is required. The
ends shall be finished so that they are uniform and smooth.
Rubber gaskets for bell-and-spigot joints shall consist of an O-ring rubber gasket,
rubber profile gasket, or gasket conforming to the pipe manufacturer’s
specifications.
Gaskets may be either natural rubber or neoprene and shall conform to ASTM
C443. All gaskets shall be stored in a cool place, preferably at a temperature of
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December 2012 3-15 Standard Specifications
less than 70 degrees Fahrenheit. In no case shall gaskets be stored in the open
or exposed to direct sunlight. No gasket that shown signs of deterioration, such
as surface cracking or checking, shall be installed in a pipe joint. When the air
temperature is 10 degrees F or lower, the gaskets shall be warmed to a
temperature of 60 degrees Fahrenheit, for a period of 30 minutes, before being
placed on the pipe.
In addition to all other requirements set forth in this specification, the following
additions shall apply to RCP being jacked: Pipe shall be Class V, unless
otherwise specified in the Sewer Plans; grouting nipples shall be spaced no more
than 8 feet apart on the installed pipeline; and pipe shall include steel joint rings
(bell-and-spigot) conforming to ASTM C361.
The following shall be clearly marked on the interior and exterior surfaces of the
pipe:
Name or trademark of pipe manufacturer;
ASTM specification designation (C76);
Class and size;
Date of pipe manufacture;
Lot or serial number;
Name of lining applicator;
Name of lining product;
Thickness of lining; and
Date of lining application.
3.2.3 Construction Details
A. Survey Requirements
i. Survey Cut Sheets
The Contractor shall be responsible for providing survey cut sheets to the Field
Engineer in an Approved format and prior to commencing with sewer
construction activities. Survey cut sheets shall be sealed by an Arizona
Registered Land Surveyor and include all grade stakes to be used for the
construction of new Public Sewers. Survey cut sheets shall also include a
description for any unusual conditions, such as extra cuts, extra cover, and
drainage. Any errors or omissions in the survey cut sheets that result in improper
sewer construction shall not be the responsibility of the Department.
Any revisions to the Sewer Plans that may occur during the progress of
construction shall require a re-submittal of the survey cut sheets to the Field
Engineer.
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ii. Construction Survey Stakes
Survey stakes, for the construction of Public Sewers, shall be provided on an
appropriate offset line at no greater than 50-foot intervals along the sewer line. At
least two survey stakes shall be provided for each manhole and one stake shall
be provided for each HCS/BCS cleanout. Each stake shall be marked and match
the data provided in the survey cut sheets. The distance and direction of the
offset line (N, S, E or W) shall be shown in relation to the sewer line. For
example, if the offset line is ten feet north of the sewer line, then the offset
distance and direction shall be "10’N." Stationing shall begin at a known
permanent point (such as a monument or property pin) and remain visible after
completion of construction.
Survey stakes shall be offset far enough away from excavation to avoid being
lost during excavation or cave-ins. It shall be the responsibility of the Contractor
to immediately replace lost or damaged stakes.
The Contractor shall provide sufficient checks and verifications of the sewer line
grades and alignments during construction to ensure that new Public Sewers are
constructed within the allowable tolerances per Subsection 3.2.3(D)(vii).
B. Installation of Pipe
i. General
Sewer pipe and appurtenances shall be handled so as to ensure delivery to the
trench in sound and undamaged condition. Sewer pipe shall be unloaded near
the location at which it will be installed. Sewer pipe shall not be stored along
residential streets for more than 10 days or along a business street for more than
3 days. The interior of the sewer pipe shall be thoroughly cleaned of foreign
material before being lowered into the trench.
Installation of sewer pipe shall be in finished trenches free of water and debris,
and commence at the lowest point of the sewer line with the spigot ends pointing
in the direction of the flow. Each pipe shall be laid true to line and grade, with
uniform support under the full length of the pipe.
Any adjustment of line and grade shall be made by excavating or filling under the
pipe. Wedging or blocking under the pipe ends is prohibited.
When work is not in progress, open pipe ends shall be securely closed with an
Approved pipe plug or end cap so that no water, earth, animals or other foreign
objects will enter the pipe. If any debris is found in the pipe prior to testing, the
pipe shall be cleaned by propelling a snug-fitting inflated ball, or other Approved
device, through the pipe with water.
Pipes made from unlike materials shall be coupled together in accordance with
S.D. RWRD-103.
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ii. Vitrified Clay Pipe (VCP)
VCP shall be installed in accordance with ASTM C12 and the latest installation
publications available from the National Clay Pipe Institute (e.g. Clay Pipe
Engineering Manual).
After a sewer line reach (manhole-to-manhole) has been backfilled to finish
grade, it shall be tested for excessive leakage in accordance with the applicable
testing requirements of ASTM C828 or ASTM C1091.
iii. Polyvinyl Chloride (PVC) Pipe
PVC pipe shall be installed in accordance with ASTM D2321 and the latest
installation publications available from the PVC Pipe Association (e.g. UNI-PUB-
9 and UNI-B-6). Embedment requirements for PVC pipe shall conform to S.D.
RWRD-104.
Care shall be taken during the transportation of the pipe to ensure that the tie-
down methods do not damage or deflect the pipe. PVC pipe shall be delivered to
the job site and stored on palletized units, not to exceed 40 inches in height.
Stacking of palletized units at the job site shall not exceed 8 feet in height. PVC
pipe shall not be removed from the pallet or laid out along the ditch more than 24
hours prior to installation in the trench.
In addition to the tests at the manufacturer's plant, the Field Engineer may
require that tests be performed on pipe specimens selected at random at the
point of delivery or at the job site. The Department will bear the costs of such
tests that shall be in accordance with ASTM D2412 and D2444.
Any imperfections, which, in the opinion of the Field Engineer, may adversely
affect the performance of the pipe or joints, shall be cause for rejection of the
PVC pipe.
All surfaces of the joint, upon which the gasket may bear, shall be smooth and
free of any imperfection that could adversely affect sealing ability. All pipes shall
have a “stop-mark” on the spigot end to indicate proper penetration when the
joint is made. Pipes at joints are not to be inserted beyond “stop-mark” on spigot
end.
A resilient connector per ASTM C923 (i.e. water stop) shall be installed on the
PVC pipe where it connects into a concrete manhole. After a reach (manhole-to-
manhole) of installed PVC pipe has been backfilled to finish grade, it shall be
tested for excessive leakage by a low-pressure air test, conducted in accordance
with ASTM F1417.
The testing method selected shall properly consider the existing groundwater
elevations during the test. If the test section fails the test for excessive leakage,
the contractor shall repair or replace all defective materials and/or workmanship
at no additional cost to the Department.
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Deflection testing shall be conducted in accordance with Subsection 3.2.3(D).
iv. Ductile Iron Pipe (DIP)
DIP shall be installed in accordance with ANSI/AWWA C105/A21.5 and the latest
publications available from the Ductile Iron Pipe Research Association (e.g.
Installation Guide for DIP).
The Field Engineer may require field testing of protective linings for DIP. Pipe
found with damage or Holidays to the protective lining shall be removed and
replaced, or repaired immediately. Repair of damaged areas of the protective
lining shall be in accordance with the recommendations of the lining applicator.
Repaired areas shall be equal, in all respects, to undamaged lined areas.
An Approved coating material shall be used for field cuts of DIP pipe. A minimum
coating thickness of 10 mils shall be applied to the exterior surface of the pipe
spigot and overlap the internal lining by 4 inches. The area of lining to be
overlapped shall be roughened to a profile roughness height of 3 to 5 mils prior to
the coating application. The coating material shall be allowed to dry properly
before pipe assembly.
Direct-bury installations of DIP shall be encased with polyethylene wrap.
Exposed installations of DIP and ductile iron fittings (e.g. above ground, vaults,
wet-wells and casings) shall have an applied exterior coating in accordance with
the Sewer Plans or as directed by the Field Engineer.
After a reach (manhole-to-manhole) of installed DIP pipe (gravity) has been
backfilled to finish grade, it shall be tested for excessive leakage by a low-
pressure air test, conducted in accordance with ASTM C924. Gravity sewer
reaches with composite pipe materials (e.g. VCP, PVC and DIP) shall be tested
in accordance with Subsection 3.2.3(D)(iii).
For DIP force main installations, after all pipe, fittings and appurtenances have
been completely installed, they shall be tested for excessive leakage by a
hydrostatic pressure test in accordance with ANSI/AWWA C600.
v. High-Density Polyethylene (HDPE) Pipe
Force main installations with HDPE pipe shall be installed in accordance with
ASTM D2774, AWWA M55 and the latest installation publications available from
the Plastic Pipe Institute (e.g. Handbook of Polyethylene Pipe).
Prior to the site delivery of the pipe, the Contractor shall provide the following
information to the Field Engineer:
Detailed procedures to be used in joining and installing the piping system,
including manufacturers’ recommendations;
Interface of piping system to equipment and appurtenances; and
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Bill of materials, indicating material composition of pipe, pressure rating,
nominal size with wall dimensions, and its locations on the piping
installation drawing.
HDPE pipe and fitting joints shall be heat fused by a qualified technician trained
by an approved manufacturers’ representative, in accordance with the
manufacturer’s recommended fusion procedures. Training shall have occurred in
the previous 12 months or submittals verifying field installation experience within
the previous 12 months for all technicians performing heat fusion on HDPE pipe
and fittings shall be submitted prior to the start of installation.
All necessary precautions shall be taken to prevent damage or contamination to
the pipe and other incidental materials during shipment and delivery. All materials
shall be securely fastened to the truck or rail car to prevent movement or damage
during shipment. The Contractor shall examine all materials before unloading.
All pipe materials shall be handled so as to prevent damage. HDPE pipe shall not
be dropped, rolled, or pushed off from any height on delivery, storage, or
installation.
All pipe materials shall be stored off the ground in a dry location. Pipe shall be
stored to prevent sagging or bending. Stored pipe shall be protected from
exposure to ultraviolet light.
All piping shall be inspected to assure that it is free from defects in material and
workmanship. The compatibility of all pipes and fittings shall be verified.
Pipes, fittings and accessories that are cracked, damaged, unidentifiable, or in
poor condition, shall be rejected. Pipe sections or fittings containing significant
scratches, dents or marks that are not in accordance with the manufacturer’s
criteria for such blemishes, may be cause for rejection at the sole discretion of
the Field Engineer.
The Field Engineer shall have free access to all joints, including test joints, for
determining the suitability of the joining procedure. Where construction
restrictions limit inspection of joints, the Field Engineer may direct the individual
joining the pipe and/or fittings to perform a test in a manner that it can be clearly
and easily observed. The Field Engineer shall select the method of testing from
either visual examination, bent strap testing, or ultra-sonic testing. Ultra-sonic
testing shall conform to the requirement of the U.S. Department of Transportation
as found in the code of federal regulations 49, Part 192.285(b)(ii) or (b)(iii).
HDPE pipes and fittings shall be heat-fused together to create a homogeneous
joint. Joining shall be performed in accordance with the manufacturer’s heat
fusion recommendations. Solvent weld joints are not permitted.
Personnel responsible for heat fusing the joints shall demonstrate proficiency by
fusing trial joints and testing the trial joint by bent strap testing or ultra-sonic
testing. Trial joints shall be allowed to cool completely before testing and shall
not fail at the joint. During construction, the first fusion of the day shall be a trial
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Regional Wastewater Reclamation Department for Construction 2012
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fusion that shall be allowed to cool and tested either by a destructive bent strap
test or with an ultrasonic testing device. If the joint fails, additional trial joints shall
be made and tested until successful fusions are completed. The procedure used
to join the trial joint shall be used for the balance of the day’s work, provided the
procedure is in compliance with that recommended by the manufacturer. The
Field Engineer shall provide written notice to the Contractor of the unacceptability
of any welding technician who is deemed deficient in welding HDPE pipe. In any
case, the welding technician shall not be utilized by the Contractor unless the
individual undergoes additional training and re-certification for HDPE pipe
welding.
HDPE pipe shall be installed to minimize shear and tensile stresses and in
accordance with S.D.s RWRD-104 and -500 or as indicated in the Sewer Plans.
After HDPE piping has been backfilled to finish grade, it shall be tested for field
leaks by a hydrostatic pressure test in accordance with ASTM F2164.
vi. Fiberglass Reinforced Pipe (FRP)
For direct bury installations, trench construction shall conform to Subsection
3.1.3(A). Bedding and shading material for FRP and FRP fittings shall be in
accordance with the Sewer Plans and the manufacturer’s requirements. Backfill
material shall conform to the requirements of Subsections 3.1.2(C) and 3.1.2(D),
as applicable. The placement and compaction of shading and backfill material
shall conform to Subsections 3.1.3(E) and 3.1.3(F).
For slip lining and tunnel carrier installations, annular space grouting shall not
damage the liner and shall conform to the manufacturer’s requirements.
FRP shall be handled with textile slings, other suitable materials or a forklift. Use
of chains or cables is not permitted.
The jointing of FRP shall be accomplished as described in following:
(1) Clean ends of pipe and coupling components;
(2) Apply joint lubricant to pipe ends and elastomeric seals of coupling. Use only
lubricants approved by the pipe manufacturer;
(3) Use suitable equipment and end protection to push or pull the pipes together;
(4) Do not exceed forces recommended by the manufacturer for coupling pipe;
and
(5) For direct bury installations, join pipes in straight alignment then deflect to
required angle. Do not allow the deflection angle to exceed manufacturer’s
limits.
Manholes for FRP shall be constructed using pipe tee base fittings that are
encased in concrete. The encasement shall be designed to prevent distortion of
the tee base from heavy loads. This encasement shall also serve as the base to
support pre-cast or cast-in-place concrete riser structures per Subsection
3.3.3(B)(i).
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Regional Wastewater Reclamation Department for Construction 2012
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Where an FRP end must be connected into a concrete manhole, a resilient
connector per ASTM C923, or joint coupling per ASTM D4161, shall be installed
on the pipe to provide a watertight connection.
Field testing for direct bury, jacking and tunnel carrier installations of FRP shall
conform to the following:
(1) Each reach may be tested by low-pressure air per Subsection 3.2.3(D)(iii).
The system passes the test if the pressure drop caused by leakage through
the pipe or pipe joints is less than or equal to the specified amount over the
prescribed time period;
(2) For pipes large enough to enter, individual joints may be pressure tested per
Subsection 3.2.3(D)(iv) in lieu of line infiltration, exfiltration or low-pressure air
testing; and
(3) Deflection testing shall conform to Subsection 3.2.3(D)(iv).
Field testing for sliplining installations of FRP shall be based on a CCTV
inspection per Subsection 3.2.3(D)(viii). The CCTV inspection shall be performed
after grouting to assure that all joints are properly assembled, that no damage
exists and that any leakage or deformation is within the allowable limits in
accordance with Subsection 2.3.2(D)(iv).
vii. Reinforced Concrete Pipe (RCP)
In addition to any deficiencies not covered by the applicable ASTM
specifications, individual concrete pipe sections shall be subject to rejection if any
of the following occur:
Surface defects indicating honeycombed or open texture that would
adversely affect the function of pipe sections. Onsite repairs may be
made, if Approved by the Field Engineer;
Damaged ends, that would prevent making a satisfactory joint;
Pipe that has been excessively patched or repaired. The manufacturer
may request that the Field Engineer perform an inspection at the plant,
prior to delivery, to assess patching and/or repair work on conduits. Pipe
damaged during shipment or construction may be repaired with the
Approval by the Field Engineer;
Exposed reinforcement with the exception of the ends of longitudinals,
stirrups, and spacers, that are used to position reinforcing steel, and may
be repaired with the Approval by the Field Engineer;
Concrete pipe delivered to the site greater than 5 calendar days prior to
the start of sewer construction unless otherwise Approved by the Field
Engineer;
Broken bells or spigots on installed pipeline; and
Joint gaps greater than manufacturer’s allowable limits.
Acceptance of the pipe at point of delivery will not relieve the Contractor of full
responsibility for any defects in materials due to workmanship.
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Regional Wastewater Reclamation Department for Construction 2012
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RCP shall be installed in accordance with ASTM C1479 and the latest installation
guides and procedures of the American Concrete Pipe Association (e.g.
Concrete Pipe Installation Guide).
RCP shall be placed with the grove or bell end upstream. Each conduit section
shall be set into position and checked for line and grade prior to continuing
placement. The manufacturers’ recommendations shall be closely followed
during installation.
The Contractor shall ensure that all RCP is kept clean and free from gravel, dirt
and debris during and after installation. Precautions shall be taken by the
Contractor to eliminate soil and debris from being washed into the sewer prior to
completion of sewer construction.
For RCP 30-inches in diameter and greater, if the end-face joint gap is greater
than or equal to 65% of the manufacturer’s limits, the entire internal joint
perimeter shall be grouted with an Approved non-shrink grout product. If the end-
face joint gap is greater than the manufacturer’s limits at any point around the
internal joint perimeter, the adjoining pipe sections will be rejected.
After a reach (manhole-to-manhole) of installed RCP has been backfilled to finish
grade, it shall be tested for excessive leakage in accordance with the applicable
testing requirements of ASTM C924.
C. Service Lateral (HCS/BCS) Connections
Direct connections of 4-inch service laterals to the Public Sewer line shall be
installed in accordance with S.D. RWRD-401 or as Approved per the Sewer
Plans. The spacing between a tapping saddle and: another tapping saddle, a
pipe joint or a manhole shall conform to the pipe manufacturer’s
recommendations. No portion of the tapping saddle or service lateral shall
protrude into the sewer line.
Where indicated in the Sewer Plan, the connection of 4-inch service laterals into
manholes shall conform to S.D. RWRD-402. The connection of 6 inch diameter
service laterals and greater into manholes, shall conform to S.D.s RWRD-200 to
-204. Drop manhole connections for service laterals shall be avoided, unless
indicated in the Sewer Plans or Approved by the Field Engineer. Drop manhole
connections service laterals less than or equal to 6 inches in diameter, shall be
constructed per S.S.D. RWRD-403. Drop manhole connections for service
laterals greater than 6 inches in diameter shall be constructed per S.S.D.s
RWRD-229 or -230, as applicable.
With exception to wye fittings and saddles, the horizontal alignment of service
laterals (HCS/BCS) shall be perpendicular to the sewer line and without bends,
unless otherwise indicated in the Sewer Plans or as Approved by the Field
Engineer.
The vertical alignment of service laterals shall conform to pipe manufacturer
recommendations, local building codes and S.D. RWRD-401. For new or existing
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underground utilities or other obstacles that will hinder the vertical alignment of a
new service lateral, the service lateral may be rerouted per S.D. RWRD-400.
For existing service laterals encountered during non-sewer related construction,
the service laterals shall be protected, repaired or rerouted per S.D. RWRD-400,
as the situation dictates and at no expense to the Department or the property
owner.
Backfill material for service laterals, located within Right-of-Way and Public
Sewer easements, shall be compacted in accordance with Subsection 3.1.3(F).
Cleanout risers shall be constructed for 4-inch service laterals per S.D. RWRD-
404. For buried cleanout risers (i.e. Type III), the Contractor shall be responsible
for completing and submitting a Memorandum of Understanding for Type III
Buried Cleanout Risers form to the Field Engineer, prior to Construction
Acceptance. The completed form must be signed and dated by the
owner/developer of the Project and a representative from the home builder.
Contact the Field Engineer for the latest version of this form.
Temporary caps shall be furnished and installed at the end of new service
laterals. Installed caps shall be capable of withstanding earth loads and low-
pressure air testing.
An Approved marking tape for service laterals shall be installed in accordance
with S.D. RWRD-401. The marking tape shall have continuous printing stating,
“CAUTION: PRIVATE HCS/BCS”, unless otherwise Approved by the Field
Engineer.
The method of disconnection and abandonment for existing service lateral
connections will be determined on a case-by-case basis by the Field Engineer.
Any damage to existing Public Sewers as the result of a new service lateral
connection shall be reported immediately to the Field Engineering section. On
weekends, Holidays or after business hours, immediately report to the Pima
County Sheriff’s office. Any costs incurred by the Department for repairing
damage to Public Sewers will be billed to the Applicant of the new sewer
connection. The Agency having jurisdiction over the building codes will be asked
not to release permits or certificates of occupancy until the Department has
received payment.
D. Sewer Line Testing and Tolerances
The construction of new Public Sewer lines shall be inspected and tested in
accordance with the applicable methods specified in AAC R18-9-E301(D) and as
required by the Department.
i. General
During the construction of Public Sewers, the Contractor shall provide access to
the trench and installed pipe to allow for inspections by the Field Engineer.
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ii. Mirror Inspections
Mirror inspections shall be used for identifying alignment deficiencies in a sewer
line during the progress of construction and prior to the final CCTV inspection.
Each sewer line reach (manhole-to-manhole) shall be visually inspected by
directing a beacon of light into the pipe from a light source such as a flashlight or
reflecting sunlight with the use of mirrors. If the illuminated interior or “moon” of
the pipe indicates deficiencies in alignment such as bellies, sags, reverse slopes
or offset joints, the Contractor shall correct the alignment deficiency prior to the
final CCTV inspection.
iii. Low-Pressure Air Testing
After new sewer lines and service laterals (HCS/BCS) are constructed and
backfilled to finish grade, each reach shall be tested for no excessive leakage by
low-pressure air testing. The requirements for low-pressure air testing shall be in
accordance with the applicable methods specified in AAC R18-9-E301(D) and
the installed pipe material’s air testing requirements. Sewer lines and service
laterals found with excessive leakage shall be corrected by the Contractor and
re-tested as necessary until the results are passing. Testing results and any
required corrections shall be documented by the Contractor and provided to the
Field Engineer.
Low-pressure air testing for a reaches sewer line with composite pipe materials
(i.e. PVC with DIP sections) shall be in accordance with the predominant pipe
material within that reach.
iv. Joint Testing
For sewer lines greater than 48 inches in diameter, low-pressure air testing may
be superseded by testing each pipe joint for no excessive leakage in accordance
with ASTM C1103 (RCP) and the applicable pipe manufacturer
recommendations. Pipe joints found with excessive leakage shall be corrected by
the Contractor and re-tested as necessary until the testing are passing. Testing
results and any required corrections shall be documented by the Contractor and
provided to the Field Engineer.
Specific guidelines for joint testing procedures are provided in the following:
(1) Joint Testing Equipment
The Contractor shall provide all materials, labor and equipment necessary for
joint testing.
The joint tester frame assembly shall be constructed of a heavy gauge metal
that can be broken down easily into small sections for ease of handling and
installation/removal from sewer manholes.
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Regional Wastewater Reclamation Department for Construction 2012
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The joint tester shall have either single or double-bladder construction. The
single bladder shall be of a one-piece construction within an outer layer of a
soft, natural rubber, between the pipe and tester.
The double-bladder tester shall have 2 inflatable bladders constructed of
rugged heavy-duty elastomer. The bladders shall be stretched and positioned
onto the joint tester frame assembly so that they can be aligned over the joint
to be tested. When inflated, the bladders shall create an air-tight seal against
the pipe wall.
The control panel for the joint test shall provide a reliable means of controlling
and monitoring bladder and center cavity pressures. The control panel shall
be conveniently mounted onto the joint tester frame assembly and require
only input air from the compressor.
Wheel assemblies shall be mounted to the inside surface of the joint tester
frame. The Contractor shall be capable of efficiently moving and centering the
joint tester to each pipe joint.
An air reservoir shall be included in the joint test system and shall have a
maximum volume of 2.5 cubic feet. Hoses shall be provided to route air from
the control panel to the air reservoir and from the air reservoir to the center
cavity chamber.
(2) Joint Testing Procedure
The test pressure shall be 3.5 psi unless otherwise specified by the pipe
manufacturer.
Position the joint tester so the bladder(s) are properly located over the joint to
be tested. Inflate the bladder(s) to 50 psi or in accordance with testing
equipment and manufacturer's instructions.
Begin pressurizing the center cavity chamber. When the testing pressure is
reached, turn off the pressure source and allow the pressure to stabilize for
approximately 10 to 15 seconds.
If the pressure drops less than or equal to 1 psi for a period of 5 seconds, the
pipe joint is acceptable. If the pressure drops more than 1 psi for a period of 5
seconds, the joint is defective and shall be repaired and retested.
When the joint test is completed, all pressure must be exhausted from center
cavity to 0 psi and then from the bladder(s) to 0 psi. The joint tester can then
be transported and positioned on the next joint to be tested.
(3) Sealing of Failed Joints
If Approved by the Field Engineer, the Contractor may seal a joint to ensure
that it is watertight instead of a joint test. The sealing method shall consist of
the following steps:
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Regional Wastewater Reclamation Department for Construction 2012
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Prime the sides of the concrete joint according to the primer
manufacturer’s instructions;
Install a backer rod of a certain size, in the bottom of the joint, so as to
leave a ½- to ⅝-inch depth for the flexible sealant; and
Install a non-sagging, two-component elastomeric sealant in accordance
with the sealant manufacturer’s instructions.
v. Hydrostatic Pressure Testing
After a new force main is backfilled to finish grade, it shall be tested for no
excessive leakage by hydrostatic pressure testing. Water from a potable water
source shall be used for this testing procedure. The requirements for hydrostatic
pressure testing shall be in accordance with the applicable methods specified in
AAC R18-9-E301(D) and the installed pipe material’s testing requirements. If the
results of the testing indicate excessive leakage in the force main, it shall be
corrected by the Contractor and re-tested as necessary until the results are
passing. Testing results and any required corrections shall be documented by the
Contractor and provided to the Field Engineer.
The Contractor shall verify that all inline valves and air relief valves, located
along the test section of the force main, are completely open during filling and
testing of the force main with water. After the force main is filled with water, it
shall stand under a slight pressure (3-psi) for at least 48 hours prior to performing
the hydrostatic pressure test. This retention period is necessary to allow for the
release of entrained air and entrapped air bubbles. During this retention period,
bulkheads, valves, and other accessible pipe connections shall be examined for
leaks and repaired by the Contractor, prior to hydrostatic pressure testing.
vi. Mandrel Deflection Testing
New sewer lines having flexible pipe materials (e.g. PVC, HDPE, FRP), shall be
tested for uniformity in shape, by a mandrel deflection test. The mandrel
deflection test shall occur at least 7 days after backfill compaction has been
completed and prior to Construction Acceptance of the Project. Deflection testing
shall be conducted using a deflection testing mandrel (go/no-go mandrel) per
S.D. RWRD-107. Mandrels shall be pulled completely through each reach by
hand (1 person) and without requiring the use of excessive force (e.g. use of
tools, leverage or machinery). If a mandrel becomes caught or bound, the reach
shall fail the test. Failed reaches shall be corrected by the Contractor and re-
tested as necessary until passing.
For sewer lines greater than 48 inches in diameter, other methods of deflection
testing such as direct measurements using extension rulers or the successful
completion of joint testing, may be Approved by the Field Engineer.
vii. Slope Tolerances
The Contractor shall make every effort possible to ensure that the constructed
slopes of sewer lines conform to the Sewer Plans. If a slope error is found in the
Sewer Plans or if the constructed slope of a sewer line does not conform to the
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-27 Standard Specifications
Sewer Plans, the Contractor shall notify the Field Engineer immediately. Table
3.1 is provided as a guideline for determining the allowable slope tolerances for
8-inch diameter sewer lines. For larger diameter sewer lines, the allowable slope
tolerances will be determined by the Department. In no case, shall slope
tolerances allow for constructed slopes to be less than the minimum slopes
required per AAC R18-9-E301(D)(2)(e).
For constructed slopes of sewer lines that are not within the slope tolerances
specified by the Department, the Contractor may request a Variance in
accordance with the Design Standards, Subsection 2.3. The Department will
review the request and elect one of the following options:
Approve the Variance request;
Require the As-Built Plans to be certified by the Design Engineer with a
statement indicating that the constructed sewer meets the intent of the
design and conforms to R18-9-E301 – 4.10 General Permit; or
Require unacceptable sewer construction to be removed and
reconstructed in accordance with the Sewer Plans.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-28 Standard Specifications
Table 3.1
Allowable Slope Tolerances for
8-inch Diameter Sewer Lines (ft/100ft)
Slope per Sewer
Plan Tolerable Range
Lower Limit Upper Limit
0.33* 0.33* 0.39
0.34 0.33* 0.40
0.35 0.33* 0.41
0.36 0.33* 0.42
0.37 0.33* 0.43
0.38 0.33* 0.44
0.39 0.33* 0.45
0.40 0.34 0.46
0.41 0.35 0.47
0.42 0.36 0.48
0.43 0.37 0.49
0.44 0.38 0.50
0.45 0.39 0.51
0.46 0.40 0.52
0.47 0.41 0.53
0.48 0.42 0.54
0.49 0.43 0.55
0.50 0.44 0.56
0.51 0.45 0.57
0.52 0.46 0.58
0.53 0.47 0.59
0.54 0.48 0.60
0.55 0.49 0.61
0.56 0.50 0.62
0.57 0.51 0.63
0.58 0.52 0.64
0.59 0.53 0.65
0.60 0.54 0.66
0.61 0.55 0.67
0.62 0.56 0.68
0.63 0.57 0.69
0.64 0.58 0.70
0.65 0.59 0.71
0.66 0.60 0.72
0.67 0.61 0.73
0.68 0.62 0.74
0.69 0.63 0.75
0.70 0.64 0.76
0.71 0.65 0.77
0.72 0.65 0.79
0.73 0.66 0.80
0.74 0.67 0.81
0.75 0.68 0.83
0.76 0.68 0.84
0.77 0.69 0.85
*Minimum slope per AAC R18-9-E301(D)(2)(e)
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-29 Standard Specifications
viii. CCTV Inspection
Each reach of newly constructed sewers shall be inspected by CCTV after it has
passed all other required testing per Subsection 3.2.3(D). The CCTV inspection
shall occur at least 7 Days after the compaction of backfill is completed. The
CCTV inspection shall serve as a final verification that alignment deficiencies do
not exist within the newly constructed sewers. Alignment deficiencies may,
include, but are not limited to; bellies, sags, reverse slopes and offset joints. If
alignment deficiencies are found during the CCTV inspection, it shall be
corrected by the Contractor and the reach re-tested and inspected as necessary
until the results are passing.
The Department will be responsible for providing one CCTV inspection service
for each reach. The Contractor shall be responsible for subsequent CCTV
inspections of any reach. CCTV inspections may occur after the Bill of Sale is
issued and during the Contractor’s warranty period. The Contractor shall be
responsible for providing required corrective actions as a result of alignment
deficiencies that may be found.
On the day before the scheduled CCTV inspection, the Contractor shall perform
a “water dump” for the reaches to be inspected. The “water dump” shall supply
water, from a potable source, to the upstream manholes of the new sewer lines
so that water runs completely through. The downstream manhole(s) of these
reaches shall be dewatered prior to the CCTV inspection.
The Contractor shall provide sufficient vehicular access to the reach manholes.
The Contractor shall ensure that the reaches to be inspected and associated
manholes are free of dirt and debris. If dirt or debris is found in a reach, the
CCTV inspection for that reach will be abandoned and rescheduled for another
day. A remobilization fee will be charged to the Contractor for rescheduled
inspections due to dirt or debris within a reach.
If any standing water is found within a reach, the maximum depth and length of
the sag will be measured with CCTV equipment. Table 3.2 provides guidelines
for determining if corrective actions are required by the Contractor for found
sags.
The Contractor shall bear all costs incurred for required corrective actions and
subsequent CCTV inspections of repaired reaches. The corrective actions by the
Contractor shall minimize the use of repair couplings, as directed by the Field
Engineer. Required corrective actions as a result of pipe material defects or other
construction defects will be determined the Field Engineer on a case-by-case
basis.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-30 Standard Specifications
Table 3.2
Allowable Tolerances for Sags Found within a Reach
Reach Dia.
[inches] Sag Depth
[inches] Sag Length
[feet] Corrective
Action
Required
8 to 12 Less than or equal to ⅝
inch N/A No
8 to 12 Greater than ⅝, but less
than or equal to 1¼ inches Greater than 10 or more than
3 occurrences within 100 feet Yes
8 to 12 Greater than 1¼ inches N/A Yes
14 to 24 Less than or equal to
1¼ inches N/A No
14 to 24 Greater than 1¼, but less
than or equal to 2 inches Greater than 20 or more than
3 occurrences within 100 feet Yes
14 to 24 Greater than 2 inches N/A Yes
Notes:
(a) Corrective actions required will be determined by the Field Engineering section for reach
diameters greater than 24 inches having sags greater than 5% of the diameter.
(b) Ponded water as a result of manhole construction shall require corrective action.
(c) For multiple sags, corrective actions shall occur in the order of severity (highest first).
For CCTV inspections services provided by the Department, the Field Engineer
shall be responsible for:
Scheduling CCTV inspections with the Contractor;
Monitoring “water dumps”;
Monitoring CCTV inspections;
Within 1 Day of the CCTV inspection, providing the Contractor with a copy
of the CCTV inspection reports and photos of any alignment deficiencies;
and
Within 1 Day of the CCTV inspection, providing the Contractor with a written
report disclosing all required corrective actions.
The Contractor shall provide written notice to the Field Engineer, at least 3 weeks
in advance, to schedule CCTV inspections.
If possible, the Department will accommodate CCTV inspection scheduling for
special circumstances. Such requests shall be arranged with the Field Engineer
during the pre-construction meeting. If a CCTV inspection is scheduled less than
3 weeks of the pre-construction meeting, the Department will commit to an
inspection date at the pre-construction meeting.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-31 Standard Specifications
The Contractor shall re-confirm the scheduled CCTV inspection with the Field
Engineer a minimum of 2 Working Days in advance. The Field Engineer will also
notify the Contractor of any scheduling delays, a minimum of 2 Working Days in
advance. If the Contractor cancels a scheduled CCTV inspection less than 2
Working Days in advance, a re-mobilization fee will be charged to the Contractor.
CCTV inspections may be phased if Approved by the Field Engineer, however, a
mobilization fee will be charged for additional trips.
If the Department cannot commit to a requested date for CCTV inspection, the
Contractor may obtain CCTV inspection services by a qualified subcontractor, in
accordance with the following guidelines:
At the time of scheduling, the Contractor shall obtain Approval from the
Field Engineer for CCTV inspection services by a subcontractor;
CCTV inspection by a subcontractor shall be conducted under the
observation of the Field Engineer;
CCTV inspections by a subcontractor shall be conducted in accordance
with NASSCO guidelines;
CCTV inspection reports and a continuous video of each reach (DVD
format) shall be provided to the Field Engineer;
CCTV equipment and software shall be expressly designed for pipeline
inspection purposes and operated by NASSCO-certified personnel;
Subsequent CCTV inspections by a subcontractor shall use the same data
management processes as the prior CCTV inspection;
CCTV equipment and software shall be Approved by the Field Engineer
prior to use;
The CCTV camera shall have a mechanical gauge to record the depth of
any standing water; and
The mechanical gauge shall clearly indicate markings of ⅝-inches and
1¼-inches for reaches having a nominal diameter of 8-inches to 12-
inches, and markings of 1¼- and 2-inches for reaches having a nominal
diameter of 15 inches to 24 inches.
If the CCTV inspection services by a subcontractor strictly adhere to the
Departments standards, it shall serve as the final CCTV inspection. Non-
conforming or incomplete CCTV inspections for any reach may require a
subsequent CCTV inspection by the Department, prior to Construction
Acceptance.
E. Markers and Monuments
Force mains shall be installed with a tracer wire and metallic marking tape in
accordance with S.D. RWRD-500 and -501. Test stations per S.D. RWRD-501
and force main monuments per S.D. RWRD-503, shall be located as indicated
per the Sewer Plans.
Abandonment monuments per S.D. RWRD-503 shall be located in accordance
with the Sewer Plans or as Approved by the Field Engineer.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-32 Standard Specifications
F. Casing and Carrier Pipe
Casing pipe material for Public Sewer lines shall conform to Subsection 3.4.2
and installed in accordance with S.D. RWRD-100. Casing joints shall be
continuous circumferential welds in accordance with AWWA C206. Any casing
showing signs of failure shall be rejected and replaced.
All casing spacers and end seals shall be Approved and installed in accordance
with S.D. RWRD-100 and the manufacturer’s recommendations. Refer to the
Department’s List of Approved Products for the recommended casing spacers
and end seals.
G. Modifications and Repairs
Modifications and repairs to existing sewer lines shall conform to S.D.s RWRD-
102 and RWRD-103. All sewer modifications and repairs shall be inspected by
the Field Engineer prior to being backfilled. Placement and compaction of
bedding, shading and backfill material shall conform to the applicable
requirements of Subsection 3.1.3.
The Contractor shall replace "in kind" any existing survey monuments damaged
or disturbed during construction (including property pins). This replacement shall
be performed by an Arizona Registered Land Surveyor and shall also require a
record of survey.
H. Abandonment of Pipe
Existing Public Sewer lines that are to be abandoned shall be removed
completely. Where indicated in the Sewer Plans or Approved by the Field
Engineer, existing Public Sewer lines that are to be abandoned-in-place shall be
filled with grout. Existing Public Sewer lines that are abandoned-in-place shall be
marked with an abandonment monument per Subsection 3.2.3(H) and S.D.
RWRD-503.
The removal of asbestos cement pipe material and other asbestos containing
material shall conform to the requirements of Section 940 of the PAG Standard
Specifications.
Debris that is generated by the removal of existing Public Sewer lines shall be
removed from the site by the Contractor and disposed of at an appropriate solid
waste facility. The Contractor shall furnish the Field Engineer the original copy of
the dumping receipt. Disturbed areas shall be backfilled with backfill material per
S.D. RWRD-104 and compacted to a minimum density of 95% of the standard
proctor density in accordance with the provisions of the Arizona Test Method 225
and the compaction standards set forth by the Agency controlling the Right-of-
Way.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-33 Standard Specifications
3.3 Sanitary Sewer Manholes
3.3.1 Description
The work under this subsection consists of furnishing all materials required to
construct, modify or adjust sanitary sewer manholes as indicated in the Sewer
Plans and the Standard Specifications and Details.
3.3.2 Materials
A. Concrete
Portland cement shall conform to the requirements of ASTM C150. Type II
Portland cement shall be used for concrete unless otherwise specified in the
Sewer Plans or the Special Provisions. All other materials furnished for Portland
cement concrete shall conform to the requirements of Section 1006 of the PAG
Standard Specifications. Concrete design mixture shall be class “S” and have a
minimum 28-day compressive strength of 3,000 psi, unless otherwise specified in
the Sewer Plans or Special Provisions.
B. Reinforcing Steel
Materials furnished for reinforcing steel shall conform to the requirements of
Section 1003 of the PAG Standard Specifications.
C. Grout and Mortar
Portland cement shall conform to the requirements of ASTM C150. Type II
Portland cement shall be used for grout and mortar, unless otherwise specified in
the Sewer Plans or Special Provisions. All other materials furnished for grout and
mortar shall conform to the requirements of Section 914-2.03 of the PAG
Standard Specifications.
Approved non-shrink grout products shall conform to the requirements of Section
1017-4 of the PAG Standard Specifications. Refer to the Department’s List of
Approved Products for the recommended non-shrink grout products.
D. Water
Water shall conform to the requirements of Subsection 1006 of the PAG
Standard Specifications.
E. Precast Concrete Manhole Sections
Precast concrete manhole sections shall be free from cracks, voids and other
defects and shall conform to the requirements of ASTM C478 and AASHTO
M199. Precast concrete manhole sections shall include:
Bases
Risers
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-34 Standard Specifications
Cone and Flat Top Transitions
Cones
Flat Top Slabs
Grade Adjustment Rings; and
Joint Adapters.
F. Interior Corrosion Protection
Refer to the Department’s List of Approved Products for the recommended
products for the interior corrosion protection of manholes.
G. Steps
Steps for precast and cast-in-place manholes shall be approved and conform to
the requirements of ASTM C478, D4101 and A615. Steps shall be reinforced
with ½-inch diameter, grade 60 steel and coated with polypropylene plastic.
Refer to the Department’s List of Approved Products for the recommended
manhole steps.
H. Frames, Covers and Hatches
Frames and covers for Public Sewer manholes shall conform to S.D.s RWRD-
213 to -218, unless otherwise Approved by the Field Engineer. In these cases, a
certificate of compliance with Subsection 3.3.2(H) shall be provided from the
manufacturer upon request.
All castings shall be true to pattern, in form and dimension, and free from pouring
faults, sponginess, cracks, blowholes, or other defects in locations affecting their
strength for the service intended. Castings shall be filleted boldly at angles and
the risers shall be sharp and true. Before the castings are removed from the
foundry, they shall be thoroughly cleaned and the parting lines, gates and risers
shall be ground flush. No plugging or other stopping of holes shall be allowed.
The castings shall be thoroughly cleaned of all lumps and shall be subject to a
careful hammer test.
Lettering for covers shall be standard raised block type, and shall be 1½ to 2½
inches high. The total width of individual letters are to be such that letters and
words are equally spaced and balanced to form a complete circle with spaces
before and after words.
The top surface of the cover shall sit flush with the top surface of the frame. A
uniform ⅛ inch clearance shall exist between the edge of the cover and the
frame. All horizontal bearing surfaces shall be machine finished.
The weight of the frame and cover shall be no more than 2% less than the
approximate weight specified in the applicable standard detail for each
component.
Frames and covers shall be manufactured from gray iron, conforming to the
requirements of ASTM A48, Class 35B. Frames and covers shall be designed for
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-35 Standard Specifications
H-20 loading inclusive of the proof load requirements outlined in Section 7 of the
American Association of State Highway and Transportation Officials (AASHTO)
Standard Specification for Drainage Structure Castings, ASSHTO Designation M
306.
Frames and covers shall be made from ferrous materials using at least 75%
post-consumer waste. The basic design, initial sample castings and first article
inspection (also known as first proof load tests) must be Approved by the Field
Engineering manager before delivery to suppliers or Contractors.
The bearing surfaces of the frames and covers shall be machine finished so that
the covers will seat themselves firmly onto the frame. Vehicular traffic shall not
cause the frame to move. A 1/8-inch annular clearance shall be provided between
frame and cover.
The design and construction of private sewers may utilize, or make reference to
certain Department specifications and details; however, the covers for private
manholes shall not be imprinted with the words "Pima County Sanitary Sewer".
Manholes to be owned and operated by a private entity shall be unlabeled or
have the following words cast into them "Private Sanitary Sewer", or other
appropriate designation.
I. Flexible Joint Gaskets
Preformed flexible plastic gaskets for the sealing the joints of precast concrete
manhole sections shall be Approved and conform to ASTM C990 or AASHTO
M198B. Refer to the Department’s List of Approved Products for the
recommended flexible joint gaskets.
3.3.3 Construction Details
A. Excavation and Backfill
Excavation for new manhole construction shall be in accordance with Subsection
3.1.3(A) and Section 203 of the PAG Standard Specifications. The foundation for
new manhole bases shall conform to Subsection 3.1.3(B) or as Approved by the
Field Engineer.
The Department assumes no liability for damage to, or removal of, any
vegetation, above ground or below ground facilities, surface treatments,
materials, equipment, or structures placed within Public Sewer easement or
within 20 vertical feet of its surface.
Backfill material for new manholes shall conform to Subsection 3.1.3(E) and S.D.
RWRD-104.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-36 Standard Specifications
B. Installation of Manholes
i. Manhole Bases
For 48-inch and 60-inch diameter manholes, the base and the flow channel
configuration shall be constructed in accordance with S.D.s RWRD-200, -201
and -202, unless otherwise indicated in the Sewer Plans or as Approved by the
Field Engineer. For larger diameter manholes, the base and flow channel
configuration shall be constructed as indicated in the Sewer Plans.
In no case shall any pipe within the manhole discharge onto the surface of the
bench.
Flow channels shall be constructed to conform in size and shape to that of the
interior surface of the connected pipes. Flow channels shall be free of sags and
sloped to convey flow from the influent pipes to the outgoing pipes. Flow
channels shall not obstruct flow or cause water to pond within the influent pipes.
If additional concrete or mortar is needed after the initial set, the receiving
surface shall be primed and mixed with an Approved adhesive in order to secure
a surface that is as chip-proof as possible. The base shall be set a minimum of
72 hours before the manhole construction is initiated.
For a new manhole constructed over an existing sewer line, a saw cutter shall be
used to remove the top portion of the pipe. This cut-out shall take place under the
inspection of the Field Engineer. The Contractor shall be careful to prevent
cuttings from falling into the pipe. If this occurs, the Field Engineer may require
the Contractor to clean the sewer line. After a cut-out, the edges of the pipe shall
be filled and smoothed with mortar.
ii. Block-Outs
Where designated in the Sewer Plans as a provision for the connection of a
future sewer line, a block-out shall be built into the manhole per S.D. RWRD-203.
iii. Precast Concrete Manhole Sections
Precast manhole sections shall be installed in accordance with S.D.s RWRD-205
and -206 and the manufacturer’s recommendations.
Precast sections will be inspected by the Field Engineer at the job site and may
be rejected if any of the following deficiencies exist:
Fractures or cracks passing through the wall, except for a single end crack
that does not exceed the depth of the joint;
Defects that indicate imperfect proportioning, mixing, and molding;
Surface defects indicating honeycombed or open texture;
Damaged or cracked ends, where such damage would prevent making a
satisfactory joint; or
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-37 Standard Specifications
Any continuous crack having a surface width of 0.01 inches or greater and
extending for a length of 12 inches or greater, regardless of position in the
section wall.
Proper equipment shall be provided for lowering the precast sections into
position. The tongue end of the section shall be placed in contact with the base
structure, unless otherwise Approved by the Field Engineer. Not more than two
lifting holes shall be cast or drilled in the wall of each section. All lifting holes shall
be filled with an Approved sealing compound on the exterior side of the wall and
a minimum of ½-inch deep on the interior side of the wall. Any precast section
damaged during transportation or placement shall be repaired or replaced at the
option of the Field Engineer and at the Contractor's expense.
All precast manhole section joints shall be sealed with a preformed flexible
plastic gasket in accordance with Subsection 3.3.2(I). The gasket shall be
installed in accordance with the following requirements:
The sealing compound shall be packaged in an extruded pre-formed rope-
like shape of proper size to completely fill the joint when fully compressed;
The material shall be protected by a suitable, removable wrapper;
The joint surfaces shall be clean and free of mud, silt, gravel or other
foreign material prior to the installation of the sealing compound; and
Installation shall be accomplished in accordance with the manufacturer's
instructions as to the method of application, quantity of material, quality of
material, and the application temperatures.
For manholes located in ground water conditions, the exterior surface of precast
sections and joints shall be coated with an Approved waterproofing sealant.
iv. Steps
Steps for precast manholes shall be installed during the manufacture of precast
sections and configured per S.D. RWRD-210. Steps within each manhole shall
be of the same product and size. Loose steps shall cause rejection of the precast
manhole section.
Steps for cast-in-place manholes shall be installed in accordance with the step
manufacturer’s installation requirements. Holes for step installation shall be
properly sized and formed prior to casting, or the holes shall be drilled into the
walls after the concrete has fully cured. The use of grout to secure loose steps
shall be prohibited.
v. Cast-in-Place Manholes
When specified in the Sewer Plans, manholes with diameters greater than 60-
inches may be cast-in-place. Class “S” concrete, having a minimum compressive
strength after 28 Days of 3,000 psi, shall be required for manhole bases. Class
“S” concrete, having a minimum compressive strength after 28 Days of 4,000 psi,
shall be required for manhole walls. Class “B” concrete shall be used for all other
portions of the manhole not subjected to corrosive gases (e.g. protective collar).
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-38 Standard Specifications
Portland cement shall conform to the requirements of ASTM C150 for Type II
cement, unless stated otherwise in the Sewer Plans.
Cast-in-place concrete manholes shall be placed in accordance with the
requirements of Section 601 of the PAG Standard Specifications and ACI-318.
The location of the manhole shall conform to the requirements of the Sewer
Plans, unless otherwise Approved by the Field Engineer and before the
placement of concrete.
All absorptive surfaces that may come in contact with the concrete, shall be
moistened sufficiently to minimize moisture loss from the freshly-poured
concrete.
The trench or excavated area must be free of water, dirt, mud and debris before
the concrete is poured.
Floor slabs with walls shall be washed free of sawdust, chips, and other debris,
after wall forms are built and immediately before the concrete pour. Should the
form work confine sawdust, chips and other loose matter in such a manner that it
is impossible to remove by flushing with water, a vacuum cleaner shall be used
for removal. Following this action, the cleaned surfaces shall be flushed with
water.
Before pouring concrete, the forms shall be coated with a non-staining lubricant
to prevent adherence of concrete. All forms and form lumber, once used, shall be
thoroughly cleaned and contact surfaces re-coated before being used again.
Dirty forms shall not be used. Forms may be either metal or wood, and shall be
built true to shape, line and grade. Forms shall be mortar-tight and sufficiently
rigid to prevent displacement or sagging between supports. Deformed, broken or
defective forms shall not be used and removed from the job site.
Contact surfaces for exposed concrete shall be made from plywood, metal or
non-warping fiberboard. The pieces used shall be as large as the form layout
permits. Small pieces shall not be patched together.
Square-edge lumber may be used as forms for concrete surfaces that will be
buried or not exposed to view after construction is completed.
All form work shall have adequate cleanout openings to permit inspection and
easy cleaning after all reinforcement has been placed.
When the forms are removed, no metal form ties shall remain within ¾-inch of
the surface of the concrete or any holes larger than ⅞-inch diameter in the
surface of the concrete. Ties made from wire shall not be permitted.
All external angles of beams, columns, edges of concrete structures and sides of
walls shall have a ¾-inch chamfer unless otherwise indicated in the Sewer Plans.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-39 Standard Specifications
vi. Grade Adjustment Rings
Adjustments for existing manholes shall conform to S.D.s RWRD-304 and -305.
A minimum of one precast concrete grade adjustment ring shall be provided to
allow for flexibility in future elevation adjustments. The maximum height of grade
adjustment rings shall not be greater than 12 inches (e.g. two 6-inch rings). The
inside diameter of the grade adjustment ring(s) shall not be less than the inside
diameter of the manhole frame.
vii. Frames, Covers and Hatches
Frames and covers for new manholes shall be installed and adjusted in
accordance with S.D. RWRD-205, -206 and -207, as applicable. Frame
elevations shall be as indicated in the Sewer Plans unless otherwise Approved
by the Field Engineer. Where the frame is located in pavement or a traveled way,
its surface shall be flush with the finish grade. A protective concrete collar shall
be constructed in accordance with S.D. RWRD-211 if required by the Agency
having jurisdiction over the Right-of-Way or if indicated in the Sewer Plans.
Where the frame is located outside of pavement or a travelled way, a protective
concrete collar shall be constructed in accordance with S.D. RWRD-212, unless
otherwise Approved by the Field Engineer.
The Contractor shall thoroughly scrape and clean all foreign materials from the
manhole frames and covers prior to their installation. All frames and covers shall
be free of grease, oils, asphaltic materials, and any other deleterious materials.
All vent holes, pick bars and bolt holes shall be free of dirt, rocks, concrete and
other obstructions prior to Construction Acceptance.
Hatch assemblies for larger manholes and vaults shall be cast into the top of the
slab, unless otherwise Approved by the Field Engineer.
viii. Interior Corrosion Protection for New Manholes
If interior corrosion protection is required for a new manhole, it shall be applied to
the walls, benches and flow channels. All surfaces shall be cleaned and prepared
in accordance with the coating manufacturer’s recommendations. Concrete
surfaces that may be contaminated with oils, grease, or other substances, shall
be scarified or chemically cleaned. All cracks and voids shall be filled with an
underlayment to provide a smooth surface. All manhole joints, and cracks that
exist between the manhole steps and the wall, shall be caulked using a hybrid
novolac-epoxy caulk, or other Approved caulk. Trowel marks and other minor
surface irregularities shall be removed from all surfaces that will be coated. Any
new concrete added to the surface shall receive a dry abrasive brush-off blasting
using a minimum pressure of 90 psi to lightly abrade the surface and open up
subsurface holes and voids and etch the surface sufficiently (to approximately a
60 grit sandpaper texture) to allow the coating to bond satisfactorily.
An epoxy primer/sealer coat shall be applied to all concrete surfaces before the
final coating is applied. The temperature of the existing concrete surfaces shall
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-40 Standard Specifications
not vary 15° F or greater, from the top to the bottom of the manhole. The epoxy
primer/sealer shall be applied in accordance with the manufacturer’s instructions.
The color of the final coat shall be charcoal gray or white, unless otherwise
Approved by the Field Engineer. The final coating shall be applied with a
minimum dry film thickness coating of 3/16 inches. Spray application of coatings
will be allowed if the spray equipment complies with the coating manufacturer’s
recommendations. A rougher surface shall be provided for the bench by using a
short nap mohair paint roller. After the coating has been applied, all surfaces
shall be tested for Holidays utilizing a dry conductive probe with a minimum of
17,000 volts. If no Holidays are found, a certification shall be submitted to the
Field Engineer.
The Contractor that will apply the coating for the interior corrosion protection of
manholes shall meet the following requirements:
Provide a performance history showing a minimum experience of 5 years
in applying either the specified coating or an equivalent coating used in the
wastewater industry;
Have a current AE type license with the Arizona Registrar of Contractors
for the application of specialized coatings for sanitary sewer manholes;
Provide a certification from the manufacturer for the application of the
coating that will be applied;
Provide 3 references relating to the quality of workmanship performed on
other Projects that use the same coating that will be applied or an
equivalent coating;
Provide a 3-year warranty, from the date of Construction Acceptance. The
warranty shall include a bond that is payable to the Department. The bond
shall cover both the material costs and the labor costs associated with the
coating. The bond shall be unconditional in nature covering any type of
failure in the coating. The bond shall agree to repair or replace the coating
at no cost to the Department. The bond and warranty shall not apply to
manhole frames and covers. Due to the limits on available bonding terms
for coatings, the Contractor may supply a two-year bond, followed by a
one-year bond;
Provide a warranty from the coating manufacturer that is addressed to the
bonding company and the Department. At a minimum, the warranty shall
state that if the coating is applied in accordance with the manufacturer's
recommendations, it will not fail for a period of 5 years, while the coating is
immersed in either an acidic or an alkaline solution that is maintained at a
temperature of 85° F. The acidic solution shall be considered a 10% by
weight concentration of sulfuric acid. The alkaline solution shall be
considered a 25% by weight concentration of sodium hydroxide. Blistering,
cracking, brittleness or softening of the coating shall constitute failure;
The Department will conduct inspections of the coating and may request any
necessary corrections, prior to expiration of the bond.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-41 Standard Specifications
ix. Reinforced Joints
When specified in the Sewer Plans or as directed by the Field Engineer, precast
manhole sections shall be installed with reinforced joints per S.S.D. RWRD-209.
C. Manhole Installation Testing and Tolerances
For pipe deflection angles from 0 to 9 degrees, the flow channel shall not be flat
and shall drain into the downstream pipe. For pipe deflection angles from 10 to
45 degrees, the pipe invert elevation tolerance may be plus or minus 0.05 feet.
For pipe deflection angles from 46 to 90 degrees, the pipe invert elevation
tolerance may be plus or minus 0.10 feet.
In any case where there is a deviation in the constructed pipe invert, the following
criteria shall be met:
Pipe slope tolerances per Subsection 3.2.3(D) are followed;
Flow is conveyed through the flow channel to the downstream pipe; and
There is no standing water in the flow channel or in the upstream
connected pipes.
The Field Engineer may require testing to verify that the manhole is watertight.
Testing shall be conducted after the trench around the manhole has been
backfilled. The negative air pressure test, as specified in ASTM C1244, or a
water test, as specified in AAC R18-9-E301, shall be used to test all manholes.
Repairs shall be provided whenever leakage exceeds the test limit.
D. Modification of Existing Manholes
Prior to commencing work on any existing Public Sewer manhole, a sewer
Construction Permit shall be secured from the Department. The Contractor shall
be responsible for payment of all applicable fees associated with the
Construction Permit. See Subsection 1.4.1 for more information. Each manhole
shall be thoroughly cleaned and kept clean throughout the duration of sewer
construction.
The Contractor shall observe all traffic requirements set forth by the Agency
having jurisdiction over the Right-of-Way. Streets shall be kept open for passage
of traffic. Protection for the public shall be provided when the manhole excavation
occurs. The manhole construction work shall be completely and adequately
covered when no work is being done. Flow management of wastewater from
Public Sewers shall be accomplished by pumping to a nearby existing manhole
or to a tank truck for proper disposal.
i. Reset Frame and Cover
Grade adjustments for existing manholes shall conform to S.D.s RWRD-304 and
-305. Where an existing manhole will be adjusted for roadway improvements, the
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-42 Standard Specifications
Contractor shall contact the Field Engineer as early as possible to arrange for an
inspection and identify any additional requirements (e.g. reconstruction).
Prior to any adjustment, the bench and flow channels shall be protected with a
cover in accordance with S.D. RWRD-306. The cover shall be removed only after
all modification work is completed or as Approved by the Field Engineer.
If and existing frame and cover will be temporarily removed for pavement
construction, a steel plate of a size and thickness, Approved by the Field
Engineer, shall be placed over the manhole opening. After paving is completed,
the steel plate shall be removed by cutting and removing the material above it.
Care shall be taken so that materials are not disturbed beyond the edges of the
plate and that debris is kept from falling into the manhole. The frame shall be
protected with concrete collar constructed in accordance with S.D. RWRD-211 or
as required by the Agency having jurisdiction over the Right-of-Way.
The Contractor shall thoroughly scrape and clean all foreign materials from the
manhole frames and covers prior to their installation. All frames and covers shall
be free of grease, oils, asphaltic materials, and any other deleterious materials.
All vent holes, pick bars and bolt holes shall be free of dirt, rocks, concrete and
other obstructions prior to completion of the Project.
Frames or covers that are damaged by other than the Contractor or that cannot
be cleaned to the satisfaction of the Field Engineer shall be replaced at no cost
to the Department.
ii. Damaged Frames and Covers
Existing manhole frames and covers shall be replaced if the age, condition or
type of the existing frame and cover warrants such action. Replacement shall be
directed by the Field Engineer. Existing manhole frames and covers, which are
lost or damaged by the Contractor, shall be replaced at no additional cost to the
Department.
iii. Coring
The following procedures shall be followed when connecting a new sewer line
into an existing Public Sewer manhole:
Core through the concrete at the bench level or in the barrel section to
accommodate new pipe;
After the new sewer line is laid, the opening through the wall around the
new pipe shall be sealed with material compatible with existing manhole
wall components;
The new bench and channel shall be formed WITH mortar of Class “S”
concrete, using an epoxy additive to assure adequate bonding to the
existing bench; and
All surfaces shall be steel-troweled to create smooth, dense surfaces.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-43 Standard Specifications
iv. Brick Manholes
Grade adjustments for existing brick manholes shall conform to S.D. RWRD-304.
Prior to reconstruction, the Field Engineer will inspect the existing brick walls to
assess its condition. The cone section shall be removed to an elevation within
the barrel section where the brick and mortar is not deteriorated and as
designated by the Field Engineer. Precast concrete manhole sections shall be
used to reconstruct the manhole. Prior to installing the precast sections, a
concrete leveling course with a formed joint, per S.D. RWRD-208, is required.
Reconstruction of any Public Sewer manhole shall be Approved by the Field
Engineer.
v. Connections to Existing Sewers
Where connections to existing manholes are required, the Contractor shall
reconstruct the existing bench. All flow channels within new manholes shall be
shaped and formed to provide a smooth transition of flow between inlet pipe(s)
and outlet pipe(s).
When a new manhole is constructed over an existing sewer line, verification of
the horizontal and vertical location is required by the Contractor before the
manhole is built. When the horizontal or vertical location of the sewer line does
not match the Sewer Plans, the Contractor shall notify the Field Engineer. The
Field Engineer may require the Sewer Plans to be updated by the Design
Engineer in order to to proceed with construction of the manhole.
vi. Interior Corrosion Protection for Existing Manholes
When an interior corrosion protection is required for an existing manhole, its
interior shall be cleaned and prepared, prior to applying a coating in accordance
with Subsection 3.3.3(B)(viii). During the cleaning and preparation, reasonable
means and methods shall be used to prevent foreign matter from entering
existing sewer line. A cover per S.D. RWRD-306, modified with a fine-mesh drain
screen, may be allowed with Approval by the Field Engineer.
The interior surfaces of the manhole, including the walls, benches and flow
channels, shall receive a wet abrasive blasting using a minimum water pressure
of 5,000 psi until all loose and deteriorated concrete has been removed. Only
silica sand and water may be used in the wet abrasive blasting. After the wet
abrasive blasting has been completed, these areas shall be flushed with water at
a minimum water pressure of 5,000 psi to remove any residual sand. Following
the wet abrasive blasting, a dry-abrasive blasting shall be done to remove any
remaining deteriorated concrete. The dry-abrasive blasting shall use only copper
slag and at a minimum pressure of 90 psi. Cleaning and preparation of the
manhole shall also conform to the requirements of the coating manufacturer.
A new manhole, constructed over an existing sewer line with a diameter of 18-
inches and greater, shall have interior corrosion protection. Any other new
manholes, located within 200 feet upstream of the connection to existing, shall
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-44 Standard Specifications
also have interior corrosion protection. This requirement does not apply to new 8-
inch diameter sewer lines or less that connect into an existing manhole having a
sewer line with a diameter of 18-inches and greater.
If a new force main will connect into a manhole, the manhole shall have interior
corrosion protection.
All new manholes, or extensions to manholes with existing PVC lining, shall have
one of the previously specified coatings applied to both the concrete and the
steel surfaces of the new manhole or the extension to the new manhole. For the
purpose of this note, a diversion structure will be considered a manhole.
E. Abandonment of Manholes
Brick manholes to be abandoned-in-place shall be demolished to an elevation at
least 3 feet below finished grade. Precast concrete manholes to be abandoned-
in-place shall remove the top cone or riser section. The interior of the manhole
shall be cleaned and sterilized prior to being filled with backfill material. Backfill
material shall conform to Table 1 of S.D. RWRD-104 and be installed in
accordance with Subsection 3.1.3(E). The manhole frame and cover shall be
salvaged, cleaned and delivered to the Department. All manholes that are
abandoned in place shall be marked with a monument per S.D. RWRD-503.
Debris generated by the removal of existing Public Sewer manholes shall be
removed from the site by the Contractor and disposed of at an appropriate solid
waste facility. The Contractor shall furnish the Field Engineer the original copy of
the dumping receipt. The manhole and disturbed areas shall be backfilled with
select material and compacted in accordance with the standards set by the
Agency controlling the Right-of-Way. In all cases a minimum density of 95% of
the standard proctor density, in accordance with the provisions of the Arizona
Test Method 225, shall be achieved.
3.4 Other Sanitary Sewer Appurtenances
3.4.1 Piles
Piles for supporting sanitary sewer pipe shall conform to the requirements of
S.S.D. RWRD-101. All steel plates shall conform to ASTM A36/A36. All welding
electrodes shall conform to ASTM 233-62T and AWS A5.1 grade E70XX. All
bolts and nuts shall conform to ASTM A307/A307M.
3.4.2 Casing Pipe
Casing pipe for Public Sewer lines shall be extra strong new steel pipe, Schedule
40.
Pima County Standard Specifications and Details
Regional Wastewater Reclamation Department for Construction 2012
Section 3
December 2012 3-45 Standard Specifications
3.4.3 List of Approved Products for Public Sewers
For a current List of Approved Products for Public Sewers, check the
Department’s website at: www.pima.gov/wwm/eng/ or contact the Field
Engineering section.
Pima County
Regional Wastewater Reclamation Department
SECTION 4
STANDARD DETAILS
Standard Specifications and Details for Construction

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