September  1975
        HIGH VOLUME AND GAS BUBBLER
     SAMPLER PREPARATION, INSTALLATION,
            AND AUDIT PROCEDURES
                  Region V
   Regional Air Quality Assurance Network
prepared by:  John Logsdon and Walter Kocal
              Centra]  Regional Laboratory
              1819 W.  Pershing Rd.
              Chicago, IL  60609

-------
i
i
V ,
                                                                    Date:   9/11/75
                                                                    Revision 1
                                                                                 Page:
                                    Tab!e of Contents

            Secti on   *      Topic
              1.0            Introduction
              2.0            High Volume Equipment Maintenance Schedule
              3.0            High Volume Sampler Equipment Description and Service
              4.0            High Volume Sampler Calibration Procedures
              5.0            High Volume Sampler Field Audit Procedures and Data
                             Reporting
              6.0            Bubbler Sampler Equipment Maintenance Schedule
              7.0            Bubbler Sampler Equipment Description and Service
              8.0            Bubbler Sampler Audit Procedures
              9.0            Station Set-up
             10.0            Sampler Audit Data Evaluation Criteria
             11.0            Station Evaluation and Inspection

-------
                                             Date:  9/11/75
                                             Revision 1
                                                          Page:
                         List of Figures

 Section   Figure   Title
 2.2          1     High Volume Sampler Operations  Flow  Chart
 3.2          2     High Volume Shelter Unit
 3.3.1        3     High "Volume Motor  Assembly
 3.4.1.        4     Recording Transducer  Unit
 3.4.2.1      5     Transducer Calibration  System
 3.4.2.2      6     Transducer Calibration  Data Sheet
 3.5.2        7     Step Down Transformer - 16 volt drop
 3.5.3        8     Step Down Transformer - 32 volt drop
 4.2.2        9     Orifice Calibration Set-up
 4.2.2.5     10     Orifice Calibration Data Sheet
 4.2.2.12    11     Orifice Calibration Data Plot
 4.3.1       12     Sampler in Service Position
 4.3.2.6     13     Sampler Calibration Data Sheet
 5.3         14     High Volume Sample Audit Data Sheet
 6.3         15     Bubbler Operations Flow Chart
 7.2         16     5-gas  Sampling  Rack
 7.4         17     Membrane Filter Unit
 8.2         18     Bubbler Leak Check Data Sheet
 9.5         19     High Volume Sampler Support
 9.5         20     High Volume and Bubbler Sampler Support
11.1         21     High Volume Sampler Inspection  Sheet
11.1         22     Bubbler Sampler Inspection Sheet
                                 11

-------
                                              Date:   9/11/75
                                              Revision 1
                                                           Page:
1.0  Introduction
1.1  This manual describes the operations required of Environmental
     Protection Agency (EPA)  personnel  for set-up, calibration, and
     maintenance of Regional  Air Quality Assurance Network (RAQAN)
     particulate and bubbler  samplers.   Operating and analytical  proce-
     dures are described in detail  in other manuals.1'2}3'l+  It is  not
     the purpose of this manual  to  rewrite the manufacturers procedures,
     but to reemphasize and clarify certain points.  Rather,  portions
     of the manufacturers "user manuals" are referenced and applied
     specifically for RAQAN use.
1.2  Maintenance schedules are outlined and provide expected  service,
     calibration, and audit intervals.   Revisions of this  manual  will
     follow as experience suggests  the need for change.  Close adherence
     to the procedures in the current revision should be maintained.
2.0  High Volume Equipment Maintenance Schedule
2.1  Routine maintenance to be performed by the station operators is
     described in other manuals.1'2
2.2  High volume sampler maintenance and audits should be  performed  as
     directed by the schedule in Table I.
     This schedule describes  audit  and maintenance outputs for each  site
     on a relative timetable.  The  absolute timetable is left to  the
     discretion of each District Office.  A flow chart of the operations
     1s shown in figure 1.

-------
Step
 1
 2
 3
  Time
(months)
   0
   0
   0
5
6
7a
8a
9a
10a
11
6
6
12
12
12
12
12
                                                    Date:  9/11/75
                                                    Revision 1
                                                                 Page:
                   Hiqh Volume Maintenance and Audit Schedule
Operation
Sampler Preparation
Installation
Multi-point Calibration
and Single-point Audit
Two-point Audit
Routine Preventive
Maintenance
Multi-point Calibration
Two-point Audit
Routine Preventive
Maintenance
Special Maintenance
Multi-point Calibration
Orifice Unit Recalibration
aRepeat every 6 months.
                                                      Output
                                                      Calibration  Curve
                                                      Audit Report,
                                                      Field Inspection Sheet
                                                      Calibration  Curve
                                                      Audit Report
                                                      Field Inspection  Sheet

                                                      Calibration Curve
                                    TABLE  I.
                                        la

-------
High Volume Sampler Operations Flov; Chart
        Equipment Purchase,
           • Preparation
              Sampler
            "Calibration
                       Fail-
           Installation
              Routine
             Operation
            Multi-point
            Calibration
                               Evaluate Audit Data
                               Reject/Accept Data
                Figure 1.
                   Ib

-------
                                             Date:  9/11/75
                                             Revision 1            ~
            '                                              Page:    e-
2.2.1  This schedule requests a number of important outputs for data
       evaluation and station maintenance.  Samplers prepared and cali-
       brated at the laboratory and taken to the field require an audit
       after installation to verify the accuracy of the earlier cali-
       bration that no damage has occured during transit.  On-site cali-
       bration and audit is an alternative.
       After 6 months of routine operation and pending no field operation
       failures during this time, a two point calibration audit should
       be performed.  If the audit data are acceptable (criteria given
       in section 10.), the past 6 months monitoring data are accepted,
       routine and special maintenance are performed, and the sampler
       is recalibrated.
       If the audit data are unacceptable, the air quality monitoring
       data will be rejected, corrective action for the sampler taken,
       and calibration performed.
2.2.2  Steps 7 through 10 are performed every 6 months.  This schedule
       allows for good preventive maintenance practices and provides
       a continuing record of the sampler's performance.
       Maintaining this schedule is essential since it provides a mechanism
       for identifying blocks of suspect data and qualifying blocks of
       acceptable data.
3.0  High Volume Sampler Equipment Description and Service
3.1  One objective of the RAQAN is to replace all existing samplers with
     aluminum General Metals Works* shelters equipped with 2000 M motors,
*Mention of manufacturer's name does not constitute endorsement of the
 equipment by the EPA or the Central Regional  Laboratory.

-------
                                             Date:  9/11/75
                                             Revision 1            ,
                                                          Page:    J
       recording transducers, voltage reduction transformers, and program-
       mable automatic timers.  Only procedures pertaining to these units
       will be presented.  However, various combinations of these units
       may exist,and the specific device procedures will still apply.
       The procedures are formatted to illustrate installation of a new
       sampler.  However, most procedures are applicable to old units
       as well.
3.2  High Volume Shelter
3.2.1  Figure 2 shows a high volume shelter unit.  Assembly consists
       of only attaching the roof to the main unit via the hinges and
       removing all packing material.  Check for and report any damage
       to new units to the CRL.
         «
3.2.2  Check all  latches for easy operation.  It may be necessary to
       bend the latches or hinges to get a firm fit.
3.2.3  Inspect the structure for loose screws or components and make
       repairs as necessary.  Also inspect the shelter for sharp and
       hazardous  edges.  If necessary, file the edges to avoid injury
       to personnel.
3.2.4  Using a 1" x 1" or 1" x 2" firring strip, cut a length of the
       wood strip to  fit from the front of the shelter to the top of
       the inside of  the open roof.   Figure 2.   This will avoid undesired
       closing of the roof during service of filter insertion.
3.2.5  Using a stencil, paint the words:
                             U.S. EPA
                             REGION V
       on the outside of the roof and on the side panel  of each shelter.
       The motor  number from the metal  plate attached to the side of
       the motor  should be recorded  inside the  shelter roof.  This number

-------
                      Figure 2.
             High Volume Shelter Unit
                                                                     Js
Voltage reduction
  transformer
Programmable
   timer   ~~
                     US  EPA
                   R E G I  0 N V
                                          . Roof latch
Sampler motor
                                                         Recording
                                                         transducer

-------
                                             Date:  9/11/75
                                             Revision 1
                                                          Page:   4

       must be changed to reflect any changes in the motor used, i.e.,
       replacing a burned out unit.
3.3  High Volume Sampler Motor Assembly
3.3.1  Figure 3 shows a motor assembly and a parts schematic  diagram.
       This diagram also shows a filter adapter.
3.3.2  Remove the motor assembly from the shelter by unplugging the
       electrical cable, disconnecting the pressure hose from the side
       of the motor and carefully lifting the motor through the top
       of the shelter.
3.3.3  Inspect the filter adapter for damage.  Be sure that the face-
       plate is not bent and fits squarely on the adapter.   Also, check
       the rubber gasket for a tight seal to the faceplate and no dried
       or cracked sections.
       Every 18 to 24 months it may be necessary to replace this gasket.
       The life of each gasket is a function of the sampler location
       and must be checked at least every 18 months.   Replace any
       gasket that does not seal properly or is damaged.  This will
       be noticed by the station operator or the CRL  since the filters
       will show rough  borders for the particulate matter.
3.3.3.1  Remove the faceplate and using a razorblade  or putty knife,
         remove the old gasket.  Scrape the faceplate clean.
         Using rubber cement, attach the new gasket,  place the faceplate
         on the adapter, tighten the wingnut clamps carefully, and wipe
         any excess cement off the unit.  This cement sets  up quickly.
         Inspect the unit to verify proper installation.
3.3.4  Inspect  the retaining ring fit to be sure it  is not cross threaded.
       Using a strapwrench (if available), tighten the ring until the

-------
j

-------
                                             Date:  9/11/75
                                             Revision 1            c
                                                          Page:
       units are sealed together.   Do not overtighten the unit.
3.3.4.1  It may be necessary to change the gasket under the retaining
         ring if the gasket is cracked and dried.  Simply loosen the
         ring, replace the gasket, and retighten the retaining ring.
3.3.5  Motor Brush Replacement
3.3.5.1  Every 6 months the motor  brushes should be replaced to avoid
         commutator damage and motor burnout.   New motors require burn
         in as described in section 3.3.5.8.   Refer to the GMW 2000 H
         manual for details.5
3.3.5.2  Remove the filter adapter.
3.3.5.3  Remove the 4 screws on the adapter mounting plate.  Remove
         gasket #1, motor, gasket  #2, and the ring.
         Carefully push or pull the three wire cord until a sufficient
         working length is through the housing.
3.3.5.4  Remove the brushes noting their original position.  Inspect
         the commutator for excessive wear such as grooves, chipping,
         or burned spots.  The armature may also have to be replaced.
         If the condition of the motor is acceptable, install  new brushes,
3.3.5.5  Inspect gaskets #1 and #2 and the wiring.  Replace or repair
         the unit as necessary.
3.3.5.6  Replace the motor unit being careful  not to bind the  cord inside
         the assembled unit.  Replace the adapter mounting plate and
         the 4 screws.
3.3.5.7  Attach the filter adapter and install a clean filter  or the
         orifice calibration unit  and the 18 hole plate.
3.3.5.8  With a variac, apply 50 volts to the motor.  Carefully look
         Into the motor exit orifice for excessive sparking.  If noted,

-------
                                             Date:   9/11/75
                                             Revision 1           6
                                                          Page:
         the brushes or the armature may be defective.  Repair the motor
         as necessary.  Run the motor for 15 minutes at 50 volts to
         "burn-in" the new brushes.   Advance the voltage to 100  volts
         and again inspect the motor for excessive  sparking.   Proceed
         if no problem is apparent.   Otherwise,  make repairs  as  necessary
         by going over the procedures once again and very carefully
         checking the commutator.   Run the motor an additional  15 minutes
         at 100 volts.
3.4  Recording Pressure Transducer
3.4.1  Figure 4 shows a recording  transducer unit.   Refer to  the figure
       and the manufacturer's manual  for the following procedures.6
3.4.2  Every pressure transducer should be calibrated when received
       or when service has been done to the unit.
3.4.2.1  Set up a calibration system as shown in Figure 5.  Restrict
         the open side of. the first  "tee" until  the system may be
         adjusted easily for pressures from 0-10 inches of water.
3.4.2.2  Using a chart calibrated  from 0-10 inches  of water (supplied
         with each new transducer),  adjust the transducer zero control
         for a zero reading.  Apply  8-10 inches  of  water pressure
         (measured by the water manometer) and determine the  reading
         on the transducer chart.   If the chart reading is not within
         ±1 inch of water pressure,  adjust the recorder span  control
         in the back of the unit.  Readjust the  zero and span controls
         until the span reading is within ±1  inch of the true pressure
         and the zero is within ±0.5 inches of zero.  Check at least
         2 additional points and record the results in the data  sheet
         1n Figure 6.

-------
 8
                                                              - Pen
                                                                Time Set
                                                                 Point
                                                 Zero Set
                      Front View
Zero Set
Bellows
               T
                Chart Drive Motor
                      (
Pressure Tap

  Figure 4.  Recording Transducer
                                                       'Back View

-------
                 Figure 5.  Transducer Calibration System
Restricted Tee   _f
                 H
                                 Transducer Unit
                                                           Water Manometer
                                  To Air Supply (  20 in.  HO)

-------
             Figure 6.
Tranducer Serial No.
Operator
Date
Point
Zero
Span
1
2
3
4
Actual Pressure
in H20






Chart Pressure
in H20





j
Error
in H20






                 6c

-------
.'     •        -           .                            '      Date:  9/11/75
 i                                                          Revision 1          7
                                                                        Page:  '
              3.4.2.3  Adjust the recorder span control by removing the back of the
•]                     transducer, carefully loosening the adjustment screw, moving
                      the slip arm to a new position, tightening the screw, and check-
                      ing the zero and span recorder values.  Continue this adjust-
.*   "                  ment operation until the recorder span reading is within ±1
                      inch of the true reading.
                      This is a delicate operation and may require some practice
                      before the operation can be done quickly.  Replace the back
                      of the transducer being careful to seat the gasket properly.
              3.4.3  The chart motor may fail occasionally.  The CRL maintains some
                    replacement units and upon request will send them out for
                    replacement by District Office personnel.
              3.4.4  The pen is the most frequent part to fail.  During each site
                    visit, check the pen for dried ink and carefully clean it with
                    acetone, alcohol, or hot water.  Also, check the pen arm to be
                    sure it applies sufficient pressure on the pen to the chart.
                    Repair or replace the pen arm as necessary.  If the pen does
                    not ink properly, vary the pressure by sliding the pen point
                    on the pen arm toward or away from the chart.  It is not necessary
                    to bend the pen arm.
»
              3.5  Voltage Reduction Transformer
              3.5.1  Each sampler is equipped with a voltage reduction transformer.
                    This transformer should be wired to provide sufficient drop to
                    make the air flow rate through a clean filter be about 50 cubic
                    feet per minute (1.35 nr/min).
              3.5.1.1  Determine the correct voltage by using a variac to supply the

-------
                                             Date:  9/11/75
                                             Revision 1           0
                                                          Page:   8
         the motor.  Set the variac for an air flow rate of 50 cfm
                o
         (1.35 m /min).  Measure the voltage on the variac.  Wire the
         transformer for the voltage drop that will yield a voltage
         closest to that measured from the variac.
3.5.2  16 volt drop.  Figure 7 shows the wiring diagram for a 16 volt
       drop.  The windings X1X2 and X3X4 are wired in parallel.  Be
       careful to not leave any wires   exposed that could cause shock
       injury.
3.5.3  32 volt drop.  Figure 8 shows the wiring diagram for a 32 volt
       drop.  Windings X1X2 and X2X3 are in series.  The resultant
       voltage will be about 81 volts.   Once again, pay attention to
       lead dress.
3.6  Each new sampler is equipped with  a programmable automatic timer.
     The operation of the timer is described on the weather door and
     in the field operations manual.1
3.6.1  Any service for this timer should be referred to the CRL at this
       time.  Additional information will  be distributed as it becomes
       available.
3.6.2  It may be necessary to add an additional outlet to be able to
       carry enough current to operate  both the high volume sampler
       and gas bubbler.  General  Metals Works is providing an accessory
       outlet that can be operated by the  timer and provide switched
       contacts to handle up to 15 amps continuous.  Consult the CRL
       for the availability and installation of these units.
3.6.3  Each elapsed time indicator should  be checked for accuracy before
       installation in the field.   Record  the elapsed time indicator
       reading in a log book or on the  motor calibration data sheet

-------
                           Figure  7.
                      It   VOL  T   DROP
                ^
                                                   U//A
                                 lit,  VOLT
                                                  A C  IWP UT
V/IHTE
                                                   Hi
                                                           iHtf

                                                           X*
                                                           Xy
                          /•'t/iCK
                  t
                  I

      loo  voi,r   (
        OVTPvT    I
                 • '  - - .
                                                    I;/  OUT
                                                   ttj\
                                    Ol/Tfl/T
;
                                                 
-------
                   Figure 8.
                                                   V   t.
       s rEP- DOWV
             33   VOLT
                      /// VOLT
                      3 UtVT
                  y

                                   Hi
Hy
*y
                                     s/>/'£".'
                                  AC/
                                     $
                                    AC50
1


-------
                                             Date:  9/11/75
                                             Revision 1
                                                          Page:    y
       in figure 13.  Record the timer serial  number, start the timer,
       and record the time of day from an accurate clock.  Consult the
       local telephone company or a bank time  system if necessary to
       verify the clock accuracy.
       After about 24 hours, record the time of day and elapsed time
       indicator reading.  Determine the difference of the true (clock
       time) and the indicated time.  The error must be less than ±4
       minutes to satisfy the Reference Method specifications.    If
       the error is too great, contact the CRL for a new elapsed time
       indicator.
4.0  High Volume Orifice Calibration Procedures
4.1  High volume sampler motors are calibrated with an orifice  calibra-
     tion unit.  The orifice units will be calibrated at the CRL on
     a yearly basis or at the District Office's request.
4.2  Orifice Calibration
4.2.1  The following equipment is necessary:
4.2.1.1  Positive displacement flowmeter (Rootsmeter)
4.2.1.2  -Water manometer (0-16 inches of water)
4.2.1.3  Mercury manometer (0-120 mm Hg)
4.2.1.4  AC voltmeter (0-150 volt)
4.2.1.5  Stopwatch (0.01 sec accuracy)
4.2.1.6  Connecting tubing
4.2.1.7  Logarithmetic Graph Paper (2x3 cycle)
4.2.1.8  Variac (variable voltage transformer)
4.2.2  Set up the calibration system as shown  in figure 9.
4.2.2.1  Attach the orifice calibration unit to the intake of the

-------
  Orifice

Calibration

   Unit
H   To Water Manometer
                            1
                           tl

X"

«»OA
!>*...* *




«^"*"^
1


•BMMMMK!


P   To Mercury Manometer
                                            Roots Meter
                                  Hi-Vol Motor
                                   To  110 vac Source
      Figure 9.   Orifice Calibration  Set-up

-------
                                             Date:  9/11/75
                                             Revision 1           ,n
                                                          Page:   IU
         rootsmeter.
4.2,2.2  Connect one end of the water manometer to the differential
         pressure tap of the orifice calibration unit; the other end
         is open to the atmosphere.
4.2.2.3  Connect one end of the mercury manometer to the inlet pressure
         tap of the rootsmeter; the other end is open to the  atmosphere,
4.2.2.4  Attach a high volume sampler motor to the exhaust of the roots-
         meter.  Attach the variac to the motor power cord and plug
         the variac into the wall outlet.
4.2.2.5  Record the ambient temperature and pressure on the data sheet
         in figure 10.
4.2.2.6  Place the load plates , one at a time, between the orifice
         and rootsmeter.  Turn on the high volume sampler motor and
         allow it to warm up for 10 minutes.  Also adjust the variac
         to obtain 110 VAC to the motor.  Maintain this voltage through-
         out the entire calibration.
4.2.2.7  Record the v/ater manometer and mercury manometer readings on
         the data sheet.
4.2.2o8  Record the time, in minutes, required to pass the known volume
         of air.
4.2.2.9  Repeat 4.2.2.6, 7, and 8 until data for all 5 load plates are
         obtained.
4.2.2.10 Calculate the airflow rate measured by the rootsmeter for each
         load plate.
                        .Nm      Pa     t
         where  Qm = True air flow rate at ambient conditions (rrr/min)

-------
W
I
O
n
i
5
           (4
           Q
           O
           O
           •H
 g
•H
 rt
            ri
 0>
 o
JS
•H
                  i
                   i
                  •H
                  C/3
                  O
                  55
                   0>
                   0>
                  P
                   O
                   o
              fn
              O
                         13

                         ^
                         JH
                         O

                         rt
                         M
                         ^J
                                +J
                                ri
                            U
                            rt
                                       O
                                       0)
                                       W)
                                       rt
                                       P
                                       t—(
                                       O
                                       M
                                      nr,
o>
M
3
                                       o
3

rt

 o cy
o p ^
C rt
o a: c
t-t -H
•USE
«H O ^s.

a.' U, E
cy
T3 O v— '
M rt C
3 Pi -H
o) o to
2 -H E
p 'o
0) C
E 1/1 -H
•H W E
H rt
a.
o / — \ •
^-J ?~M £^
(J> C-. -H
q '— '
trt bft
•H
c> rt
P (0 g
rt ed E
3=
^ 	 V
E
o a,
LJ *-.-.- -*
•P 3
o w to
•-i i/i K
C a>
H f-l g
9"
•O IO
IH CD E
C 
                                                                                                                                       3
                                                                                                                                       ^-<
                                                                                                                                       to
                                                                                                                                       o


                                                                                                                                       rt

                                                                                                                                       E

                                                                                                                                       II

                                                                                                                                       O
                                                                                                                                       c/
                                                                                                                                   c:
                                                                                                                                  •H
                                                                                                                                              0
                                                                                                                                              O
                                                                                                                                             •H
                                                                                                                                              O
                                                                                                                                          O
                                                                                                                                          o
                                                                                                                            o

                                                                                                                             I

                                                                                                                            o
                                                                                                                                              o
                                                                                                                                              &
                                                                                                                                II

                                                                                                                               o\°
                                                                                                                            CO
                                                                                                                            CTl
                                                                                                                            CN
                                                                                                                                              O
                                                                                                                                              \O
                                                                                                                                              r-
                                                                                                                                           E

                                                                                                                                           H
                                                                                                                                       E
                                                                                                                                       a,
                                                                                                                                        i
                                                                                                                                       as
                                                                                                                                       a,
                                                                                                                                              p

                                                                                                                                              X

                                                                                                                                              ri
                                                                                                                                              O.

-------
,  f
                                                            Date:  9/11/75
                                                            Revision 1
                                                                         Page:  11
                                a = Ambient Pressure  (mm Hg)
                                a
                               Pm = Rootsmeter  inlet differential pressure  (mm Hg)
                                                            o
                               V  = Volume of air measured  (m )
                               T  = Time  to pass Vm (min)
               4.2.2.11  Correct each flow rate  to reference conditions of 760 mm Hg
                        and  298°K.
                                                                          •3
                       where Q  = Air flow rate at reference conditions  (m /min)
                             Tm = Ambient temperature during calibration  (°K)
                             Pm = Ambient pressure during calibration (mm Hg)
                             Qm = True air flow rate at ambient conditions (nr/rnin)
               4.2.2.12 Plot the water manometer reading (AH) vs. reference  air flow
                       rate (Q ) on 2x3 cycle logarithmic graph paper and determine
                       the best fit line.  An example of the data is shown in figure 11.
               4.2.2.13 Calculate the deviation of each point from the best line and
                       record the result on the data sheet.
                             Percent deviation  = -~ - - x 100
                                                    %
                       where Q0 = measured point
                             Qc = corresponding point from line
                       If the devjition is ±3% or greater, for any one or more points ,
                       the compl ete^caJLihrati on.-mustJ3e~perfDrmed»aga-iru_
               4.3  High Volume Motor and Transducer Calibration
               4.3.1  Place the sampler motor in the service position.  Figure 12.
                     If the calibration is geing done in the laboratory, an empty
                     .shelter or a wooden frame may be used to mount the motor in.

-------

-------
Figure 12.  Sampler in Service Position

-------
                                                                                   h
                                                                                  •e
Orifice S/N
Transducer S/N
                                  Figure 13.


                 HIGH VOLUME SAMPLER CALIBRATION DATA SHEET
Hi-Vol Motor S/N


Date
Sampler Location


Calibrator
                             NASN Site No.
                Office
Ambient Temperature
   Pressure
Voltage
Clean  Filter Reading
Calibration Equation    Slope:
                   Intercept:
Load
Plate
No.
18
13
10
7
5
Manometer
Reading
in. H20





Transducer
Chart
Readirg





Air
Flowrate
M /min





Error
%












-------
                                              Date:  9/11/75
                                              Revision 1
                                                           Page:   12
4.3.2.0  Calibration Procedure
4.3.2.1  Replace the filter adapter with the orifice calibration unit
         using the 18 hole load plate.
4.3.2.2  Connect one side of the water manometer to the orifice calibra-
         tion unit.
4.3.2.3  Install a clean recorder chart.
4.3.2.4  While lightly tapping the recorder, turn the zero adjust screw
         in the lower right hand corner until  the pen reads zero.
4.3.2.5  Connect the motor directly to the variac, bypassing the trans-
         former.
4.3.2.6  Record the ambient temperature and pressure on the data sheet
         (figure 13).
4.3.2.7  While watching the water manometer, adjust the variac until
         the differential pressure indicates an air flow rate of 1.7  nr/min
         Record the voltage and maintain the same voltage for the entire
         calibration.
4.3.2.8  Let the motor run for 10 minutes, then read and record the
         transducer chart and differential pressure.
4.3.2.9  Repeat steps 4.3.3.4 through 4.3.3.8 for each of the 5 load
         plates.
4.3.3  Data Calculations
4.3.3.1  For each load plate, determine the air flow rate corresponding
         to the orifice differential  pressure (DH) from the reference
         orifice calibration curve.
4.3.3.2  Plot the reference flow rate vs.  transducer reading on linear
         graph paper.  Determine the line  of best fit by eye or least
         squares.  This plot is already at reference conditions and

-------
                                            Date:  9/11/75
                                            Revision 1
                                                         Page:    13
         does not need further correction.   See Appendix A.
4.3.3.3  Determine the deviation of the measured points from the best
         fit line.
                                    QO - QC
                percent deviation = —Q	x 100
         where Q0 = Measured point
               Qc = Calculated point from best fit line
         If the deviation is ±5 percent or  more for one or more points,
         check the calibration system and recalibrate  the point in
         question.  If it still is out of control, recalibrate the  motor
         using all 5 load plates.
4.3.3.4  Replace the filter adapter and voltage reduction transformer.
         Attach a clean filter and turn on  the motor.   The flow reading
         should be between 1.13 and 1.7 riP/min.  The optimum value  is
         1.5 nrVmin.  Record this value on  the motor calibration data
         sheet.
4.3.3.5  Submit copies of both the calibration data sheet and data  plot
         to the CRL.
5.0  High Volume Sampler Field Audit Procedures and Data Reporting

5.1  Each high volume sampler must be audited to verify its  calibration
     in the field and laboratory and proper  operation.   The air flow
     rate is audited using an orifice calibration unit,  other than  the
     one used to calibrate the motor.  At best, the audit should be
     performed by someone other than the person who calibrated the  unit.
5.2  Every 6 months and before any field motor replacement or recali-
     bration, the calibration must be audited.   This allows  each set

-------
                                            Date:  9/11/75
                                            Revision 1
                                                         Page:    14
     of data to be verified by knowing the initial  and final sampler
     accuracy over the total number of sample periods.  This audit is
     one of the most important factors for the operation of the RAQAN.
5.3  Using a calibrated orifice calibration unit, place the motor into
     the service position and attach the orifice with the 18 hole plate.
     Turn on the sampler and allow it to run for 10 minutes.  Read the
     differential manometer pressure and transducer chart and record
     the data in figure 14.
     Repeat this operation for the 13 hole plate.
5.4  Determine the reference flow rates from both the orifice calibra-
     tion curve and the motor calibration curve.   Compare the flow rates
     and calculate the percent error.  If the flow rate error is greater
     than ±6 percent, check the transducers tubing, amd motor for damage.
     Make any necessary repairs and recalibrate the system. If the result
     are acceptable, continue with routine scheduled maintenance and
     sampler recalibration.
5.5  Report the calibration audit data to the CRL on the report form
     (figure 14).  Any action taken at the site,  in the event of an
     audit failure should be documented.
6.0  Bubbler Equipment Maintenance Schedule
6.1  Routine maintenance for the gas bubbler sampler should be performed
     by the station operator and is described in  another manual.2
6.2  A relative maintenance and audit schedule is shown in Table II.
     This schedule lists the operations and audits  to be performed and
     should be scheduled to coincide with the high  volume sampler mainte
     nance and audit visits.

-------
                              Figure 14.
                     Calibration Audit Data Sheet
                 Site Location
                 Sampler Motor No.
                 Operator	
                 Auditor 	
                 Date
                 Barometric Pressure
                 Ambient Temperature
                 Orifice Serial  No.
Plate
No.
18
13
Transducer
Chart


Orifice
Pressure


Flow rate1
From Orifice


Flow rate1
From Sanioler


Error2
HI
K


      rates should always  be at  reference  conditions.
2Error = Orifice Flow Rate - Sampler Flow  Rate    ,n_
                 Orifice Flow Rate              x  IUU
                                 14a

-------
           :                            '      Date:  9/11/75
                                             Revision 1
                                                          Page:    15

6.3  The Table lists a number of outputs  requested for an operation
     such as the leak test audit report sheet.   These data provide a
     continuous record of the performance of the sampler and are used
     to validate data and identify problems.  Each operation is  described
     in detail in section 7, 8, and 9.
     An operations flow chart is given  in figure 15.

7.0  Bubbler Sampler Equipment
7.1  The procedures for the sampler set-up and  maintenance assume a
     unit is being prepared from a new  Research Appliance Company (RAC)
     5-gas Sampler in the All-Weather Shelter.7  If a unit is being
     serviced that has already been assembled,  go to the step covering
     the operation being performed and  proceed.  These procedures will
     be applicable to most types of ges bubbler equipment and are not
     unique to RAC samplers.
7.2  The All-Weather Shelter contains a vacuum pump,  vacuum gauge, 5-gas
     sampling rack, and heater.  Figure  16.   If  the unit is new,  extra
     supplies will be shipped in the 5-gas sampling rack.   Save  these
     extra parts.  Some can be used for servicing the sampler.
7.3  New samplers are equipped for use  with 5 sample  tubes.   The RAQAN
     only measures SC^ and NC^.  Therefore, remove the 3 bubbler trains
     farthest from the manifold inlet from the  rack.
     Cap the unused glass manifold ports  with polypropylene caps (these
     cops are used as closures for the  sample tubes sent to the  station
     operator arid are available from the  CRL).   It may be  necessary
     to heat the caps to get a good force-fit seal.  Small yellow plastic
     caps are available from the CRL to close the unused vacuum  manifold
     ports.  As an alternative, rubber  septums  or 1/8 inch gas chromatograph

-------
                                                 Date:  9/11/75
                                                 Revision  1
                                                             Page:
                                 TABLE  II.
Step
1
2
3
4
5
6
7
8
9
10
11
Time
(months)
0
0
0
6
6
6
12
12
12
12
12
Operation
Sampler Preparation
Leak Check
Installation
System Leak Check
Change Membrane Filters
and Septums
System Leak Check
System Leak Check
Change Membrane Filters
and Septums
Perform Sampler Clean-up
Check Pump System
System Leak Check
                                                     Output,




                                                     Audit  Sheet




                                                     Audit  Sheet

                                                     Field  Inspection Sheet



                                                     Audit  Sheet

                                                     Audit  Sheet
                                                     Field Inspection Sheet
Repeat steps 4 through 11  every year.
                                    14b

-------
Bubbler Sampler Operations Flow Charl
       j Equipment Purchase
         System Preparation
           System Audits
     -Fail-
                     Pass
            Installation
'J
         Routine  Operation
                             Fail-^—
              Major Repair
              Data Evaluation
        Routine  Maintenance
                     Pass
                                      Rejection
         Routine  Operation
                                      Data  Evaluation
                                      Rejection
             Figure  15.
               15a

-------
Manifold Rack

D
Z)
33
^




i
C
a
c
c
              Metal Manifold

        Glass Manifold
                  Teflon
                 Tubing
             Sample  Tube
                                                                      Vacuum Pump
                                                        Membrane Filter
Mist Trap
                 Figure  16.  5-Gas Sampling Rack and Manifold

-------
                                            Date:  9/11/75
        •   .                                 Revision 1
                                                         Page:    16
     column caps may be used.
     These caps should be checked at installation and each visit there-
     after for visual signs of leaks or cracks and replaced if necessary.
7.4  Remove the remaining two sample trains.  Note their configuration.
     Referring to figure 17, press the membrane filter holder together
     tightly and seal the halves together using acetone or methylene
     chloride.  Every filter unit should be sealed prior to installation
     to avoid air leaks in the system.  Be sure the tygon tubing attach-
     ing the filter to the glass tubing is also sealed to the filter
     housing.
     Again, it may be necessary to seal the tubing and filter unit
     together with acetone.
7.4.1  When replacing the filters during the Semiannual maintenance
       visits, prepare the assembly as shown in figure 17 in advance.
       This assembly may be prepared from V I.D.  tynon, filter unit;
       straight and 90° bent pieces of glass and rubber septum.  The
       glass pieces should be reused and the old filter and tubing
       discarded.  The filters should be replaced every 6 months.
7.4.2  Check the tygon tubing for a tight fit at the inlet and outlet
       ports of the mist trap.  Also, be sure the tubing to the absorber
       tube fits tightly.  Replace any tubing that is defective or does
       not fit tightly on the absorbers or mist traps.
7.4.3  Replace the bubbler trains and attach the teflon inlet tubing
       directly to the glass manifold.  Also attach the rubber tubing
       from the vacuum pump to the metal vacuum manifold.
7.5  Check the vacuum pump and gauge by turning on the pump and pinching
     the rubber vacuum tubing tightly.  The gauge should read 20 or

-------
            90U Glass Elbow
Membrane Filter
   Assembly
     Rubber Septum
^^^  x"
                                     Tygon Tubing
          Tygon Tubing
                                     Straight Glass Tubing
                                      Tygon Tubing
                 Figure 17.   Membrane Filter Unit

-------
                                            Date:  9/11/75
                                            Revision  1            17
                                                         Page:    ''
     greater.  If not, the pump or gauge needs repair or replacement.
7.5.1  The gauge may be replaced by simply unscrewing it from the "Tee."
       When installing the new gauge, use Teflon tape to insure a good
       seal and avoid damaging the pipe threads.
7.5.2  The vacuum pumps may fail.  Usually the pump diaphram and inter-
       nal gaskets fail before the motor.  When a pump fails, it should
       be replaced with another unit in the field and repaired at the
       laboratory.  Pump rebuild kits will be available upon request
       from the CRL or the pump may be sent to the CRL for repairs.
7.6  Heater units are provided in the bottom of the bubbler rack section
     of the All-Weather Sampler.  This 35 watt heater should be connected
     to an always-on power source from late Fall to Spring to avoid
     sample loss due to freezing.  The heater will be warm to the touch
     when operating properly.  The box temperature should be between
     10-34°C dependent upon the ambient temperature.
     If a unit fails, replace the heater.  The CRL will  supply extra
     heaters upon request.
7.7  Replace the sampling train; be sure all  the tubing is properly
     attached.  Plug the pump into a timer switched outlet and the
     heater into an always-on outlet if the weather is cold.
     The sampler should be operated only on sampling  days with needles
     and absorbing solutions in place,
8.0  Bubbler Audit Procedures
8.1  Air leaks are a major source of error for gas sampling systems.
     The bubbler trains can leak air at the rubber septum, membrane
     filter, and all tubing connections.  Any air leak will  cause the

-------
                                            Date:  9/11/75
                                            Revision 1
                                                         Page:     '8
     data to be biased lev/.  Therefore, after preparation, 6 months
     of operation or service, the system should be checked for leaks.
8.2  Referring again to figure 16, install  the dummy absorbing tubes.
     Attach  the water manometer from an orifice calibration unit to
     the inlet of the glass manifold.  Attach a hypodermic needle to
     one of the open vacuum manifold ports.   Close the other with a
     plastic cap, rubber septum, or another needle.  Turn on the vacuum
     pump.  Push the needle through the rubber septum and carefully
     watch the vacuum develop on the water  manometer.  When 10-15 inches
     of water differential  pressure develops, pull the needle from the
     septum.  Both bubbler trains and glass  manifold are now sealed.
     Record the differential  pressure in figure 18.
     Wait one (1) minute and  record the final differential pressure
     in figure 18.  Determine the difference.  If the differential
     pressure dropped more than 1 inch of water, a leak exists.   Check
     all joints and seals and repair the leak.  Repeat the test until
     the change in differential pressure is  1 inch or less.  Report
     the data to the CRL.
     This is a requested output (Table II)  and must be performed regularly.
9.0  RAQAN Station Set-up
9.1  When locating air monitors, adhere to  siting guidelines OAQPS
     No. 1.2-012  Table I  as closely as practicable.
9.2  The High Volume Air Sampler and Gas Bubbler must be mounted securely
     to a sturdy base,and the base must be weighed down with building
     blocks to prevent being  blown over by  high winds.
9.3  Material List for High Volume Sampler  Installation

-------
                            Figure 18.
                     Bubble Systeni Leak Check
Sampler Location
Sampler Serial No.
Auditor                                   Date
New Unit   j	j   ,     before service  LJ
                      after service   Q
Test 1
Set Pressure:
  Initial Differential Pressure	in. H20
Wait 1 minute:
  Final Differential  Pressure             	ia H20
  Difference                              	in. H20
  If Difference is 1  in.  HpO or less,  unit passes  test.   If greater
  than 1 in. h^O, repair leaks, perform  another test,  and repeat process
  until acceptable criteria are met.
Test 2
Set Pressure:
  Initial Differential Pressure	 in.  H20
Wait 1 minute:
  Final Differential  Pressure            	'_	in.  hLO
  Difference                             	 in.  O
                               I8a

-------
                                            Date:  9/11/75
                                            Revision 1
                                                         Page:    19
9.3.1  4 - 2" x 4" x 6' lumber
9.3.2  2 - 1" x 6" x 18" lumber
9.3.3  2 - building blocks
9.3,4  8 - V x 3" lag screws
9.3.5  4 - V -x 2V round-head stove bolts and nuts
9.3.6  16 - 5/16" I,D., 3/4" O.D.  flat washers
9,3.7  8 nails
9..3.8  V1 thick, 14" x 14" plywood
9.4  Paint or treat all of the lumber with 2 coats of paint or wood
     preservative.  Let it dry 24  hours between coats and before instal-
     lation,
9.5  Sampler station set-up.  Figure 19 shows a top view of the support
     necessary for a high volume shelter.   The following procedures
     are for placement of a single hi-vol  only.  However, by using the
     parts list in section 9.7, and making the appropriate changes in
     the procedure, a support for  both a hi-vol and a bubbler can be
     constructed as in figure 20.
9.5.1  Set the Hi-Vol Sampler on a h" thick 14" square section of ply-
       wood or similar material.  This will  provide the clearance between
       the building roof and the sharp corners of the shelter legs.
       Lay a 2 x 4 on the roof with the wide side against the shelter
       legs.  Center the 2 x 4 and drill 5/16" holes through the 2 x 4
       and the shelter legs.  Bolt the shelter to the 2x4 with V x
       2V1 stove bolts, nuts, and  washers.
9.5.2  Do the same with the second 2x4.
9.5.3  Remove the V thick 14" square section of plywood.
9.5.4  Nail the 1" x 6" x 18" boards across  the top of the 2 x 4's,

-------
                /     -4 x 3" lag screws
%- 	 - - 	 	 	 	 \J ' - ' ' '• -*"
•» *»
fi !!
f
k x 2%" stove bolts,
washers and nuts
t

«
t>

%
*



^_ ,'7tf _
f J)
|r n
Hi- VOL
L. _J



it
%
«
•-
*
»
i;
^ >
_L 6"
BLOCK
SUPPORTS
i"x6"xl8"
1
€
s
C?
^ 6
. 1.
k
'
>
*< it
             x 3" lag bolts
Figure 19.  High Volume Sampler Support

-------
                                            Date:  9/11/75
                                            Revision 1
                                                         Page:   20
       six inches from the end of the 2 x 4's.  This will support the
       building blocks.
9.5.5  Fasten the 3rd 2 x 4 against the ends of the pair of 2 x 4's
       supporting the shelter.  Use 4 - V x 3" lag screws.
9.5.6  Fasten the 4th 2x4 against the opposite ends of the 2 x 4's
       supporting the shelter.
9.6  For the power line use a weatherproof three conductor #16 gauge
     cable if only one Hi-Vol sampler is being installed.
9.6.1  If a Hi-Vol Sampler and a Gas Bubbler are to be installed, use
       #14 gauge 3 conductor cables.  Use a weatherproof outlet box
       and three prong receptacle.
9.7  Material List For Hi-Volume Sampler and Gas Bubbler Installation
9.7.1  2 - 2" x 4" x 6" lumber
9.7.2  2 - 2" x 4" x 8" lumber
9.7.3  2 - 1" x 6" x 18" lumber
9.7.4  8 - V x 3" lag screws
9.7.5  4 - V x IV lag screws
9.7.6  4 - V x 2h" stove bolts and nuts
9.7.7  16 - 5/6" I.D., 3/4" O.D.  flat washers
9.7.8  2 - building blocks
9.7.9  8 - nails
9.7.9.1  V x 14" x 14" plywood
9.7.9.2  2 - V x 5/8" round-head stove bolts
9.7.9.4  1 - V x 10' thinwall conduit
9.7.9.5  12'  - 5/16" teflon tubing
9.7.9.6  1 - polypropylene funnel  - V O.D.  stem

-------
                  x 3" lag screws
 x 2V stove bolts,
washers and nuts
x IV lag screws
                 HI-VOL
                    15'
                   GflS '
                 BUBBLES
                                 3'
                            J
                                N
                                 BLOCK
                                SUPPORT
                                I"x6"x|8"  8
                                   ,11
               t       '     J
                ^ x 3" lag screws
      Figure 20. High Volume and Bubbler Sampler Support

-------
                                             Date:  9/11/75
                                             Revision 1
                                                          Page:   21
10.0  Sampler Audit Data Evaluation Criteria
10.1  Sampler calibration and system audits are described within the
      test, i.e., Hi-vol flow rate audit error limit is ±6 percent.
      However, to assess the overall  quality of the monitoring data,
      the audit data must be summarized and reported to cause acceptance
      or rejection of the monitoring  data.
      At the time of this writing, no sufficient amount of field audit
      data are available to set limits and  specific evaluation criteria.
      However, as soon as 6 months of auditing data are available,  this
      section will be revised to describe specific evaluation techniques
      for determining the quality of  the air monitoring data.

11.0  During each site visit, as well  as performing routine maintenance,
      a record should be made of the  action taken and any deficiencies
      that must be corrected during the next visit.
11.1  Figures 21  and 22 show suggested inspection record sheets.   (Pre-
      pared by Peter Gill en of MWDO)   The sheets  should be filled  out
      for each site after each visit.   A copy should be submitted  to
      the CRL.

-------
Hi-Vol Serial No.

RASN Site No. 	

Site Location 	

Street Address 	

City & State 	
                                       Figure 21.

                                        U.S. EPA

                                  Equipment Evaluation
                                 Hi-Volume Air Sampler
                                    DATES

                                Inspection
                                Last Calibration _

                                Last Brush Change
        Item
Deficiency
Action taken
 Action Required at
next inspection/visi
Shelter
Shelter base
Weights
Cover Latch

Motor housing
Rotor
Brushes

Filter cone
Screen
Pins
Wing nuts
Hold-down plate
Filter gasket
Rubber gasket

Transducer (S/N
Tubing

Voltage reducer

Timer (S/N

Electrical cords
Electrical plugs
Comments on changes affecting height of site,  obstructions  or factors  affecting the site
and other comments.

-------
Bubbler Serial No.

RAQAN Site No. 	

Site Location 	

Street Address 	

City & State 	
                                       Figure 22.

                                        U.S. EPA

                                  Equipment Evaluation
                                      Gas Bubbler
                                 Date

                               Inspection
      Item
Deficiency
Action taken
  Action Required
next inspection/vi
Shelter Box
Shelter Base
Weights

Pump
Vacuum gage
Vacuum tubing

Electrical cord
Electrical plugs
Timer
Probe
Tubing
Funnel

Heater
Heater cord

Bubbler insulation
Bubbler rack
Glass manifold
Brass manifold
Manifold plugs
T-jbing
Tubing connections
Demisters
Demister sponge or wool
Demister connections
Membrane filters

-------
                                            Date:  9/11/75
                                            Revision 1
                                                         Page:
                            References


^'Regional Air Quality Assurance Network - Particulate Sampling Procedures
 (High Volume Method)," EPA, Central  Regional  Laboratory,  August, 1975.

2"Regional Air Quality Assurance Network - Sulfur Dioxide  and Nitrogen
 Dioxide Sampling Procedures - Twenty-four Hour Bubbler Method," EPA,
 Central Regional Laboratory, August, 1975.

3"Region V Air Quality Assurance Program - The Determination  of Suspended
 Particulates - High Volume Method  -  Laboratory Operations Manual,"  EPA,
 Central Regional Laboratory, July,  1975.

'•"Region V Air Quality Assurance Program - The Determination  of Sulfur
 Dioxide and Nitrogen Dioxide by the  Gas Bubbler Method -  Laboratory
 Operations Manual," EPA,  Central Regional  Laboratory, July,  1975.

5"0perators Manual  - Model  GMWL 2000  and Model  GMWL  2000H," General  Metals
 Works, Cleveland,  Ohio.

6"0perating Manual  for Dickson Recording Instruments," The Dickson Company,
 Addison, IL, 1973.

7"0perating Instructions  for 5-Gas  Collector Sampler,  Catalog No.  2333A,"
 Research Appliance Company, Allison  Park,  PA,  April,  1972.
                               22

-------
                           Appendix A
                                                                             .11
                                                                  JL
          _ TEMPERATURE AND PRESSURE  CORRECTION SCHEME

The type of temperature and pressure corrections  for high  volume  air
sampler calibrations and flow rate measurement(s)  have  been  questioned
for a considerable length of time.   In  February,  1975,  Dr. Randy  Korda
of the Wisconsin Department of Natural  Resources  and I  discussed  the
topic at length and agreed upon a correction  scheme.  The  equations  are
as follows:

1.  Orifice calibration with a positive displacement flow  meter (Roots Meter)
           Va . lEi^AEl Vm
    Va = Air volume at atmospheric conditions T-j  and P-,  (M^)
    P] = Barometric pressure (mrnHg)
    AP = Pressure drop at inlet of roots meter (mmHg)
    Vm = Uncorrected volume measured by roots meter  (M^)
              Ql = Va/t
    Q-j = Air flow rate at atmospheric conditions  corresponding  to a
         differential  orifice pressure,  AH, (M^/min)
    t  = Time to pass  air volume Va
    QR = Air flow rate  at  reference conditions TR and PR  (M^/min)
    TI = Ambient temperature  at time of orifice calibration  (°K)
    P! = Ambient pressure  at  time of orifice calibration  (mmHg)
    TR = 298°K
    PR c 760 mmHg

-------
The orifice calibration curve is constructed by plotting AH vs. QR on
log-log graph paper.  This curve is the same as if the orifice had
been calibrated at reference conditions.
                                    *
2.  Sampler Calibration with a Calibrated Orifice Unit.
Orifice differential pressures (AH) and flow indicator device readings'1^
{recording transducer) are recorded for each of 5 load plates.  The
flow rate at reference conditions is determined from the AH vs. QR curve
and is plotted on linear, graph paper vs.  indicator readings (Qp< vs. I).
This plot is the flow rate at reference condi 'cions and is not_ dependent
upon the conditions when the sampler was  calibrated.

3.  Air Volume Sampled Determination.
The reference flow rate, QR, from I is corrected to the conditions
during sample collection.
    0.2 = Air flow rate at field conditions  T2 and ?2 (
    T£ = Field temperature during sample collection (°K)
    ?2 = Field pressure during sample collection (mmHg)

Note that this correction yields the flow rate, Q2, that would be observed
directly from the motor calibration curve, QR vs.  I, if the motor calibra-
tion had been performed and reported at field conditions.
The air volume sampled at field conditions is:

-------
      V2 c Q2 x t
      \2 ~ Air volume sampled at field conditions  T£ and P£
      t =  Sampling time (min.)

The volume is corrected to reference conditions  using the gas law equation:
This volume is used to calculate the particulate concentration.

4.  The air flow rate and volume correction scheme described here has been
verified experimentally at the Central  Regional  Laboratory and found to
yeild errors of 2% or less from the actual  values determined with positive
displacement flow meters.

An orifice was calibrated at 26°C and at 53°C  and the AH vs. QR curves
drawn to reference conditions as described  in  Section 1.   The differences
between the two calibrations are shown  below:

Load Plate No.      AH     QR (26° Calibration)   QR(53° Calibration)  % Error
18
13
10
7
11.6
9.68
7.18
4.76
1.65
1.49
1.31
1.07
1.64
1.50
1.32
1.06
-0.6
0.7
0.7
-0.9
If the correction was not applied,  the  errors  would  be  from 4 to 5 percent.

To verify the sampler corrections  in sections  2  and  3,  a high volume sampler
was calibrated at 26°C and the flow rate  vs. flow indicator reading (I) curve
drawn to reference conditions  as described  in  Section 2.   Air was then sampled
at 53°C and the flow rate measured  by I and a  positive  displacement flow

-------
meter.  The flow rates were then corrected to reference conditions
and the air volume sampled determined,
The volumes found from the flow indicator reading and the roots meter
were compared.
I(cmH20)
16.7
14.1
11.0
7.1
QR(M3/min)
1.64
1.50
1.32
1.06
VR^CALC M3)
94.6
85.4
75.1 '
60.8
VR2(Roots Meter M3)
96.0
85.9
76.0
61.4
% Error
-1.5
-0.6
-1.2
-1.0
^ Air volume sampled at reference conditions for 60 minutes.
p
Air volume measured by Roots Meter and corrected to reference
conditions for 60 minutes.
Once again, had no corrections been applied,  the error would have been
3 to 5 percent for this data.
Therefore, the procedures described here and by Dr.  Korda minimize the
errors in air volume measurement to less than 2 percent.   The corrections
are simple to employ and improve the quality of the  data.

-------