United States         Office of Air Quality           EPA Publication No. 340/1-89-003
           Environmental Protection    Planning and Standards         June 1989
           Agency            Washington, DC 20460

           Stationary Source Compliance Series                          	
oEPA   Field
           Inspector's
           Audit  Techniques
           Gas CEMS's
           Which Accept
           Calibration  Gases

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                                                       340/1-89-003
Field  Inspector's  Audit  Techniques
       Gas  CEMS's  Which  Accept
              Calibration   Gases
                        Prepared by:

                      Wayne E. Reynolds
                    CEM/Engineering Division
                   Entropy Environmentalists, Inc.
               Research Triangle Park, North Carolina 27709
                     EPA Contract 68-02-4462
                     Work Assignment No. 36
                  EPA Project Officer Aaron Martin
                  EPA Work Assignment Manager:
                      Anthony P. Wayne
                        Prepared for:

          UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                 Stationary Source Compliance Division
               Office of Air Quality Planning and Standards
                     Washington, DC 20460

                         June 1989

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                                   DISCLAIMER
    This material has been funded wholly or in part by the United States
Environmental Protection Agency under Contract No 68-02-4462 to Entropy
Environmentalists, Inc.  It has been subjected to the Agency's peer and
administrative review, and it has been approved for publication as an EPA
document.  Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.

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                           TABLE OF CONTENTS
1.   Overview	  1

2.   Planning	  2
    2.1  Gather Information	  2
    2.2  Determine Number of Audit Gases Per Channel	  2
    2. 3  Select Audit Gases	  2
    2.4  Arrangements With Source	  3
    2.5  Legal Authority and Liability	  4

3-   General Principles of Audit Gas Injection	  5
    3.1  Audit Gas Injection for an Extractive CEMS	  5
    3.2  Audit Gas Injection for a Point In-Situ CEMS	  5

4.   Conducting the Field Audit	 15
    4.1  Audit Gas Injection	 15
    4 .2  Number of Gas Injections	 15
    4 . 3  Data Recordkeeping	 16

5 .   Post-Audit Activities	 17
    5-1  Plot CEMS Response as Function of Audit Gas Concentration.... 17
    5.2  File Data	 17
    5 .3  Follow-Up Activities	 17
    5.4  No Correction of Reported Emissions Data	 17

6.   Data Forms	 18

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                                   1.   OVERVIEW


     This  guideline*  is for the use of control agency field inspectors in plan-

ning and  conducting  audits of continuous emission monitoring systems (GEMS's)

for  gaseous  pollutants.   The document includes:

     •  An outline-of planning activities;

     •  An outline of principles  for  audit  gas injection;

     •  Procedures for conducting a field audit;

     •  A discussion of post-audit, activities;  and

     •  Example data forms.

The  audit procedures in this report:

     •  Are  only applicable to gas GEMS's configured to  accept  cylinder  gas
        injections;  and

     •  Assume the availability of a  source technician to  assist  with the
        audits as directed by the control agency  field inspector.

     •  May  be used  to conduct cylinder gas audits (CGA's)  of 40  CFR 60,
        Appendix F,  Procedure 1,  provided:

         (1)  audit gases are selected  according to Appendix F criteria, and

         (2)  each gas is injected  into the GEMS three times rather than two.
* Prepared under EPA Contract No.  68-02-4462,  Task  No.  36,  by Entropy Environ-
  mentalists, Inc., Research Triangle  Park,  North Carolina.

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                                   2.   PLANNING

    Preparation for the audit  should  begin  well  in  advance  of  the  target  audit
 date.   If  all  audit gases  are  not  on  hand,  a  gas vendor  will need  at  least  30
 days  lead  time to  prepare,  analyze, and  ship  the gases.  A  Pre-Audit  Data Form
 is  provided  in Section 6.   Much  of the necessary information will  be  on file at
 the Agency;  the remainder  can  be obtained from the  source contact.  Major steps
 in  the  pre-audit preparation process  are discussed  below.

 2.1  GATHER  INFORMATION
    Information that will  be needed in the  audit gas selection process
 includes:

    1. the  range of each gas measurement  channel;
    2. the  typical  concentration  level  of the  effluent; and
    3- effluent concentrations  at the  level  of the applicable emissions
      standards.

    Information regarding  gas  measurement ranges should  be  contained  in the
 Performance  Specification  Test (PST)  report on file at the  agency.  Information
 regarding  typical  effluent levels  can  usually be obtained from both the
 relative accuracy  data in  the  PST  report and  the emissions  reports or excess
 emissions  reports  on file  at the agency.  Pollutant concentrations at the level
 of  the  standard can be calculated  from the  emissions limits and typical diluent
 concentrations.

 2.2  DETERMINE NUMBER OF AUDIT GASES  PER CHANNEL
    The goal of a  CEMS audit is  to determine  whether the emissions data
 reported to  the agency are of  acceptable quality.   This  goal can be accom-
 plished with one audit gas per measurement  channel.  Each additional  audit  gas
 provides valuable  information  regarding  CEMS  performance, but  increases the
 overall cost of the audit.  Two  gases  per channel are recommended  for the
 audits  discussed in this document.

 2.3  SELECT  AUDIT  GASES
    There are  two  points in the  measurement range of a CEMS that are  of primary
 concern: (1) the average effluent  emissions level;  and  (2)  the level  of the
standard.   When the  audit  is conducted with a single audit  gas for each
channel, the concentration  of  this gas should approximate one  of these levels.
                                       2

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    When the audit is conducted with two gases per channel, these gases should

bracket the effluent and emissions standard levels.  Other acceptable criteria

for audit gas values are as specified in Appendix F for Cylinder Gas Audits

(CGA's).  These criteria are:


                   Pollutants: 20-30% and 50-60% of span
                           02: 4-6% and 8-12% 02

                          C02: 5-8% and 10-14% C02


    Each audit gas in the agency inventory should be listed on the "Inspector's
Quick Check Audit Gas Data Sheet"; an example data sheet is included in Section
6.  Each gas should be given a label (e.g.,  "S02 #1," S02 #2,"- N0x #1," etc.)
for easy gas identification.  The gas label  and its certified concentration
should be recorded in the appropriate columns.   This data sheet can be taken
into the field by the inspector.  Accuracy acceptability can be determined at  a
glance by comparing the audit results to the error band on the gas data sheet.
    Some or all of the audit gases should be designated as "blind" gases,  and
their exact concentrations should not be revealed to the source.  The use  of
blind audit gases precludes the possibility  of CEMS response data being
intentionally biased to enhance apparent CEMS accuracy.


2.4  ARRANGEMENTS WITH SOURCE
    Unless the audit is intended to be "unannounced," the following
arrangements should be made with the source:

    1.  Audit Date
        Check with the plant environmental coordinator to ensure that the
        target audit date does not conflict  with the plant's projected
        operating schedule.  Avoid scheduling audits during times when sourc'e
        maintenance outages are planned.  A  source need not be operating for
        its CEMS to be audited, but technicians are generally in short supply
        during outages, and major CEMS maintenance is often scheduled to
        coincide with the unit outage.   Point in-situ CEMS's employ temperature
        compensation circuitry which is normally optimized for the generally
        encountered range of effluent temperatures.  Stack temperatures during
        an outage are far outside these ranges.

    2.  Audit Logistics
        Determine the location of and access to important CEMS components,
        whether gas cylinders can be conveniently transported to the sampling
        location,  and if necessary, the length of audit gas transport line
        needed to carry the audit gases to the sampling location.

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    3-  Availability of a GEMS Technician
        A CEMS technician should be  available to assist with the audit.  He
        will assist with:
        •  Determining data  acquisition system  (DAS) capabilities and
           limitations;
        •  Locating key CEMS components  (sample points, analyzer enclosures,
           DAS displays);
        •  Identification of CEMS operating cycles;
        •  Physical contact with the CEMS hardware, such as connection of the
           audit gas system; and
        •  Data retrieval at the completion of the audit.

    Unannounced audits should not be attempted until the auditor and source
personnel are familiar with  the necessary audit activities.

2.5  LEGAL AUTHORITY AND LIABILITY
    Before going to the site, list the legal authority under which the audit
will be conducted and summarize the  relevant regulations or permit conditions.
    To minimize any liability for damage to the equipment, the auditor should
not have any physical contact with the CEMS hardware.  Connecting the audit gas
system, or other physical contact with the installed equipment, should be done
by the CEMS Technician.  As a general rule, the auditor should not adjust the
installed equipment or direct the CEMS Technician to make any adjustments or
changes.   The purpose of the audit is to define the condition of the CEMS at a
specific time.  Changes which may result from the audit are the responsibility
of the source owner.

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                  3.   GENERAL PRINCIPLES OF AUDIT GAS INJECTION

     To  evaluate the  entire sampling system,  audit gas needs to be injected as
 close to  the  sampling nozzle as possible.   Injection procedures depend on the
 type of CEMS  (i.e.,  extractive or in-situ).   The agency field inspector should
 review  the gas  injection system with the source technician for the CEMS being
 evaluated.

 3-1  AUDIT GAS  INJECTION FOR AN EXTRACTIVE CEMS
     Extractive  sampling systems may be configured in a variety of ways.
 Regardless of the configuration,  it is important that the  sample stream
 pressure  and  flow rate to the analyzers are the same during audit gas  analysis
 as during normal effluent sampling.  This  is accomplished  by supplying an
 excess  of audit gas  to the probe at atmospheric pressure while the CEMS
 operates  in its normal sampling mode;  the  CEMS withdraws audit gas at  its
 normal  sample flow rate while excess audit gas is vented to the atmosphere.
     Two general audit techniques are described in Subsections 3-1-1 and 3-1.2.
 Subsection 3-1-1 is  intended for those CEMS's which automatically vent excess
 calibration gas through the probe into the stack.   Subsection 3-1-2 covers
 those CEMS's  which require an external atmospheric vent to ensure that that
 audit gas is  supplied at atmospheric pressure.
     The audit gas manifold shown in Figures  1 through 4 is optional.   An audit
 gas  manifold  is recommended,  especially when several audit gases are required.
     Most  extractive  systems incorporate a  spare sample line,  a calibration gas
 transport line,  or both in the sample  line bundle between  the probe valve box
 and  the analyzer enclosure.   For convenience,  one of these lines may be used to
 transport audit gases from the analyzer location to the probe location.   If  the
 calibration gas transport line is used for this purpose, it should be
 disconnected  from the calibration valves at  the analyzer location so the CEMS
 does not  have to be  in the calibration mode  for the audit  gases to flow to the
 probe location.

 3.1.1   Probe  Vent Audit Technique
    This  technique is applicable  to extractive sampling systems which  vent
excess  calibration gas through the probe to  the stack.   Examples are systems
which introduce  calibration gas  into a Tee or a filter chamber at the  probe
exit (Figure  1)  and  in-stack  dilution  probe  systems (Figure 2).  These figures
                                        5

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                      CHECK
                      VALVE
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 TRANSPORT LINE  .
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                                 PROBE
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     SAMPLE
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       SYSTEM CONFIGURATION
        FOR NORMAL SAMPLING
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 AUDIT
  GAS
                                                                    PROBE
                                      STACK
                                       OR
                                       DUCT
                                                  SYSTEM CONFIGURATION
                                                 FOR SAMPLING AUDIT GAS
                                                  AUDIT GASES
                             Figure 1. Extractive probe with calibration gas line into filter chamber on probe outlet.
3780 5/89

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                                             Figure 2. In-slack dilution probe type extractive system.
3780 5/89

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illustrate the normal sampling configuration and the audit gas injection setup

for these systems.
    The audit gas flow rate must be higher than the CEMS sample stream  flow

rate to prevent dilution of the audit gas.  The CEMS technician should  use the

following procedure to establish the correct flow rate.


    1.  Connect the audit gas system to the CEMS injection port as  shown in
        Figure 1 or 2.

    2.  Inject a zero gas.  Slowly increase the regulator delivery  pressure
        until the flow meter indicates the rate recommended by the  CEMS
        vendor.   (In the absence of vendor information, 1 1pm is generally
        acceptable for in-stack dilution probe systems; for other extractive
        systems, choose a flow rate (1-2 1pm higher than the indicated  total
        sample stream flow rate.)  Allow sufficient time for the analyzer(s) to
        achieve a stable response.  Record the stabilized response(s).

    3.  Decrease the gas injection rate by 0-5 1pm.  Allow the analyzer
        responses to stabilize and record the responses.  If the responses at
        both flow rates are the same,  use the manufacturer's recommended flow
        rate; proceed to Step 6.

    4.  If the monitor's zero response is greater at the lower flow rate,
        increase the flow rate in 0.5 1pm increments until the zero response
        remains unchanged with further flow rate increases.   This indicates
        that the flow rate is high enough to prevent dilution of the audit gas
        with effluent.

    5-  Inject all audit gases at a rate of 1 1pm higher than the minimum flow
        rate determined in Step 4 to prevent audit gas dilution.

    6.  Record the gas flow rate used and the time allotted for injection of
        each gas.


    After completion of the audit, be sure the CEMS is returned to  its  original

configuration and that all fittings are properly tightened to prevent ambient

air from entering the sampling system during normal operation.


3-1.2  External Atmospheric Vent Audit Technique

    This technique is applicable to extractive sampling systems which have no

provisions for venting excess calibration gas.  Two such systems are shown in

Figures 3 and 4.  These figures also illustrate the external atmospheric vent

audit gas setup.  The rotameter can be monitored visually to verify excess

flow.   Note that in the absence of excess flow, ambient air will enter  the

sampling system through the flow meter and will dilute the gas.

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              3-WAY
           CALIBRATION
              VALVE
    CALIBRATION GAS
    TRANSPORT LINE
    HEATED SAMPLE LINE
     TO VALVE BOX OR
    ANALYZER LOCATION
       SYSTEM  CONFIGURATION
       FOR  NORMAL  SAMPLING
                                    STACK
                                     OR
                                     DUCT
PROBE
    SAMPLE
      IN
                                                     EXCESS
                                                      AUDIT
                                                       GAS
                                             ROTAMETER
                                                                                                   PROBE
                                        AUDIT GAS
                                      TRANSPORT LINE
                                       HEATED SAMPLE LINE
                                        TO VALVE BOX OR
                                       ANALYZER LOCATION
STACK
 OR
 DUCT
                                               SYSTEM   CONFIGURATION
                                              FOR  SAMPLING  AUDIT  GAS
                                                 AUDIT GASES
                                 Figure 3.  Extractive probe with 3-way calibration valve on outlet.
3780 5/89

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                    J
o
HEATED SAMPLE LINE
 TO VALVE BOX OR
ANALYZER LOCATION
         SYSTEM  CONFIGURATION
         FOR   NORMAL  SAMPLING
                                     STACK
                                      OR
                                     DUCT
                                 PROBE
                                      SAMPLE
                                        IN
                                                                                 EXCESS
                                                                                  AUDIT
                                                                                  GAS
                                                                           ROTAMETER
                                                                    AUDIT GAS
                                                                  TRANSPORT LINE
                                                            Xh
                                                            -04
HEATED SAMPLE LINE
 TO VALVE BOX OR
ANALYZER LOCATION
                                                                  rtX
                                                                  -M
                                                                  -M
                                STACK
                                 OR
                                DUCT
                                                                                              PROBE
       SYSTEM   CONFIGURATION
      FOR  SAMPLING AUDIT GAS
                                                                AUDIT GAS
                                                                MANIFOLD
                                                 AUDIT GASES
                                     Figure 4.  Extractive probe without 3-way calibration valve.
 3780 5/89

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    The CEMS technician  should  use  the  following procedures  to  inject  the  audit
gases.

    1.  Connect  the  audit  gas system  to  the CEMS sampling  system  as  shown  in
        Figure 3  or  4.
    2.  Select each  gas  in turn and adjust the regulator delivery pressure to
        provide  an excess  flow  of 1 to  1.5 1pm.  Allow each  analyzer to
        stabilize before recording  its  response to an audit  gas.  Record the
        gas injection  rate used and time allotted for each gas.

    After completion of  the audit,  be sure the CEMS is returned to its original
configuration and that all fittings are properly tightened to prevent ambient
air from entering the  system during normal operation.

3.2  AUDIT GAS INJECTION FOR A  POINT  IN-SITU CEMS
    Figure 5 shows an  audit gas injection set-up for a point in-situ CEMS.  The
audit gas manifold is  optional.  The  audit gas flows through the calibration
gas injection port,  through a stainless steel tube within  the probe, and into
the measurement  cavity within the in-stack ceramic filter on the end of the
probe.  The audit gas  flow rate must  be adjusted so that there is sufficient
flow to force effluent from the ceramic filter (see Figure 6).
    Excessive flow can cause errors due to (1) compression of the audit gas
within the ceramic filter,  or (2) inadequate time for audit gas to warm to
stack temperature while  traversing  the length of the probe.  The proper gas
injection rate will  depend on the condition of the in-stack filter.  Since the
condition of the  filter  will vary with time, the proper flow rate must be
verified each time a system is  audited.  The CEMS technician should use the
following procedure  to establish the  correct flow rate:

    1. Connect the audit gas .system to the CEMS injection port as shown in
       Figure 5 and  adjust the  regulator delivery pressure to about  10 psig for
       each of the calibration  gases.
     !.  Inject a high range audit gas (use S02 for SO /
       NO  only for NO  monitors).  Slowly open the r]
                                                 ,/NO  and  S0_ monitors;  use
       only for NO  monitors).  Slowly open the  flow  control valve  until
   the flow meter indicates  the rate recommended by the manufacturer.   (For
   LSI SM810 analyzers,  the  recommended rate is  2 1pm.)   Allow  sufficient
   time for the analyzer to  achieve a stable response.  Record  the
   stabilized response.
3. Increase the gas injection rate by 0.5 1pm.   Allow the monitor response
   to stabilize and record the concentration value indicated by the
   monitor.  If the monitor  response at both flow rates is the  same,  use
   the manufacturer's recommended flow rate; proceed  to Step 6.
                                   11

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                              OPTIONAL ON-STACK
                           FLOW CONTROL EQUIPMENT
3780 5/89
                                   ROTAMETER
   FLOW
! CONTROL
j  VALVE
                                                               TEFLON
                                                               TUBING
                                                                              GEMS
                                                                           TRANSCEIVER
                                                                    CALIBRATION
                                                                   GAS INJECTION
                                                                        PORT
              AUDIT GAS MANIFOLD
                                                                                                  STACK OR DUCT
                             AUDIT GASES

                                        ^^
                                           Figure 5. Point in situ GEMS audit gas injection setup.

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                                tttttttt/x
                                f •.s.t'A j '"ft...,. --vy' . . -•   j&fcfet;'-L-C^ > ' .''.'•Jx^i'TTTNw. »
                 CALIBRATION
                   GAS
                                     EFFLUENT
3780 5/89
                      Figure 6. Point in situ calibration gas injection.

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    k. If the monitor response is greater at the higher flow rate, inject  the
       same gas at 0.5 1pm below the recommended flow rate, allow the  response
       to stabilize, and record the results.  If the response at this  flow rate
       is the same as at the recommended flow rate, inject the audit gases at a
       rate of 0.25 1pm lower than the recommended flow rate; proceed  to Step
       6.

    5- If the monitor response at the lower flow rate is lower than at the
       recommended flow rate, inject a zero level gas at the recommended flow
       rate and note the stabilized zero level response.  (A small positive
       offset may be observed; some monitors amplify positive noise and ignore
       negative noise.)   Decrease the gas injection rate in increments of  0.25
       1pm until the stabilized zero response begins to rise.   This indicates
       that the gas injection rate is too low to prevent the diffusion of  stack
       gases into the measurement cavity.  Inject all audit gases at a rate of
       0.25 1pm greater than the fl'ow rate which exhibits the increased zero
       response.

    6. Record the flow rate used and the time allowed for injection of each
       gas.

    After completion of the audit,  be certain the gas injection port is sealed
tightly to prevent ambient air from entering the system during normal sampling.

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                          4.   CONDUCTING THE FIELD AUDIT


    A "General Audit  Information"  data form is provided in Section 6.  On this

form record general audit information regarding plant contacts, audit

participants  (agency  and  source),  how data are collected, factors which may

affect data manipulation  or  audit  results, problems noted, etc.  Additional

notes and comments should be attached to this sheet if necessary.

    The actual field  audit is  conducted by injecting each audit gas into the

GEMS a minimum of two times.   The  CEMS should be set-up to exclude audit data

from the emissions averages.   If this cannot be done, alternative procedures

will be needed to isolate and  record analyzer responses to the audit gases.

Except for the exclusion  of  audit  gas response data from calculated emission

averages, the CEMS should be operating in its normal mode.


4.1  AUDIT GAS INJECTION
    1. Instruct the CEMS  technician to connect the audit gases, as outlined in
       Section 3-  On  the Audit Gas Injection Record (provided in Section 6)
       record the  time when effluent sampling is interrupted  (e.g., when the
       sample line is  removed  from the probe) .

    2. Adjust the  audit gas delivery rate according to the procedures in
       Section 3•

    3- Inject each gas until a stable response is obtained.   If the CEMS
       operates with a periodic sampling and analysis cycle,  inject each gas
       for a minimum of one complete cycle.  Record the beginning time for each
       gas injection on the Audit Gas Injection Record.


4.2  NUMBER OF GAS INJECTIONS

    1. Each audit gas  should be analyzed twice.  These analyses should be
       separated by the analysis of a different audit gas or  a zero gas.

    2. If the system responses for the two analyses of the same gas vary from
       each other by more than 10% of the gas value, a problem with one of the
       injections should  be suspected.  In this case, a third analysis should
       be run.  The third analysis should be separated by the analysis of a
       different audit gas or  a zero gas.

    3. If three gas injections are done, calculate a mean response from the two
       results which are  closest to each other.
                                       15

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4.3  DATA RECORDKEEPING

    1. The results of each gas analysis should be recorded on the Audit Results
       form.   Acceptable accuracy levels for each audit gas are available from
       the Inspector's Quick Check Audit Gas Data Sheet.  Example forms are
       shown in Section 6.

    2. Often,  a zero level response will be available for each monitoring
       channel.  For instance, an 0_ audit gas for an extractive CEMS will also
       be a zero level audit gas for the S0_ channel.  Recording these zero
       responses is optional,  but is encouraged because they provide additional
       CEMS performance data with no additional resource expenditure.

    3- A copy  of the completed Audit Results Form may be left with the source.
       Since the Inspector's Quick Check Audit Gas Data Sheet reveals the
       concentrations of the blind audit gases,  it should be treated as
       confidential.   It will  not be shown to or left with source personnel.
                                      16

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                            5-  POST-AUDIT  ACTIVITIES

    Post-audit activities will vary  from agency  to agency.  This section
includes a brief description of  several activities that should be done and one
data manipulation  activity  that  should not be done.

5.1  PLOT CEMS RESPONSE  AS  FUNCTION  OF AUDIT GAS CONCENTRATION
    A Graphic Presentation  of CEMS Response form is provided in Section 6.  Use
of this optional presentation of audit data is encouraged.  Plot the actual
audit gas concentration  along the horizontal axis and the CEMS responses along
the vertical axis.   If zero level response data  are available, include them on
the plot.  By connecting the plotted points, a good estimation for the CEMS
performance over a wide  range of concentrations  is obtained.

5-2  FILE DATA
    Copies of the  completed AUDIT DATA FORM should be filed at the agency
according to the agency's filing procedures.

5-3  FOLLOW-UP ACTIVITIES
    When the audit reveals  unacceptable CEMS accuracy, follow-up activities
should include encouraging  the source to remedy  the problem and scheduling a
follow-up audit.   When the  audit reveals acceptable accuracy, the source should
be notified, along with  a few words  of thanks and appreciation for its
cooperation.

5.4  NO CORRECTIONS  OF REPORTED  EMISSIONS  DATA
    Do not "correct" reported emissions data based on the audit results.  The
audit results demonstrate the performance  of the CEMS at one point in time.
The audit is intended to determine the acceptability of emissions data, and
does not provide a basis for adjustment of the data.
                                        17

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                                6.0  DATA FORMS

    Facsimilies of data forms designed to facilitate gas CEMS audits are
provided in this section.  Example forms are also provided showing data
obtained from a hypothetical audit.
                                       18

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CO
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OB
GO
09
                                           PRE-AUDIT  DATA FORM
               Plant Name
              Company Name
              Plant Contact
              Phone Number,
              Address 	
              Company Contact
              Phone Number	
              Address
              CEMS Type (extractive, point in situ, etc.)
              Manufacturer (KVB, LSI, etc.)  	
EMISSIONS:

 Typical
 Standard
                                 SO
                         NO
                             Other
                       Diluent
                          (Ib/mmBtu)   (PPM)    (Ib/mmBtu)   (PPM)     (Ib/mmBtu)   (PPM)
                          *  Concentration at level of the standard and typical diluent concentration
              Analyzer
              SO 2
              NOx
              Diluent
              Other
              Other
  Maker
   Model
Fufl Scale VaLte
                                                                           S/N
               Gases
              Needed
               SO 2
               NOX
               02
              CO 2
              Other
Low Level
High Level
             Probe Location(s)
             Access to Probe Location
             Need Gas Transport Line (Y / N)
                            Length of Transport Line Needed
                                                ft.

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                     GENERAL AUDIT JNFORMATION
 AUDIT DATE:
  PLANT CONTACT:

  Name 	

  Phone 	
 Address.
  AUDIT PARTICIPANTS:
               Name                       Affiliation            Phone Number
How is CEMS audit data collected? (Computer screen.
Correction apolied to emissions data?
Correction applied to audit data?

printout, stripchart)



NOTES:
                                                                  3736 8/88
                            20

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                    AUDIT  GAS INJECTION  RECORD
Plant




Date
Unit No.
             Time when effluent sampling is interrupted:
Injection
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
I
Gas
Name















I
Time
Injection
Begins















GEMS Responses
so2
ppm















NO x
ppm















Diluent
















Other
















Other
















                 Time effluent sampling resumes:
                           21
                                                                        3736 8/88

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                             AUDIT RESULTS FORM
 Plant Name

 Company	

 Unit No.	
                    Auditor,


                    Date	
GEMS Sample Location
Measurement
Range
Example
Low SO 2
High SO 2
Zero (optional)
Low NO x
High NO x
Zero (optional)
Low Diluent
High Diluent
Zero (optional)
Other: Low
High
Zero
Other: Low
High
Zero
Gas
Name
SO2 #EX















Gas1
Cone.
Blind















Analysis
#1
154















Analysis
#2
160















Analysis ^
#3
















Mean
Response
157















Accuracy
Level
A















1 Write "blind" if gas concentration is to remain unknown to the source.

2 Analysis #3 should be performed only if the difference between analyses #1 and #2 exceeds 10%
  of the gas value. If Analysis #3 is performed, use the two analyses with the least difference to
  calculate the mean response.
                                22
                                                                               3780 6/89

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                 GRAPHIC PRESENTATION OF CEMS RESPONSE
     Plant Name


     Company_


     Unit No.
             Auditor


             Date —
     CEMS Location.
Measurement Channel


Instrument Span	
LU
co

O
D_
CO
UJ
cc

CO
2
LU
O
            JJL
                                                                      IDEAL
                                                                      RESPONSE

                                                                      CURVE
                                   GAS VALUE
                                                                          3780 5/89
                                  23

-------
              INSPECTOR'S  QUICK  CHECK  AUDIT GAS  DATA SHEET

Status

Blind













Gas
Examples:
SO2 EX#1
O2 EX#2













Cone.
150 ppm
12.4 %













Accuracy Levels
Acceptable
A <5%
142 - 158
11.8- 13.0
-


-
-
-
-
-
-
-
-
-
-
B< 10%
135 - 165
11.2 - 13.6
-
-

-
-
-
-
-
-
-

-
-
C<15%
127- 173
10.5 - 14.3
-
•

-
-
-
-
-
-


-
-
Unacceptable
D>15%
<126 >174
<10.4 >14.4
< >
< >
< >
< >
< >
< 2
<. >
< >
< >
< >
< >
< >
5 >
1.  Each audit gas in the possession of the agency should be included on this sheet.

2.  Write "Blind" in the status column beside those gases whose concentrations will remain unknown to source
   personnel, ft is recommended that a portion (or all) of the agency's audit gases be designated as blind.

3.  Column "Cone.": Write certified value of audit gas in this column to the nearest ppm or 0.1%, as appropriate.

4.  Column A: Lower Limit  = (Certified Cone.) x (0.95)  [round down]
            Upper Limit = (Certified Cone.) x( 1.05)   [roundup]

   Column B: Limits = (Certified Cone) x (0.9) and (1.1) [round as above)

   Column C: Limits - (Certified Cone) x (0.85) and (1.15) [round as above)

   Column D: Outside Level "C" limits, to the nearest ppm or tenth of percent.                     3736  8/8
                                 24

-------
u
O3
OS
CD
09
                              PRE-AUDIT DATA FORM
 Plant Name
                                                             (^->^S-/£/S/3 r,,  .y/^-    _, „
 Company Name
 Plant Contact
 Phone Number,
 Address	
 Company Contact
 Phone Number	
 Address
                                  J-^ ^_) _ —
 CEMS Type (extractive, point in situ, etc.)
 Manufacturer (KVB, LSI, etc.)       •< f
                   so,
                                         NO
                                                                            Other
EMISSIONS:        ^2                  ,,~ x
            (Ib/mmBtu)   (PPM)     (Ib/mmBtu)   (PPM)    (Ib/mmBtu)   (PPM)
 Typical         (?- ^'    ? ^       ^.5"' J>   ? ~i        -—    	
 Standard      '- ^~ &     -T-22. *    £?• TV     yav  •     —~~     	
                                                                            Diluent
                                                                             (%) ^
                                                                            6.  '
             ' Concentration at level of the standard and typical diluent concentration
Analyzer
SO 2
NOx
Diluent
                  Maker
                                                   Model
 Other
                                                     Ful Scale VaLe
                                                             r^
                                                                            SvN
 Gases
Needed
SO 2
NOX
02
CO 2
Other
                Low Level
                                                High Level
                                 $-0a —

              Probe Location(s)
                            /C
Access to Probe Location
                                          F/*t,

                                                                  -
Need Gas Transport Line (Y / N)
                                           Length of Transport Line
                                                                                   ft.
                              25

-------
                      GENERAL AUDIT  INFORMATION
-r-__^ - <* **
PLUIT CONTACT:
Phnno ' xx , ' • - ///- ~ 1- ^ —




<^.#\-

  AUDIT PARTICIPANTS:
                Name                         Affiliation             Phone Number
                                                                      -' 7-
                                                               -« -< ** —
How is CEMS audit data collected? (Computer
Correction aoolied to emissions data? ^z-r
Correction applied to audit data? >^-r/ t-*'
screen, printout, stripcnart)
^"j.-«_C/ <=rr\ cS^.// Z*+~e -»• J^»--n ^/CtCl4;
^c/,., -,p/.^ *y ~~r^

NOTES:  ^>>? ^i  ,^f.#(:t.-r;t>M   ^x/^/
-------
                       AUDIT GAS INJECTION  RECORD
   Plant
   Date
                                              Unit No
               Time when effluent sampling is interrupted:
                                                             O
  Injection
    No.
 Gas
Name.
 Time
Injection
Begins
                                                 GEMS Responses
                                 SO
ppm
                                NO
ppm
                     Diluent
                     Other
Other
               3
                                          -5"
                /
                    2/0. 3
               2
                                        /a j —
               Z
       / y .- /
           3/V.2.
               Z
        /•/: 2.6
                              31 :f.

                                             . 2
                                                      -  4,
               /
                       . 7
   10
                                / 7
a
   2.
                                          _  /
                                   3 7
               2.
                                           /7
  14
  15
                   Time effluent sampling resumes:
                                                                         3736 8/88
                             27

-------
                              AUDIT RESULTS FORM
Plant Name .	€_

Company	

Unit No.	
/•e,.   <^~f_
                                       r/6.
Auditor
                                                                    y
                                CEMS Sample Location
Measurement
Range
Example
Low SO 2
High SO 2
Zero (optional)
Low NO %
High NO x
Zero (optional)
Low Diluent
High Diluent
Zero (optional)
Other: Low
High
Zero
Other: Low
High
Zero
Gas
Name
SO #EX
J£^
JT^ Y
SsC<2
fi/Ox 3
&, 0L.
0^ ^
O* 1
//^, &L






Gas1
Cone.
Blind
3^7 /
BJ>»J
O
8/i»,l
^rt
0
M^
B/,-«l
0






Analysis
#1
154
3/y
?/
-------
         GRAPHIC  PRESENTATION OF CEMS RESPONSE
Plant Name ^ c-~^/£.
Company — •*-_.„/<>
Unrt No. ~
CEMS Location S~/cJ.

/^r,<,^J,^ *-/: -i_*~, /h/»),f*2.
£/ — " '
r~t f *^ ~^^~" J -^ / ^? 5 J?
MPa^lirPm^rrt P.hannpl ^ C/->~


o
a.

01
cr

C/3
2
01
        I  | | | | I | | | |  | | ||  MM  I I M I I  I I  MM  II I I I I I I I


            300       6a°        7l"~

                           GAS VALUE (
                                                           IDEAL

                                                           RESPONSE

                                                           CURVE
                                                             3736 8/8£
                       29

-------
          GRAPHIC PRESENTATION  OF GEMS  RESPONSE
 Plant Name



 Company	



 Unit No.	

C *•,. ,*,-• . f_
••."•• Auditor



— Date —

CEMS Location
                   Measurement Channel


                    Instrument Span
UJ
at
a:
UJ
           M i i liuil n ii In nlni i IIM i IM ti
                                              Cut-*-
                                                                   IDEAL

                                                                   RESPONSE

                                                                   CURVE
                               GAS VALUE ' ,-/X '
                                                                      3736
                      30

-------
       GRAPHIC  PRESENTATION OF GEMS  RESPONSE
Plant Name '-vo
Company -*^*
Unrt No. ^
CEMS Location

"•/?/£. ^'nt.r-'T,^* J/6X -?>, Aud'tnr /rfi'-r.-^e.m /ItJeyr^
~V/
-------
              INSPECTOR'S  QUICK  CHECK AUDIT  GAS  DATA  SHEET
                                                             Accuracy Levels
                                                    Acceptable
                                                                   Unacceptable
    Status
Gas
  Cone.
  A  15%
            Examples:
            SO2 EX#1
          150 ppm
              142- 158
                 135- 165
                  127- 173
5126  >174
    Blind
  EX#2
                         12.4%
              11.8- 13.0
                                      11.2- 13.6
                                    -14.3    510.4  >14.4
                                          - /3V
            J&L    2-
                                                                     7  -  £ JJ
                   y
          **'
                                                                > £22.
           J&i.
                              7f
           /!/
                              „«
                                                                                        > 72.3
                  3
                              Ptin
                   52 J  - 5
  Bin I
   /
#5-
. 3   -9-7
. O  -  -3.0
                                                                  < 3- 7
                                  
-------
                                    TECHNICAL REPORT DATA
                             (Please read Instructions on the reverse before completing)
 1. REPORT NO.
    340/1-89-003
                              2.
                                                            3. RECIPIENT'S ACCESSION NO.
 4. TITLE AND SUBTITLE
 Field  Inspectors Audit  Techniques: Gas GEMS's  Which
 Accept Calibration Gases
                                                            5. REPORT DATE
                                                               June 1989
                                                           6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)
                                                            8. PERFORMING ORGANIZATION REPORT NO.
 Wayne  E.  Reynolds
 9. PERFORMING ORGANIZATION NAME AND ADDRESS

  Entropy  Environmentalists,  Inc.
  CEM/Engineering Division
  PO  Box 12291
  Rp<;p3rrh Tri'annlo Park  NT  ?77flQ	
                                                             10. PROGRAM ELEMENT NO.
                                                            11. CONTRACT/GRANT NO.
                                                                  68-02-4462
              nn |
12. SPONSORING AGEtfCY NAME AND ADDRESS
U.  S.  EPA,  Stationary  Source Compliance Division
401 M  Street, SW   Waterside Mall
Washington, DC  20460
                                                             13. TYPE OF REPORT AND PERIOD COVERED
                                                            14. SPONSORING AGENCY CODE
 15. SUPPLEMENTARY NOTES
 Work Assignment Manager:  Anthony P. Wayne, U.  S.  EPA, Region VI
 16. ABSTRACT
        This  document presents guidance for planning and conducting audits of
   continuous emission monitoring systems  (GEMS's)  for gaseous  pollutants.  It
   provides simple, cost  effective audit procedures for control agency field
   inspectors to verify the accuracy of CEMS  data.   The audit procedures are based
   on the use of audit gases and are applicable only to gas CEMS's configured to
   accept calibration gases.  The document includes an outline  of planning
   activities,  principles of audit gas injections,  procedures for conducting a  field
   audit, a discussion of post-audit activities,  and example data forms.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                               b.lDENTlFIERS/OPEN ENDED TERMS
                                                                         c.  COSATI Field/Group
     Air Pollution  Monitoring
                                               Continuous Emission
                                                  Monitoring

                                               Gas Audits

                                               Audit  Procedures
 8. DISTRIBUTION STATEMENT

       Release to  Public
                                              19. SECURITY CLASS (ThisReport!
                                                Unclassified
21. NO. OF PAGES
        36
                                               20. SECURITY CLASS (Thispage)
                                                  Unclassified	
                                                                          22. PRICE
EPA Form 2220-1 (R«v. 4-77)   PREVIOUS EDITION is OBSOLETE

-------