Sample Setup Guide Sampling Train — Multiple Sorbent Tubes Publication 1451 PDF

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Sampling Train — Multiple Sorbent Tubes

Sample Setup Guide

SKC Inc. 724-941-9701 SKC South 434-352-7149 SKC Gulf Coast 281-859-8050 SKC-West 714-992-2780

www.skcinc.com

Publication 1451 Rev 1707

Multiple-tube sampling provides many beneﬁ ts when collecting hazardous gases and vapors

from air. This method reduces time in the ﬁ eld and uses fewer sample pumps because multiple

contaminants requiring different sample tubes can be sampled with one pump. Multiple-tube

sampling also allows collection of Time-Weighted Averages (TWAs) and Short-Term Exposure

Limits (STELs) and side-by-side simultaneous sampling at different ﬂ ow rates. This Sample Setup

Guide demonstrates how to set up a Sampling Train Using Multiple Sorbent Tubes.

Required Equipment

1. An air sampling pump capable of sampling at the

recommended ﬂ ow rate with the sampling medium in line,

such as:

• SKC Pocket Pump® TOUCH with Constant Pressure

Controller Cat. No. 224-26CPC-10 (for use in constant

ﬂ ow mode only)

• SKC AirChek® Series with Constant Pressure Controller

Cat. No. 224-26-CPC and Adjustable Multiple Tube

Holder Cat. No. 224-26 Series

2. An airﬂ ow calibrator such as:

• SKC chek-mate Calibrator Cat. No. 375-07550N

• TSI 4146 Calibrator Cat. No. 740-4146

3. An Adjustable Multiple-tube Low Flow Holder:

• Dual (for 2 tubes) Cat. No. 224-26-02

• Tri (for 3 tubes) Cat. No. 224-26-03

• Quad (for 4 tubes) Cat. No. 224-26-04

4. The sorbent sample tubes speciﬁ ed in the method

5. The appropriate size protective covers for the

Adjustable Low Flow Holder:

• for 6-mm OD x 70-mm L tubes Cat. No. 224-29A

• for 8-mm OD x 110-mm L tubes Cat. No. 224-29B

• for 10-mm OD x 150-mm L tubes Cat. No. 224-29C

• for 10-mm OD x 220-mm L tubes Cat. No. 224-29D

Optional Equipment

1. SKC Tube Breaker:

• Cat. No. 226-03-055

Figure 1. Multiple-tube sampling train with AirChek TOUCH

Introduction

To determine the correct ﬂ ow rate for the chemical of interest,

refer to the appropriate analytical method. See the operating

instructions for the pump to ensure that it can sample at the

correct ﬂ ow rate.

1. Preparing the Sorbent Tubes

Using a tube breaker, break off both ends of each sorbent

tube to provide an opening of at least one-half the internal

diameter. These tubes will be used for calibrating the ﬂ ow

and not for collecting the sample.

2. Setting Up the Calibration Train with Adjustable

Multiple-tube Low Flow Holder — Figure 1

If using a Pocket Pump TOUCH in constant ﬂ ow mode or any

of the AirChek Series pumps, use ﬂ exible tubing to connect

the CPC to the pump inlet. Using ﬂ exible tubing, connect

the adjustable low ﬂ ow holder to the CPC (or to the pump

inlet if using a Pocket Pump TOUCH in constant pressure

mode). Place the sorbent tubes into the black rubber sleeves

of the adjustable low ﬂ ow holder. The printed arrow on the

sorbent tube shows the direction of the airﬂ ow and should

point toward the holder. If there is no arrow printed on the

tube, insert the end of the tube with the smallest sorbent

section (backup section) into the holder.

Pump

Inlet

Tygon

Tubing

Quad Adjustable

Low Flow Holder

Sample

Tubes

with

Covers

CPC

Notice: This publication is intended for general information only and should not be used as a substitute for reviewing applicable government regulations, equipment operating instructions, or legal standards. The

information contained in this document should not be construed as legal advice or opinion nor as a ﬁ nal authority on legal or regulatory procedures.

SKC Inc. 724-941-9701 SKC South 434-352-7149 SKC Gulf Coast 281-859-8050 SKC-West 714-992-2780

www.skcinc.com

Publication 1451 Rev 1707

Sampling Train — Multiple Sorbent Tubes

Figure 2. Multiple-tube calibration train with

Pocket Pump TOUCH (constant ﬂ ow mode)

Figure 3. Top view of a quad adjustable low ﬂ ow holder

Figure 4. Dual-tube sampling train on worker

3. Calibrating the Flow Rate — Figure 2

Allow the pump to equilibrate from one temperature

extreme to another and to run for 5 minutes before

calibrating. Note the ﬂ ow rates speciﬁ ed by each sampling

method and add them together. Set the pump to a ﬂ ow

rate at greater than or equal to 15% higher than that

sum. Calibrate the ﬂ ow rate through each tube. The ﬂ ow

rate through any one tube cannot exceed 500 ml/min.

To calibrate the ﬂ ow rate, connect the open end of one

sorbent tube to an external calibrator.

Adjust the ﬂ ow adjust screw on the corresponding port

on the tube holder until the desired ﬂ ow rate is achieved.

Turn the screw clockwise to decrease the ﬂ ow. For tri

and quad models, ﬁ rst rotate each anti-tamper cover

to expose the ﬂ ow adjust screw (Figure 3). Disconnect

the tube from the calibrator and calibrate the next tube.

Changing the ﬂ ow on one tube will not affect the ﬂ ow

through tubes already set. When using a multiple tube

holder, ensure that all ports contain sorbent tubes. If

sampling with fewer tubes than the number of ports,

insert unopened sorbent tubes in the empty ports to seal

them. Calibrate the ﬂ ow rate for each tube as speciﬁ ed in

the analytical method for the chemical of interest. When

the ﬂ ow rate has been calibrated, remove the calibrator

and set aside the sorbent tubes used to calibrate the

ﬂ ow. These tubes will be used after sampling to verify

the ﬂ ow rate. Record the pre-sample ﬂ ow rate.

4. Sampling — Figure 4

When ready to start sampling, break off both ends of new

sorbent tubes in the same manner used for calibrating

the ﬂ ow. Insert the sorbent tubes into the rubber sleeves

of the adjustable low ﬂ ow holder. Ensure unused ports

contain unopened tubes to "seal" each port. Place a

protective cover over each sorbent tube. Attach the clips

to a worker’s collar and the pump to the worker’s belt.

The sorbent tubes should be placed in a vertical position

during sampling. Turn on the pump and note the start

time and any other sampling information. If one tube is

removed from a multiple tube holder during sampling,

immediately replace it with an unopened tube for the

remainder of the sampling period.

5. After Sampling

At the end of the sampling period, turn off the pump and

note the ending time. Remove the sorbent tubes, seal

the ends of each tube with the caps provided, and record

pertinent sample information.

Using a calibrator, calibrate the ﬂ ow rate with

representative sorbent tubes in line (the sorbent tubes

originally used to calibrate the ﬂ ow) to verify that the ﬂ ow

has not changed by more than 5%.

Submit ﬁ eld blanks from the same lot number as the

sample tubes. Field blanks should be subjected to

exactly the same handling as the samples (open, seal,

and transport) except that no air is drawn through them.

Pack the sample sorbent tubes, ﬁ eld blanks, and all

pertinent information securely for shipment to a laboratory

for analysis.

CPC

Pump

Inlet

Dual Adjustable

Low Flow Holder

Flow Adjust

Screws

Sample Tubes

Tygon

Tubing

chek-mate

Tygon Tubing

Sample Pump

Anti-tamper

Cover

Flow Adjust

Screws

Dual Adjustable

Low Flow Tube

Holder

Tygon Tubing

CPC

Inlet

Sample Pump

Protective Covers

with Clips

Sample Setup Guide Sampling Train — Multiple Sorbent Tubes Publication 1451 PDF

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