United States      Office of Air Quality       EPA-340/1 -83-013
Environmental Protection  Planning and Standards      January 1983
Agency        Research Triangle Park NC 27711

Stationary Source Compliance Series
Performance
Specification
Tests for
Pollutant
and Diluent
Gas Monitors:

Reporting
Requirements,
Report Format,
and Review
Procedures

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                                           EPA-340/1-83-013
Performance Specification Tests for Pollutant
            and Diluent Gas Monitors:
   Reporting Requirements, Report Format,
              and Review Procedures
                           Prepared by:

                        GuyB. Oldaker III, Ph.D.
                         James W. Peeler

                      Entropy Environmentalist, Inc.
                        Research Triangle Park
                          North Carolina
                           Prepared for:

                           Louis R. Paley
                    Stationary Source Compliance Division
                             and
                         Anthony Wayne
                           Region VII

                 United States Environmental Protection Agency
                      SSCD Contract No. 68-01-6317
                  U.S. ENVIRONMENTAL PROTECTION AGENCY
                  Office of Air Quality Planning and Standards
                    Stationary Source Compliance Division
                       Washington, D.C. 20460

                          January 1983

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The Stationary Source Compliance  series  of reports  is  issued  by the
Office of Air Quality Planning and  Standards,  U. S. Environmental
Protection Agency, to assist Regional  Offices  in  activities related  to
compliance with implementation plans,  new source  emission  standards,
and hazardous emission standards  to be developed  under  the Clean Air
Act.  Copies of Stationary Source Compliance  Reports are available -
as supplies permit - from Library Services,  U.S.  Environmental
Protection Agency, MD-35, Research  Triangle  Park, North Carolina
27711, or may be obtained, for a  nominal  cost,  from the National
Technical Information Service, 5285 Port  Royal  Road, Springfield,
Virginia  22151.

This report has been reviewed by  the Office of Air  Quality Planning
and Standards, U.S. Environmental Protection  Agency, and approved  for
publication as received from Entropy Environmentalists, Inc.   Approval
does not signify that the contents  necessarily reflect  the views and
policies of the U.S. Environmental  Protection  Agency, nor  does  mention
of trade names or commercial products  constitute  endorsement  or
recommendation for use.

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                                  ABSTRACT
This document presents recommended reporting requirements for  performance tests




of continuous emission monitoring systems installed at fossil-fuel  fired  steam




generators subject to New Source Performance Standards (NSPS).  The  recommended




reporting requirements are applicable to performance  tests  conducted  according




to  40  CFR 60,  Appendix  B,   Performance  Specifications 2 and 3  (promulgated,




Federal Register,  Vol.  40,   No.  194,  October 6,  1975).   The document  details




procedures for reviewing such performance tests.
                                  111

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                        TABLE OF CONTENTS
Section  1.   Introduction	    1

Section  2.   Discussion of the Review Process	    7

             2.1  An Overview	    7
             2.2  Preparing for the Review	    8

                  2.2.1  Pretest Protocol Statements 	   10
                  2.2.2  The Observer's Notes and Records	11

             2.3  The Level of Review	11
             2.4  Conducting the Review	13
             2.5  Reviewer's Report	14

Section  3.   Test Report Format	17

Section  4.   Review of Test Procedures, Data and Results of Monitor
               Performance Tests for S09 and NO  Monitors	27
                                       L.       X
             4.1  Calibration Error Test	28

                  4.1.1  Background	28
                  4.1.2  Review of Calibration Error Test Data and
                           Results	29

             4.2  Conditioning Period; Operational Test Period 	   31

                  4.2.1  Background	31
                  4.2.2  Review of Operational Test Period	32

             4.3  Response Time Test	35

                  4.3.1  Background	35
                  4.3.2  Review of Response Time Test Data Sheet and
                           Strip Chart Records	37

             4.4  Zero and Calibration Drift Tests	43

                  4.4.1  Background	43
                  4.4.2  Review of Zero and Calibration Drift Tests.  . .   45
                  4.4.3  Review of 2-Hour and 24-Hour Drift Test
                           Strip Chart Records	50

             4.5  Relative Accuracy Test	51

                  4.5.1  Background	51
                  4.5.2  Review of Relative Accuracy Calculations.  ...  52
                  4.5.3  Determinations of Continuous Monitor System
                           Values	58
                  4.5.4  Review of Reference Method Data and Results  . .  60

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Table of Contents
(continued)
Section 5.  Review of Test Procedures, Data, and Results of Monitor
               Performance Tests for CC>2 and 0^ Monitors.  .	   107
            5.1  Background  	  .....   107
            5.2   Reviewing  Diluent Monitor Performance Test  Reports.  .  .   110
            5.3  Calibration Gases	   H2
                                    VI

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                               1.0  INTRODUCTION
     Continuous monitoring  of  gaseous  pollutant emissions  —  sulfur  dioxide

(S0_) and nitrogen oxides (NO )  —  is required at stationary sources subject to
   ^                         A
New   Source   Performance  Standards  (NSPS).   Requirements   for   continuous

monitoring are contained in 40  CFR  60.13.  Paragraph  60.13(c)  states  that "the

owner or operator of any affected  facility shall conduct continuous monitoring

system  performance  evaluations  and furnish the  Administrator  within 60  days

thereof .. .copies  of a  written  report   of the  results  of such  tests."  The

contents of this  written report are mentioned   in  Performance  Specification  2

(40 CFR  60, Appendix  B) , which  explicitly requires  reporting  of the  following

information :

     (1) The data and results from  determinations of :

         (a)  Calibration gas concentrations (Figure  2-1).

         (b)  Calibration error  (Figure  2-2).

         (c)  Relative accuracy (Figure  2-3).

         (d)  2-hour zero and calibration drifts  (Figure  2-4).

         ( e)  24-hour zero and calibration drifts (Figure  2-5).

         ( f )  Response time (Figures 2-6).

     (2) The method  used  to determine  the  integrated  averages from
         the  continuous  emission  monitor  for the  relative accuracy
         test  (this requirement appears  as a  note at  the  bottom  of
         Figure 2-3).

     (3) For relative accuracy tests of wet-basis continuous emission
         monitors,  the  moisture   test  method   and  the  correction
         procedure  employed  to  place  the  reference  method  and
         monitoring measurements on a consistent basis.

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     Moreover,  additional  reporting may be necessary depending on the  manner  in

which the Reference  Methods are employed during the performance testing program

(which may commence  with the  analyses of calibration gases two  v«eks  prior  to

the initiation of the operational test  period).   Thus, the  introduction  to  40

CFR  60,  "Appendix  A - Reference  Methods"   addresses  the necessary  reporting

requirements to  be  observed   when  the  tester  elects to  employ materials  or

procedures identified  therein as "optional," "equivalent,"  or  "subject  to the

approval of the Administrator."


      A  performance  test  report  containing  only  the  explicitly  required

information would provide little support for the  results  of monitor performance

testing.  Indeed, this type of support is critical to prove that the monitors,

as operated  and  installed at the source, are  providing  quality emission rate

data  because  subsequent decisions  and actions presuppose the  accuracy of the

 indicator, i.e.,  the continuous monitor.


      This manual  has been written with a threefold purpose:

      (1)  Provide a model  for  the complete reporting  of the  results  of
           continuous monitor  performance tests.

      (2)  Provide  test  report  reviewers  with  sufficient   background
           information    about   the    continuous   monitor     performance
           specifications so  that they may review such reports effectively.

      (3)  Provide  test report  reviewers  with   detailed  guidelines  for
           conducting   reviews  so   that  the   review   process  may  be
           facilitated .


       The  interpretation of "reporting completeness"  is  not entirely objective,

 and  the recommended reporting requirements contained  in  this manual  may  be

 viewed  by some  as  burdensome.   However , the  recommendation  includes only the

 reporting of data generated  as a  matter  of course, if the  procedures detailed

  in   the  Performance   Specifications  and  Reference  Methods  are  followed.  In

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addition, the material  based  on  report  formatting and  stylistic  conventions




(e.g.,  Introduction,  Table  of Contents,  Discussion  of Results, etc.),  would




also be included  as a  matter of course  in  engineering report documentation.






     Standard, complete  performance  specification  test  reporting  can  have




beneficial effects.  It  will  promote  adherence  to  Performance Specification and




Reference Method  procedures, which in turn will  help ensure quality services to




sources  who  contract for  testing.   For  the  agency,   standardized,  complete




reporting  can  facilitate  consistent comparisons  of  performance  among  many




monitors (which may be useful  in  recognizing  invalid  emission rate  data), ease




manpower  restraints, and  increase the cost effectiveness of continuous monitor




certification programs.






     This manual   is intended  to  accompany the  continuous  monitor  Performance




Specifications promulgated  October 6, 1975 (Federal Register, Vol.  40,  No.  194,




pp.  46250-46271).  Since  that time,  however,  revisions to  these  Performance




Specifications have been  proposed  twice:  Federal  Register,  Vol. 44,    No.  197,




Wednesday, October 10, 1979, PP.  58601-58636,   and  Federal  Register,  Vol.  46,




No.  16,  Monday,   January 26,   1981,   pp.   8351-8363.    The  revisions   proposed




October 10,  1979  were quite extensive in  scope, and in addition, the revisions




addressed required  reporting  in  some detail.   The revisions proposed January




26,  1981,  on the  other  hand, are  significantly  streamlined relative  to  the




currently promulgated Performance Specifications,   and  emphasize  the assessment




of performance in  terms  of  the  relative accuracy  test results.  Both revisions




require determinations of system  relative accuracy in  terms of Ib pollutant/10




Btu  when  diluent monitors are  used   in  conjunction   with  pollutant monitors.




Thus,  the  revisions  implicity include  a relative accuracy  specification  for




diluent  monitors.   Revised  Performance  Specifications in  the   form  of  those




proposed January  26, 1981,  are favored for promulgation.

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     Other  regulatory actions and  issues that may ultimately affect  the  use  of




this manual include:  (1) the introduction of additional  Reference  Methods  for




determinations  of   SO   and   NO    emission  rates   (Ib   pollutant/10    Btu);




(2) revisions  to  the  current   Reference  Methods  so  that  quality  assurance




provisions are  included;  and   (3) the  promulgation  of Appendix  F,  which will




specify quality assurance  programs for  continuous monitors.






     In spite  of the current regulatory flux, it is hoped that this manual will




establish uniform reporting  requirements and be a useful guide  for reviewers of




performance test reports.






     Although this manual  explicitly addresses  monitor performance test report




requirements  for  NSPS  sources,  much of this  information  may apply  to  reports




for monitors installed at  sources subject  to State  Implementation  Plans (SIPs)  ,




since many of the continuous monitoring requirements  contained  in the SIPs  are




patterned  after  the  specifications  and  procedures  of 40  CFR 60,  Appendices A




and  B.   For  similar  reasons, applicability  may extend to  continuous monitors




installed as required by waivers, consent  decrees, etc.






     This  manual  is  divided   into  five  sections.   Section  2.0  provides




background material concerning  the nature  of the  report and  also discusses the




review  process.   Included within  the  background  material  are  discussions that




deal with: (1)  the  function of the  pretest meeting, any  ensuing test protocol




decisions, and  the use of this  information by the reviewer; and  (2)  the role of




the  agency observer  during  the test and  the use of  the  observer's  report  and




field notes by  the reviewer.

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     Following  this information, the  goals of the  review are listed.   These




goals are the basis  for  subsequent discussions that address (a)  procedures for




reducing  the  complexity  of  the  reviewing  task;  (b)  the  organization and




strategy of the  review;  (c)  the depth  of the review;  and  finally,  (d) the




actions the reviewer should  take upon completing the review.






     Sections  3.0 and 4.0 deal with the reporting  format  and  requirements and




the review of pollutant  gas  monitor  performance test reports.   The material  is




divided into the  two sections for convenience. Section 3-0 is  covers  the body




of  the  test  report: the  introductory  background  information;  the  source,




monitor, and test descriptions; and  the test results.  The discussions focus  on




the format, content, and purpose of  this introductory material.






     Section 4.0 deals with  the raw  data generated  during  performance  tests  of




gas  monitors.   Each test of  the  complete  performance  specification test  is




separately  introduced   and  discussed.   Each introduction  includes  a   brief




description of the  test  and  its  purpose.   Ihe discussions that follow address




reporting  format,  reporting requirements, and review  procedures.   Additional




data   that  supplement   the   tests,  such  as  data   generated   by  moisture




determinations, are also included  in Section  4.0  and are treated similarly.






     Section  5.0   addresses  the   reporting   and   review of  the   raw  data




accompanying  performance  test   reports   of  diluent  monitors.  Because  the




performance tests of diluent  monitors closely parallel  those of gas monitors,




much  of  Section  5.0  is  devoted   to directing  the  reviewer  to   analogous




discussions pertinent to gas monitors (the subject of Section  4.0).

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                     2.0  DISCUSSION  OF  THE  REVIEW  PROCESS






     This manual  is designed  for the  novice  reviewer.  The reviewer  is  expected




to have  some  familiarity  with  Methods 3,  4, 6, and 7  (40 CFR 60,  Appendix  A)




and  Performance  Specifications  2  and  3  (*»0  CFR  60,   Appendix  B) .   As  the




reviewer gains experience, this  manual  should  become  more a  reference,  rather




than  a  guide.   This is  especially   true  of  the  many  introductions  to  the




individual test procedures.






2.1  AN OVERVIEW






     The primary goal of the  test report review is  to  determine the performance




status of the tested monitor.






     Clearly, the  amount  of  data and supporting information  contained  in  the




report   will   limit   the   accuracy  of  the  continuous  monitor   performance




assessment.  Sufficient data  should be reported to  allow a priori recalculation




of the test results from the  field data, laboratory data, and  monitor  records.




Accordingly, completeness is  the primary aspect of  the report to be assessed by




the reviewer.






     The  reviewer  must determine  whether  acceptable  testing procedures  were




employed  in  the  monitor performance  evaluation.   In  general,  test procedures




must provide accurate data for determining whether  the monitor is in compliance




with  the  performance   specifications.  Finally, the  reviewer  must  determine




whether  the reported test results have been calculated correctly and accurately




from the  reported data.

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     Based upon the results of  the  report review, the  reviewer must conclude

that:

          (1)  the  reported  results  of   the   test   conform  with  the
               applicable monitoring specifications,

          (2)  the reported results do not  conform  with  the  monitoring
               performance specifications,  or

          (3)  the performance status of  the continuous monitor cannot  be
               determined from the  reported results.


     A complete monitor test report  includes a plethora of information.  Figure

2. 1   illustrates  the  complexity of  the  complete  review process  for  an   S0?

monitor relative accuracy test.  The diagram  also  shows how the review  can be

effectively approached by employing  two guidelines:  (1) divide  the review  into

workable units, and (2)  work  from  general to specific  (e.g.,  first  check  the

final result; second,  the  supporting intermediate results;  and,  finally,   the

raw data).


2.2  PREPARING FOR THE REVIEW


     Before starting the review of  a monitor test report,  the  reviewer  should

assemble as much  supplementary  information as possible.  This may include  the

following:



       (1)  pretest protocol statements;

       (2)  observer's report, notes, or  checklist;

       (3)  previous monitor performance  test reports;  and
            reports; and
       (4)  previous source performance test reports.

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                  Result
                v Ve/lccurcict/ C&lculat/on$

J S^amp I in o
   Calculation^
  COiltlr cut ion
       &-
                           \r
  9
                      L
a
                          ac/
                         nd
                                    th
       docii
Wenkmcr
                Calcu
                FIGURE 2-1
    Review Process for a Relative Accuracy Test of
                an SO  GEM
                Calculations'

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     Some of  the  items above  may  aid  the  reviewer  in  validating  the  test




procedures;  this is true for the statements of protocol and  information  provided




by  the  observer.   Other   sources  of  information  can   aid   the   reviewer  in




identifying  and  evaluating  anomalous  data.   In  general,   the  more  supplemental




information the reviewer has, the  more easily the  review  can  be performed,  and




the more easily and accurately the  required level of review can be achieved.








2.2.1  Pretest Protocol Statements






     Conducting a monitor performance  test is not always  straightforward.   Many




problems can  arise  which show  that  there  are  neither "standard"  sources  nor



"standard"  monitors.   The  nature  of  the  source,  monitor,  or  the  monitoring




location may  require modification of  the performance  specification test  (PST)




procedures.   In this regard, a fair degree of procedural latitude is permitted in




both the Reference Methods  and Performance Specifications.






     A pretest meeting  is  often held  at which  representatives from the  agency




(usually the  observer), the  source,  and  the test  team  discuss the  potential




problems  associated  with  the   PST ' and   agree  upon   necessary   procedures,




modifications,  and  reporting  requirements.  The  agreed   upon  procedures   are




sometimes documented within a pretest  protocol statement prepared by either the




source or the  tester, and the  statement may be submitted to the  agency.   In  some




cases,  the   only  record  of   the   pretest  meeting  agreements  is  the  agency




representative's notes. Whatever the  situation,  the  reviewer  should obtain  all




documents of pretest procedural  decisions and agreements because such information




may prove invaluable for the test report review.
                                  10

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 2.2.2  The  Observer's  Notes and Records






      Because  owners  or operators  of continuous monitors  are  required  to  notify




 the  Administrator no less than 30 days before the monitor operational  test  period




 [40  CFR 60.7(a)(<5)  and 40 CFR 60.13(c)], an  observer  is usually present  during




 the  PST.






      If  an  agency  observer  is  present,  a   written  report  and/or  observer's




 checklist may be  available,  Tne  report/checklist  should contain brief  summaries




 of any  inconsistencies observed during  the  test  and an estimate of their  effect




 Of, the  test results, Obviously,  without having observed  the  test,  the  reviewer




 cannot  fully evaluate the validity  of the  test  procedures  and raw data,  The




 observer's report may supply the  reviewer with valuable  supplemental  information




 to facilitate the review and/or aid  the reviewer  in  the review strategy.






 2.3   THE LEVEL OF REVIEW






      There are three  levels of review:









          Level I.     Cursory  check of results.




          Level II.    Spot check of  report.




          Level III.   Complete review.








      In a  Level   I  review,  the  reviewer checks  the  results to determine the




performance   capability of the monitor  and  confirms  that  the  report contains




sufficient raw data to  permit  a higher  level  of review.  Insufficient data  would




limit the  review  to this  level.







     For Level II, the reviewer recalculates  the results of one or  more   tests




from  the raw data.  Tne reviewer makes  additional checks of the reported data and
                                  11

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procedures using available pretest protocol statements and  information  provided




by the observer .






     A  Level  III review  requires considerable  effort  and  a significant  time




commitment.   The  reviewer  checks all  results  thoroughly, which  may  require




extensive recalculation, and evaluates all procedures, diagrams, and data  using




any supplemental information.






     In selecting the level of review, there  are several   factors  to  consider.




The reviewer should  consider the importance of the test and  the  significance  of




the results.   For example,  when the  accuracy  of  the  values  of  the  reported




results is  more important than  the  status of  the monitor  (i.e., whether  the




monitor passes  or  fails  the  performance  test)  , a  Level  III  effort  would  be




required. Tne results of a particular  part  of  a  performance test,  e.g.,  response




time, can also dictate the level  of review.   For example,  when the results  of a




test  conclusively show that  the monitor failed  the   particular  part  of  a




performance test, and a glance  at the  raw  data supports  this conclusion, further




review  should be unnecessary.   A  Level  I review,  in this case, would suffice.






     Supplemental information can also influence the  selection  of  the  level  of




review.   If an agency observer  has thoroughly  documented one or more tests and is




satisfied  that the results are  valid,  the  reviewer may decide  to  conduct a Level




I  review.  On the other hand, special  tests, e.g., tests  to detect  or to  quantify




stratification  at the  monitoring location, may require  additional  effort on the




part of the reviewer.






      The  review process is  a  dynamic  activity;  the  level of review  may change




between the time the review is  initiated  and  the  time  it is completed.   Thus, the




reviewer  must be sensitive to the review process  and flexible  in his approach.
                                     12

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2.4  CONDUCTING THE, REVIEW






     As the reviewer gains  experience,  he  will probably develop  his  own review




strategies. Two basic guidelines are  offered  to  the  novice. First,  focus  on a




manageable part of the  report  and  then  proceed  from  the  general  to the specific.




For instance,  in reviewing a relative accuracy  test,  first  check the calculation




of the relative accuracy,  then validate  the  reported monitor  data  from the strip




chart  records,  and  finally,  validate  the  reported  Reference  Method  data  by




recalculating   the  results   from   the   field   and  laboratory  raw  data,   Tnis




progression from  the  general   to  the  specific  may  be  terminated  at any point




corresponding  to the  selected  level of review, or may  be terminated  upon   finding




any major discrepancy in the  reported data  or  results.   (A major  discrepancy is




considered any error  that  affects the performance status of the monitor.)






     The  following paragraphs present   a  synopsis  of a Level  III  review.  The




reviewer is assumed to be  well supplied  with supplemental information.






     (1)  The  reviewer  should check  the introductory  material   of  the  report




          against  the observer's report and the  statements  within   the   pretest




          protocol and  note any discrepancies and  evaluate  their  effect  on  the




          results  of  the test.






     (2)  The  reviewer should  examine the results of the test  and  the discussion




          of the  results, focusing  upon those  tests  that  represent  borderline




          cases, i.e., where the monitor is close to the specification, either on




          the  passing  side  or  on  the  failing side.  The  order  in  which  the




          individual  tests comprising  the   PST  are  reviewed  should  be  decided



          using  this criterion.






     (3)  Before proceeding  to the raw data  and calculations,  the reviewer should




          inspect  the  test report  to verify that  all  the  raw data necessary  to






                                    13

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         recalculate  the results  are  available.  Onissions of  data  should  be




         noted.  At the  same time, the reviewer  should estimate the significance




         of  these  omissions  with  regard   to   their  perceived   effect  on  the




         reported results.






    (4)  After  identifying  data  omissions and  evaluating  their  effect  on




         reported results,  the reviewer can  then  recalculate  the results.  This




         is the bulk of the task and can require a significant amount of effort.




         The  reviewer  should divide the task   into  workable  units  and  should




         proceed from the general  to the specific.  Data  should be examined with




         regard  to reasonableness.  Here, common  sense  and  experience will,  in




         most cases,  suffice in evaluating most  of the reported  data. For these




         recalculations, errors and other omissions  should  be noted, and their




         effects on the reported  results should  be evaluated.






     (5)  When  all  the  procedures,  data,  calculations,  and  results  have been




         evaluated, he or she is  then  in a  position  to answer  the questions:








         (a)   Has the testing been properly conducted?



         (b)   Have adequate data been reported  to  permit a thorough review?




         (c)   Have all calculations been  performed correctly?



         (d)   Vhat is the  status of the monitor as indicated by the data?






2.5  REVIEWER'S REPORT






     The  reviewer should  promptly submit to  the  source the results of the  review.




The report  should answer  the questions listed  at the  end  of Section 2.4.  Tne




report should  identify  those errors,  omissions,  and  inconsistencies that  the




reviewer  feels  may have significant effect  on  the  results of  the test.  Where




appropriate,  the reviewer should  supply corrections  and should   provide  his  own





                                      14

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evaluation of the impact of the  problems  on  the results.  The reviewer may also

recommend future actions.


     The report should  include the reviewer's  evaluation  of the  status  of the

monitor, as  indicated  by the  available  data,  and   should  reach  one  of  the

following conclusions:
     (1)  The data indicate that the monitor  passed  the  performance  specification
          test;

     (2)  The data indicate that the monitor  failed  the  performance  specification
          test;

     (3)  The status of the monitor  cannot  be determined from the available data.


     The second and  third  conclusions  require  recommendations.   If  the monitor

failed  the  PST,  the applicable  tests  should  be  identified,  and  appropriate

retesting  should  be  recommended.   If  the  status  of  the  monitor  cannot  be

determined, the reviewer should  recommend either submission of additional data or

retesting.
                                     15

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                            3.0  TEST REPORT FORMAT


     A  standardized  format  for  continuous  monitor  PST  reports  is  highly

recommended,  because  report  review can  be  accomplished  more  efficiently,

effectively,  and  accurately.   In  addition,  the  adoption  of  standardized

reporting   requirements   that  emphasize   completeness   could   promote   the

application of  quality PST procedures.  A  standardized  test reporting  format

would be beneficial for both agency and source.


     In  the  paragraphs   that  follow,  a report   format  is  recommended.   The

criteria considered for the development of this recommended format  include:


     (1)  the need for formal  elements, such as title pages, certification
          pages, table of contents, etc.;

     (2)  the need  for background   information  necessary  to present data
          and results in the proper  technical  and  regulatory perspective*,
          and

     (3)  the need for sufficient data to determine the performance  status
          of the tested monitor.



     The following format reflects  minimum,  recommended reporting requirements,

which are  detailed in subsequent  sections  of this manual.   Because  minimum

reporting requirements are  reflected,  the  format  would not  apply  to all test

reporting situations.  Rather, the  format is a skeleton, which  may be added to

as necessary, recognizing that  PSTs  and accompanying  test reports are best

handled  on a case-by-case basis.


     The recommended  format is first  presented  in  outline form in Figure 3-1;

the individual  elements are discussed in order of their presentation.
                                    17

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                             FIGURE 3-1.






                             RECOMMENDED




                  ELEMENTS OF A CONTINUOUS MONITOR




                       PERFORMANCE TEST REPORT








 1.0  Title  Page






 2.0  Certification  Page






 3.0  Table  of  Contents






 4.0  Introduction






 5.0  Summary of  Results






 6.0  Discussion  of  Results






 7.0  Description of Source






 8.0  Description of Monitors






 9.0  Discussion  of  Testing  Procedures






10.0  Performance Testing  Data  Sheets








Appendices






     Appendix  I.    Reference Method Raw Data






     Appendix  II.  Strip  Chart  Records






     Appendix  III.  Calibration  Data









                               18

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 (1)   Title  Page






      The  title page should include  the  following:   (1)  identification  of the




 affected  facility  and  its location;  (2)  the  type  of pollutant  monitor tested




 (e.g.,  S02  or N0x monitor);  (3)  identification  of  the  organization submitting



 the  test  report; and (4) the  date on which the report was submitted.






 (2)   Certification Page






      For  engineering  test  reports,  the   test  team  leader  and  a  professional




 engineer  should  verify that  the report  is  accurate  and  has  been  reviewed.




 Review   by   a  professional   engineer,   however,  is   not   mandatory.    The




 certification  page also  provides  the  Agency  reviewer  with  the  name  of  a




 knowledgeable  person to contact in the event that questions arise.






 (3)   Table of  Contents






      A  table  of contents  aids the reviewer  in  locating pertinent  sections  of




 the report.  The pages of the report should be numbered.






 (4)  Introduction






     The  introduction   to   the  test  report  should include   the  purpose  and



 background of  the  test.   It  should be  brief,  and the  following items  should




 also  be  included:   (1) the  name and  location  of  the  affected  source;  (2)  a




 description of the  source  process  (e.g.,  fossil-fuel  fired  steam  generator);




 (3)  the process  production  rate  (e.g.,  MW);  (4) the  fuel  category  (e.g.,




bituminous  coal);   (5)  an   identification  of  the  regulation(s)   requiring




monitoring of  emissions;  (6)  if  applicable, an  identification of  the  local




 agency  with  jurisdiction  over  the  source;  (7)   a  discussion  of  pertinent




pre-test protocol;  (8)  the  names  of the  testing  firm,  source,  and  regulatory
                                19

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agency observers present  during  the testing;  (9)  the  types  of monitors  used




(mfg. and model, e.g.,  Munkus Model  666 S0? monitor);  and  (10)  the  dates  of the




operational test period.
(5 )  Summary of Results






     The summary of results is the heart of  a  monitor test report.  It  should




be tabulated.  If the  results  are juxtaposed  with  the applicable  performance




specifications, interpretation and review will  be greatly  facilitated.   Figure




3-2 illustrates an example "Summary of Results."









(6 )  Discussion of Results






     A discussion of  the  results  should  follow  the  summary  of results.  This




discussion  should  be  brief  and  should   focus  on   those   tests  in   which:




(1) anomalous data were obtained,  (2) departures  from standard  test  procedures




were observed, or  (3)  failure  to  meet the  performance specification occurred.




Possible causes  for these  anomalies, deviations,  and/or failures  should  be




presented and discussed.






(7)  Description of Source






     The report should contain a brief description of  the  source, with emphasis




on  those  aspects  of  source  operation  that directly   affect   the  monitor




performance  test.   For example,  if  the  source is  a   fossil-fuel  fired   steam




generator, then the description should address the  heat  input rate, the  fuel,




and the location of the monitor within the  effluent  handling  system.  The  heat




input rate determines the  necessity for monitoring.  The  fuel,  be it gas,  oil,




or coal,  determines the  appropriate  continuous  monitor   span.  The  continuous




monitor location helps to  determine the representativeness of the  sample.  The




                                   20

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                            FIGURE 3-2
                              EXAMPLE
                         SUMMARY OF RESULTS
S02 Monitor
    Relative Accuracy
    Response Time
    Calibration Error

    2-hour Zero Drift
    2-hour Calibration Drift
    24-hour Zero Drift
    24-hour Calibration Drift
    Operational Test Period
    Result

       15%
     81 sec
mid   2%
high  0.4%
      0.3%
      0.1%
      0.3%
      1.0%
 June 1-7, 1982
Speci fication

   £20%
 £15 min
   £5%
   £5%
   £2%
   £2%
   £2%
  £2.5%
  >168h
NOX Monitor
    Relative Accuracy
    Response Time
    Calibration Error

    2-hour Zero Drift
    2-hour Calibration Drift
    24-hour Zero Drift
    24-hour Calibration Drift
    Operational Test Period
    Result

      37%
     110 sec
mid   2%
high  2.7%
      0.3%
      1.7%
      0.2%
      0.6%
 June 1-7, 1982
Specification

   £20%
 £15 min
   £5%
   £5%
   £2%
   £2%
   £2%
  £2.5%
  >168h
02  Monitor

    Response Time
    2-hour Zero Drift
    2-hour Calibration Drift
    24-hour Zero Drift
    24-hour Calibration Drift
    Operational Test Period
    Result
Specification
70
0.
a.
0.
0.
sec
09%
1%
1%
1%

°2
°2
°2
°2
£1
£0
£0
£0
£0
5 min
.4%
.4%
.5%
.5%
02
°2
°2
°2
 June 1-7, 1982
  >168h
                               21

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location of the monitor  (i.e.,  the region or point within the  effluent  stream




where pollutant emissions  are  measured)  should  be  addressed  within  all  PST




results regardless  of the  source category.








(8)  Monitor Description






     The test report should include a brief description of the monitors tested.




This is  important  because, as applied,  PST procedures are  generally  monitor




specific.  For example,  the calibration error tests for  extractive  and  in-situ




monitors differ radically.  Extractive monitors require injection of calibration




gases, while in-situ monitors require the use  of cells containing  calibration




gases.  Another  example  is the measurement  basis of  the monitor.   Moisture




measurements   must   be   performed   concurrently   with   reference    method




determinations during relative  accuracy testing  of wet  basis pollutant  gas




monitors.






     The monitor description should  include  the  following  information:  (1)  the




make and model  of  the monitor;  (2)  the analytical measurement  process  (e.g.,




infrared, second derivative ultraviolet,  galvanic concentration cell);  (3)  the




moisture basis (wet or dry); (H)  the  measurement  mode (extractive  or in-situ);




and  (5) the method employed for  calibration.
                                    22

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       The  test  report should  contain  a drawing  that  illustrates  the general




 locations  and  relative  positions of  the monitors  and  the  reference method




 sampling  probe(s)  within  the  effluent   handling  system  (a  schematic   is




 acceptable).   This  drawing  serves  two  purposes.    It  aids  the  reviewer   in




 examining  anomalous  data  with  reference  to  process  dependent  aberrations.




 Secondly, a  drawing  will  denote  proper  or  improper monitoring  and   sampling



 locations.








 (9)  Discussion of Testing Procedures






      The test  report  should   include a  section that discusses  the procedures




 employed during the PST.  Ihe  discussion should be  brief  and  should  emphasize




 those parts  of  the test  for which no established  procedures  exist and/or  those




 parts of  the  test  in  which  deviations from  established  testing  procedures




 occurred.   Several examples of procedures that should be discussed are  provided



 below.






      When  concentrations  for  calibration  gases  are  determined   using   the




 reference methods, procedures  for  sampling  gas cylinders  should  be described.




 This  is  particularly  true  for Methods 6 and  7, because these  methods do not




 directly apply  to high  pressure  samples.   Tne pertinent  sampling  procedures




 should be discussed within the "Testing  Procedures"  section of  the report, or  a




 reference for the procedures should be  cited.   In  the latter case, it would be




 helpful  to include within  the  report's appendices a copy of the  citation that



 is not readily available.






     An analogous example  would  be the documentation of  the method  used  for




determining effluent moisture,  if  relative accuracy  testing was performed for a




wet-basis continuous emission monitor.   Since  Performance  Specification 2 does
                                   23

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not  prescribe  a method  for  determining  moisture, testers  may choose  among

several methodologies.   If  Reference  Method 4 is not used, then the tester must

provide a description and discussion  of the employed method in the test report.

In this regard.  Performance  Specification 2 explicitly  states  that  the method

used  for  determining moisture  and  the calculation  procedures  employed  for

correcting between  differing measurement bases (e.g., wet-basis  or  dry-basis)

are to be reported .


     Performance Specification 2  requires the reporting  of  the  method used for

obtaining the continuous emission monitor's concentration data for the relative

accuracy  computation.   Therefore,  a  description  of  this  method   should  be

included within the  "Testing Procedures" section of the  test report.


     Descriptions of monitor-specific  PST  procedures  should also  be included

within the "Testing  Procedures"  section.  Two  such monitor-specific  aspects of

the  PST include:
     (1)  the pressures and  flow rates  for  calibration gas injections, and

     (2)  the  use  of  mixed  calibration  gases,  e.g.,  S0?  and  0   in
          nitrogen, for monitors that have  dual analysis capability.
     Finally, the "Testing  Procedures"  section should  address  all  deviations

from the  reference methods  that  occurred  during the  performance  program.   In

this regard, the introductory paragraphs of 40  CFR  60, Appendix A, state:

         ".  . .an owner electing to  use.  .  .techniques  [cited as 'subject
    to  the  approval  of the  Administrator1  or  as  'or equivalent']  is
    responsible  for  .  . .(2) including   a  written  description  of  the
    alternative method  in  the test  report  (the  written  method must  be
    clear  and  must  be  capable   of  being  performed  without  additional
    instruction, and the degree of detail  should be similar to the detail
    contained in the  reference methods);  and  (3)  providing any rationale
    or  supporting data  necessary to  show  the validity of  the alternative
    in the particular application."
                                     24

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 (10)  Performance Testing Data Sheets
      The test report should, as appropriate, contain docunentation  as  specified
 within Figures 2-1, 2-2, 2-3, 2-4,  2-5,  and 2-6 of  Performance  Specification 2

 and within Figures 3-1,  3-2, and 3-3 of Performance  Specification 3.


 (11)  Appendices

      The test report  should  include  all  the raw data that figured into the FST.

 In general,  these  raw data  fall  into  three  categories: (a)  data from reference
 method  (and  moisture)  testing,  (b)  continuous monitor data  records,  and  (c)
 data from calibration activities.

      The  reference method (and moisture) raw data should  be  assembled  in  one

 appendix  and, as appropriate, should include: sampling data  for SO  NO   and
                                                                    2*   x'
 H20, and  analysis  data for SO  and NO .

      Copies  of the data  recorded  by the  continuous monitor  over  the  entire
 operational test period should be included in another appendix.

     All  calibration  data should be  included  in  a   separate appendix.  These
 calibration data may derive from pre- and post-test dry gas meter calibrations,
 thermometer calibrations, and  sampling  and  analysis  of SO   NO , CO ,  and 0
                                                          ^    X    £,       £.
 calibration gases.

     Finally,  a separate appendix should  be included for  copies of procedures
cited within the "Testing Procedures"  section.
                                 25

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              4.0  REVIEW OF TEST PROCEDURES, DATA. AND RESULTS OF

               MONITOR PERFORMANCE TESTS FOR S00 AND NO  MONITORS
               	2	-x	





     This  section  provides  detailed  procedures  for  reviewing   the   data,




calculations,  and  results  of the various monitor performance evaluation  tests




conducted  for  SO   and  NO  monitors.   Included  are  background  information  and
                £.        X



review  procedures   for  evaluating  calibration  standards,   calibration   error




tests, conditioning period/operational test period  requirements, response time




tests,  zero   and  calibration  drift  tests,   and  relative  accuracy  tests.




Background information outlining  the  specific  tests and associated  procedural




requirements is included  at the beginning  of each subsection.






     The procedures presented  here  provide specific guidelines  for  review of




the reported data  and results.  In most cases, the recommended  review proceeds




from a review of the general  results to a  review of  specific data.  Example data




sheets  and calculations are  provided  for each of  the monitor  performance




evaluation tests.






     The performance specifications  for pollutant continuous monitors are  shown




below.
                                    27

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        Parameter                 Specification
        Accuracy          £ 20%  of the mean value of the
                            reference method test data

     Calibration error     £ 5% of each (50%, 90%) calibration
                            gas mixture value

     Zero drift  (2  h)1     £ 2% of span

     Zero drift  (24 h)1      £ 2% of span

     Calibration drift       £ 2% of span
      (2 h)1

     Calibration drift     £ 2.5% of span
      (24 h)1

     Response  time         £ 15 min maximum

     Operational period    > 168  h minimum
  Expressed as sum  of absolute mean value plus 95%
      confidence  interval  of a series of tests.
4.1  CALIBRATION ERROR TEST


4. 1. 1  Background


     The calibration error test  for  pollutant monitors (SO  and  NO  )  is  a test
                                                         c.       X

to determine the accuracy and  repeatability of the monitor response relative to

calibration  standards equivalent  to  50% and  90%  of  the  instrument  span

(normally either 1000 or 1500 ppm) .  Since the  calibration  error test involves

measurements at  0%,  50%, and  90% of span, this test also  provides a  check of

the linearity of the monitor response over its measurement range.


     Performance Specification  2  allows  the  calibration  error  test   to  be

performed  either in the laboratory or  in the  field.   Tnus, the  calibration
                                   28

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 error test is not ,necessarily conducted during the operational  test  period.






     Performance Specification 2 states that, for an extractive monitor, three




 different concentrations of  the  appropriate  pollutant gas  must  be introduced




 into the monitoring  system:  0%,  and "approximately 50% and 90%  of span."  The




 performance  specification  also  states  that  no  gas  concentration  may  be




 introduced   twice  in   succession.    The   test  requires    15  non-consecutive




 measurements and 5  measurements  with each  gas.   If the monitoring system  is




 non-extractive, the mid-  and  high-range data are obtained  by  using gas  cells




 "vhose  concentrations  are  certified  by the  manufacturer   to  be   functionally




 equivalent to these concentrations."






     Performance Specification 2 utilizes only the  results  from  the mid-range




 (50% span)  data and the high-range  (90?) data in  determining calibration error.








 4.1.2  Review of Calibration Error  Test Data and  Results






     The review of the  calibration  error  test should  include: (1)  a  check  to




 verify  that  the  mid-range  and  high-range  calibration   errors  have  been




 calculated  properly from the reported  data,  (2) a check of the adequacy of test




 procedures  and  data obtained,  and  (3) a  verification  of  the  concentration



 values of the calibration standards  employed.






     The determination  of  calibration  error employs  the  same equations  for




 computing differences,  mean  difference, and  confidence interval  as does  the




 determination of relative accuracy.   (See  the example  calculations provided  in




 Section 4.5  of this manual.)  The mid-range  and  high-range  calibration  errors




 are  determined  separately  from   the  5   mid-range  and   the  5  high-range




measurements,  respectively.    The   mean   difference  must   be   calculated




 algebraically  (retaining  the   signs   of  the differences).   The  confidence
                                   29

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interval  must  also  be calculated using the algebraic values of the differences.




The correct value  for  tfi Q7(.  used  in  the confidence interval  calculation  is




2.776 for 5 measurements. The  calibration error is computed as  the  sum of the




absolute  value of  the  mean of  the differences and  the  confidence  interval,




divided by the appropriate  calibration gas concentration.






     Based on the  experience of  the reviewer  and  on the  particular  data set




reported, the reviewer must decide  either  to recalculate the  mid-range and/or




high-range calibration error results or  to  accept  the reported  result.   At a




minimum,   the  calibration   error   test   data  form  should be  reviewed  for




completeness by  checking that  each calibration  point  (zero,  mid-range, and




high-range) is represented  by 5  independent measurements.   Gonformance  with




specified  procedure  may be  checked  by  verifying  that  the   datum   for  each




calibration point was obtained in  a non-consecutive fashion.






     If  the calibration  error test  was  conducted   during  the  operational test




period,  the reviewer should examine the strip charts  for consistency between




the data reported  on the calibration error  data  form and the  values  indicated




by the charts.  Also, the duration  of each  measurement  at 0%,  50$,  and 90% of




span,  as indicated by the  strip  chart,  should be greater than  the  reported



response time of the monitor.   Tnis may be difficult  to determine visually if,




for example, the response time is  approximately one minute and the strip  chart




speed  is approximately 1 inch/h. The concentrations of the mid-  and  high-range




calibration gas  mixtures should be approximately   50% and  90?  of the  required




instrument span.   Tne reviewer must interpret the  acceptable limits established




by  the  word   "approximately,"  since  Performance   Specification 2   does not




elaborate  on  its meaning.   (The  October  10,    1979  proposed  revisions  to




Performance Specification  2 require that the  high-range gas  concentration be
                                  30

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between 80%  and 90%  of span,  and  that  the mid-range  gas concentration  be




between 45% and 55% of the  span.)






     The interpretation of the recorded responses to  zero  gas  injections must




be  approached   with  caution,  because  anomalous  data may reflect  the  test




technique,  fundamental  limitations  of  the  monitor,  or  impending  monitor




malfunction. Without a firm understanding of monitor operation, it is generally




difficult to draw valid conclusions about monitor  performance  from  what appear




to be anomalous zero data.






     The actual values of  the calibration  standards  employed  directly affect




the  outcome of  the  calibration  error  test.   Errors in  the  values  of  the




calibration gases  cannot  be distinguished from  monitor  non-linearity in  the




results of the calibration  error  test.  Thus, the  true concentration values of




the calibration gases or functionally equivalent concentrations of calibration




cells must be determined.  The reviewer is  directed  to Section  4.5.1.4 of this




manual, where guidelines for checking reported  calibration  standard values are




provided.






4.2  CONDITIONING PERIOD; OPERATIONAL TEST  PERIOD






4.2.1  Background





     Performance Specification 2  requires  that  pollutant  continuous emission




monitors be operated  for an initial  168-hour conditioning   period  in a  normal




operating manner.  Tne strip chart recorder should be offset approximately  10%




during the conditioning period to facilitate  observation  of negative  drift.  At




a minimum,  the "normal operating  manner"  requires  that  the monitor zero and




span be  checked daily,  and  that  the  monitor  operate continuously over  the




168-hour  period.   Monitor  failure  during  the  conditioning   period  requires
                                      31

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reinitiation  of the  conditioning  period  once  the  monitor  is  repaired.   In




contrast, if  the  source  shuts down  during the conditioning  period,  then  the




168-hour period is  interrupted  and  then is continued  when  the source  resumes




operation.






     The  168-hour operational test  period; is  conducted after  the  conditioning




period  is completed.   The  operational  test period need not  immediately follow




the conditioning period.   During  the operational  test period,  the  response time




test,  relative accuracy  test,  and  zero  and   calibration  drift tests  are




conducted.  The calibration  error  test is  most  often conducted  in the  field




during  the operational test  period;  however,  as  pointed  out  in Section  3-2.1,




Performance Specification  2  permits the  accomplishment  of this   test  in  the




laboratory also .






     During   the  operational   test  period,  the   continuous  monitor   must




continuousl y monitor the  effluent,  and  the data  recorder  zero  should be  offset




approximately  10%.   Performance  Specification 2  states,  "during   the  168-hour




operational  test  period,  the   continuous  monitor  shall   not   require   any




corrective maintenance,  repair, replacement, or adjustment  other  than  that




clearly  specified  as  required   in  the operation  and maintenance  manuals  as




routine and expected during a one-week  period."








4.2.2   Review of Operational Test Period






     The strip  chart  records (or computer printouts) for the  operational  test




period  should  be  included  in the test  report.  The  reviewer  should check  the




data record to ensure that the requirements of the operational test period  are




met.
                                    32

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     The source  of the monitoring  raw data obtained during the operational test




period is usually  strip  chart records.  These  records must be  accurately and




extensively documented.  Furthermore, copies of  the   strip  charts  included  in




the report must be  of high quality.   If these conditions  are  not met,  it  is




often neither cost effective nor  possible to  check the accuracy of the reported




monitor data .






     Dates and clock times  should  be  accurately documented  on  the charts.  The




time should be indicated  either on a 24-hour basis or labelled  with either  FM




or AM.  (Chart paper is available  printed with clock times;  however, such paper




does not guarantee the accuracy of the  printed times.) At least once daily, the




chart  should  be  labelled  with  the  appropriate date -  including   year.   In




addition, all pertinent  traces  should  be marked  to   indicate the  clock time.




Such marking will  ensure  that the  chart  recorder  is chronologically accurate.






     The  identification  and  description  of the  concentration-dependent  axis




must be precise and complete if the chart is  to be interpreted correctly.  This




should include: (1) the span indicated  by the chart paper both with and  without




the  105& zero offset; and  (2) an indication  of whether  a  zero offset is present.




The reasoning behind these  reporting  requirements can  be illlustrated with the




following example.   If the chart  has a  1000 ppm span,  and  the  zero is offset




10!6,  then the new  span  could  either  become 900  ppm  (the entire  range was




shifted)  or remain  at  1000 ppm (the  entire  scale was proportionally reduced).



This  problem  can  often  be resolved  by  investigating  the  responses observed




during monitor  calibration,  but  this is not always  possible,  especially when




only poor copies of the strip charts  are available.






     All  pertinent  traces  should  be  identified.  An  often overlooked  problem




with  strip  chart  documentation is the  identification of traces  by pen  color:
                                    33

-------
this information is  not  translated by black and white copy.






     The reviewer should watch  for  disparities between reported  and  recorded




times; this may indicate problems  with  chart speed  control.   Variations  in




chart speed can be determined  by measuring time intervals with a rule.






     Those traces corresponding to  tests for  response,  calibration  error, and




drifts should be  clearly identifed  on  the  strip  charts.   Most  important, the




strip chart should be marked  to indicate those time periods that supplied the




data for the relative accuracy computation.






     Other explainable  variations  in  monitor  response  (e.g.,  unusual monitor




responses  observed  while  the  test  team   initially  establishes   the   proper




calibration  gas  flow  rates/ injection  pressures)   should  also   be  clearly




identified  to  prevent misinterpretation  of these events  as monitor  failures.




Other  than the above  instances,  the continuous  monitor  should  provide  an




uninterrupted data record for the  entire  operational test  period.   Data records




indicating  unexplained  periods of  zero  readings,  offscale  readings, exactly




constant  readings,  or  widely fluctuating  emission values  should be considered




suspect by  the  reviewer, because they suggest instrument malfunction.
                                  34

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 4.3   RESPONSE  TIME  TEST






 4.3.1   Background






      The  continuous monitoring requirements of  40 CFR  60.13(e)(2)  state, "All




 continuous monitoring systems  ... for measuring  oxides of nitrogen [and]  sulfur




 dioxide ...  shall  complete  a  minimum  of  one  cycle  of operation  (sampling,




 analyzing, and data recording)  for each successive 15 minute period." To  ensure




 that  this  requirement   is  met,  Performance  Specification  2  limits  monitor



 response  time  to 15 minutes and  defines  response  time  as,  "the  time  interval




 from  a  step  change in pollutant  concentration  at  the  input to  the  continuous




 monitoring system  to  the time  at which 95  percent  of the  corresponding  final




 value   is  reached   as  displayed  on  the  continuous  monitoring  system  data




 recorder." It  is important  to  note that  the regulations  clearly indicate that




 the response time test is intended to include the entire monitoring system.






     For  response   time  tests  performed   on  extractive   monitors,   gases




representing 0%  and 90?  of  the  applicable  span concentration  are  introduced




into the monitor in sequential  order, and  the times required for the  monitor to




attain  95%  of  the  resultant  step  changes  are  recorded.   Both  upscale  and



downscale  responses  are  measured   three  times   each.    This  is   readily




accomplished by  alternately  switching  from  zero   to  span  conditions.   The




response  time  for  a  particular  step  change  is  the  average  of  the  three



measurements,  and the reported  monitor response  time is the slower of  the  two



average response times.






     The  calculation  procedures  of  Performance  Specification  2  (Paragraph




7.2.1),  as distinguished  from  the  performance specifications contained  in  Table




2-1,  address the matter  of  differing upscale and downscale response times;  a






                                    35

-------
maximum difference of 15% relative to the slower response time is specified.





     The  response  time  test  procedures  of  extractive  and  non-extractive



(in-situ) continuous monitoring  systems  are not the  same.   For  response  time



tests of non-extractive monitors,  the  analyzer is evaluated with  respect  to  a



calibration  gas  cell and  a  simulated zero  condition.  The  resultant  analyzer



response time is predominately dependent on the time required  for  the  cells  to



be placed within the light path of the analyzer.  (Most non-extractive monitors



use the attenuation of electromagnetic radiation,  i.e.,  infrared, ultraviolet,



etc.,  for  determining  the  concentration  of  a pollutant  specie.)  The  total



response time  of a non-extractive monitoring  system may  also be  dependent  on



whether  the  analyzer provides instantaneous  or integrated  values and whether



the analyzer serves  to monitor  more than one  pollutant  (or  diluent)  gas.   For



example, many in-situ monitors are designed with "sample and hold" circuitry to



display  integrated  sampling values.   In  this  situation,  the  monitor  must



complete a  full  integration cycle  before  a  new  emission value  is  displayed.



Also,  some  in-situ systems monitor more than one pollutant;  alternating,  for



example, between SO  and NO  for short intervals.
                   ^       X




     The operation of extractive  monitors,  on  the  other  hand,  requires  the



transport of the effluent  sample to the  analyzer.  The  process of transporting



the sample takes a finite  amount  of time,  which is dependent  on  the  flow rate



of  the sampling  system  and  the  length  of the  sampling line.   Consequently,



extractive   monitors  generally  show  a  delay  between  the  time  of  sample



acquisition  and  the  time of  analysis and recording.





     To  a  large  degree,  measured  response  times  of  extractive  continuous



emission  monitors reflect the  time demanded  by sample  transport.    In  this



regard  the reviewer  should recognize that the  length of connections between gas




                                    36

-------
 cylinders and the tested monitor can affect  the  response  time test result  if

 these  connections  are  inordinately long.   For  well  calibrated  extractive

 monitors, failure to meet  the  response time  specification  is rare, and  when

 failure does occur  it  most frequently  is  a  result  of inappropriate  testing

 technique.


      For  extractive  monitors,  response  time also  may be lengthened because  of

 physicochemical  interactions, such as adsorption or desorption of the  pollutant

 on  or  from  the  sampling   interface and/or  dissolving  and  degassing  of the

 pollutant  to or from  liquid  phases.   These  effects  are  dependent  on the

 duration  of  the response  time  tests,   the  span  gas  concentration, and the

 sampling  history of the monitor.  Fhysicochemical interactions  can  manifest

 themselves as  widely differing  response times for the  upscale  and downscale

 responses. Such  problems, however, are generally encountered  during  calibration

 error testing, if such testing is performed  in the field.


     Finally, for some  extractive monitoring  systems,  a  single  analyzer may

 monitor  several  sampling locations; the analyzer is  time-shared  between the

 various  sampling locations.  The time  required  to complete a  full  sampling

 cycle,  which includes  all  sampling locations,   should  be  included   in the

 reported response time.


 **• 3- 2  Review of Response Time Test  Data Sheet
       and Strip Chart Record's             ~



     The  small  amount of data generated for  a response  time test makes  the

review straightforward and  relatively easy.   The   reviewer  should  confirm the

following: (1) the reported  span  gas  concentration is "approximately"  90% of

the applicable span,  (2)  three  upscale and three downscale  response time tests
                                    37

-------
                                 RESPONSE I
Plant  and location

Monitor
Date of  test
Span gas  concentration
Monitor  span setting
                         /5~Q(7
  ftature
                                                                be JC>C7<,  er
                                                         extract rue
                                            Value,
                                           Spa/7
                                                  7/7 J-ttU
                                                         ava//G-itc,  cett
                                             C ^n ces? t-rcuts 0/7.
        Response
rvg. Upscale  Response
 Cownscale Response
                      2	#'JT   seconds
 Avg. Downscale  Response    j7/  _ seconds | /{vo .
System  response time  (slower time) =
                                      $      seconds 0/C7M/?T
 F}ercent deviation from slower _ \ (a v e r age  u P_s_caJ_e)  -_(average dpwnscaj
 systen average  response
                                           slower  tine
                                                is
                                                                           -£//ne- .'
                                           38

-------
 are reported, (3) the  reported  values  for  the average response times (upscale

 and downscale) are correct,  (4)  the  reported  system average  response  time is

 the longer average response time, and  (5)  the  value  reported  for the "percent

 deviation  from  slower  system  average response"  is  correct.    The  reported

 response  time is  intended  to  reflect  the   response  time  for  the  entire

 monitoring system.  It  includes  the  full   sampling  cycle  time if  the  monitor

 samples multiple  gases  or  at multiple locations.


      Performance  Specification 2  limits  average response  times   (upscale  and

 downscale)  to a maximum of  15  minutes  (900 seconds) .  An  additional limit  is

 placed  on  the  percentage  difference  between  the  average  response times;  the

 percentage deviation of the two response times, relative to  the  slower  average

 response  time, must  be less than  or equal  to  155L   This is summarized by  the

 following  formula:
 %  deviation
   from  slower
 system average
   response
average         average
upscale         downscale
response     -  response
time            time
                        slower average response  time
x  100*
     This latter  specification  (Paragraph 7.2.7,  Performance  Specification 2)

is not listed with the monitor performance  specifications that appear in Table

2-1 of Performance Specification 2.


     In  the  limit  of  fast   response  times,  the  specification  regarding

percentage deviation  can  cause  interpretive  problems  outside  the  intent  of

Performance  Specification 2.  For example, if  the  average upscale response is

25 seconds,  and the  average downscale  response  is  30 seconds,  the percentage

deviation is 17?.   In this example, the monitor  response  is  very fast compared
                                    39

-------
to  the   15-minute  response  time  specification,  but  the  monitor  fails  the




specification for percentage deviation.   Obviously,  this is not  the  intent of




the  percent  deviation  specification.   Accordingly,  the  proposed  revisions




(October 10, 1979) address only the slower response time.






     The  reviewer may  attempt  to  verify  the  reported  response  times  by




consulting  the appropriate  strip  chart records.  The  strip charts  should bear




the following information:  chart  speed,  labelled points marking the initiation




of each response  time  test, and labelled  points  marking the  positions  of all




maximum deflections.   In most cases, reviewing the strip chart  records entails




either  visual  inspection  or an  approximation with  a rule,  depending  on  the




response time of the  monitoring system.






     In those  cases  in which  the  reported  response  times  are  close  to  the




15-minute limit and in which the final value  is  approached  asymptotically, the




strip  chart  records  should  be   checked  with  a  rule.  The  most  commonly




encountered  problem  in  attempting to  verify  the  reported  response  time  is




either that the  point marking  the initiation of  the  concentration  step  change




is not labelled on the strip chart or that the times for gas injections are not




contained  on  the  data  sheets.   This  situation  prevents  the  reviewer  from




verifying the response time data.






     There  are situations in which the reviewer  will  be unable to  obtain the




response times from the strip  charts.  For example,  if  the response time of a




monitor is  very fast relative  to  the  chart speed, the  response  time test will




appear  as  a  spike on  the  paper.   Although  the  monitor response  time  cannot




usually be  determined from these records,  it is often  evident  that  the monitor




meets the  response time specification.  The strip chart records  serve only to




document that the response time test was conducted.
                               40

-------
     If the strip chart is accurately documented  and  if  the trace shows three




uniformly spaced pairs of alternating  upscale  and  downscale  responses within a




time period significantly less than 90  minutes  (i.e.,  15 minute response time




test x  6  tests) ,  it  is  reasonable  to presume  that the  monitor meets  the



response time specification.
                                41

-------
U.il  ZERO AND CALIBRATION DRIFT TESTS




M.4.1  Background






     The drift tests described  in Performance  Specification  2  provide estimates




of   the  temporal  stability  of  the  monitor's  calibration.   The  zero  and




calibration drifts are determined  by two  independent tests: the 2-hour zero and




calibration drift test, and  the 24-hour zero and calibration drift test.






     For extractive monitoring  systems,  the drift  tests  involve  introducing




zero and span gases into the monitoring system.  For in-situ monitoring systems




that cannot  accept calibration gases,  a calibration  gas cell  "functionally




equivalent to 50  percent of span  concentration"  is  used  in lieu of  span  gas.




In addition, such  in-situ monitors must  have  some means  of producing  a  "zero




condition that provides a system check of the analyzer internal mirrors and all




electronic circuitry including  the radiation source and the detector assembly."




The  performance  specification  permits an  extrapolative method as an alternative




to simulating a  zero  condition, if the monitor  lacks direct  zeroing  ability.




For example, three or  more calibration gas cells are inserted  in  the monitor,




and  extrapolation  from  these  values  p-ovides  the   zero  response.   Owners  or




operators of these monitors are required  to retain  a graph  which illustrates




the  extrapolation operation.  The validity of this  extrapolative  technique  is




based upon the following assumptions: (1) the monitor response  over  the entire




range of extrapolation can be described by a linear  equation;  (2)  the three  or




more points are  well  spaced over  the  instrument's  measurement range;  (3)  the




concentrations of the  gas cells  are known to a high degree of accuracy; and (M)




the extrapolation to the zero value is not affected  by  span drift.  Evaluation




of these extrapolative procedures  must be conducted on a case-by-case basis.
                              43

-------
4.4.1.1  2-Hour  Drift  Test






     The 2-hour  zero  and  calibration drift  tests require  15 data sets collected




at 2-hour intervals.   This  particular  test is  intended  to  quantify  drift on a




short  term  basis.   For example,  the  test is  capable  of  identifying  diurnal




variations in monitor  response.






     The  important  data  obtained  from   the   2-hour   drift  tests  are  the




differences between consecutive  zero and  span measurements. Adjustments to the




monitor during the 2-hour  drift  tests  are not allowed.  A minimum  of  16 data




sets of zero and span measurements should  be  acquired,  because  15 differences,




determined  at 2-hour  intervals,  are required  for  the  test.   Thus, the  first




data set is the starting  point for obtaining  the  first  difference data.






     The data are not allowed to represent non-consecutive measurements;  thus,




in the event that a series of 2-hour determinations  is interrupted, a  new set




of data must be generated  as  a  starting  point  before more difference data may




be obtained.








4.4.1.2  24-Hour Drift Tests






     The purpose of the 24-hour  drift  tests is  to reveal variations in monitor




calibration  which may occur  on  a day-to-day basis. Measurements are conducted




at  24-hour  intervals until   7  drift   determinations  are  obtained.   Since  8




consecutive  sets of  zero and span  readings  are  necessary to  provide  7  drift




determinations, the  24-hour  zero and  calibration  drift  tests normally  define




the  time of the operational test period.






     According  to  Performance   Specification  2,  manual  adjustments   to  the




monitor during the 24-hour drift tests are permitted  only at  24-hour intervals,
                                 44

-------
unless  the  monito,r  manufacturer  specifies  a  shorter  interval  for  manual




adjustments.  Automatic  adjustments,  on  the other  hand, are  allowed  at  any




time.  Specifically,  the 24-hour  drift tests require the  following procedure at




24-hour intervals: (1)  measurement  of the zero value;  (2) adjustment  of  the




zero response to the correct value, if necessary;  (3)  measurement of the span




value;  and  (4)  adjustment  of the  span  response  to  the  correct  value,  if




necessary. The chart  recorder  zero value must be sufficiently offset  during  the




tests,  to  allow  for  the   determination  of  negative  drift.   Performance




Specification 2 states  that the  offset  should  be  approximately  1051.  However,




for  practical reasons smaller offsets may be  validly employed  as long  as  all




drifts are recorded on scale.






     Some monitor vendors suggest that the adjustments not be  made  at 24-hour




intervals; they  would rather allow the  drift  to  accumulate  for  the  entire




operational  test  period,  provided   that the  total  drift does  not  exceed  the




respective performance  specification drift limitations.  If this  procedure  is




employed, then   the   24-nour  zero   and  calibration  drift  values  should  be




calculated in the same manner  as  in  the  2-hour drift tests.






     For  the  24-hour  drift  tests,  the  zero  is  adjusted   after  the  zero




measurement  but before  the  span  measurement.   Consequently, the  procedure  for



conducting the  24-hour  drift  tests  automatically  removes the  effects of zero




drift  from  the  span  measurements.   The  measured   span drifts  are,  therefore,




equivalent to calibration drifts, and  no  further  manipulation  of the data  is




required .






4.4.2  Review of Zero and Calibration Drift Tests






     In reviewing  the drift  test data  and   results  for both  the  2-hour  and




24-hour tests the reviewer should perform  the  following  checks:  (1) check the
                                45

-------
                                               _
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         46
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-------
concentration value of the calibration  gas or calibration gas cell used to span




the monitor, (2) check for  the  required  number  of zero and span measurements,




(3) check the individual  zero  and  calibration drift calculations, (4) check the




reported zero and calibration  drift determinations against the individual drift




measurements, and (5) check the values recorded on the data  sheet  against the




strip chart records.






4.4.2.1  2-Hour Erift Tests






     For extractive monitors,  the  90% of  span calibration gas  is specified for




use in  the 2-hour  drift  tests.  For  non-extractive  monitoring systems,  the




calibration gas  cell  is  specified  to be  equivalent  to  50%  of  span.   The




reviewer should check the  report for comformance with these specifications.






     The 2-hour drift tests require 15 sets of  drift  determinations,  in which




each data  set  is   composed  of initial   and  final  zero  and   span  readings.




Consecutive  drift   determinations may utilize  the  same  data   set  (i.e.,  a




particular zero and  span  value  can be  used  as  the  final measurements  in one




drift determination  and  as the initial  measurements   in  the following  drift




determination).  Thus,  at  a minimum, 16 sets of  zero and span measurements must




be acquired.  An additional set  of measurements  is required each time the drift



test sequence  is interrupted.   It  should  be noted  that  2-hour drift testing may




span and even  include the  time period when 24-hour drift measurements are made,




as long as no  adjustments  to the monitor  are performed  during the 24-hour drift




test for that  particular day.   If, on the  other  hand,  adjustments occur  during




the affected 24-hour drift test, then  the 2-hour  drift testing  is  interrupted




and the testing sequence must  be reinitiated.
                               47

-------
     Deviations from exact  2-hour  timing  are  not  uncommon.  Because Performance




Specification  2  does not  address  this  subject,  the  significance  of timing




deviations must be assessed on a  case-by-case basis  by the reviewer.  In this




regard, it is recommended that the  reviewer  base  his judgement  on whether the




drift data indicate that the  monitor's  calibration is  stable over  short time




periods.






     For  each  drift   determination  (initial    and   final   zero   and   span




measurements), the zero  drift  is determined as the final  zero reading minus the




initial zero reading.   Similarly,  the span  drift is determined  as  the   final




span reading minus  the  initial span  reading.   The calibration drift  is then




determined as the span drift minus  the  zero  drift.  The reviewer should  check




to  see that  the  above  subtractions are   performed  consistently,  and  that




algebraic  values are employed  in determining  the calibration drift.






     The mean zero drift is determined from the algebraic sum (retaining signs)




of  the  15 zero  drift determinations.  The  confidence interval  for  the  zero




drift test is  also  calculated by employing  algebraic  values of  the measured




zero  drifts.   The  value   of t        for   use   in  the  confidence  interval
                                u. y t j


calculation  is  2.145 for  15  measurements.   (A  detailed  example  confidence




interval  calculation  is  included   in  the "Review   of   Relative  Accuracy




Calculations" section of this  manual .) The  reported 2-hour  zero drift should be



calculated as:
   zero drift =
                  Mean Zero Drift
+  Confidence Interval
                       x 100
                              Instrument  Span
                                  48

-------
     Ihe  reported  2-hour  calibration  drift  is  determined   from   the   15




calibration drift determinations in exactly the same manner  as  the zero drift




is calculated .






4.4.2.2  24-Hour  Erift Tests






     The review of the 24-hour  zero  and calibration drift tests is very similar




to the review of the  2-hour  drift  tests.  Ihe same requirements apply  to  the




value of the calibration standard used to span the system for both drift tests.




The  value   of  the  zero  offset  employed  should   also  be  determined  before




reviewing data  acquired  from  the strip chart records.






     The 24-hour  drift test requires 8  sets of zero and span measurements  to




facilitate  7  zero  and  calibration   drift   determinations.   The  procedure




prescribed by Performance  Specification 2 requires adjustments to  the  zero  and




span values following  the  respective zero and  span measurements.  Provided that




this procedure  is followed, the individual  zero drift values  are calculated  as




the zero value  measured  at the end  of the  24-hour  interval,  minus the correct




zero value.  In the same manner, the calibration drift is the span value at the




end of the  24-hour  interval  minus  the  correct span value.   The  adjustment  of




the zero value  after the zero reading and before the span reading automatically




removes the effects of zero drift on the  span measurements.   Thus, no further




correction of the span measurements  is necessary.






     For reasons discussed   in Section  4.4.1.2,  rather  than   performing  the




24-hour zero and  span  adjustments, testers  often allow drift to accumulate.   If




this  procedure  is  employed,  the   24-hour  zero  and   calibration  drifts  are




determined in exactly the  same  manner as  for the 2-hour drift tests.

-------
     The calculation procedure for determining  the  reported  24-hour  zero  and

calibration drifts  from the individual drift measurements is the  same as  that

described for the  2-hour drift tests.   The  mean zero drift, mean calibration

drift,  and  respective  confidence  intervals  are determined  using  algebraic

values.  (Pertinent, detailed  example calculations are included  in the "Review

of Relative Accuracy Calculations"  section of this manual.) The value of tQ

for  use  in  the  confidence   interval  calculation  is   2.44?   for  7  drift

determinations.  The reported  24-hour  zero and  calibration drifts are computed

as:
                  Mean Zero D-ift
                       or
                  Mean Span D-ift
+  Confidence Interval
zero drift
    or     :	
span drift                                             x 100
                           Instrument Span
4.4.3  Review of 2-Hour and 24-Hour Drift Test Strip Chart Records


     The  reviewer  should  confirm  the  accuracy of the  span  and  zero  values

reported  in  the  drift test data  sheets by comparing  them  with corresponding

values on the strip chart  record.  In addition, the reviewer should verify that

all  drift traces are on scale.   Traces  which  reflect  pegging  at either end of

the  strip chart will  necessarily invalidate  a drift  test,  because  the true

magnitude of the pegged  response cannot be determined.  Finally,  the reviewer

should  check that  the times  reported  on  the data  sheet  match  the  times

indicated on the strip chart recording for the zero and span measurements.
                                     50

-------
 4.5  RELATIVE ACCURACY TEST



 4.5.1  Background





      The  relative  accuracy test  is  performed  to assess  the  adequacy of the



 calibration  technique  of  the  continuous  monitor.   The  test  entails  the



 comparison of pollutant concentrations determined  by the continuous monitor to



 concentrations  concurrently  determined  by EPA  Reference  Methods 6  and/or  7.



 When  relative accuracy tests are conducted  on continuous monitors that measure



 pollutant concentration on  a  wet basis, these  two  reference methods  must  be



 suplemented by  an  Agency  approved method  for determining  the  effluent stream



 moisture content.  The result from the moisture  determination  is used to  place



 all the effluent measurements on a consistent moisture basis.





      The reported relative accuracy result  is calculated  from three terms.  One



 term  is  the  algebraic  mean  difference   observed  between  the  monitor  and



 reference method concentration measurements. This mean difference term may  be



 interpreted as the  absolute bias or inaccuracy of the  monitor  measurements.   A



 second term, the 95? confidence  interval, is  the precision estimate associated



 with the determination of  the  mean difference.   The  remaining  term  used  in the



 computation is  the mean concentration  of the  reference  method determinations.



 The  sum  of  the  confidence  interval  and  the   absolute  value  of  the   mean



 difference divided  by the  mean  reference  method  concentration,  affords the



 relative accuracy which is expressed  as a percentage.





      Performance Specification 2 calls for 9 Method 6  measurements  when  tests



 are  conducted   to  determine  the relative  accuracy  of  an  SO   monitor.   A



determination  of the relative accuracy of  an  NO  monitor likewise  requires  9
                                                X


measurements of  the  pollutant  concentration, but in  this  case  each measurement



 is  the  average  of  three   Method   7   determinations   each   conducted   over
                                 51

-------
approximately three  minute  intervals.   Thus,  27  determinations  of  the   NO




concentration in  the  effluent are required for the relative accuracy  test.






     Since the  determination  of  relative  accuracy  involves  a  considerable




amount of reference method sampling and analysis, the amount of  attendant data




is exceptionally large, relative to the other monitor  performance tests.   The




effort required  in  reviewing  relative  accuracy tests  is  likewise  increased




proportionally.






     The review of the  relative accuracy test can be divided into several major




areas: (1) review of the relative accuracy  calculations;  (2)  determination of




continuous monitor values; and (3) review of reference method sampling data  and




results.  The following subsections  in this report treat each of  these topics




separately.








*». 5. 2  Review of  Relative Accuracy Calculations






     The most common error in monitor  performance  evaluation  test reports is




the  incorrect calculation  of  relative  accuracy  from  the   reported  data.




Therefore, if there  is any  doubt  about  the  value  reported  for  relative




accuracy,  the  reviewer should  perform  the  entire  calculation  as   a check.




Because of the frequency of this error, a detailed discussion and an  example of




the relative  accuracy computation are provided below.






     The reviewer should first check the relative accuracy data  form   for the 9




data  sets, required  as the minimum  number  of  sampling  runs  by  Performance




Specification 2.   In many cases, a reference  sample  is inadvertently lost or




invalidated.   This situation is not uncommon because much sampling  is involved:




9 S>0  samples; 27 NO   samples; and in some cases, 9 H_0  samples.   The  reviewer




may decide to accept  less  than  9  data  sets,  provided  the  results clearly
                                52

-------
indicate compliance  with (or  failure of) the relative accuracy specification.






     The review of  the  relative accuracy  test  data  form  should  next  focus on




the   times   reported   for   the  reference   method  sampling.    Performance




Specification 2 states that no more than  one  run  may be conducted in any one




hour. The interpretation of this requirement calls for flexibility.  Deviations




of several minutes do not violate the intent of this specification.






     The reviewer should verify that the  monitor  and  the  concurrent  reference




method values are accurately reported and  the differences  have been determined




accurately.   According to  Performance  Specif ication  2,  these  differences are




computed by subtracting  the reference method value from  the  concurrent monitor




value.  Thus, positive differences arise when the monitor reads higher than the




reference method  values.   There  will  be  no  effect on  the  value of the




calculated relative  accuracy result if the  subtraction operation  is  performed




in  the  reverse  manner,  provided  the   subtraction  operation   is   performed




consistently throughout  the calculation.   Pbwever,  the  interpretation of the




individual data  is  reversed  if the  subtraction  operation is reversed,  i.e.,




negative  differences  will  occur  when  the  monitor  reads  higher   than the




reference method  sampling  results.






     After checking  that  the differences are correctly determined,  the reviewer



should compute the mean reference method  value, the  mean  of the  differences,



the confidence interval ,  and finally, the  relative accuracy.








(1)  Mean Reference  Method Value






     The mean Fteference  Method value is simply the arithmetic average of  the  9




reported pollutant determination results.   It is employed in the  denominator of




the relative accuracy calculation to express the accuracy on a relative basis.
                                  53

-------
                                                .
                       ACCURACY DETERMINATION (S02 AND
Source and  Location  ,
 ' 3 n"'" c r
 Nine
 run pe>r ft
                            3" Samp/es p&r
                                          r
 v5-Tr  ref. n.ethod
 --•s:  value '::)
test value (NO )
            A
                                         Mean  of
                                         the differences	\_fajiL.
       z-5  T:nfidence intervals  = +

       Accurac
           _ppm (S02), = ± 	A
                 	..   .  ^..     	     Ppm (NO,)

; c s JMeu-D_.°f th c  differences! + 9SV confidence interval^
  " ^          Tlcan "reference method value              ^ 100 =

      	«(S02) , =   3^7    £ (NOX.) .
         E-.^lain and report method used  to determine integrated averages
                                   calculation
                                   above been
                                           54
                                             Us
                                             i /

-------
 (2)  Absolute Value of  the  Mean of the Differences


     The  algebraic  differences between concurrent Reference Method  values and

 monitor  values  are  summed and averaged. Summing  algebraic  values requires the

 retention  of the sign  of the  differences.   Consequently,  the  computed  mean

 difference  may  be a negative or  positive  number,  or even zero.  (It  should  be

 noted that  the  sum  of the differences result  also enters  into the calculation

 of the  95$ confidence interval, and therefore, repetitive  calculations can  be

 avoided by  recording this value for later use.)




 (3)  The 95% Confidence Interval (C.I.n QC.)
                 " " '    '  ~~           ~v • y j*


     The determination of the 95% confidence interval is the greatest source of

 error.  The formula used in the determination is given by:
                 C-I-0.95 =
Where:

   C.I.Q g   = 95 percent confidence interval;

    n       = number of data points (In this example,  n = 9);

    x.      = algebraic value of a measurement
              (Some versions of the performance speci-
              fications define x  as the absolute value
              of a measurement; this is not correct.)

    x       = sum of the n measurements;

    fcO 975  = fc score for checking both upper and lower limits
              its with 95 percent certainty,  corrected for n
              degrees of freedom.
                                55

-------
     For  the  relative  accuracy  test,  the  operations  required   for   the




calculation of the confidence interval  apply strictly to  the  data  represented




by the  differences.   Again,  attention  should  be  placed on  summing  algebraic




values (as opposed to absolute values)  in  computations  of the 95? confidence




interval .






     A common error in the calculation  of  the  95% confidence  interval  is  the




use  of an  incorrect  tn     value.    The  reviewer   should  verify  that  the
                        u. y (o


calculation employs the correct value.   In the majority of cases, the  error is




the  result  of  the use  of an adjacent value  from   the  tabulated  t  scores




(tn jyjc-) .   A detailed example confidence  interval  calculation is  provided  in
  u. yI\)



Figure 4-5.






(4)  Relative Accuracy






     The reported  relative  accuracy should be calculated as:
  Relative

  Accuracy  =
  Mean of

Differences
C.I.
                     0.95
                               x 100
                Mean Reference  Method Value
     It  should  be  emphasized  that the  absolute value  of  the  mean  of  the




differences is used in calculating  the relative accuracy.  As a final step, the




reviewer should check that the calculated  relative accuracy  value  is  the  same




as the value listed in the "Summary of Results" section of the test report.
                                56

-------

                       II             //
Ui
                 I
                       II
                      fo
N
^
-
<
                      o
                                                                     a'
                                                                     h
                                                           N
                                                           "I
                                                          H
                                                                               x
                                                                                              i      t

                                                                                                                                                        H

-------
4.5.3  Determinations of Continuous Monitor  System Values








     The relative accuracy test  entails  comparing the concentrations determined




by the continuous monitor to concentrations  determined by the reference method.






     The following factors should  be considered  when quantifying the continuous




monitor  system  measurements from   the chart records:   (1)   the  time interval




(duration)   for  comparison of monitor  system  data  to  sampling  data,  (2)  the




method  of  integrating  or  averaging  the continuous monitor  system  data ,  and




(3) the response time of the monitor system.






     Performance  Specification  2,   (Paragraph 7.2.  1)  requires  the  continuous




monitor  data  to  be  determined  by integrating  or  averaging  the  pollutant




concentrations over each  of the time intervals  concurrent  with each reference




method  testing  period.    The data  form  (Figure  2-3)  provided  in  Performance




Specification 2 indicates that an  hourly average of the pollutant concentration




should  be  used  for  comparison  with reference  method data.   towever, it  is




generally recognized that  this  hourly averaging note  is  inconsistent with the




sampling times observed  for EPA  Methods  6  and 7:  20 minutes and approximately  3




minutes, respectively.   Accordingly, the average concentration  measured by the



monitor ordinarily is determined over time intervals corresponding to reference



method sampling times.






     If  strip chart records served as the  source  for  the  average  monitor




concentrations  obtained  during  the  relative  accuracy determinations,  those




portions of the  trace  corresponding to  the tests  should  be  bracketed  and




labelled according to run number.






     The method of  integrating  or  averaging  the   continuous  monitor  system




output over the time interval corresponding to  the  reference  method  tests may





                              58

-------
 affect  the  accuracy  determination.   If  the  monitoring  system   provides  a




 nunerical  output or  integrated  averages,  then  the  problem  is  usually not




 significant.   However,  equal  intervals must  be used to  average  the data.   If




 the  monitoring  system  provides  a  continuous  record   (strip  chart),  then




 averaging  the  data  may be more difficult, particularly where large variations




 in  the  pollutant concentration with time are encountered.  In this situation,




 taking  as many  readings as  the resolution  of the  data record  permits and




 averaging the readings may provide good  results.






     In many cases, the  strip  chart record  can be integrated  by simple visual




 inspection.






     Performance  Specification  2 states that  the  method  for  performing  this




 integration is to  be reported.   The  reviewer  should check that  the  reported




 method  can be  applied  to  the  monitoring   data   record to  afford  results




 equivalent to  those  contained  in the relative accuracy test  data  sheet.   The




 reviewer may find  that  the  method for determining  the  integrated  averages  is




 not reported.   In addition,  cases may arise  when disparities  occur  between the




 recorded averages and the reported averages.   For both these possibilities, the




 reviewer should  weigh the significance of the report deficiencies  against the




 impact of these deficiencies on the  relative  accuracy result.   For  example,  if




the relative accuracy result  would  change from 1% to 13% as  a  consequence  of




errors in  figuring  the  integrated  averages  from the  continuous  emission  data




monitor record, the change would be considered  insignificant  because indicated




performance is  unchanged relative to the  specification < 20%.
                                59

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H. 5.4  Review of Reference  Method  Data  and  Results






     This section details the review of  the  reference method sampling results




employed  in  the  relative  accuracy determination.    In  this  portion of  the




monitor performance test review,  the  reviewer attempts to  accomplish several




objectives:   (1)  to  determine  whether  appropriate  sampling   and  analytical




procedures were employed;  (2)  to determine  whether sufficient data are included




in the documentation of the  testing;  (3)  to verify the accuracy and correctness




of calculation  procedures employed in  determining the final  test results; and




(4) where  possible, to  establish the  validity of the data  and  results  by




comparison with other parameters,  e.g., fuel  analysis  data.






     The  agency observer  bears the  primary  responsibility for  ensuring  that




proper  testing  procedures  were employed.   If an agency observer  was present




during the monitor performance test, then the  observer's report and field notes




should be reviewed  and  compared with  the data and  results from  the  reference




method sampling.






     The reviewer cannot always  ascertain  that correct sampling and analytical




procedures were employed.  In  some cases,  the range of values  for particular




data or  intermediate results can  be  bracketed.    Results or  data that  fall




outside  of reasonable  and  normal  ranges  require  additional   scrutiny.   The




skilled reviewer is often able to  determine quickly  which parts of the sampling




data and results require a  closer  check or  additional  documentation.






     The  following  subsections  treat  the  subjects  of  SCU,  NO  ,  and  moisture




determinations  separately.   Background  information  for the  novice reviewer and




procedures for  reviewing  field sampling data,  laboratory  analytical  results,




and  calculations  of gas  concentrations  are  included  in  each  section,  as




appropriate .




                                   60

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4.5.4.1  Reference Method 6 -  SO-
 Background







     EPA  Reference  Method  6  is   specified   for  determining  dry  basis   SO




 concentrations  in stationary source effluent  streams.   The application of  the




 method  essentially entails sampling a measured  volume  of the effluent through




 impingers  containing  hydrogen  peroxide  where  SO-   quantitatively  reacts  to




 sulfate  ion,  which  is  determined titrimetrically  using   the  barium-thorin




 method.  When  applied to monitor relative  accuracy  tests,  Reference  Method 6




 sampling  is conducted with  the  probe  positioned adjacent to  the monitor's




 probe.   This positioning  ensures  that the  comparative results  will  be based




 upon measurements  performed  on equivalent  samples.   The  barium-thorin method




 does  not necessitate a  laboratory environment;  consequently titrations   are




 often conducted in the  field.







 Review of Field Sampling Data







     Raw data  sheets  documenting  the  Reference  Method 6  sampling should  be




 included in  the monitor test  report. Data sheets should  be  included  for all of




 the sampling runs  reported on the  relative accuracy  data  sheet.   The reviewer




 should check these data to ensure  that the  required  sampling  procedures  were




 followed, that  sufficient  data  were reported, and that  the  reported  data  are




within reasonable  ranges.   Each raw data sheet  should  provide the information




necessary  to  calculate  the  volume  of  effluent sampled,   corrected  to   dry




standard  conditions.   This  volume,   in  conjunction  with  the   laboratory




analytical  data, is used to calculate the SO- concentration of the sample.
                                 61

-------
     Each raw data  sheet  should  contain the following identifying  information

(see example sheet):   (1)  plant  name and location;  (2)  date  of the  test;  (3)

sampling location;  (4) initials of the sampler(s);  (5)  run number;  (6) material

sampled  for  (in this  case,  SCL); (7)  barometric  pressure;  and  (8) a  number

identifying the meter box used and its associated value of Y (the dry gas meter

calibration coefficient).


     Reference Method  6  specifies that the dry  gas  meter  reading,  flow rate,

and dry gas meter temperature be  recorded at  5-minute  intervals.   Accordingly,

these readings and  respective  times  should  be included  on  the  raw data sheets

that document sampling.


     For Method 6,  the volume of  effluent sampled at dry standard conditions is

calculated according  to the following equation:
                     KYV P,
                        m  bar
       Vm,   ,\ =
          (std)          T
                         m
   Where:                    =    Dry gas  volume  expressed  at
                                standard conditions, dscm
                                (dscf).

                                0.3858 °K/mm Hg
                               (17.64 °R/in. Hg).

                 Y          =    Dry gas  meter  calibration
                                coefficient.

                            =    Dry gas  volume expressed  at
                                meter  conditions,  dcm  (dscf).

                            =    Barometric Pressure, mm Hg
                                (in. Hg).

                            =    Dry gas  meter  temperature,  K,  (  R)
                                     62

-------
 The  variables  above  are  discussed  in  the  paragraphs  that  follow.   Where




 possible,  guidelines are provided  for  checking or verifying that  the  reported




 values are within reasonable and expected  limits.







      The reviewer should note that  the  reported standard sample volume has  the




 greatest potential for  error.







 (1)   Flow  Rate







      Reference  Method 6  states that the flow rate should be maintained at  1.0




 liter per  minute  +_ 10%, (2.1  standard cubic feet  per hour).   The  reviewer




 should  check   that  the reported   flow  rate measurements  fall  within  the




 acceptable range.   Sampling  rates  that   exceed   1.1  L/min  are   undesirable,




 because  the  decreased  residence  time of  the  sample  within  the  impingers




 containing the  hydrogen peroxide   may result  in  diminished   S0_  absorption




 efficiency,  which would  be   ultimately  reflected   as  a  negative   bias  in  the




measured   concentrations  of  S02.   (As a  note,   information   is  unavailable




regarding  the magnitude  of the flowrate  at  which this bias becomes  significant;




thus,  the  reviewer  should  be somewhat  liberal in  interpreting the technical




validity  of results  obtained  from sampling  at   higher than  prescribed  flow




rates.) Low flow rates,  on the other hand,  will affect  the  quality  of the data




only  if  the amount of SO  sampled is insufficient  for analysis.







     If  the  reviewer has doubts  concerning the validity of  the reported  flow




rates, he may check  them by  comparison  to  the  average  sampling rate, which is




easily computed by: (1) subtracting the  initial dry gas  meter reading from  the




final  reading,   (2) correcting   the  results   by   multiplying   by   the  meter




calibration coefficient, and  (3) dividing the  corrected  volume  by  the reported




sampling time.
                                    63

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(2)  Meter Volume (V )







     A sample volume requirement is neither specified within Reference Method 6




nor  within Performance  Specifiation 2.   The  sample  volume  and  sample  time




requirements  specified  within the  subparts  that  describe  source  performance




tests  are  generally adopted  for  conducting  monitor performance  evaluations.




For  example,  for fossil-fuel  fired steam generators,  Subpart  D  specifies  a




minimum sampling  time  of 20 minutes and  a minimum sample volume of  0.02  dscm




(0.71 dscf).







     When  the volume is  measured  in cubic  feet, the  dry gas  meter readings




should be reported to a precision characterized by three digits to the right of




the decimal point (e.g., 68.035 dscf). This will ensure that the sample volumes




are measured  to three significant figures.







     The reported metered  sample  volume will,  in  all  likelihood,  differ  from




the   sample   volume   corrected  to  standard   conditions,   reflecting  volume




dependence upon  the  meter temperature,  barometric pressure, and  dry gas meter




calibration coefficient.   Thus,  the sample volume at dry standard  conditions,




rather than the meter volume,  should be employed  to  assess whether  the minimum




sample  volume  requirements  have   been  met.   However,   the  reviewer  should




recognize that sample volumes  less  than the minimum may be technically valid.







(3)  Meter Temperature (T  )







     The measured dry gas  meter temperature is  used  for  correcting  the metered




sample volume to an equivalent sample  volume  at  (dry)  standard  conditions of




standard temperature  and pressure.
                                  64

-------
      The dry  gas meter  temperature  should be reported  for  each set of  5-minute




 entries.    Reporting  the   temperature   to  the  nearest   whole  degree  is  of




 sufficient  precision.   Small  errors in  the  temperature measurement have  little




 effect on the calculated SO^  concentration  because  the measured temperature is




 converted   to   an   absolute   basis   for   all   calculations.    For  example,  a




 temperature of  68° F  (20° C)  becomes  528° R  (°R  =  degree  Rankine,  absolute




 temperature scale  in  English units)  or  293° K  (°K =  degree  Kelvin,  absolute




 temperature scale  in metric units).   The temperature that  figures in  the  volume




 computation will always be known to  three significant  figures.






      The  reviewer  should   check that  the  reported   average  dry   gas  meter




 temperature has been correctly determined.  The range of meter  temperatures




 usually  encountered is between ambient temperature  and   15°  F above  ambient




 temperature at  the meter location.






 (4)   Dry Gas Meter Calibration  Coefficient  (Y)






      The dry gas meter calibration coefficient (Y)  relates the volume measured




 by  the  subject dry gas meter  to  the  true  volume  measured  by  a  gas  meter




 standard.   This  coefficient   is  employed  in  computing  the  sample   volume




 corrected to standard conditions.  The reviewer should  check to see whether the




 value of Y used in  the  calculations is consistent with the value  appearing on



 the calibration data form.






      Reference Method 6, Paragraph 5.1.1, states that dry  gas  meters  are  to be




calibrated  before their initial use and after every use in the  field. In  order




to ensure completeness,  the test reports should include data sheets documenting




the initial  calibration and  the post-test calibration  check for every  dry gas




meter used  in  the  monitor performance test.
                                   65

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     The data sheet documenting  the  initial  calibration of the  dry gas  meter



should include the data for three (3) calibration runs.   The rotameter  readings



should each be approximately 1  L/min  (2.1  dscfh), and  the dry gas meter  volume



readings should  each  be approximately  0.5 dscf  or  greater.   The  regulations



require that no  individual  Y may  differ  more than  2%  from  the  mean  Y.   The



reviewer should check for conformance with these  specifications.





     The data sheet documenting the post-test calibration check  should  include



data  for  at  least   two   runs.   The   rotameter  readings  should   each   be



approximately 1 L/min (2.1  dscfh),  and the dry gas meter volume  readings  should



each be  approximately 0.3  dscf or  greater.  Again,  no  individual  Y  should



differ from the mean Y by more than 2%.   The  mean value  of Y  obtained  from  the



calibration check  should differ  by no more than  5%  from the mean  value of  Y



obtained from the initial calibration.





     If the  5%  specification is not met, the dry gas meter  is required  to  be



recalibrated as  per  the  initial calibration.  This  would necessitate  a  third



data form  for  a  dry gas meter.  The  regulations state  that  the Y  (of the  two



initial calibrations) that "yields the lower  gas volume for each test run is to



be  used."  This  requirement  is  intended  to apply to  source  performance  tests



rather  than  to monitor  performance  tests.   An  average  Y  value   for  monitor



performance tests may be more reasonable for these situations.





(5)  Barometric Pressure - P.
     	—	-bar




     The barometric pressure is used in computing the  sample volume corrected



to  standard conditions.  The reviewer can reasonably judge the  accuracy  of  the



reported barometric pressures  in light  of the  range  of pressures  that  could



ordinarily be  expected to  occur.   "Rules of  thumb"  can  be  offered:  (1)  the
                               66

-------
                  GASEOUS POLLUTANT SAMPLING DATA
Plant

Plant Location

Date  .a   &1,  / e>rfo
                                                  y	*-/	
                                 •  67
            an adequate
     Cample  volurne bees
      &l>ta/si
                                         \> 0.71 oLs-cf)    J

-------
range of pressures ordinarily observed  at sea level  range  between  29  and  31  in.




Hg;  and (2) for locations above sea level,  the pressure  decreases  approximately




1.0  in.  Hg for  every  1000  feet.   (This  rule underestimates  the  barometric




presure above 3000 ft by  about 2.5%).
                                 68

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 Laboratory Analyses


     Accurate  laboratory  analytical  results are  essential  to  the  validity of

 relative  accuracy tests  because  these analyses  determine the  masses  of  S0p

 sampled.  However,  unlike the data generated during  sampling,  laboratory data

 are not as abundant and, because of this, they do not  permit  quite  so thorough

 a  review.   Nevertheless,  data  forms documenting laboratory  analyses for  S0p

 should accompany the relative accuracy sections of monitor  test reports.  This

 practice should ensure reporting completeness and promote quality and adherence

 to  Reference  Method 6.   In addition, thorough  documentation will  permit  the

 identification and correction of any errors that occur.


 SCL Analyses


     The mass of SO  absorbed during sampling is calculated using the following

 equation:
          m    = 32.03N(V  -V )V  . /V
           buo           t   b  soln  £
  Where:  mso  = Mass of S02 absorbed, mg.

  32.03 mg/meq = Equivalent weight of SO ,
                 mg per milliequivalent rmeq) of titrant.

            Vfc = Average titrant volume, mL (two titrations).

            Vfe = Volume of titrant required for the blank, mL.

             N = Normality of the barium titrant in meq/mL.

         V  ,   = Total volume of solution in which the S0?
                 sample is contained (most often, 100 mL)f mL.


            V  = Volume of the sample aliquot titrated
                 (most often 20mL),  mL.


A review of the  analytical  phase of Method  6  requires data for all  the  terms

listed above; thus,  at  a  minimum, all  these  terms should  be recorded on  the
                               69

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laboratory data sheets.  Sample data sheets accompany  this  section (see Figure



4-7).  The pertinent data will be discussed individually.





(1)  Normality  (N)






     The normality  of  the  barium perchlorate, BaCClO^)    (or  barium chloride,



BaCl2)  solution used  in  titrating  the  samples  should be  reported  to  three



significant  figures;  the value  should lie within  the range  of 0.00980 N  to



0.0102 N.  Reported concentrations that fall outside this range will not affect



the results of the analyses as long as sufficient titrant volumes are used.





(2)  Volume of Titrant for Blank






     The volume of titrant required for the blank V  should always be reported.



The value  should be less  than 0.5  mL,  or reagent  contamination  is  suspect.



Without identification of the  source and identity of  the  contamination,  it is



not possible to assess accurately the impact on the analyses.





(3)  Average Titrant Volume






     Each S02 sample is titrated twice, and the volumes for  the  two titrations



are averaged.   Data  for  all titrations should be  recorded on laboratory  data



sheets.  For each set of titrations,  the volumes should agree  within  1 percent



or 0.2 mL,  or the titrations are  invalid according to  Reference  Method  6.   In



summary, three  titrant  volumes should  be  reported   for  each  analysis:  the



volumes from the two titrations and their average.






(*O  Volume of Solution V  ,  and Volume of Aliquot V
     ——	spin	3	a





     The volume of solution  in  which  the S02 sample is contained  and the volume



of the aliquot titrated are usually  100  mL and 20 mL,  respectively.   If  these



values are consistent  throughout the  analyses, it is  necessary  only  to  state
                             70

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 JOB
 ANALYSIS LOCATION
                                  FIGURE 4-7
             EPA  REFERENCE METHOD 6  (SO2   ANALYSIS WORKSHEET
PLANT  NAME/UNIT 4

   ..	ANALYST
                                 DATE
H2S04
Volume
VM1)
(mL)

Ba2 +
Vo lume
vt(l)
(mL)

Ba2 +
Norm .
Nl
(meq/mL)

H2S04
Volume
Vh(2)
(mL)

Ba2 +
Volume
Vt(2)
(mL)

Ba2 +
Norm .
N2
(meq/mL)

H2S04
Vo lume
Vt(3)
(mL)

Ba2 +
Vo lume
Vt(3)
(mL)

Ba2 +
Norm .
N3
(meq/mL )

Nx =  l''h
-------
this fact on the laboratory data sheets.  If sample dilution is due to high S0?



concentrations, the pertinent dilution factors should be reported.
4.5.4.2  Reference Method 7 - NO
                                x




Background





     EPA  Reference  Method  7  is  applicable  for  determining  dry  basis  NO



concentrations in stationary source effluent streams.  In applying this method,



an  effluent sample  is  drawn  via  a  heated  probe  into   an  evacuated  flask



containing a solution that oxidizes the NO  to nitrate ion.  The nitrate ion is



then determined  spectrophotometrically  using the phenoldisulfonic  acid (PDSA)



method.  According to convention, the NO  concentration is reported as NO .
                                        X                                c.




     For testing  N0x monitor  relative  accuracy, the inlet  of the  Reference



Method 7 probe  is placed adjacent to the  monitor's probe  to  ensure  that  both



monitor  and  reference method  are applied  to  equivalent samples.   A  relative



accuracy test consisting of 9 runs will include 27  Reference  Method  7 samples,



since  3  samples  are  defined  as  one run.  NO   analysis  is  rarely  (if  ever)



performed  in  the  field during  the  operational  test  period because  of  the



extended period required for complete oxidation  of  the NO  and  because  of the
                                                          X


need for laboratory hood space.





Review of Method 7, NO  - Data  and Results





     If  a complete  review  is  to  be performed,  the  documentation of  Reference



Method  7  sampling  must  provide  sufficient  data  to  recalculate  all  NO
                                                                              x


concentrations.   The  novice  should   note  that  a   substantial  amount of  data



manipulation is required to recalculate the concentrations  of NO .
                                   72

-------
      In reporting  the  concentration of NC>x,  the  greatest potential  for error
 lies in calculating the sample volume, i.e., the volume of effluent sampled on
 a dry basis and corrected to standard conditions, V  . The second  major source
                                                    sc
 of error occurs in the analysis phase, specifically where the spectrophotometer
 calibration factor is determined.  The review should focus on these two aspects
 of the report as a minimum.

      The following discussions treat  individually  all  the raw data  that enter
 into  the  determination of  N0x  concentrations.   Emphasis  is  placed  on  the
 following:  (1)  the precision requirements  of these  data;   (2)  factors  affecting
 these data;  and (3) the normal  range of values of these data.

 Data Reporting

      In  order to  be complete, each raw data  sheet should  contain the  following
 identifying  information (see example sheet):  (1)  the  source name and  location;
 (2)  the  sampling date;  (3)  the  sampling  location,  e.g.,  stack  breeching, or
 duct;  (4) the initials  of the sampler;  (5) run  and sample  numbers documented on
 the  data sheet; and  (6)  the  material   sampled  for (in this case, NO  ).
                                                                   x'
     If the reviewer is to recalculate the sample volumes, the data that appear
on the  raw data sheet should  include  the  following tabulated  information and
data: (1) the run number;  (2)  the flask identification;  (3)  the  volume of the

flask,  Vf; (4) the volume of absorbing solution contained in the flask, V  ; (5)
                                                                         3
the initial temperature of the flask, t.; (6) the initial  relative pressure of
the  flask  (as  measured  with  a  mercury  manometer),  P.;  (7)  the  initial

barometric pressure, P^  ..;  (8)  the final temperature of  the  flask,  tf; (9)

the final relative pressure of the  flask (measured  with a  manometer),  P ; and
(10)  the final barometric  pressure,  P
                                     bar  f
                                73

-------
     In order to compute the volume of effluent  sampled,  it is first necessary

to place the initial and final temperatures and  pressures on an absolute basis.

This  is accomplished  by  adding the  standard  absolute  temperature  and   the

associated barometric pressures, respectively.   These  and  the  other data above

are  then  used  to  compute  the  standard  sample  volume  using  Equation  7-2  in

Reference Method 7:
                        V   = K (v. -V )
                         sc    1  £   a
Pf
Tf     T
  Where:              P   =    Final absolute pressure of
                               flask, mm Hg (in. Hg).

                      P.  =    Initial absolute pressure
                       1       of flask, mm Hg (in. Hg).

                    P     =    Standard absolute pressure,
                     std       760 mm Hg (29.92 in. Hg).

                      T   =    Final absolute temperature
                       t       of flask,  °K  (°R)

              K   = P     =    0.3858 °K/mm Hg, metric units
               1     std       (17.64 °R/in. Hg, English
                               units)

                      T   =    Initial absolute temperature,
                                °K (°R).

                    T fj  =    Standard absolute temperature,
                               293  K (528 °R).

                     Vgc  =    Sample volume at standard
                               conditions (dry basis), mL.

                      Vf  =    Volume of flask and valve, mL.

                      Va  =    Volume of absorbing solution, mL.


CD  Volume of the Flask and Valve


     Reference Method 7 specifies the use of two-liter (2000 mL) flasks for the

collection of N0x  samples.  The  flasks  must  be  equipped with  3-way  stopcock

valves in order  to allow for evacuation and isolation of the  sample.  The  flask
                                   74

-------
volume  (Vf)  is the  combined  volume of  the  flask  and  the  valve.   Reference



Method 7 states that the flask volume should be reported to the nearest  10  mL.



Thus, the  flask  volume  should  be  known  at  a  minimum  to  three  significant


figures.





     The volumes  of the flasks  will  not  all  be 2000  mL; the  reviewer will



encounter a range  of volumes from 1950  to  2050  mL.
                                                                             x
      The  reviewer  should  note  that  the  accuracy  and  precision  of  the  NO



 determination is not affected by  the flask volume  per se;  rather,  it is  the



 resultant standard sample volume  that  potentially affects  the  quality of  the



 result.





 (2)  Volume of the Absorbing Solution





      A relatively small  measured volume  of  absorbing  solution is placed within



 the sampling flask in order  to  react with  the  NO  and  thus trap  it  for  the
                                                   A


 subsequent laboratory analysis.  The  volume  occupied  by the absorbing  solution



 reduces the  flask's available volume  and, as a  result,  the calculation of  the



 volume  of effluent sampled,   corrected  to standard conditions  (V  ), requires



 that  the volume  of  absorbing solution  (in  mL) be  subtracted  from  the  flask



 volume.





     Reference Method 7  specifies  that  the  volume of  absorbing  solution  be 25



 mL.   In  most  cases,  the  reviewer will find  the absorbing  solution  volume



 reported  to  the  nearest  mL.   Such precision is  easily obtained  by  dispensing



 the absorbing solution with a graduated  cylinder.





     The reviewer may safely  assume that the volume of  absorbing  solution may



vary between 20 mL and 30 mL without  any effect  on the quality of the  result.



Volumes of absorbing solution smaller  than 20 mL may be incapable of  completely





                              75

-------
reacting high  concentrations of  NO  .   Volumes larger  than  30  mL,  while  not




affecting the quality of results, may interfere with the  stated  methodology of




the laboratory phase  of the analysis because larger  volumetric  flasks may be




necessary.






(3)  Initial Relative Flask-Pressure






     The initial flask relative pressure is measured with a  mercury  manometer.




Since the manometer indicates the pressure of the flask relative to  barometric




pressure and since the  flask  is  under  vacuum, the  initial flask pressure must




be  a  negative  quantity.   If  the  same vacuum  pump  is  used   throughout  the




sampling,  the  reported  initial  flask  pressures  are generally  very close  in




magnitude.






     Under conditions  of fair  weather  and elevation not  far above  sea  level,




the initial flask relative pressures will normally fall between -26 and  -28 in.




Hg  (-660 mm  Hg to -711  mm  Hg).   This  range  of  values reflects the  specified




criterion that the initial  absolute  pressure  of  the flask must  be less than 3




in.  Hg   (75  mm  Hg).   Adequate  precision is  maintained  if the  pressure  is



reported to the nearest  0.1 in. Hg (2 mm Hg).






(4)  Initial Absolute Pressure of the Flask






     This quantity is required by Method 7 to be less than 3  in.  Hg (75  mm Hg).




Adherence to this criterion ensures that an adequate volume  of effluent  will be




sampled.






(5)  Final Flask Pressure






     The  final  flask  relative   pressure,  like  the  initial   flask  relative




pressure, is measured with a mercury manometer and is thus a  relative quantity.




Unlike  the  initial  flask  pressure,  the  final  flask  pressure  may  be  lower

-------
  (negative),  greater  (positive),  or  equal  to  barometric  pressure.  The sign  and




  magnitude  of  the   final   flask pressure   are  dependent  on  the   following




  parameters:  (1)  the  difference  between the  stack pressure during sampling  and




  the  barometric  pressure  before  clean-up;   (2)  the  pressure  of  the effluent




  stream  sampled;   (3)  the  moisture  content  of the  effluent  stream;  (4)   the




  difference  between  the  absolute  temperatures  during  sampling  and  before




  clean-up; (5) the evacuated pressure of the flask before  sampling;  and (6) the




  presence of  leaks  in the  flask. All relative  pressures  should be  reported  to



  the nearest 0.1 in. Hg (2 mm Hg).







      When checking these relative pressure data, the  reviewer  should  recognize




  first that Method 7 does not address the acceptable range of the data. Second,




 the  reviewer  should   nonetheless recognize  that   anomalies  in  the  data may




 indicate possible problems  with  sampling  and sample integrity.  The  impact  of




 such  problems on the  test  results  generally cannot  be  quantified; therefore,




 the reviewer  should interpret with  caution.   The  following paragraphs provide



 example  anomalies.






      Improper venting of the flasks to  the  effluent will result  in  low  final




 relative flask  pressures,  e.g.,   -10 in. Hg.   While not  specifically  addressed




 within Method 7,  such situations simply mean  that less  effluent  is   sampled,



 which may potentially affect the  precision of the determination.






     Final flask relative pressures consistently 0.0 in.  Hg in magnitude may be




 indicative of leaks.  This criterion is somewhat difficult  to  apply because of



 the potential  for coincidence.






     Finally,  large positive final  relative  pressures should  be  viewed  with




suspicion because,  for example,   without  restraining  clips  the design of the




flask/valve assembly does not permit the build-up of  large  relative  pressures





                             77

-------
(greater than 2 in.  Hg).   Thus,  if the  Method 7  raw data  sheets showed  two  sets



of relative pressures, e.g.,  flask pressures greater than 2  in.  Hg and  flask



pressures of 0.0 in. Hg,  some of the flasks could have vented  themselves to the



atmosphere.  The reviewer would  have to assess the significance of venting  on a



case-by-case basis.





(6)  Final Absolute  Pressure of  the Flask





     This quantity is obtained  in  a fashion analogous to the  initial  absolute



pressure discussed  above.   As such, the dependencies, precision, and  range of



values will reflect  the final flask relative pressure and the  final  barometric



pressure.





(7)  Barometric Pressure (P.  )
     	bar—




     The reviewer can reasonably judge the accuracy of the reported  barometric



pressures in light of the range  of pressures that could  ordinarily  be  expected



to occur.  "Rules of  thumb" can be offered:  (1)  Pressures ordinarily  observed



at sea  level  range  between 29 and  31  in.  Hg;  and (2) For locations above sea



level, the pressure decreases approximately 1.0 in. Hg for every 1000 feet.





(8)  Initial Temperature of the Flask (t.)





The  values reported  for  the initial  flask temperatures for the  most  part



reflect  the  sampling  environment, and,  as  such,  must be   viewed  as  being



dependent  on  the weather,  the  time of  day, the  time  of  the  year,   and  the



sampling location at the  source.   Since  flasks  are ordinarily cleaned  up  in a



laboratory environment,  the values reported  for  the final flask temperatures



usually reflect room temperatures.
                               78

-------
The reviewer  should  exercise his  own  common  sense  in reviewing  the  reported



temperatures.  For example,  a reported  temperature  of  140°  F for  either  the



initial or the final  flask temperature should be viewed  with  suspicion because



of the obvious limitations of the human body under such conditions.





(9)  Volume of Effluent Sampled, Corrected to Standard Conditions (V  )
     	SQ—


     This value may not be directly  accessible to the reviewer,  in  which case



it would  be necessary  to  compute it  from the  raw  data.  The  value  for  V
                                                                             sc


should lie between about 2000 mL and  1000 mL.   Values lower than 1000 mL may be



indicative of incomplete venting  of  the flasks  to the  effluent or the  use  of



smaller flasks than those  specified.
                                79

-------
Laboratory Analysis


     The laboratory analysis  for  NO  provides the mass  of NO   collected.   To
                                    A                         X

ensure adherence to the  Reference Methods and to  promote  data  quality,  it  is

recommended  that  data   forms  documenting  the  laboratory  analyses  for  NO

accompany the relative accuracy sections of monitor test reports.
NO  Analyses
     The mass of NO  absorbed during sampling is calculated using the following

equation:
                =2KcAF
Where:
          K
                = Mass of NO  (computed and reported as
                  NO ) absorbed, yg.
                = Empirically determined spectrophotometer calibration
                  factor, yg NO /unit absorbance.

                = Measured sample absorbance.
             2  = Aliquot factor.

             F  = Dilution factor (used only if necessary).
     The review of the majority  of the NO  laboratory data  is straightforward

and  primarily  involves   checking  the   accuracy  of  simple  multiplication

operations.  Errors that  may  have occurred in  the  analytical  phase,  however,

cannot  be  detected  by  such  checks.   The  parameter,   K ,  should  be  well

scrutinized.  The parameters important to the analyses for NO  and which should
                                                             A

be included in the test report are discussed individually below.
                                         81

-------
(1)  Mass of NO  Sampled





     The laboratory data  sheets  should  include the mass of  N0x  (in   yg)   for



each acquired sample.   The reporting convention for the analysis is that N0x is



reported as  N02.   The  reviewer should ensure  that  a  one-to-one correspondence



exists between the  number of reported masses  and  the  number of  reported  NO^




concentrations.








(2)  Aliquot Factor (2)





     The  analytical phase of  Reference  Method 7  specifies  the analysis  of  a




25-mL aliquot  from the  total sample volume of  50 mL.  Thus,  50 mL/25 mL = 2. If



Reference Method 7 is strictly followed, the aliquot  factor  should be implicit




in all  the  determinations and  needs to be shown only  in a  sample calculation.






      The analytical results  are not necessarily  affected  by  aliquot factors



 other than  "2."  If factors other than "2" are  used, they  should be reported on



 the laboratory data sheet, and  the  deviation  from prescribed procedure should




 be addressed in  the text of the  report.





 (3)  Dilution Factor  (F)





      Occasions  arise   when  sample  absorbance  is outside   the  range  of  the



 spectrophotometer calibration. The sample must be  precisely  diluted  with  water




 in order to determine the NO  concentration in a valid manner.  If dilution is



 required, the appropriate dilution factor should be  reported on the  laboratory




 data  sheet.   If proper  laboratory  technique  is  applied, dilution  should not




 affect the quality of the analysis result.
                                     82

-------
 (4)  Measured Absgrbance of the  Sample  (A)





      For  each sample,  the  abscrbance  as  read  from the spectrophotometer  should



 be  reported.   The  values reported  will ordinarily range  from 0 to  approximately



 1.5.  The  absorbances of  all samples should be less  than the  absorbance of the



 most  concentrated  calibration standard.  The results  from  samples not meeting



 this  criterion may be  biased  high.





 (5)  Spectrophotometer Calibration  Factor





      The  single most important element in the determination of  the mass of NO
                                                                              x


 sampled is the spectrophotometer calibration factor, K .  In the analysis phase
                                                      c


 of  Reference  Method 7, standards are prepared which  cover the  linear operating



 range of  the  spectrophotometer.  A numerical method is then  employed to fit the



 resultant concentrations and  associated absorbances to a  line, and  the slope of



 the   line,  K ,  is subsequently used  for  assigning   concentrations  to  the
             C


 absorbances indicated  by  NO  samples.   The  value for K   is computed using the
                            X                           C


 following equation:
                       = 100 AI  + 2A2  + 3A  + 4A,
 Where:  AI = Absorbance of a 100- yg NO standard.



         Ap = Absorbance of a 200- yg NO- standard.



         A- = Absorbance of a 300- yg NO  standard.



         Aj. = Absorbance of a 400- yg N0? standard.
     It  is  highly  recommended  that  all  the  pertinent  absorbances  for  the



determination of  the  spectrophotometer  calibration  factor  be  included  within
                                       83

-------
the  data  sheets  that  document  the  laboratory  analysis  of   NO .    These




absorbances  should  be  correctly labelled  so  that  the  value  of  K   can  be
                                                                     C



determined  by  the  reviewer.  Alternatively,  the  calibration  data  can  be




presented  graphically  with  the  calibration  points   and   their  associated




absorbances  well  labelled.   Example  data  sheets  follow  (see Figures  U-8  and




4-9).






     The reviewer should check the linearity of the reported  calibration. This




can  be  accomplished either  through  the use  of a calculator having a  linear




least squares program or graphically.  (The reviewer  should note that the value




of K  afforded  by linear least  squares  will not  necessarily equal  the  value




obtained  through  the  use of the equation  above.  In  addition, the  reviewer  is




reminded  to  include the origin data in the linear least squares computation.)






     Ideally, all calibration points  should  lie  on  the  computed  calibration




line; this will be  obvious  if a calibration  is checked  graphically. Using the




calculator,  the  ideal  case  would  be  indicated by  a correlation coefficient




value of 1.00.    (This  function is  generally included as part  of  the  linear



least squares program.)






     The  current  version  of Reference Method 7 does  not  address  the precision



of the spectrophotometer calibration; thus, neither  established  guidelines nor



specifications are  available regarding the limits to  which  calibration points




may  deviate  from  the calibration line before calibration is considered to be of




insufficient quality.   The  reviewer,  nevertheless,   should   recognize  the




critical  importance of the spectrophotometer calibration  factor  in ultimately




providing the  NO  concentration result: the  accuracy and  precision (i.e., the




quality)  of  the  spectrophotometer calibration is a direct  factor in  determining




the  reported NO   concentration.
                                     84

-------
w
M
p-l
    K
     !
      A
                    V
 I
\
I
                              *
V   <
    ^

                                                                                         V
                             CM  ^  V
-   ^  h
                                                                                                                                                         K    c\
                                                                                                                                                         ^ N  v
                                                                                                                                                       -K  X1
                                                                                                                                                        ^0>
K
                                                                                                                                                                                                  LO
                                                                                                                                                                                                  OO

-------
                 FIGURE 4-8 (Cont'd.)
<27
3*0
AT?.
                           a
   0, 574
   O.S8I
   0,
   0.
   o,

            &
             ?. #oc
                           86

-------
                       FIGURE 4-9.
of "
   Concen traztbn
                                      -orIDeEermma.t(bn
                                      l 7
                               svr2>ance .
           !• Job  _
             Initials*
    0.60O
    0.500
8
K
    0.400  •-
    O.JOO --
    0.200 •-
    0.10O !•
                                        =  723.1
                     " Concentration (/JLJ/J[(?omL)
                        87

-------
     It is not  uncommon  for  the PDSA method, as  ordinarily  practiced,  to show


_+ 5% deviations from  the calibration  line.   Indeed, higher  deviations (e.g.,


+ 10$) are not  rare, especially at the  lower  concentration  calibration points.


Consequently, in assessing the adequacy of the reported NO  concentration data,


the reviewer  must  weigh  the  significance  of spectrophotometer  calibration  in


light of  the  precision  commonly  associated  with the  method and  the  reported


relative accuracy status of the subject continuous  emission  monitor.   Clearly,


the  review of  the spectrophotometer  calibration  factor  is  approached  on  a


case-by-case basis.





4.5.4.3  Moisture Sampling/Moisture Correction Factors




Background




     Pollutant  concentration  measurements  are expressed  as the  ratio  of  the


mass of the  pollutant  of interest to  the  total  gas sample  volume.  Wet  basis


measurements include the  quantity of water  vapor  in  the effluent sample  as part


of  the  total  volume  of gas  (denominator).   Dry  basis  measurements  do  not


include water vapor as part of  the  total  gas volume.  Water vapor dilutes  the


pollutant concentration;  thus,  for  a  given   sample,  the  dry  basis  pollutant


concentration will be  greater than the  corresponding wet basis  concentration.




     Many continuous monitors measure  gas  concentrations  on a  wet basis.   In


contrast.   Reference   Methods  6  and   7    provide  pollutant   concentration


measurements on a dry  basis.  Thus,  it  is  often  necessary to apply a moisture


correction factor so that all measurements are on the same moisture basis.  A


moisture correction factor can be applied to  either  the monitoring data or  the


reference  method data.   However, it is  more consistent to  apply  the correction


to the  reference method data because  these  determinations  of SO , NO ,  and H 0
                                                               2    x  	  2
                                    88

-------
  all  entail  classical,   i.e.,   wet-chemical   methods,   as  distinguished   from




  instrumental  methods,  e.g., continuous monitors.   Nevertheless,  equally valid




  results and interpretations will be  provided  if  corrections are applied to the



  continuous  emission monitor data.






       The moisture correction factor  is determined from  the  results of effluent




  moisture measurements.  The  appropriate monitor sample  stream  moisture  content




  is  not  always the same as the effluent moisture  content.  All  in-situ monitors




  provide wet basis  measurements;  therefore, the moisture  content  of  the  stack




  gases must  be determined  for relative  accuracy  tests.   Extractive  monitoring




  systems, on  the  other hand,  may  contain conditioning  systems  that  remove




 moisture from the sample prior to analysis; thus  a dry basis measurement may be




 afforded. Extractive monitors also are available that measure  on a wet  basis.




 Finally,  there  are  extractive   monitors   with  sample  handling/conditioning




 systems that remove  a  portion of  the  water  vapor  from  the  sample stream.  Thus,




 the  concentrations  indicated by such  a  monitor are  somewhere between  dry-basis




 and  wet-basis.  For purposes of  relative accuracy testing,  the moisture basis




 is generally assumed,  for  convenience,  to be  either one moisture  basis or  the




 other.   The  choice is often  dictated by  the moisture  basis of the associated




 diluent  monitor,  if such  a  monitor  is used  conjunctively.  Accordingly,  the




 performance  specifications  require  that such pollutant-diluent  combinations



 must be  either total wet basis or total dry basis.





 Moisture Sampling







     The regulations are not  explicit regarding the  methodology  to  be  employed




 in  determining  moisture  correction  factors.   Performance  Specification  2




states, "Determine the  correction  factor by  moisture  tests concurrent  with the




reference method  testing  periods.  Report  the moisture  test   method  and the
                                   89

-------
correction  procedure  employed." Since  the  moisture correction  factor  is  an




integral part of the relative accuracy calculations, pertinent raw data, sample




calculations, and a brief description of methodology should be  included in the




test report.  Also, it is necessary to have a record of  each  correction factor




used, identified according to which reference method test it complements.






     Reference Method 4,  "Determination  of Moisture Content  in Stack  Gases,"




describes  two sampling  methods -  a  reference method  and  an  approximation




method.  The  reference  method  employs  Smith-Greenburg  impingers, whereas the




approximation method uses midget  impingers.   Reference  Method  4  is not often




used in monitor  performance  evaluations,  because the same  information  can  be




obtained  through the use of  midget  impingers,  which  are also  employed  in




Reference  Method  6.   Used instead  are modified  versions  of  the  approximate




Method 4,  acceptable for monitor performance tests.  This modified  methodology




is described  in,  "An  Alternative  Method for Stack  Gas Moisture Detemination,"




by  Jon Stanley  and  Peter  R. Westlin.   Therein,  two  alternative  sampling




procedures  are  described:   (1)  a  modified  approximate  Method  4,   and  (2)  a




modified Method  6  sampling  train  used  to  measure moisture content   and  S0?




concentration simultaneously.   For both  sampling  procedures,  midget  impingers




in an  ice  bath  are used as  condensers and are  followed  by a silica gel trap.




The  sampling  train  is  weighed  to  the  nearest 0.01  gram before  and  after




sampling,   thus  affording  a  gravimetric  determination  of  the  moisture.  The




weight gain of the sampling  train  is  used to  calculate  the  moisture  content  of




the sample stream according  to the  following  equations:
                                      90

-------
                         we
                              1.336 x 10~3w
   Where:
                  we
                Volume of water vapor con-
                densed, corrected to
                standard conditions, scm.

                Total weight gain of the
                condenser and silica gel
                trap assembly, g.
        Where:   V



                Y

                P
 mstd
   Where:
                m
                m
                m
                ws
B
                ws
Dry gas volume measured by
meter, corrected to
standard conditions, dscm.

Meter calibration coefficient, dimensionless.

Absolute meter pressure, mm Hg.

Absolute temperature at meter, °K

Dry gas volume measured by meter, dcm.
                V
           - - — - x 100
                            we
                                                    .  .
                                                 m std
Water vapor content in stack gas,
percent by volume.
     The  above equations  apply  to  any  condenser  type  moisture method.   An

example data sheet for condenser methods follows.


Review of Moisture Sampling Data and Results


     The reviewer may evaluate the reported moisture sampling results either by

checking the raw data and calculations or by checking that the reported results

fall within reasonable  limits.   In particular,  the  reviewer should  check  the

volume of the  effluent  sampled,  corrected  to dry standard  conditions,  and  the

subsequent calculation of the sample stream moisture content.  The  reviewer is

directed  to  the  discussion   of  the  review  of  Method   6   sampling  data  for

procedures explaining the check of effluent sample volume data.
                                     91

-------
     The reviewer should check that all reported moisture contents  fall  within




reasonable limits.   For determinations of  moisture in  effluent  streams  from




fossil-fuel  fired   steam  generators,  nomographs  are  available   which   allow




estimations of the percentage of  water  vapor in the effluent, based  upon:  (1)




the  fuel  used,   (2)  %  excess air,  (3)  free  water  in  the  fuel,   (4)  ambient




temperature, and (5) relative humidity (see Fig. 4-10).  Even if measured  values




are not available for all of the  parameters listed  above,  the  reviewer  should




at least be able to bracket the moisture content by  using  estimated ranges  for




those various parameters.






     It  should  be  emphasized  that  the  moisture  content   of  the   stack  gases




cannot  exceed  the  moisture  content  at saturation  conditions.   For  example,




after  the effluent  passes  through  wet  scrubbers,  stack  gases   may  contain




entrained water droplets.  In this instance, any condenser type moisture method




may yield erroneously high results.






     Such situations are addressed within Reference  Method 4, which states that




if water  vapor  saturation is suspected within  the effluent stream, or  if  the



effluent  stream contains entrained  water  droplets,  then,  using   the  effluent




stream   temperature  as  a   reference,  moisture   should   also  be  determined




simultaneously   either   by:   "(1) using  a  psychrometric   chart   and   making




appropriate corrections if stack  pressure is different  from that  of the chart,




or (2)  using  saturation vapor pressure tables." Method  4  states  that the lower




of the  two moisture determination results shall be considered  correct.
                                   92

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Moisture Correction Factors


     Once the moisture  content of the  stack gas  is  determined, the  moisture

correction factor should be calculated and applied to  the reference method test

results.  The following generalized equation is applied to adjust the reference

method results from a dry basis to a wet basis:
              reference
               method
            concentration
                            dry
100
 reference
  method
concentration
                            wet
                                94

-------
 4.5.4.4  Calibration  Standards and Calibration






 Background






      Calibration  is  the  single  most  important  parameter   evaluated  during




 performance  tests  of  continuous  monitors.   Indeed, with the  exception  of the




 response  time  test,  all  the  remaining   tests  address  calibration.   Thus,




 calibration  accuracy  and  precision  are quantified  by the  calibration  error




 test.   Calibration  stability is  quantified  on a  short-term  basis  by 2-hour




 drift  tests  and on a long-term  basis  by   24-hour  drift  tests.  Finally,  the




 adequacy of the routine calibration procedure, embodied within the calibration




 error test, is assessed by the relative accuracy test.






     The  absolute   accuracy  of  calibration  is   a  critical  factor  for  the




 calibration error and  relative accuracy tests.  Flit  simply, a  poorly calibrated




 instrument is less  likely to  pass these two  tests, because both  place  strong




 emphasis on the monitor's response relative  to known inputs,  e.g., calibration




 gases (or  cells)  or  effluent  samples  with  concentrations established  using




 reference methods.   (The  drift  tests, on the  other hand, entail  only measuring




monitor response to a  constant input;  the  tests do not explicity  address  how




 accurately the monitor should measure  this  constant input.)   Fundamental  to  a




 properly calibrated  monitor are calibration  standards known to a high degree of



accuracy and  precision.






     Performance  Specification 2  describes  the necessary calibration  standards




employed during  continuous monitor  performance tests.  For  ex tractive monitors,




gaseous   pollutant   standards  are  required  which  have  concentrations   of




approximately 50 and 90 percent of instrument span.   (The  current Performance




Specification  2   does   not   anplify   the   interpretation   of   the   word
                               95

-------
"approximately".   The revisions  proposed  October 10,  1979,  may  be  used  for



guidance in this regard.  Accordingly, the  proposed  revisions  specify that  the



gas concentrations be  45  to 55  and 80 to 90 percent  of span.)  "Calibration  gas



cells whose concentrations are  certified by the manufacturer to be functionally



equivalent  to  these  gas  concentrations" are also  permitted   in   lieu  of  gas



standards.   The  performance   specification  provides  assurance  that  the  gas



standards are not affected by  temporal variations  in concentration  by  stating



acceptable components of  the gas mixtures, e.g.,  sulfur dioxide  in  nitrogen,



and by implicitly specifying  an expiration date  for  the analyzed  gas  mixtures:



"triplicate analyses of gas mixtures  shall be  performed  within two weeks prior



to use using Reference Method 6 for  SO  and Method 7  for NO ."
                                     C,                    A




     The concentration assigned  to the calibration  gas  is  the average  of  the



three analyses.  The criterion  for acceptable  analytical results  is  that "each



sample test  result  must  be  within  20  percent of  the averaged result  or  the



tests shall  be repeated."  This criterion gives  testers considerable  latitude



with regard  to the  quality of data  afforded  by  determinations of calibration



gas concentrations; however, this latitude is attended by the risk that  the



inaccuracy and imprecision of the calibration  gas  analyses  will compromise  the



results of the calibration error  and  relative  accuracy tests.





     More  stringent  criteria  for  acceptable calibration gas analytical  results



are contained in the revisions to Performance  Specification 2 proposed  October



10,  1979.   Many  testers  have adopted these criteria  in order to ensure that



performance  tests  are  not  biased  by  gaseous  calibration  standards of poor



quality.





     The  performance  specifications  do  not  specify  the  appropriate  sampling



methodology  to  be   employed  in  sampling   calibration  gas  cylinders.   The
                               96

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 reference methods  vere  developed  for  sampling  effluent  streams  at close  to




 ambient pressures, while  cylinders  containing calibration gases  are at  high




 pressures.   Procedures for  sampling  from gas cylinders have not yet appeared  in




 the Federal  Register; hovever,  P.  R.  Westlin and  J.  W. Brown of the  U.  S.  EPA




 have offered several  sampling methods in their paper,  "Methods  for  Collecting




 and Analyzing  Gas  Cylinder  Samples"  (Source Evaluation Society Newsletter,  Vol.



 3,  No.  3, September 1978).






      Some modifications  of the reference methods are often either possible  or




 necessary, because  calibration  gases are of defined  composition  and are  also




 free from impurities.  For example, the analysis of  sulfur dioxide calibration




 gases using  Reference Method  6  requires  no  final  purge because the absence  of




 sulfur  trioxide  (SC^)   in  the  sample  obviates   the  need   of   the  imping er




 containing   isopropanol   (IPA).   (Hovever,  a  purge   is  necessary  if an  IPA




 imping er  is  used because so  is absorbed by IPA.)  The analysis of nitric oxide




 (NO)  calibration gases using  Reference  Method  7 requires modification because




 of  the  necessity for having oxygen  (Og)  present in the flask to ensure complete




 reaction  of  the  NO to  nitrate. Since the cylinders  are oxygen-free, sampling




 must be interrupted before  the  flask  is totally filled  with the calibration




 gas, and oxygen is then  admitted by venting  the flask to the atmosphere.   This




 procedure is described in greater  detail within Reference Method 7,   Paragraph



 4. 1.2.






     Performance   Specification  2  allows the  calibration  error  test  to  be




performed  either  in the  laboratory  or in the field.   While  it could  be  argued




that the laboratory option v»uld be an  unwise choice,  in practice the choice of




when  and   vhere   the  calibration  error  test  is   performed  is  ordinarily




inconsequential.   Accordingly,  before  initiating  the operational  test  period
                              97

-------
testers ordinarily  will  optimize  the  monitor's  calibration  to  ensure  the




successful  completion  of the  performance  test.   The  lost  time  and  effort




incurred by an  aborted  or  unsuccessful relative  accuracy test  are  sufficiently




great that  this test  vail  not be started until  the testers are confident  that




the monitor passed  or could  pass the calibration error test.






     Calibration gases  are  also  required by  Performance  Specification 3  for




evaluations of diluent (oxygen  or carbon  dioxide)   monitors.   The  reviewer




should  note that  the  specifications for  concentration  ranges and  triplicate




analyses are  similar  to those within Performance Specification 2.   However, the




calibration  standards  have  a  diminished   role  because  of  the   lack  of




specifications  for calibration error and relative accuracy within  Performance




Specification 3.






     Because  of the vital  role calibration  standards  play in  performance tests




of continuous monitors, it is highly recommended that test reports contain data




that document  and  support the concentrations  assigned  to the  standards.   For




concentrations  established using  Reference Method 6  or  1, raw data  sheets for




sampling and   analysis  should be  included.   If  cells  are   used  during  the



performance test,  the report should  include documentation of cell concentration




certification.








Review of Calibration Gas  Analysis






     If possible,  the reviewer should check  the  composition  of the calibration




gases to ensure that  the appropriate diluent gas (nitrogen, air)  is used.






     The reviewer  should check the  consistency of  the reported calibration gas




concentrations  by comparing  the  average values  from  triplicate analyses  with




the values reported  for use in the calibration  error test, drift  tests, and
                               98

-------
 response  time test.  The triplicate analyses of the  calibration gases should be




 checked   in  order  to   confirm   the  accuracy   of  the   reported   average




 concentrations.






      The  reviewer  should verify that  the three individual  analyses  are each




 within 20%  of the  reported  average.   This criterion is easily attainable. The




 reviewer  should  recognize analyses  that  approach  the limit  of  this criterion




 may  have an  effect on  the  observed  monitor  performance.   Fbwever,  without




 additional  analytical data, the  effect cannot  be  accurately quantified.  For




 example,  if a   test  report  indicated that  the  monitor did  not  meet  the




 specification for calibration  error  and if the calibration gas analyses showed




 poor  precision,  the  reviewer  could  reasonably  recommend  that  the calibration




 error test be repeated  with  more  precisely known calibration  gas standards.






     Finally, the reviewer should check that the dates of the  analyses of the




 calibration gases are within two  weeks of the dates of their use  in the tests




 of the affected  monitors.  Deviations  from this  criterion  should be judged on a




 case-by-case basis  allowing  a  liberal  interpretation.






     The  complete  review of the analyses of  the  calibration gases  requires




 review of the reference method sampling and  analytical data.  The reviewer  is




 directed  to the  "Review  of  the  Reference  Method Data and  Results"  section  of




 the  Relative  Accuracy discussion  of  this  manual   for  guidance   in  reviewing




 reference method sampling data, analytical data, and calculations.








 Calibration  Gas  Cell  Certification






     Continuous  monitors do not  necessarily provide  for  the introduction  of




calibration  gases for tests  of drift, calibration error, or response time, used




instead  are  cells containing concentrations of gases functionally equivalent  to
                               99

-------
the gas concentrations required in tests of extractive monitors.  According  to

Paragraph  6.1.2  of  Performance  Specification  2  and   Paragraph  6.2.3   of

Performance Specification  3,  the concentrations  of gases  in  the  cells are

required to be certified by the  manufacturer.   Analyses of  the gases in the

cells is not possible.   Moreover, there are no  simple procedures  available for

verifying the  gas concentrations  in  the cells. The regulations do not  specify

what constitutes manufacturer certification.


     As  a  minimum, a  statement  by  the instrument  manufacturer or  operator

regarding the gas concentrations of the cells  should be  included in the test
                                                                     \
report.  Ihe reviewer should check  the consistency of  these values in  those

tests that employ the  cells.
                                  100

-------
 4.5. M. 5  Monitor Location and Reference Method Sampling Location






 Background






      Performance  Specification  2,   Paragraph  4,  requires  gas monitors  to be




 located so that "measurements can be made which are directly representative, or




 which can be corrected so as  to  be representative  of the total emissions  from




 the  facility."  The  Performance  Specification  states that conformance with the




 requirement  of representative  measurement location  can  be  accomplished  by




 installing the continuous monitor eight or more equivalent diameters downstream




 from   positions  of   air  in-leakage.   Stratification,   the  condition   of




 non-representativeness, is  defined by  Performance  Specification  2,   Paragraph




 3.9 as "a condition identified by a difference  in excess of  10 percent between




 the average  concentration in  the duct or  stack  and the concentration  at any




 point  more   than  1.0 meter  [3.3  feet]  from   the  duct or  stack wall."   This




 stratification definition implies that all locations less than  1.0 meter from a




 duct or stack wall  are suspected  of being  stratified.






     Performance Specification  2  does  not contain detailed  methodology for




 determining  the degree of stratification;  thus, the specification  states  only




 that the tester may  perform a traverse to characterize any stratification of



 effluent   gases  that  might  exist.    The reviewer   should  recognize   that




 technically valid assessments of stratification must account  for  the temporal




variability  of  concentrations  within the  effluent stream.  Documents  that




address valid stratification test  procedures are available  from  the  U.S.   EPA,



SSCD.






     If the  results from  testing  indicate the  absence  of stratification,  then




the established  representativeness  of the  effluent  ensures  that the  continuous
                                 101

-------
monitor may be acceptably located  anywhere  within  that  location.  The converse




situation  is  addressed  within  Performance   Specification  2,  which  provides,




essentially, the choice of either:  (1)  determining  the pollutant concentration




in  a  manner  vhich  permits  correction  to  representative  conditions,  or




(2) accounting for the impact of stratification by monitoring the concentration




of either oxygen or carbon dioxide.  The  reviewer should  note that  no owner or




operator of a continuous monitor has  opted  for  the  first  choice  because  of the




technical difficulty associated with verifying the adequacy  of the correction




technique.   Thus,  diluent monitors (continuous monitors  for  CO   or CL)  are




employed  instead.   (Indeed,  for  sources  required to  report pollutant emission




rates in units of Ib NO  or  S0?/10  Btu,  a diluent monitor, in conjunction with




the pollutant monitor,  is absolutely essential.) The proper  use of  a diluent




monitor   for  purposes  of  accounting   for   stratification  effects   implicity




requires that the diluent and pollutant monitors  measure effluent  samples with




approximately equivalent  composition.   This requirement  is  reflected  by the




specification that both monitors be of the  same "type" (both extractive or both




in-situ) .   Nevertheless, established  guidelines regarding the proper  placement




of pollutant and diluent probes in stratified effluent streams are  unavailable.




Clearly,  the  problem  is moot if both pollutant and diluent determinations are




performed, either on one sample obtained from a common probe or  within the  same




sample path  (for in-situ monitors)  .






      Location  is  an   issue  that must  be  considered  during   the  monitor




performance  test.   During the sampling  phase of a relative accuracy test,  it is




imperative  that  the gas  stream  sampled  according  to the  reference  method is




equivalent to the gas stream sampled  by the monitor.   Performance  Specification




2,  Paragraph 6.2.2.1 addresses the relative positions of the  probe tips  for an




extractive  pollutant monitor  and  for  the  reference  method  during relative
                                  102

-------
 accuracy  tests:  "For   continuous  monitoring   systems  employing   extractive




 sampling,  the  probe tip  for the continuous monitoring system and the probe tip




 for the reference method sampling train should be placed at adjacent locations




 in the duct."  However,  the distance implied  by the  word "adjacent"  is not




 quantified.   Also,  the  above  criterion  is applicable only to  extractive and




 in-situ monitors that analyze at a point  within the effluent.   The  performance




 specification  does  not  provide  guidance  regarding  the relative  placement  of




 reference  method  sampling  probes when  tests of multipoint  extractive monitors




 or across-stack in-situ  monitors are  performed.   A technically valid approach




 would  be  to  traverse the  monitor  measurement path  with the  reference  method



 probe .






  Reporting and  Review






     The issue  of monitor  location should  have  been settled long  before the




 monitor  performance test is conducted.   Nevertheless, the  reviewer  should,  to




 be  thorough, check the drawings included  in the test report  to confirm that the




 monitor  location  is  acceptable.   The  reviewer  should  approach the relative




 locations of monitor  and  reference method probe tips in a similar fashion.






     To permit such review,  the monitor performance  test  report  should  contain




 a drawing that shows  the  position of the monitor  in  the  effluent stream.  This




 drawing should display approximate distances from the monitor to: (1) the walls




 of  the  stack  or  duct;  (2)   control  equipment,  such  as  precipitators  or




 scrubbers; (3) points  or  sources  of air in-leakage; and (4)   points at which gas




 streams  with  dissimilar  gas  concentrations  are   combined.    (Performance




Specification 2 requires that  the monitors be  located  eight  or  more  stack




diameters downstream  of any positions of  air in-leakage.   Equivalent diameters




for non-circular ducts are  defined  in UO CFR  60, Appendix  A,  Reference  Method
                                 103

-------
1).  This same downstream distance criterion  should  also  be  applied  to points




where dissimilar gas  streams are combined.






     The reviewer should examine the monitor  location  drawings to verify that




the monitor is  installed sufficiently  far  downstream of  potential  sources  of




stratification.  The  reviewer should  also check to be sure that single point or




short path length monitors  are  installed  to  sample  more  than one meter (3-3




feet) from the stack  wall.






     If tests  were conducted to detect or  to quantify stratification  of the




effluent, a brief statement  of the results of  these tests  should be included in




the monitor performance test report.   The reviewer should  examine  these results




in  order  to attempt  to verify that  the  monitor  sampling  location provides




measurements representative of the entire effluent stream.






     The relative positions of the monitor  sampling region and  the probe tip of




the  reference  method  sampling  train  should  be illustrated.   These  positions




could be  indicated on the  drawing showing  the position of the monitor  in the




effluent stream, or  the  sampling  positions could be  the subject  of a separate




drawing.   Distances should  be indicated in  the drawing  so  that these positions




can be  fixed .






     Performance  Specification  2  states that  the  probe tip  of  an  extractive




monitor  and  the  probe  tip  of the reference  method  sampling  train  should  be




placed  at adjacent  locations in  the duct  during   field  tests   for relative




accuracy.   The reviewer must decide  whether  the locations meet the  definition




of "adjacent,"  bearing in  mind that  the intent of  the word  "adjacent"  is to




ensure  that  the monitor and probe  are  sampling  identical  effluent streams.




Separation distances up to approximately 20 cm (8  inches)  between  the reference




method  sampling  probe  and  continuous monitor  sampling  region  are   usually






                                   104

-------
considered to be "adjacent."  It should be  emphasized  that  if the monitor  and




sampling probe are  not  sampling  at exactly the same location, and  if  the  issue




of  stratification  has  not  been  resolved,  then  the  failure  of  a  relative




accuracy test may be due  to  the  effect of stratification as opposed  to  monitor



inaccuracy.
                               105

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               5.0  REVIEW OF TEST PROCEDURES . DATA . AND RESULTS

                         OF MONITOR PERFORMANCE TESTS

                            FOR CO  AND 0  MONITORS



 5. 1  BACKGROUND





     At fossil-fuel fired steam generators subject to NSPS regulations  (40  CFR



 60, Subparts D and  Da)  diluent  monitors are required in addition  to  pollutant



 monitors.   Diluent monitors enable  emission rate measurements in  units of  the



 standard, Ib pollutant/10  Btu heat input (ng pollutant/Joule heat  input).   The



 diluent gas  measured  by the  diluent monitor  may be either  CO   or  0?.    The



 pollutant gas monitor  and diluent monitor must measure on the same  basis (i.e.,



 they both measure on either a  dry or a wet basis) .  This requirement  is stated



 in 40 CFR 60, Subpart  D, Paragraph 60.45(e)(1).





     Because  either  CO-  or  Op  can be  measured, and  because  emission  rate



measurements can  be  performed  either  on a  wet  or a dry basis,  a  number   of



equations for  calculating  the  emission  rates  exist.   Some  that  are commonly



used  appe?r  below:
Dry Basis (No  moisture correction)
    E=DF
         c
                    20.9 - % 0
                              2d
    E = C,F
         d c
                         100
                        % CO
                           2d
Wet Basis (Moisture correction)
    E = C F
         w w
    E = C F
         w c
   20.9
                 20.9 (1 - B  ) - % 0.
                            wa       2w
100/7, CO
        2w
J
                                107

-------
                  Where:  E = Pollutant emissions,
                              Ibs pollutant/10  Btu
                              (ng/Joule).

                      C   =   Pollutant concentration,
                              dry basis, Ib/dscf  (ng/dscm).

                      C   =   Pollutant concentration,
                       w      wet basis, Ib/scf (ng/scm).

              F, F  , & F  =   Constants determined by the
                  c     w     identity of the fuel combusted
                              combusted and the diluent
                              measured. F accompanies
                              measurement of 0  and F
                              accompanies the measurement
                              of C02. Both of these
                              constants are on a  dry basis.
                              F  accompanies measurements
                              o₯ Op  on  a wet basis.

             %0   and %0   =   % concentration of  0 ,
                d        w     dry and wet basis,  respectively.

           %CO  and %CQ   =   % concentration of  CO ,
              d        w     dry basis and wet basis,
                              respectively.
                       B   =    Mole  fraction  of moisture  in  the
                        W3
                               combustion  air.
                       B   =    Mole  fraction  of moisture  in  the
                        ws      effluent.
Because the factors F,  F  and F   are constants,  measurements of the  pollutant
                        c      w
and diluent concentrations (and as  necessary,  the moisture content)  provide  a

basis  for  calculating  the emissions  in  units of the standard.   (For  a more

detailed presentation of  emission rate calculations,  the reviewer is referred

to 40 CFR 60,  Appendix  A,  Reference  Method  19.)


Performance  specifications  and   test  procedures  for  diluent  monitors   are

contained  in   40  CFR  60,  Appendix  B,  Performance  Specification  3.   These

specifications and test procedures are very similar to those for  pollutant  gas
                                   108

-------
monitors.  the  performance  specifications  for diluent monitors  are tabulated

below.



      Parameter                   Specification

       Zero drift (2h)«          < 0.4* 0   or  C0?
       Zero drift (24h)«         < 0.5% 0":  or  CCC
       Calibration drift (2h)«    _< 0.4* 0^  or  CCC
       Calibration drift (24h)»  _< 0.5? CT  or  CO^
       Operational Period        ^ 1 68 h
       Response Time             < 10 min
(* Expressed as sum  of absolute mean value plus 95*  confidence interval  of a
series of tests.)
     Major differences  between  performance  specifications  for  pollutant  gas

monitors and  for  diluent monitors  include  the absence  of  specifications  for

relative  accuracy and  calibration  error.    Another  difference  between  the

specifications is the use of units  of concentration (* 0_ and %  C0?)  for  the

drift specifications.  This difference reflects the  fact that the  sum  of  the

absolute mean value  and  the  95*  confidence interval  is not subsequently divided

by  the  instrument  span.   Tnus,  the diluent  performance  specifications  are

expressed on an absolute basis as  a  % 0^  or  a  % C0_,  rather  than  on a relative

basis as a  percentage of the measured quantity.   (The use of %  in both cases

often creates  confusion.)  Finally,  the response  time  specification  is   10

minutes  for  diluent  monitors as  opposed to  the  15 minute  specification  for

pollutant gas monitors.


     The zero  and calibration drift tests and  the  response time  tests  for

diluent  monitors are conducted in  an identical manner  to  those  of  pollutant gas

monitors.  Tne associated calculations are  also  performed  in the same manner,

with the exception that  final division by the span  of  the  instrument  is  not

performed .
                               109

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5.2  REVIEWING DILUENT MONITOR  PERFORMANCE TEST REPORTS






     The  information  and  data  recommended  for inclusion  within  performance




specification  test  reports  for  diluent  monitors  are  identical  to   those




recommended  for  pollutant  gas  monitors  with respect  to  determinations  of




calibration values, drifts, and  response times.  Again,  it  is important to note




that relative accuracy  tests and calibration error tests  are not  included  in




diluent monitor  performance evaluations.   The absence  of  both  the  relative




accuracy test and  the calibration error test and  their  attendant  data  leaves




little (relative to reports for  tests of pollutant  gas monitors)  to  report, and




therefore, to review.






     Although no test per  ^e  is required for determining  calibration  error,  a




calibration  check  of  the   diluent monitor  is required  by  Paragraph  6.1  of




Performance  Specification  3.    Accordingly,  the   calibration  check  entails




establishing a calibration curve using  zero,  midrange  and  span  concentration




gas  mixtures.   This  resultant  curve  is  then  compared   with   the  expected




calibration  curve  as   described   by  the  analyzer  manufacturer,   and   its




"consistency" is verified.   Additional calibration gas measurements  are made or




"additional  steps  are  undertaken"  if the expected  response is  not obtained.




"Consistency" is not defined within the paragraph.






     As a minimum,  copies  of  the calibration curves  should  be provided  within




the  report  in  order to document that  the  check was performed.  An   example  is




given with  Figure  5-1.  Raw data forms  which  document the  response   time test,




the drift tests, and  the calibration checks should be included  in  the monitor




performance  test  report.    The  reviewer  should   check  the  data  from  the




calibration  check  and  should  evaluate  these  data  in  light  of the  verified




results from the drift  tests.




                                   110

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                    TIT
o
                                                                      S1
                                                           ~\~

                                       / C-^

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      Since  the  tests  for drift and  response  time  are  nearly identical to those




 for  gas  monitors,  the reviewer  is  directed to  those sections  in  this manual




 where review procedures for pollutant gas monitors are discussed in detail.  As




 a  final  note,  the reviewer should  recognize that mid-range  calibration gases




 are  used  for the 2-hour calibration drift test rather than  span gases.








 5.3   CALIBRATION GASES






 Background







      In   a  manner  analogous  to  performance  evaluations  of  pollutant  gas




 monitors, diluent  monitors  require  gases of known concentations  for  the tests




 of response time, zero drift and calibration drift, and for calibration checks.




 Calibration gases are injected into extractive monitors,  while in-situ monitors




 may employ certified gas cells functionally equivalent to  the  required  diluent




 concentrations.   Because  the  reporting  requirements  for   in-situ  diluent




 monitors  are identical  to  those  for  pollutant gas monitors,  the reviewer  is




 directed  to  the  pertinent  discussions  in  this   manual  (see   Calibration




 Standards, Section 4.5.1.4).  The following  discussion addresses  the  reporting




 requirements applicable to the concentrations  of  the  gas cells and the  review



 of the reported information.







     Depending   on  whether  the  diluent monitor  measures  carbon  dioxide  or




 oxygen,  the composition of  the calibration  gas mixture is required  to  be  either




 carbon dioxide  in air  or oxygen in nitrogen.






     The  required  concentrations  of   the   diluent   calibration  gases   are




determined by the "normal  carbon  dioxide or  normal oxygen concentration  in  the




 stack  gas  of   the   affected  facility."    Thus,   according   to  Performance




                                    112

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 Specification 3,  Paragraph  3.2,  the span of  the instrument  "shall  be set  no
 less than 1.5 to 2.5 the normal carbon dioxide or normal oxygen concentration."
 The concentration of the span diluent calibration gas is required to be 90%  of
 the instrument span.  The  concentration of the  mid-range diluent calibration
 gas is  required  to be  "representative of the  normal  conditions  [oxygen and
 carbon dioxide concentrations]  in  the  stack  gas of  the  affected  facility  at
 typical   operating  rates."   This  requirement appears   in   Paragraph   3.3   of
 Performance  Specification 3.  Finally,  Performance  Specification 3,  Paragraph
 2.2 permits  the  use  of  ambient  air  as  a  diluent  calibration  gas.   This
 provision applies  strictly to oxygen analyzers with  spans set higher than 21$
 V

     The  reviewer  may also check the  reported concentrations of the  span and
 mid-range gases with  regard  to  the  criterion that  these should  reflect the
 diluent  concentrations present in the  effluent during normal operation of the
 affected  facility.  The  concentrations can  be checked  for  reasonableness  by
 consulting  nomographs  especially  made  for   the  purpose  of  estimating  the
 concentrations  of  oxygen  and  carbon dioxide  in  the  effluents  of  fossil-fuel
 fired  steam  generators.  These  nomographs  can  provide  limits,   which  are
 dependent  on  the   fuel   combusted,  for  the   diluent concentrations.  It  is,
 however,  difficult for  the  reviewer to  fix   accurately  the   "normal"  diluent
 concentration.  Most  of the  problem stems from  the  large ranges  of  diluent
 concentrations encountered at fossil-fuel fired steam generators: 6-15% CO  and
 3-20* 02.

     The calibration gases for  extractive diluent monitors are  required  to be
analyzed within two weeks of their use in monitor performance  tests.  The  gases
are analyzed  in  triplicate, using  the methodology  of Reference Method  3 —
                                    113

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 Orsat  analyses of  bag  samples  obtained   from  gas   cylinders.    Unlike   the




 paragraph  treating   the  analyses  of  calibration gases   for  pollutant   gas




 monitors,  the  analogous  paragraph  for diluent   monitors  does  not  give  a




 criterion for the  acceptability of the results of  the  triplicate analyses.






      Reference  Method  3*   however,  provides  requirements  for   maintaining




 precision.  Paragraphs  4.2.6.1 and  4.2.6.2  of Reference Method 3  address  the




 acceptable criteria  for the  respective Orsat analyses  of CC>2 and 02.  For  C0?,




 Orsat analysis is  repeated "until the  results of  any  three  analyses differ by




 no more than (a) 0.3 percent by volume when  C02 is greater than 4.0  percent, or




 (b) 0.2 prcent by volume  when C02 is less  than or equal  to 4.0 percent."  For




 determinations of  02,  the  criteria are similar:  the analysis is repeated "until




~the results of any  three  analyses differ by no more  than   (a)  0.3  percent by




 volume when 02 is  less than  15.0 percent, or (b) 0.2 percent by  volume when 0?




 is greater than 15.0 percent." For the analyses of CO  and  0 ,  the  average of




 the three  acceptable  results  is reported  as the  appropriate  concentration.




 Thus,  the criteria for the acceptability  of  the  analyses of diluent  calibration



 gases are very similar to  those that apply to  pollutant  calibration  gases.






      The test report should  contain  documentation  of the triplicate  analysis of




 all diluent calibration gases used during the  monitor  performance test.






      The review of  the analyses  of 02 and  C02 calibration gases  is  simple,




 since the methodology (Orsat  analysis of bag  samples  obtained from cylinders)




 generates a small  amount of  data  and  does not  require  further manipulation. For




 an example, see Figure 5-2.  The reviewer  should  first  confirm the  completeness




 of  the  data  by  checking   that   each  diluent  calibration  gas  used  in  the




 performance  test  is  accompanied by a  triplicate   analysis.   Each  of  the




 individual  analyses  for  the  gases  should  meet   the  acceptability  criteria




                                      114

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                    UKbAl  MhLD iJ
            /]
Plant Name___///
Sampling  Location
                  r, , , , . T
Run and/or Sample No.
                         Leak Test?
Date^/t^Onerator^.'
Time of
Sample
Collection
ozoo
//
ft
Time
of
Analysis
Og/0
CZ3-9
JZft
Are .
co2
Reading
A
—
• —
—
• —
°2
Reading
B
e. /
g.c
'-- /
CO
Reading
C
—
—
—
•Xvi;.
%o2
B-A
f. /

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discussed above.






     The  reviewer  should  then  verify  that all  the  subtraction  operations




required  by  the Orsat  analysis are  correct,  and  that  the  reported  average




diluent gas concentration  is  also  correct.   All reported  average diluent  gas




concentrations should be compared as appropriate  to  the  concentrations  reported




in the drift  test,  response  time  test,  and calibration  check.   The  reported




values should be consistent.   Finally,  the reviewer  can  check the time  between




the analysis of  the  gases  and their use  in the performance  test.   This time




interval should be  less than  2 weeks;  however, the reviewer  should bear  in mind




that diluent calibration gas  concentrations  are  generally  very stable.
                                    116

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                                    TECHNICAL REPORT DATA
                             (Please read Instructions on the reverse before completing}
 1. REPORT NO.
  EPA-340/1-83/013
2.
                              3. RECIPIENT'S ACCESSION NO.
 . TITLE AND SUBTITLE
 PERFORMANCE SPECIFICATION TESTS FOR POLLUTANT AND
 DILUENT GAS EMISSION MONITORS: Reporting Require-
 ments, Report Format,  and Review Procedures
                              5. REPORT DATE
                                January  1983
                              6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
  Guy B. Oldaker III,  Ph.D.
  James W. Peeler
                              8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
   Entropy Environmentalists,  Inc.
   P.O.  Box 12291
   Research Triangle Park,  NC   27709
                              10. PROGRAM ELEMENT NO.
                              11. CONTRACT/GRANT NO.

                                 68-01-6317
 12. SPONSORING AGENCY NAME AND ADDRESS
   OAQPS
   Stationary Source Compliance Division
   Waterside  Mall, 401 M  Street, SW
   Washington, DC  20460
                              13. TYPE OF REPORT AND PERIOD COVERED
                                 FINAL -  IN-HOUSE
                              14. SPONSORING AGENCY CODE

                                 EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT                                                         '	~~~~	~	

  This document presents recommended  reporting requirements  for performance  tests
  of continuous emission monitoring systems installed at  fossil-fuel fired steam
  generators subject  to New Source Performance Standards  (NSPS).  The recommended
  reporting requirements are applicable  to performance  tests conducted  according
  to 40 CFR 60, Appendix B, Performance  Specifications  2  and 3 (Promulgated,  Federal
  Register, Vol.  40,  No. 194, October 6,  1975).  This document details  procedures
  for reviewing such  performance tests.
 7.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                               b.lDENTIFIERS/OPEN ENDED TERMS
                                            c. COSATI Field/Group
   Air Pollution

   Continuous  Emission Monitoring  Systems
                  Performance Tests
                  Fossil-Fuel Fired  Steam
                    Generators
                  Performance Specifica-
                    tions 2 and  3
                  NSPS
8. DISTRIBUTION STATEMENT

   Release  to  Public
                 19. SECURITY CLASS (TillsReport)
                  unclassified
21. NO. OF PAGES
   124
                                               20. SECURITY CLASS (Thispage)
                                                 unclassified
                                                                          22. PRICE
EPA Form 2220-1 (R«». 4-77)   PREVIOUS EDITION is OBSOLETE

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