EPA-650/2-74-013
PERFORMANCE SPECIFICATIONS
FOR
STATIONARY-SOURCE
MONITORING SYSTEMS
FOR GASES AND VISIBLE EMISSIONS
by
John S, Nader, Frednc Jaye,
and hilliap Conner
Chemistry and Physics Laboratory
Program Element Mo. 1\A01Q
U.S. ENVIRONMENTAL PROTECTION AGENCY
National Environmental Research Center
Research Triangle Park, N C. 27711
January 1974.
-------
PREFACE
This report provides the background and experimental data as a
technical base for the development and formulation of guidelines for
monitoring pollutant emissions from stationary sources.
References to commercial products in this report directly or by
inference are not to be considered in any sense as an endorsement of
the product by the Government. Nor does utilization of any commercial
product to generate the data reported here signify that this product
necessarily meets either the performance specifications exemplified
in this report or any guidelines that nay be proposed on the basis of
this report.
This report has been reviewed by the Environmental Protection
Agency and approved for publication. Approval doea not signify that
the contents are the official guidelines in response to the needs
stipulated in the standards of Performance of New Stationary Sources.
This report does provide the technical base from which guidelines to
monitors of specific pollutant emissions from selected source industries
will be formulated and officially proposed in the Federal Register.
anley M. Greenfield, Ph.D.
Assistant Administrator
for Research and Development
111
-------
CONTENTS
LIST OF FIGURES ,' , v
LI ST OF TABLES , .. vl
ACKNOWLEDGMENTS vi
INTRODUCTION. .'.... . 1
DEVELOPMENT BACKGROUND . „ 5
PERFORMANCE SPECIFICATIONS , 9
Parameters 9
Specifications . 14
Applicability 15
SUMMARY . .... . 19
REFERENCES . 21
APPENDIX A S0_ MONITORING CAPABILITY APPLIED TO A POWER
PLANT .... 23
APPENDIX B. NO MONITORING CAPABILITY APPLIED TO A
X
POWER PLANT , . . . 27
APPENDIX C VISIBLE EMISSIONS MONITORING CAPABILITY
APPLIED TO A POWER PLANT. 29
APPENDIX D DUKE POWER PLANT STUDY........ 43
APPENDIX E. EXAMPLE: PERFORMANCE SPECIFICATIONS AND
SPECIFICATION TEST PROCEDURES FOR MONITORS OF
POLLUTANT GAS EMISSIONS FROM STATIONARY SOURCES.... .. 49
APPENDIX F, EXAMPLE: PERFORMANCE SPECIFICATIONS AND
SPECIFICATION TEST PROCEDURES FOR TRANSMISSOMETER
SYSTEMS FOR CONTINUOUS MEASUREMENT OF THE OPACITY OF
STACK EFFLUENTS 61
IV
-------
LIST OF FIGURES
Figure Page
A-l) Flue Gas Diversion Systeip, ...... „ ............... 25
A- 2 Gas Diversion and Instrument Installation Design,,, 26
C-l Particle Extinction Coefficients for Various
Aerosols, Calculated from Mi e Theory ............ 30
C-2 Out-of- Stack Transnitta*>ce of Three Colors of
Light as a Function of In -Stack Tran snuttar.ee
of White Light for an Experimental White (Oil)
Plume ..... »,....., ......... ...... ........ . ...... 32
C-3 Qut-of-Stack Transmit tance of Three Colors of
Light as a Function o£ tn-Stack Transmit tance
of White Light for an Experimental Black (Carbon)
Plume .......... ,,,, ......... , ____ . ____ .......... 33
C-4 Calculated Error in True Light Transmit tance at
2 Degrees Detector Angle of View .... ....... , .... 34
C-5 Calculated Error in True Light Transmittanee at
20 Degrees Detector Angle of View,... ........ „ j^
C-6 In-Stack Transiittance of a Coal -Fired Power
Plant Emission for Various Transiissometer
Light Projection and Detection Angles..... ..... 35
C-7 In-Stack Transnittance of a Coal-Fired Power Plant
Emission at Various Light Projection Angles and
Wavelengths ..... .... .'.„,„.„.„.„<,,,, . ..... . .... 37
C-8 Out-of-Stack Transmittance of a Coal -Fired Power
Plant Emssion as a Function of In-Stack
Transmittance. .......................... ... ..
C~9 Transmissoneter with Collimating
C-10 Effluent Transroittance at Stack Exit as a
Function of In-Stack Transmittance and
Ratio of Stack Exit Diameter to
Transmissometer Path length,. ..........
-------
LIST OF TABLES
Table
"Performance Specifications for Pollutant Gas
Emissions from Stationary Sources
Performance Specifications for Transmissometer
Systems for Measurement of Visible Emissions
from Stationary Sources ...... .....
Design Specifications fear Transmissometer Systems for
Measurement of Visible Emissions from Stationary
Sources ........... ............. ........... . ...... 15
A-l SO Monitoring System Test Results
B-l NO Monitoring System Test Results
28
D-l S02 and NOX Monitoring System Test Results.. 44
ACKNOWLEDGMENTS
He express our appreciation to James Hcrnolva and Mike
Barnes of the Stationary Source Emissions Measurement Staff
in acknowledgment of their providing the measurement data on
the Duke Power Plant Study.
-------
PERFORMANCE SPECIFICATIONS
FOR
STATIONARY-SOURCE MONITORING SYSTEMS
FOR GASES AND VISIBLE EMISSIONS
INTRODUCTION
The phrase continuous monitoring instrumentation conveys dif-
ferent meanings to various users of air pollution control equipment, de-
pending upon the nature of the application, or the design of the system,
or ooth. The basic concept of this type of instrumentation is, however,
that the functional operation of the instrument system is automatic
and more or less continuous in tine. Differences in design, or
application or both iray be such that either the system or a component
operates in a cycle having a tine period ranging from fractions of a
second (relatively instantaneous) to tens of minutes or pore.
This report is intended to provide technical information and
discussion that will assist in the formulation of federal regulations
and state and local laws that require monitoring systems. The document
also furnishes the instrument manufacturers and users with technical
guidelines on the desired performance requirements of these systems.
In the discussion of monitoring systens for stationary-source em-
issions, the measurement of pollutant gases, visible effluents, and other
such substances involves the whole instrument system functioning auto-
matically and pore or less continuously in tine. The response time of
the system that defines the specific functioning of t:ie system with
-------
respect to time is prescribed by the performance specifications *
discussed later, The monitoring systems considered include the major
component operations of sampling, analysis, and data presentation.
The major subsystems performing these operations are defined function-
ally as follows:
1 Sampl in_g_Interface. This subsystem performs one or more of
the following operations: delineation, acquisition, trans-
portation or conditioning of a sairple of the source effluent
or protection of the analyzer from the hostile effects of
the sample or the source environment.
2" Analyser. This subsystem (often treated as a whole and in-
dependent measurement system for analytical purposes) senses
the pollutant substance or parameter and generates a signal
output that is a function of the pollutant concentrations,
3, D; ata Presentation. This subsystem provides a display of the
output signal in concentration units or other specified units
Monitoring systems are used in engineering and research studies
to evaluate performance of control equipment, in surveys of enissions
for input to dispersion rrodels, in testing for compliance with certain
emission standards, and in enforcement programs. New Source Perform-
ance Standards (NSPS) proposed and promulgated by the Environmental
Protection Agency (EPA) require the installation and operation of
inonitoring systems for specific pollutants (sulfur dioxide, nitrogen
oxides, visible emissions) emitted from specified affected facilities in
Category I and II sources It is anticipated that similar require-
ments for monitoring additional source categories (III, IV, and others)
-------
will be proposed and promulgated in the near future State Imple-
mentation Plans may also require monitoring of existing sources,
The New Source Performance Standards propose guidelines on the
selection and operation of the specified rnonitonng systems, and
the State Implementation Plans will likely follow a similar pro-
cedure.
The performance specifications presented in this document provide
technical guidelines for the application of iromtoring systems to
specific pollutants from selected source industries No constraints
have oeen placed on the sampling approach, the analytical scheme,
the system design, or the development of hardware. Test procedures
are presented to determine whether or not any given monitoring system
can meet the prescribed performance specifications
-------
Page Intentionally Blank
-------
DEVELOPMENT BACKGROUND
Of the many possible performance parameters for continuous -mon-
itors (relating, for example, to the numerous applications and the
various purposes for which data are generated), those were delineated
that are essential to reliable performance and to the generation of
valid data with a minimum of downtime and within a reasonable level
of accuracy, compatible with the current availability of commercial
systens and with the intended utilization of the data. The-determining
guidelines in the choice of the parameters and the development of these
specifications were the need to provide data to ("flag") the operator
or control officer on (1) malfunctions of control equipment, (2) ver-
ification of acceptable emission control operation, and (3) relative
levels of pollutants. Since these parameters have a degree of flexibility,
the values specified and test procedures prescribed can be adjusted
to meet the specific needs of a given source-pollutant combination.
Furthermore, other parameters may be added or some of the present
ones modified or deleted to meet special needs.
Sorne of the parameters selected have undergone changes in definition
and specification values over the period of tinie that the specifications
have been under development and evaluation. The parameters are generally
accuracy, calibration error, zero drift, calibration drift, repeatability,
response time, and operational period. These are discussed more fully
in the context of their definitions and the specifications given later.
In 1971, EPA supported several Contract programs to evaluate
(2)
commercially available monitoring systeirs for sulfur dioxide (SO,) and
-------
nitrogen oxides (NO V in power-generating plants fired by fossil fuels.
Previously," over a nuipber of years, EPA and the former Edison Electric
Institute* had conducted cooperative studies of visible emissions from
' (4)" ' '' ' ' -
power plants and the rnstrunental measurement of opacity. These
studies provided a substantial technical data base for the drafting
of a set of performance specifications and test procedures to verify
the specifications.(Summaries of three of these studies are given in
Appendices A, B, and C, illustrating the data relating to the perfor-
j ' ~ ' >,~~'' • f E< , -
mance specifications; complete'details are provided in the reports
referenced.
A draft of the performance specifications and test procedures for
monitors of SO^, NO , and visible emissions was prepared in early
1972 and circulated for review and comment within EPA and externally
to a representative cross section of instrument manufacturers, in-
dustrial users, and local governmental agencies The comments re-
ceived were incorporated (where applicable) in a revised document,
dated September 30, 1972.
In early 1973, at a power plant of the Duke Power Company, EPA
conducted research studies to evaluate (airong other objectives) the
specifications and test procedures contained in the draft of September
30, 1972. (A summary of this study as it relates to the performance
specifications is given in Appendix D.)
This study showed that all the performance specifications of
the September 30 draft were adequate, wit1! the exception of the
accuracy specification.. The range of values extended beyond the
specified *_ 5 percent maximum for the mean to as much as 8 3 percent.
Currently a part of the Electric Power Research Institute.
6
-------
The conclusion was to revise the specification for the accuracy to
be the sum of the mean and the 95 percent confidence interval. This
provided greater flexibility in the specification by prescribing the
combined rather than the individual values, In addition, the September
30 draft was revised to incorporate similar changes in the specifica-
tions of the other parameters and in some of the definitions deemed more
appropriate and consistent with the test procedures.
The decision to revise the specifications was based on a
real and significant difference between the contract studies (TRW and
Monsanto) and the in-house study (Duke plant). The former were to
provide background information for the development of the specifications
and test procedures. In the latter, the proposed specifications and test
procedures were assessed, and their applicability to a selected
source-pollutant combination was validated.
-------
Page Intentionally Blank
-------
PERFORMANCE SPECIFICATIONS
Tile technical background discussed earlier and summarized in the
Appendices irakes it possible to identify parameters that adequately
delineate the desired performance of a measurement system as it applies
to monitoring emissions fron stationary sources. This background also
provides a technical basis for a set of specifications that are realistic
and meaningfully ronsistant with the current availability of commercial
stack-monitoring systens for specific pollutants fror selected industries
(pollutant-source combination).
PARAMETERS
The parameters that adequately delineate the desired performance of
a measurement system as it applies to munitonrg missions from stationary
sources are accuracy, calibration error, zero and caliaratien drift,
repeatability, response tme and operational period. Accuracy (relative)
is defined as the degree of coirectiess with which the reasurement
system yields the value of gas concentration of a sample relative to
the value given by a defined reference method. This accuracy is expressed
in terms of error that is the difference between the oaired concentration
measurements. The error is expressed as a percentage of the itean value
determined by the defined reference method. The absolute error is the
combination of the error in the iponitoring measurement and whatever error
exists in the reference measurement. It is possible that the absolute
accuracy of the monitor may prove to be better than that of the reference
method. Theoretically, however, the assumption is made that the
reference method is one that provides the best available accuracy.
This is not always the case in practice.
9
-------
Furthermore, within a given measurenent system, the error con-
tributed by the sampling operation tends to he greater than the
error from the analytical operation and becomes trie limiting factor
in the absolute accuracy of the measurement systen as a uhole. The
contained effect of sampling in both the monitoring and the reference
measurements can result in a significant impact on the relative
accuracy,
For x'lsible-ernissions monitoring systems, relative accuracy is
not specified. The reference method could be an instrument system
based on first principles in its design or a set of design specifications
that would implicitly involve a specified error that is predictable
from theoretical considerations To designate an instrument system
as a reference method for monitoring systems that would require, in
effect, the sane design criteria by definition ivas deemed impractical
and. a circuitous approach. The decision rfas to use the design criteria
for reference purposes fron the"beginning. The design specifications
used in this docunent introdjce a riajon-rm er^or nf S nercent in opacity
/or narticle sizes that are 10 micrors i"n Hip-nster, The error decreases
with smaller sizes, approaching zero error at 0.3-micron sized particles.
Calibration error is defined as the difference between the pol-
lutant concentration indicated by the measurement svstem and the
known concentration of the test gas mixture,: This type of error is
measured by the use of a known concentration of the gas pollutant in
some clean, dry gas stream, usually air or nitrogen. Frequently,
calibration is executed by introducing the calibration test gas into
the analyzer and by-passing the sampling interface. This performance
specification requires that the entire measurement systen be included
10
-------
in the test procedure. This means introducing the calibration test
gas at the sampling interface upstream of the analyzer. Thus, the
sampling interface is provided the same opportunity to have an impact
on calibration as on the source measurement. In the case of optical
in-situ -(nonextractive) systems,, calibration test gas could be caused
to flow through a sample cell located in the optical path. An alternative
would be a cell with the calibration test gas sealed in the cell;
however, the long-term stability of the calibration test gas in the
sealed cell would need to be verified, possibly presenting practical pro-
blems.
- Zero drift is defined as the change in measurement system output
over a stated period of tine of- normal continuous operation, when the
pollutant concentration at the time of the measurements is zero. Cal-
rf •*
ibration drift is defined as the change in measurement system output
over a stated period of tine of normal continuous operation when the
pollutant concentration at the time of the measurements is the same
known upscale value. Zero and calibration drift are critical parameters
that have a direct effect on calibration error and ultimately on the
accuracy of the data output. Both short and long term drifts are
important considerations. Short-term instability can lead to Mis-
interpretation of variations in emission concentrations; long-term
instability presents a problen in interpreting long-term trends in
degradation of control equipment performance. The 24-hour cycle for
zero and calibration check and adjustment is stipulated to provide i=,
consistency and optimum utilization of data for evaluating day-to-
day and month-to-month functioning of the source emission control
facilities, or pollutant emission levels or both.
11
-------
Repeatability is defined as'a measure of the measurement system's
ability to give the same output reading(s) upon repeated measurements
of the same pollutant concentration(s). \ separate specification is not
given because it is Implicitly covered by the confidence interval included
in the calibration error.
Response time is defined as the tine interval from a step change
in"pollutant concentration at the input to the measurement system to
\
the time at which 95 percent of the corresponding final value_ is
reached as displayed on the measurement system data presentation device,
The response time of a measurement system is strongly influenced by
the sampling approach used. Its impact on the data output is also
.largely related to the combination of process operation and control
equipment ceing monitored. Generally,, in a process involving relatively
long term changes, such as a power plant that -nay require a half hour
to go from half to full load, a response time of 10 minutes may be
acceptable for monitoring purposes. On the other hand, in batch-type
processes such as nonfcrrous smelters, dramatic changes in emissions
occur within ninutes, and a short response time is more appropriate.
Extractive sampling techniques that involve several hundred feet of
sampling lines obviously introduce a more significant delay in
measurement response than an in-situ method IP which no sample ex-
traction is done and the response can be instantaneous.
The nature of the data output requirement and the rate of data
output also play a significant role in specifying a response time.
In visible-emissions (opacity) regulations on power plants, for ex-
ample, an opacity of 40 percent is allowed for 2 minutes per hour, In
this case, a response time less than 1 minute would be required. Slow
12
-------
rates of data output such as one data 'point per 5 to 15 minute in-
tervals for steady-typo processes will'allow some ireasure'iert systems
to nonitor several emission points on a'"time-snared" basis An
essential point in the overall consideration of response time ib that
some trade-off may be required between the roture and/or rate o£ data
output and cost. The cost impact will depend largely upon the neasnre-
mcat technique, the process, and the equipment utilized.
The operational period is a minimum period of time over which a
measurement systen is expected to operate within certain performance
specifications without unscheduled maintenance, repair, or adjustment,
The location of the monitoring system on a stationary source depends
laigely on the puipose for whi'ch the data is being collected For mon-
itoring pollutant concentration so as to indicate malfunction or im-
proper maintenance of control equipment or excess i\e emissions, a
measurement system can be located at an> point where reasonabl) re-
presentative sampling of the emission concentration cap be rnade. Gen-
eral guicelines include fl) consideration of convenience and acce<=s-
abilitv for maintenance of the monitoring system, and {2j location
downstream of any polljtion control equipnent and upstream of j
dilution or other process affecting the emission eonccntmtion. It
'nay be necessary to conduct preliminary nieasuremcrits traversing the
stack diameter to determine the nature of the concentration profile and
to establish a representative sampling location for the find installation
of the ironitoring systen.
Stack monitoring systems that utilize different sampling approaches
are comirercially available; tfiey include extractive, in-s-it'j, and re-
mote techniques. ' The performance specifications provide no constraints
13
-------
on the sampling interface or any other major subsystem (see Introduction)
within the monitoring system. Many source monitors that require ex-
tractive sampling are available as analyzers exclusive of the ''interface"
subsystem. Much infornation is available on the performance of the
analyzer in the laboratory under controlled conditions and on field
applications. The sampling interface has a significant impact on per-
formance reliability and is specifically related to each analyzer-source
combination. Data on the various combinations, including the inteiface_
as a total system, are very limited or nonexistent
SPECIFICATIONS
The performance parameters for gas-pollutants and visiole emissions
that have been defined are assigned values as shown in Tables 1 and
2, respectively. Table 3 shows design specifications that are tech-
nically discussed in Appendix C,
Table 1. PERFORMANCE SPECIFICATIONS FOR POLLU1ANT
GAS EMISSIONS FROM STATIONARY SOURCES
Parameter . Specification
Accuracy (relative) 520% of mean reference valuea
Calibration error < 51 of each test gas value3
Zero drift (2 hr) < 2% of emission standard3
- Zero drift (24 hr) 1 41 of emission standard3
Calibration drift (2 hr) 1 2% of emission standdrd3
Calibration drift (24 hr) < Si of emission itandaida
Response time _ 10 mm
Operational period ]68 hr
Absolute mean value •*• 95 percent confidence interval,
14
-------
Table 2. PERFORMANCE SPECIFICATIONS FOR TRANSMISSOMETER
SYSTEMS FOR MEASUREMENT OF VISIBLE EMISSIONS
FROM STATIONARY SOURCES
Parameter Specification
Calibration error " ' ±10% of test filter value3
Zero drift (24 nr)
Calibration drift (24 lir)
Response time
Operational period
£.10% of emssion standard3
5.10% of emission standarda
< 10 sec
168 hr
Absolute n>ean value + 95 percent confidence interval.
Table 3 DESIGN SPECIFICATIONS FOR TRANSMISSOMETER
SYSTEMS FOR MEASUREMENT OF VISIBLE EMISSIONS FROM STATIONARY SOURCES
Parameter
Specification
Spectral response . Peak and mean response within 500 to
600 nrr; less than 10 % of peak response
outside of 400 to 700 nn.
tagle of view ' " 5 degrees maximum (total angle)
Angle of projection ' 5 degrees maximum f total angle)
I
aThe relative response of a transmissoraeter to radiation of different wavelengths.
maximum (total) angle of radiation that is seen by the photo-detector
assembly of an optical transmissometer .'
cThe maximum (total) angle of radiation that is projected by the lamp assembly
of an optical transmissorr.eter.
3
APPLICABILITY
The performance parameters and their specified vilues in Tables
1 and 2 mast be considered in the context of their application before
IS
-------
they can be utilized with any real weaning. Furthermore, test pro-
cedures* must be established to verify that a monitoring system does
indeed meet the specifications The test procedures must be con-
sidered not only Li the context of the measurement system's application
but also, just as importantly, in relation to how the data generated by
the system is to be used. In fact, the anticipated utilization of
the data is implicit in the development of the specification values
cited in Tables 1, 2, and 3, As stated earlier, the guideline used
in the development of tnese performance specifications has been largely
a middle-of-the-road approach that would pemit optimum utilization of
commercially available monitoring systems; that is, systems that will
have the potential to meet many needs adequately.
Appendices E and F are examples of how tne specifications in
Tables 1, 2, and 3 na> be applied in conjunction with test procedures
as guidelines in the assessment or selection of monitoring systems
for pollutant gas emissions and visible emissions, respectively. It
is rietessarv to use the teguiatory language in the examples given to
naintain the integrity of tie values and definitions of the parameters
and the test procedures for the sake of internal consistency because
of tne interaction among these factors
The guidelines in appendices E and F are potentially applicable
to the following needs
1. Criteiia tlipt provide consistent and valid data relevant
ro measurement needs and ensure the generation of data of
knoun sualit\, toiv-jtible uitn specified use
specified in -\ppendices E and F
16
-------
2. Criteria that provide clearly defined objectives for in-
strument development and manufacture.
3. Performance parameters that permit maximum flexibility n
design and fabrication of the system hardware, including
electronic equipment, for mnimum cost and with irininum
complexity,
4. Criteria for the user to assess available systems on a common
1 basis and to make appropriate selection for various applications
that may include monitoring process operation, control operation,
anc emission levels.
It is possible to move toward tighter or looser specifications
than those given in the examples shown. Whether or rot it is necessary
or desirable to do so depends upon the specific pollutant-ndustry com-
bination, the intended utilization of the data, and other factors, such
as economic considerations and experience. The constraints on moving
toward tighter specifications are not the lack of present technological
capability but rather the cost impact, current availability of commercial
systems, and practical experience witn a given pollutant-industry com-
bination. Technical data on the applicability of specifications to
various pollutant-industry combinations are gradually being developed
The guidelines m the appendices are supported technically by
actual application to the pollutant-industry combinations for SO-, NO ,
and visible emissions in coal-fired power plants based on the develop-
ment background. This experience enables an understanding of the appli-
cability of the guidelines. It provides the proper basis for considerirg
any changes in the specification values and/or test procedures as may be
17
-------
dictated by special needs in the utilization of the data for these same
pollutant-industry combinations. The parameters delineated should apply
in general. The specification values and test procedures exemplified
possibly can be made generally applicable to other pollutant-industry
combinations. Any projected application to other conbinations is more
or less valid, depending on the intended or end usage'of the data generated
and on whether or not the applicability of the guidelines to the new
combinations has been demonstrated,
4
18
-------
SUMMARY
'Parameters for evaluation of the performance of continuous monitors
for th'e measurement of emissions" from stationary sources have been de-
lineated and defined. Field testing programs have been conducted to
provide technical background on the availability and applicability of
commercially available source monitoring instrumentation. The technical
data generated by these field studies are shown as the basis for the de-
velopment of performance specifications and of test procedures by
which these specifications can be verified.
Examples are given of how performance specifications may be applied
in conjunction with test procedures as guidelines in the assessment or
selection of monitoring systems for pollutant gas emissions and visible
emissions from stationary sources Applicability of these guidelines
was discussed within the constraints of specified pollutant-industry
combinations and utilizations of the data generated.
19
-------
Page Intentionally Blank
-------
REFERENCES
1, Standards of Performance for New Stationary Sources, Federal
Register, Vol. 36, No. 247, Deceniber 23, 1971; Vol. 38, No.
Ill, June 11, 1973; Vol. 38, No. 84, May 2, 1973.
2. Jaye, F, C. Monitoring Instrumentation for the Measurement of
Sulfur Dioxide in Stationary Source Emissions TRW Contract
No. EHSD 71-73. NTIS PB 220-202. Office of Research and Monitoring,
U. S. Environmental Protection Agency, February 1973. 124 p.
3. Snyder, A. D. et al. Instrumentation for the Determination
of Nitrogen Oxides Content of Stationary Source Emissions. Vol. I and
Vol. II. Monsanto Contract No. EHSD 71-30. NTIS PB 204-877 and NTIS
PB 209-190, EPA. January 1972.
4. Conner, W, 0. and J. R. Hodkinson. Optical Properties and
Visual Effects of Smoke-Stack Plumes, EPA, Research Triangle
Park, N. C. Publication Number AP-30. May 1972. 89 p.
5, Nader, J. S, Developments in Sampling and Analysis Instrumentation
for Stationary Sources. J. Air Pollut. Contr Assoc. 23:
589-591, July 1973.
6. Hodkinson, J, R. The Optical Measurement of Aerosols. In.
Aerosol Science, Davies, C. M (ed.). New York, Academic
Press, 1966. p. 289.
7. Ensor, D, S, and M. J, Pilat. The Effect of Particle Size
Distribution on Light Transmittance Measurement. Amer. Ind.
Hyg. Assoc. J. 32: 287-292, May 1971.
8. Peterson, C. M and M. Tornaides, In-Stack Transmittance
Techniques for Measuring Opacities of Particulate Emissions
from Stationary Sources. Environmental Research Corporation.
Contract No. 68-02-0309. NTIS PS 212-741. EPA. Research
Triangle Park, N C. April 1972 87 p.
9. Hoirolya, J. B. A Review of Available Techniques for Coupling
Continuous Gaseous Pollution Monitors to Source Emissions.
EPA, (Presented at 165th National American Chemical Society
Meeting Dallas, Texas. April 8-13, 1973 12 p.)
21
-------
Page Intentionally Blank
-------
APPENDIX A. $02 MONITORING CAPABILITY
APPLIED TO A POWER PLANT^2)
In September 1970, the Environmental Protection Agency contracted
with TRW Systems Group, Redor.do Beach, California, to perform the
required field tests to evaluate commercially available instrument-
ation for monitoring SO- emissions from a coal-burning power plant.
This program included an identification of commercially available
instrumentation, selection of instrumentation for the field test,
design of the field test, and operation of the field test site.
TRW surveyed the instrument marketplace to identify manufacturers,
vendors, and developers of SO. measurement instrumentation. Eighteen
manufacturers and/or vendors responded, and 17 companies indicated an
active program in the development of SO, measurement units. The survey
revealed that, as of January 1, 1971, 12 SO- source monitors were com- -
mercially available. The detection and analysis scheme consisted of
one of the five following principles spectroscopic, electrochemical,
conductometric, coulometric, and mass spectrometric. The spectroscopic
technique included UV/visible absorption, nondispersive and dispersive
IR/visible absorption. After this information was received, additional
companies announced the sale of new instruments, which operated on one
of the five principles mentioned above, except that one used flame stim-
ulated emission spectroscopy (flame photometric).
The contractor initiated the field test study with six SO, mon-
itors that were available for delivery in accordance with the required
schedule. They utilized the first four of the five analytical principles
given above.
23
-------
The field tests were conducted at a coal-fired steam generating
plant. The unit employed in the SO monitor test burned coal with
2
approximately 0.5 percent sulfur that produced an effluent SO level
of approximately 250-300 ppm. The results are summarized in Table
A-l for the test set up shown in Figures A-l and A-2.
Table A-l. S02 MONITORING SYSTEM TEST RESULTS
Test parameter
Value range
Accuracy
Calibration error
Zero drift (2 hr)
Zero, drift (24 hr)
Calibration drift (24 hr)
Repeatability
-4.0 % +_ 14% to 0.5% +_ 6.3%
0.34 +_ 0.05% to 2.9% +_ 31
0.1% to 3%
-2.2% +_ 0.1% to 3.2 +_ 3%
-0.4% +_ O.S to 1.1% +_ 2.1%
-6.1% to 0.6% . :
a All values are reported as mean values -^ 95 percent confidence intervals as
percentage of 1000 ppai span.
Accuracy expressed as mean deviation +_ 95 percent confidence interval of
instrument readings versus barium-thorin titration Method 6, Federal
Register, December 23, 1971.
c Error expressed as mean difference +_ 95 percent confidence interval between
least squares calibration curves (5 points) and single point (1080 ppra) span
calibration when measured with three other calibration gases at 190, 660,
and 880 ppip.
24
-------
SAMPLE MANIFOLD
,W!TH PROBE INSERTION PORTS
SAMPLE LINE (7.62-CENTIMETER
HEAT-TRACED ALUMINUM PIPE)
HIGH-VOLUiE OPTIONAL ACCESS
BLOWER,. FOR FILTER, / SAMPLE PORT-^ DUCT
7 82 CENTIMETER /
RETURN LINE
RETURN PORT
.3
Figure A-l Flue gas diversion system
25
-------
LEGEND
0 PROBE
DUCT
STACK '
HEAT-TRACED SAMPLE LINE
STACK GAS RETURN LINE
BLOWER
SAMPLE MANIFOLD (SEE(T
VALVE TIMERS
8 BLOWBACK COMPRESSED AIR SYSTEM
9 STANDBY BLOWBACK N2
10,11 ZERO AND SPAN GASES
12 CALIBRATION GASES
13,16 VACUUM PUMPS
14 WET CHEMISTRY
15 TYPICAL INSTRUMENT
17 DIGITAL PRINTER
Figure A-2 Gas diversion and instrument installation design
'SINGLE OR MANIFOLD
OPTIONAL OUTLETS
©OPTIONAL IN-LINE
FILTER SYSTEM
A ' VALVE ~
-*"*- ELECTRIC ACTUATOR
rt MANUAL VALVE
9 PRESSURE GAUGE
f PRESSURE REGULATOR
-------
APPENDIX B. NOX MONITORING CAPABILITY
APPLIED TO A POWER PLANT
In-December 1970, the Environmental Protection Agency'con-
l-U
tracted-with Monsanto Research Corporation, Dayton, Ohio, to per-
t
form the required field tests to evaluate commercially available
instrumentation for nonitcring NO emissions from a coal-burning
power plant. This program included (1) identification of the man-
ufacturers and users of N0x-monitoring equipment to determine the
state-of-the-art, (2) perfonr-ance of laboratory tests of suitable
monitoring equipment, and (3) performance of field testing at a
coal-fired power plant. This approach was taken (as opposed to
the approach for SO. monitoring) because, at the time of program
inception, it was determined that NO monitoring was ill-defined
and in a less advanced state than SO, monitoring.
Monsanto obtained information from 85 organizations regarding
the manufacture or use of NO monitoring instrumentation. As of
January 15, 1971, nine NO source monitors were commercially available.
The detection and analysis scheme consisted of one of the following
principles: spectroscopic, electrochemical, and mass spectrometnc.
As in the case of SO-, the spectroscopic technique included UR/visible
absorption, nondispersive and dispersive UV/IR visible absorption.
In the study, Monsanto used seven NO monitors, *hich utilized the
first two of the three analytical principles mentioned above. *•*•
The NO monitor study included both laboratory and field test -'•;
programs at a coal-fired steam generating plant. The tests at this
source showed S00 levels of 1800-2400 npm SO, and NO levels of
2 -r 2 x
27
-------
250-350 ppn, of which about 10 ppm were NO . Table B-l summarizes
the performance of several monitors in the laboratory and field
tests.
Table 3-1, NO MONITORING SYSTEM TEST RESULTS2
x
Test parameters
Value range
Accuracy ' -2 .3% ^ 4.5% to -7.4% +_ 4.3%
Calibration error0 ' -10% +_ 0.4% to 9 4% +5%
Zero drift (2 hr) ! 0.2% + 1,1% to -1.5% -4.4%
Zero drift (24 hr)
Calibration drift- (24 hr)
0.4% *_ 0.5% to 0.61 +_ 7 .n
-6.6% + 4.3% to 3.7% +8.2%
Repeatability , " <2%
Response time
10 mm
A
All values reported as nean values as percentage of 500 ppm span.
Accuracy expressed as mean deviation +_ 95% confidence interval of
instrument readings versus phenol disulfonic acid analysis Method ">,
Federal Register, August 17, 1971. (Field test,)
c Error expressed as mean deviation +_ 95 percent confidence interval of
instrument readings versus standard calibration gas.
28
-------
APPENDIX C. VISIBLE EMISSIONS MONITORING CAPABILITY
APPLIED TO A POWER PLANT
Visible emissions are measured In terms of the amount of light atten-
uated or transmitted by the emissions in the visible portion of the
spectrum relative to the incident light. The percentage of light
attenuated is defined as the opacity of the emissions. The light trans-
mitted is the ttransnittance of the emissions. The sun of the trans-
mitted light and the attenuated light constitutes the total incident
light. Therefore, a plume that does not attenuate any incident light
is invisible and will have a transmittance of 100 percent and an
opacity of 0, A plume that attenuates all the incident light is
said to be 100 percent opaque; it will have an opacity of 100 per-
cent and a transmittance of 0. An instrument that measures and mon-
itors opacity or transmittance is referred to as a transmissometer.
Instruments that monitor transmittance of an effluent within the
stack are available commercially as in-stack transmssoneters.
As many as 23 manufacturers have been identified as producers of
in-stack monitors, and more are appearing on the scene.
Two inportant optical characteristics of transmissometers must
3e specified to obtain similar performance from instruments: the
operating wavelength and light collimation of the instruments. The
operating wavelength is important because fine particalates attenuate
shorter wavelength radiation more than longer wavelengths. Proper
29
-------
selection of the operating wavelength of the transmissometer will
also minimize interference due to absorption and radiation from
gases and water vapor in the emissions. The light collimation is
important because measurement of the true transmittance and opacity
of aerosols requires the exclusion of light scattered by the aerosols
from the measurement. Collimation requires an optical design that
limits the light viewing and projection angles of the transmissometer.
No restriction on viewing and projection angles results in instru-
ments with poor sensitivity and performance,
The effect of wavelength and particle size on the transmittance
of smoke can be illustrated by examining the theoretical particle
extinction efficiency curves reported by Hodkinson (Figure C-l).
PARTICLE-SIZE PARAMETER: a = « d/ X
5 IB
15
i 2
CURVE a - Tss>ispssEf«r WMODISPEPSE SPHEDK i»«133
CURVE B-TMNSPfPEITMOIWDIbPERSE SPHERES i- -I i
CJPVEC-AeSORBINt M€TOOI$?£P5E SPHERES •", SJ -Bk&i|T!TAL EXT"!CT!t)ii)
CJ»VEO = AeSORBlN6«'aWt)iS'EPSE S'HERtS ft 53 -OSoi'SCSTTEffiNo tor, a01EliT
CJPV£E'S6?CRilNC»OtOC!S»W5t SPHERES r-^ H -U66i'SBSOI>!'TION COfPONES1
0,05 1 15 2 25 3
AREA-MEAN PARTICLE DIAMETER FOR 0 52 micrometer WAVELENGTH, imEr
-------
The particle extinction efficiency factor Q depends on the particle
refractive index relative to the surrounding nedium, its shape, ard
its size relative to the wavelength, usually expressed as a = nd/>,
where d is the particle diameter ,tacacitv of an aeiosol with particle size parameter
greater than 6 (nean dianeter of about 1 inn.ion in 0 5 nicron light)
will not geneially be a function of transpissometer wavelength, and,
if t^e aerosol 15 h.ghl) absorbing, the opacity can be independent
-------
of wavelength when the particle size parameter exceeds 3 (mean di-
ameter of about 0.5 niicron in 0.5 micron light). At smaller par-
ticle sizes, the opacity is wavelength dependent since the volume
extinction coefficient is proportional to A - n, 0
-------
100
80
o
z
60
S 40
20
"0 20 40 80 80 100
IN-STACK TRANSMIT!ANCE, peicent
Figure C-3 Out-of-stack transmittance of
three colors of light as a function of in-stack
transnittance of white light for an experimental
black (carbon) plume
The effect of the detector angle of view can be illustrated by .
use of the theoretical results reported by Ensor and Pilat. (?) These"
results were used to calculate the error in the true light transpittance
as a function of the true lignt transmittance at various particle size
distributions for detector angles of 2 and 20 (Figures C-4 and C-5).
The erroi E in the true light transnittance is defined as:
( measured - true) „,.
t - T
true
Figure C-6 shows that for a 2-degree detector angle of view the
error in the true transmittance is in general less than 5 percent
in the 40 to 100 percent transmittance range for an aerosol with
particles of size geometric standard deviation 3 and particle mass
mean diameter less than 10 microns, Figure C-5 shows that for a
33
-------
20
15
10
LU
3
IE
O
IE
CC
LU
IPARTICLE REFRACTIVE INDEX-i 5
LIGHT WAVELENGTH =1
GEOMETRIC STANDARD DEVIATION
OF PARTICLE SIZE DISTRIBUTIONS
PARTICLE MASS MEAN DIAMETER=d ~
LIGHT SOURCE EMITTANCE
ANGLE=0 degrees
20 40 60
TRUE TRANSWTTANCE, percent
Figure C-4 Calculated error in true light
transmittance at 2 degrees detector angle
of view
PARTICLE REFRACTIVE INDEX =1 5
LIGHT WAVELENGTH =0 55*m
PARTICLE SIZE STANDARD
DEVIATION -3 —
LIGHT SOURCE E1MITTANCE
ANGLE «0 degrees
20 40 60 80
TRUE TRANSMITTANCE, percent
Figure C-5 Calculated error in true 'ight
vansnvttance a' 20 degrees detector angle
of view
34
-------
10 20 . 30 40 50 60
OETECTION.ANGLE, degrees
Figure C-6 In-'stack transnittartce of a coal-
fired power p'ant emssfon for various trans-
missometer light projection and detection angles
20-degree detector angle of view, the error in true transmittance
can range up to 30 percent in the 40 to 100 percent transmittanee
range for the sane aerosol. ,In general, the error associated with
a given detector viewing angle increases with increased particle
pean diameter, and,,at a given'particle mean diameter, decreases
with increasing particle size geometric standard .deviation (increasing
polydispersity of the particle size).
An experimental study of the effect of the collimating angles
of the detector and light source of a transmissometer on the measure-
ment of the opacity of emissions from a coal-fired' steam generator
(8) * "
was conducted by Peterson and Tomaides, ; They also examined the
j
opacity of this emission at several wavelengths within the visible
light region and considered the correlation between the in-stack
opacity measurement and the opacity of the plume.
To conduct the study, the investigators developed an experimental
transmissometer with variable detector and lamp collimating angles
35
-------
and with provision for inserting interference filters. The trans-
missometer was installed alongside a reference transmissometer in
the stack of a coal-fired electric power generating plant. The
reference transmssoiieter was well collimated and had a photopic
spectral response.
The stack was of cylindrical steel construction, approximately
3 meters in dianeter. The top of the stack was 89 meters above ground
level and 55,5 meters above the boiler room roof, through which
it protruded. The stack carried the effluent from a 120- megawatt
boiler, equipped with electrostatic precipitators rated at 13 per-
cent efficient, The experimental and reference transmissoirieters
were located in the stack 15 2 and 18.9 meters above the roof,
respectively. The opacity of the emission was controlled during
the study by varying the precipitator voltage,
The collamating angle tests (Figure C-6) show that the size
of the collimating angles of the detector and light source produce
similar errors and both must be constructed as small as practical
to minimize the error in the measured transauttanee and opacity.
The trar.smittance measurements at four different wavelengths within
the visible spectrum showed that the transmittance of the emission
increased with each decrease in wavelength (Figure C-7). This
result indicates that the particle size was large enough to place
the particle extinction coefficient beyond the first maxima of
the extinction efficiency curve. The ir.-stack and plume opacity
measurements showed good correlation (pigure C-8). The in-stack
measurements were with the reference transmissometer, which had
a 3-degree angle of vietv and near 0-degree light projection
36
-------
20
FILTER^
o fl 436/iia
o 0 436^15 ,
A 0
S.
_ RECEIVER ANGLE -5 degrees
PROJECTOR ANGLE, degrees
Figure C-7 In-stack transmittance of coa>-
fired power plant emission at various light
projection angles and wavelengths
20 40 SO 80
IN-STACK TRANSMITTANCE, perceni
loo
Figure C-B Out-o*-stack transmittance of
coal-fired power plant emssion as a function
of in-stack transmittance
37
-------
angle. The out-of-stack plune transrnittance measurements were
made with a narrow 1/2 degree angle telephotometer by the method
f41
of contrasting targets described by Conner and Hodkinson. '
Clearly, the wavelength response of the transmissometer used
for compliance to opacity regulations must measure the opacity of
the emissions to visible radiation since the regulation is based
on the visibility of the emissions. This is best accomplished by
restricting the spectral response of the transmissometer to the
)
visible. Interferences caused by the absorption and emission of
radiation by hot_ gases are also at a minimum in this region of the
spectrum. This specification, can be raet by proper selection of
detector and lamp or detector-lamp-filter combination. Most
commercial instruments can easily meet this specification.
In theory, the collimation angles for the light source (pro-
jection angle) and for the detector (detection angle) should be
0 to avoid the detection of scattered light. This is an ideal
that cannot be met in practice because the execution of any in-
strument design will require a finite collimation angle. Associated
with the finite collimation angle is,a systematic error in the
transmission that is a function of the particle size and' particle
size distribution in1 the particulate emission. There are ' '
limiting" factors on how small a collmation angle, one can
can specify. As one approaches smaller collimation-angles,- in-
strument cost increases and stability and optical1alignment problems
are generated. In practice, a compromise is necessary in which a
/ '
moderate restriction on the collimating angles for the detector
and light source is specified. Accordingly, an angle of 5 degrees
38
-------
(total angle) or less is recommended. Empirical data on the emission;,
of a coal-fired steam generatorW indicate that a transnnssoineter with
5-degree colligating angles measure the opacity about 5 percent low
relative to the true value (Figure C-6) This error would approach
0 for the same transraissometer applied to j source with a particle
size distribution shifted to smaller mass mean diameters (towards
submicron sizes, Figures C-4 and C-5).
The 5-degree (naximum) specification reportedly can be met with
little or no impact on cost. It is a good compromise between large errors
introduced at larger angles and alignment and instability problems in-
troduced at smaller angles.
Most commercial transmisiOTieters do not meet this collimation
specification, however, they can ireet the specification by simply
adding light baffling or by adding tollimating lenses and apertures
to their detector and light souice A coliimated transipissometer
is shown in Figure C-9.
ANGLE OF VIE*
DETECTOR (•APERTURE
i PROJECTION ANGLE
COMPACT
-FILAMENT
LAMP '
COLLIMATWGyBil
LENS T
LENS
CLEANING
AIR
Figire C-9 Transnissometer with colliTating optics
39
-------
The design specifications discussed above are important for
performance stability and accuracy, and they 'represent minimal re-
quirements to obtain equivalent performance of different transmisso-
' • ' ,'J --
meters for measurement of the opacity of stationary, soii-rce emissions,
' >* £
Most commercial transmissometers need improvement and "testing to
demonstrate acceptability. The once-a-day minimum calibration re-
quirement is particularly difficult for most instruments since they
do not generally have in-stack calibration capability./
Since opacity is dependent upon the depth of effluent fpathlength)
through which the measurement is made, the in-stack pathlength for
the measurement and the pathlength for the applicable opacity
regulation and instrument readout must be specified It is recommended
that the pathlength for the measurement include the entire width
of the stack or duct. An installation that uses a "pathlength less
than the effluent depth would negate tie averaging advantages of
across the stack iti-situ measurements. Since the opacity legulation
is based on the opacity of the plume enitted Dy the source, an in-
stack measurement of opacity at a pjthlengtb cifferentltfroui the di--
" ' lOS'c ' "
ameter of the plume at the stack exit nust be corrected to the opacity
of the effluent for a pathlength equal to the stack exit diameter to
determine compliance with the regulation. The relation for' the cor-
rection is A -,_ •• *
log(l-02)
where 1, is the stack exit diametax and 0 is the opacity of the >
effluent at the stack exit diameter, I is the inr,stack pathlength
of the traismissometer and 0, is the nieasuied opacity of the effluent
i
within the transmissonieter path. This relation is =hown, Hi figure C-1Q
40 ' •''
-------
UJ
fe
UJ
10
2D
20 40 M
IN STACK TRANSMITTANCE, percent
60 70 10 90 100
Figure C-10. 'Effluent transmtttance at stack exit as a function of in-stack transmittance
and ratio of stack exit diameter to transmissometer pathlength
O Ji
in terms of transmittance (transmittance equals 1 minus opacity).
The transmissometer output should permit expanded display of
the in-stack opacity on a standard 0 to 100 percent readout scale.
A graph or custom-made scale should be provided with each installa-
tion to show the relation between the standard 0' to 100 percent
readout scale and the opacity of the effluent for a pathlength
equal to the stack exit diameter. The full-scale measurement should
represent an opacity approximately 1.5 times the maximum allowable
opacity of 40 percent for steam generators.
41
-------
Caution must be used in the location of the transmissotpeter.
The instrument should be located so that a representative participate
concentration passes through the viewing volume. For devices using
slotted alignment tubes, care should be taken to ensure that the
design does not interfere with free flow of the effluent through
the entire optical volume. If the transtnissometer rrust be located
near a bend or obstruction 'where a representative participate con-
centration xs in douDt, the location should be detenuned experi-
mentally.
Good operational stability requires maintenance of optical align-
ment and clean optical surfaces. Installation and design requirements
are directed toward minirpizing the effects of temperature, vibration,
and other operational conditions that can cause optical misalignment
and. lead to excessive drift. Installation requirements will
depend largely on the characteristics of the plant operation and
this factor can vary significantly among various industries. Accord-
ingly, installation costs can vary depending upon the severity of
O'. '
installation conditions. The adequacy of the system's lens cleaning
. u
irechanisp must also be judged in the context of the specific installation.
It is advisable to observe closely the performance of a system for a
period of time following installation and to take steps, if necessary,
to correct any deficiencies that may develop.
Automatic ler.s cleaning and calibration and installation will
have an impact on cost. An alternative to automatic cleaning and
calibration is manual maintenance. Aside from relative cost con-
sidcratjons, it ib necessary to consider t>ie reliability of manual
naintenance versus automatic operation. Expenorce to date is in-
adequate t.o asbCbs the trade-off possibilities and the imuact on cost.
42
-------
APPENDIX D. DUKE POWER PLANT STUDY
EPA conducted a source measurements study over a 3-month period
(January thru March of 1973) at a pulverized-coal fired power plant of
the Duke PoueV Company in Charlotte, North Carol ina. <"9J The study had
as one of its prime objectives the comparison of various sampling
approaches for the measurement of S0« by source emission iponitors and
the stability of operation of an opacity monitoring system. The
three different approaches to gas measurement included: across-the-
stack and within-the-stack (in-situ) measurement with UV absorption;
extractive sampling with UV absorption analysis; and remote sensing
with UV correlation spectroscopy. All these measurements were com-
pared to tne compliance test method (Method No. 6 of the NSPS). An
additional objective was to evaluate and validate the applicability
of the proposed specifications and test procedures for monitoring
SO,, and visible emissions on a coal-burning power plant.
Corraiercially available instrument systems that represented
the three measurement approaches to SO- ipcnitoring were installed
<.- ' ''.
on the stack of a 150-megawatt wall-fired boiler. The stack was
also instrumented with ar acrosi-the-stack transrcissometcr (opacity
monitor) for neasuieroent of visible emissions and with instrumental ion
to monitor continuously stack gas velocity. The control equipment
consisted of both hot and cold electrostatic precipitators containing
a total of 14 stages. This instrumentation permitted control of
the participate loading in the stack emissions over a range in finite
increments determined by cutting off a specific number of precipitator
stages, A small building erected at the base of the stack housed the
instrument control units and the digital data acquisition equipment
43
-------
The instrument systems were operated continuously after installation
for a 90-day period. Daring this period, the proposed (September
30, 1972, draft) performance specifications test procedures were ex-
ecuted as prescribed and were evaluated on their applicability. The
instrumentation was also left unattended for about 60 days for a more
extensive reliability test, Within tne total period, 65 measurements
by l^S'S Method No. 6 vere made as reference measurements for correlation
with the corresponding (in tine) instrumental measurements Measure-i
pent data were also obtained at three levels of particulate loading
ranging from 2 percent to 47 percent opacity, effected by appropriate
cutback on various stages of precipitator control. Table D-l summarizes
some of the results on the performance tests on the SO monitoring
systems.
Table D-l. S02 AND NOX MONITORING SYSTEM TEST RESULTS
Results, %
Test parameter SG2 NOX
Accuracy3 5.8 to 32 ' 15J ' to 35
Zero drift (2 hr)b 0.52 to i 8 0*'08-to 1.5
Zero drift (24 hr)b i.o to i S 0 2flto 3.3
Calibration drift (2 hr)b 0,82 1 3 to 6,6
Calibration drift f24 hr) 3.6 to 4.8 , 1,7 to 5.0
aResult is the sum of the absolute mean erior and the 95%
confidence interval as a percentage of tne mean measurement
by Method 6 for S02 and by Method 7 for KOX. Method 7 for
NOX has run in sets of two. Sets of three should nprove
the confidence interval and the accuracy
Result is the sum of the absolute mean value and the 951
confidence anterval as a percentage of the emission
standard (620 ppn for S02 and 525 ppm for NOX)
44
-------
The study indicated that the specifications and test procedures
j\
were applicable and valid, except that the accuracy specifications
may need to be modified if maxiirum possible utilization is to be
made of available monitoring systens. The rationale for «uch a con-
sideration is that this test s*as specifically for a selected pollutant-
source combination involving a representative cross section of measure-
ment approaches. This study was the first real assessment of the
applicability of the proposed specifications and test procedures.
Nonethelessj sach a consideration would be predicated on the purpose
for monitoring, the required accuracy, and the intended utilization
of the data.
The evaluation of the specifications and test procedures for
opacity indicated that they were applicable and valid. Most of the
effort on the opacity evaluation was directed at the zero and calibra-
tion drift parameters as a measure of the system's stability. As
long as the system was in proper functioning condition, it maintained
zero and calibration staDility that was significantly ipore than
adequate Zero and calibration drift were less than 0.5 percent and
0.3 percent opacity per week, respectively. The instrument was un-
attended and checked out on a weekly basis during the 90-day period
At each check the following actions were taken; the alignment of
the system was verified; all optical surfaces exposed to the emissions
were cleane_d; and the filters of the air purge system (to keep the
optics clean) ^ere checked and cleaned as required.
The zero drift and calibration drift were not accumulative. No
optical alignment drift was noted over the 3-month period. Cleaning
45
-------
of the optical surfaces showed no measurable effect on the zero and
calibration check or on the"opacity measurement.
During the test, two malfunctiors occurred, which resulted in
excessive instrument drift. The first malfunction took place when
a plant electrostatic particulate collector developed a leak and
enveloped the transnissoireter in a cloud of participates clogging
the filters of the air purge system used for keeping the optical sur-
faces clean. The clogged filters reduced the flow of purge air and
permitted the effluent to contaminate the transmissomcter optical
surfaces. This resulted in an increased drift of 5 and 3 percent
opacity per week in the 0 and span, respectively. After the air
filters were cleaned, the transnissometer was observed to continue
to drift because of soiling of optical surfaces for the next 2 weeks.
The 2 weeks of excessive drift following the air filter clogging
were apparently due to contamination of the air tube following the
filters. Normal drift performance returned after the tubes'were
cleaned. - ;'" '*"'**
The second malfunction'of the instrument occurrecl!/'during the
last 3 weeks of operation and appeared as an erratic instrument 0
and span check which resulted in an apparent zero and span drift
of 2 5 and 1.0 percent opacit> drift per week, respectively. Ex-
amination of the instrument at the time of removal from the' stack
showed the erratic behavior of the 0 and span check to be due to a
loose calibration reflector. It ^ould be desirable to treat the
reflector retaining screws and any critical hardware subject to
displacement by vibration by some manner to keep them locked in
place.
46
-------
A study similar to tne S02 work was condacted on NOX monitoring
systems at the Duke Power Plant in Charlotte. The same stack source
and experimental facilities were used. The monitoring systems were
operated for a period of about 3 months, September to Novenber 1973
The monitoring systems included across-the-stack UV absorption, extrac-
tive NDIR and cheipi luminescent techniques with permeation and water
condensation interfaces, and extractive visible absorption
techniques Reference Method No 7 has xun concurrently and at
various tines during the 3-month period for a total of about 50
measurements. A range of particulate loading was encountered as in
the case of the ,502 study.
The objectives of this study were to compare the results of
various analytical and sampling approaches to the measurement of NOX
and to evaluate and validate the applicability of the proposed specifi-
cations and test procedures for monitoring ,NOX emissions from a coal-
burning power plant.
Table D-l summarizes some of the results on the kQx monitoring
system. The range of values for the test parameters is of the same
order of iragnitude for the NOX monitors as those for the S02 monitors.
The accuracy values for the NOX monitors are based on a test procedure
using sets of two Method 7 measurements. The test procedure requiring
sets of three measurements should improve the accuracy values.
47
-------
Page Intentionally Blank
-------
APPENDIX E.
EXAMPLE:
PERFORMANCE SPECIFICATIONS AND SPECIFICATION
TEST PROCEDURES FOR MONITORS OF POLLUTANT
GAS EMISSIONS FROM STATIONARY SOURCES
Performance specifications for continuous measurement syste-ns
for pollutant gases are given in terms of critical operating para-
meters. Test procedures are given to test the capability of the
measurement systems to conform to the performance specifications,
1. Principle and Applicability
1.1 Principle - Pollutant gases are sampled continuously
in the stack emissions,and the gas concentration is
analyzed continuously as a function of time. Sam-
pling may include either the extractive or non-ex-
tractive (in-situ) approacb.
1.2 Applicability - The performance specifications are
given for continuous pollutant gas measurement systems
applied to specific source-pollutant combinations. The
following discussion is addressed to 862 and NOX emissions
from coal-burning power plants Instrument system should
be capable of operation within performance specifications
at particulate loadings and in a temperature range corre-
sponding to those of the environment of the installation.
2 Apparatus
2,1 Calibration Gas Mixture - Mixture of a known concentra-
tion of the pollutant gas in oxygen-free nitrogen,
49
-------
Nominal con cent rat ions of 30 percent, 60 percent, and
90 percent of span are recommended. It is strongly
recommended that the gas mixture be analyzed by a
reference method prior to use,
2.2 Zero Gas - A gas containing no irare than 1 ppm of
the pollutant gas
2.3 Equipnent for measurement of pollutant gas concentration
using the reference method.
2,4 Strip Chart Recorder - Analog strip chart recorder, in-
put voltage range compatible with analyzer system out-
put, full scale (per travel) in two seconds or less.
2.5 Continuous measurement systen for pollutant gas.
3, Definitions
3=1 Measurement System - The total equipment required for
the determination of a pollutant gas concentration in
a given source effluent,, The system consists of three
major subsystems:
1. Sampling Interface - That portion of the measure-
ment system that performs one or more of the fol-
." * * f_ •«*
lowing operations: delineation, acquisition, trans-
portation, and conditioning of a sample of the source
effluent ox protection of the analyzer from the
hostile aspects of the sample or source environment.
2. Analyzer - That portion of the system which senses
the pollutant gas and generates a signal output that
is a function of the pollutant concentration.
SO
-------
3. Data Presentation - That portion of the measure-
ment system that provides a display of the output
signal in terras of concentration units.
3,2 Span - The value of pollutant concentration at which the
measurement system is set to produce the maximum data
display output For the purposes of this method, the
span shall be set at a pollutant gas concentration of
1,5 times the emission standard or the pollutant gas
concentration of interest.
3,3 Accuracy (Relative) - The degree of correctness with
which the measurement system yields the value of gas
* • • . ^
concentration of a sample relative to the value given
by a defined reference method. This accuracy is ex-
pressed in terms of error which is the difference be-
tween the paired concentration measurements. The error
is expressed as a percentage of the reference mean
value.
, 1; • 0 H i, • , '.
3,4 Calibration Erroi - The difference between the pollutant
vrf: l '
concentration indicated by the measurement system and
the known concentration of the test gas mixture.
3,5 Zero Drift - The change in measurement system output
over a stated period of time of normal continuous
" operation-when the pollutant concentration at the time
of the measurements is zero.
3=6 Calibration Drift - The change in measurement system
"output over a stated period of time of normal contin-
uous operation when the pollutant concentration at
51
-------
the time of the measurements is the same known up-
scale value.
3,7 Repeatability - A measure of the measurement system's
ability to give the same output reading(s) upon re-
peated measurements of the sane pollutant concentra-
tion^) .
3.8 Response Tine - The time interval from a step change
in pollutant concentration at the input to the measure-
ment system to the time at which 95 percent of the
corresponding final value is reached as display on
the measurenent system data presentation device,
3.9 Operational Period - A mini»»um peridd of time over
which a measurement system is expected to operate
within certain performance specifications without
unscheduled maintenance, repair or adjustment.
4. Measurement System Performance Specifications
The following performance specifications shall be met
in order that a measurement system shall be considered
acceptable under this method.
Parameter Specification
a. Accuracy (relative) <_ 20% of mean reference value
b. Calibration Error <_ 5% of each test gas value*
c. Zero Drift [2 hour) <_ 2% of emission standard*
d. Zero Drift (24 hour) < 4% of emission standard*
*Absolute irean value * percent confidence interval.
52
-------
Parameter Specification
e. Calibration Drift (2 hour) f.2% of eiission standard*
f, Calibration Drift (24 hour) f.5% of emission standard"1
g Response Time 10 minutes (maximum)
a. Operational Period 168 hours
*Absolute mean value * 95% confidence interval.'
5. Specification Test Procedures
5 1 Calibration Error and Repeatability Test - Set up and
calibrate the complete Tieasurerrent system according to
the manufacturer's written instructions. Record the
readings of calibration gas concentrations of
approximately 30, 60, and 90 percent of span. Make a
series of five nonconsecutive readings at each con-
centration (Example: 30 percent, 90 percent, 60 percent
90 percent, 30 percent, 90 percent, 60 percent, etc.)
Convert the measurement system output readings to ppm,
/
5.2 Field test for accuracy (relative), zero drift, eal-
ibfation drift, and operation period0
5,2.1 Set up and operate the measurenent system in
accordance with the manufacturer's written in-
structions arid drawings. Operate the system
for an initial 168 hour conditioning period.
During this period the system should measure
the pollutant gas content of tae effluent in a
normal operational manner,
5.2.2 After completion of this conditioning period, the formal
168 hour performance ar.d operation test period shall
begin. The system shall be monitoring the source efflu-
ent at all times v.hen not being zeroed, calibrated, or
S3
-------
baekpurged. During this 168 hour test period, make a
minimum of nine (9) pollutant gas concentration measure-
ments using the reference method at intervals of not less
than 1 hour. For S02, each of the nine tests shall con-
sist of a Method 6 S02 concentration measurement, plus
the instrumental measurement. For NOX, each of the nine
tests shall consist of a set of three Method 7 MQX con-
centration measurements, plus the instrumental measure-
ment. In each set of three Method 7 measurements, three
samples should be taken concurrently or within a 3-minute
interval, The sampling location for the reference method
shall be as prescribed. The sampling location for the
monitoring method shall be as close to the location of
the reference method sampling point as conditions will
pemit to demonstrate the specified accuracy. The re-
ference method data shall be conpared with simultaneously
collected monitoring data for calculation of ,accur%cy.
Before and after each reference method test, record the
values given by both zero and calibration concentrations.
Record the values given by zero and calibration concentra-
tions at two hour intervals until 15 sets of data are ob-
tained. This two-hour period need not be consecutive but
may not overlap. Zero and calibration corrections and
adjustments are allowed only at 24 hour intervals or at
such shorter intervals as the manufacturer's,written
instructions specify. Automatic corrections made by
the measurement system without operator intervention or
54
-------
initiation are allowable at any time. During the entire
test period, record the values given by zero and cali-
bration pollutant gas concentrations before and after
- adjustment at 24 hour intervals. Calibration checks
are wade with one test gas concentration between 70
and 90 percent of span.
5.3 Field Test for Reponse Time
5.3.1 This test shall be accomplished using the entire
measurement system as installed including sanple
transport lines if used. Flow rates, line diameters,
pumping rates, pressures, etc., shall be at the'nominal
values for normal operation as specified in the manu-
facturer's written instructions. In the case of cyclic
analyzers, the response time test shall include one
cycle. This test shall be repeated for each sampling
point of multi-sampling point systems.
5.3,2 "Introduce a zero concentration of pollutant gas into the
- '''measurement system sampling interface or as close to the
sampling interface as possible. When the system output
reading has stabilized, switch quickly to a known concen-
tration pollutant gas at 70 to 90 percent of span. Re-
cord the tiire from concentration switching to final stable
i
response. After the system response has stabilized at the
upper lex'el, switch quickly to a zero concentration of pol-
lutant gas. Record the time from concentration switching to
55
-------
final stable response; perform this test sequence three (3)
tines The strip chart recorder charts or copies of then
from this test should be included in the data submission
with time scales and up and down scale values clearly
marked. >;
II
6. Calculation, Data Analysis and Reporting
6.1 Procedure for Determination of Mean Values and Confidence Intervals
6,1.1 The TiC'ii value of a data set is calculated according to
equation E-l.
n
x = ~ f1 x
n f-> 1 Equation E-l
where x. = i-ndividual "alues I = ^um of tbe indi-
__ vidud.1 values
x = mean x'aluc
n = number of data points
6.1.2 The 95% confidence interval (two-sided), i-s 'calr jJated according
to equdtior E-2, ' .^Jn-'i
C.I = l-n/2 \ n[Ix ) - IJx )" Equation E-2
n(n-l)
where Ex. = SUTH of all data points
/p~ = square root of the number of data points
t, ,„ = t „_,_ for n samples f^om a table of percentages
l-«/2 975 * t- s,
of the t distribution.
C.I.-r = 95% confidence interval estimate of the average mean
value
56 -'"' '
-------
Typical Values for 1 - a/2
n
2
3
4
S
6
t.975
12.706
4.303..
3,182
2.776
2.S71
n
7
, 8
9
10
11
t.97S
2.44?
2.365
2.306
2.262
2.228
n
12
13
14
15
16
t.975
2.201
2.179
2,160
2.145
2.131
The values in this table are already corrected for n-1 degrees of freedom
Use n equal to the number of samples as data points,
6,2 Data Analysis and Reporting
6.2.1 Accuracy (relative) - This calculation uses the reference method
test data and the measurenent system concentrations recorded
at the times the reference method tests were run. Subtract
the reference method test concentration from the measurement
system concentration.* Repeat for all nine test pairs. Using
this data, compute the mean difference and the 95% confidence
interval using Equations E-l and E-2. Report the sum of the
absolute mean value and the 95% confidence interval as a per-
centage of the mean reference value.
6.2.2 Calibration Error - Using the data from Section S.I suDtract
the known value from the value shown by the measurement
system for each of the 5 readings at each span test concen-
tration. Calculate the mean of these differences values
and the 95% confidence interval according to Equations E-l
and E-2, Report the sum of tne absolute mean value and the 95%
confidence interval as a percentage of test gas concentratioa.
*For S02, subtract the Method 6 values from the corresponding instrumental
value. For NOX) subtract the mean value of the set of three Method 7
values from the corresponding instrumental values
57
-------
623 Zero Drift (2 Hour) - Using the zero concentration values
measured during the, field test, calculate the mean value and
the confidence interval using Equations E-l"and E-2, Report
the sum of tne absolute mean valje and the confidence inter-
val as a percentage of the emission standard'M
6.2.4 Zero Drift - (24 Hour) - Using the zero concentration values
treasured every 24 hour's during the field test, calculate the
differences between the zero point after zero adjustment and the
zero value 24 hours later just prior to zero adjustment. Calibrate
the mean value of these points and the confidence interval
using Equations E-l and E-2. Report the sum of the absolute
mean value and confidence interval as a percentage of the
emission standard.
6 2.5 Calibration Drift (2 Hour) - Using the calibration values
obtained at two-hour intervals daring the field test, cal-
culate the differences between the readings and the test
_\ ,, ijr *
gas value These values should be corrected for the cor-
responding zero drift during that two-nour period. Calcu-
* Ft
late the mean and confidence interval of these corrected
values using Equations E-l and E-2. Report' the SUDI of the
absolute mean value and confidence interval as a percentage
of the emission standard.
6.2.6 Calibration Drift (2-1 Hour) - Using the calibration values
measured every 24 hours during the field test, calculate
tTe differences between the calibration concentration reading
after zero and calibration adjustment and the calibration
58
-------
concentration reading 24 hours later after zero adjustment but
before calibration adjustment. Calculate the mean value of
these differences and the confidence interval using Equations
E-l and E-2. Report sum of the absolute mean value and confi-
dence interval as a percentage of the emission standard.
6.2.7 Response Time - Using the charts fron Section 5.3 calculate
the time interval from concentration switching to 95% of the
final stable value for all" up scale and down scale tests.
Report the mean of the three up scale test times and the mean
of the three down scale test times. The two average times
should not differ by more than 15% of the slower time. Report
the slower time as the system response tire.
6.2.8 Operational Period - During the 168 hour performance and
operational test period, the measurement system shall not
require any corrective maintenance or repair or replacement
or adjustment other than that clearly specified as required
in the operation and naintenance manuals as routine and
-ior .,
expected during a one-weel period. If the measurement
*JO '
system operates within the specified performance parameters
and does not require corrective maintenance, repair, replace-
ment or adjustment other than specified above, during the 168
hour test period, the operational period test will be success-
fully concluded. Failure of the measurement to meet this
requirement shall call for repetition of the 168 hour test
period. Portions of the te«t which were satisfactorily
completed need not be repeated. Failure to meet any perfor-
mance specifications shall call for a repetition of the one
59
-------
week performance test period and that portion of the testing
which is relat.d to th'e failed STCCif ication. All maintenance
and adjustments requires shal- be recorded Outcut readings
shall be recorded before and after all adjustments.
7 Surrojeiripntal Refetences
Experimental Statistics, National Bureau of Standard's, ".Handbook 91,
1963, P. 3-31, Paragraph 3-3 1.4.
60
-------
APPENDIX F..
EXAMPLE:*
PERFORMANCE SPECIFICATIONS AND SPECIFICATION
TEST PROCEDURES FOR TRANSMiSSOMETER SYSTEMS
FOR CONTINUOUS MEASUREMENT
OF ,THE OPACITY OF STACK EFFLUENTS
Specifications for continuous measurement of visible emissions by
transmissoraetry are given in terrrs of critical design, perfornanee , ard
installation parameters. Test procedures are given to test the capability
of the systems to conform to the performance specifications.
1. Principle and Applicability
1.1 Principle, Transmissoimetry is a direct measurement of attenuation
of visible radiation (opacity) by participates in a stack effluent
Light from a lawp is projected across the stack of a pollution
source to a light sensor. The light is attenuated due to absorption
and scatter by the particulates in tne effluent. The percentage
of light attenuated is defined as the opacity of the emission <\
clean stack that does not attenuate light will have a transmittance
of 100 or an opacit> of 0. An opaque stack that attenuates all of
the light will have a transmittance of 0 or an opacity of 100 per-
cent
1.2 Applicability The performance specifications are given for trans-
missometer systems for continuous measurement of the opacity of
aerosol within the effluent (in-situ) of a pollution source. The
ipethod is applicable to the measurement of the opacity of the
*For coal-burning power plant.
61
-------
effluent at points in .the plune at the stack exit re-note from
the measurement point provided the characteristics of the aerosols
in the effluent are maintained between the measurement point and
the remote point of interest in the plume. Watcr^.in condensed
form is an interference to the measurenent
2. Apparatus , ., i
2.1 Neutral Density Filters. Filters with neutral spectral characteris-
tics ard known optical densities to visible light. Filters 5- or
6-inch square or 6-ineh diameter with nominal optical densities of
0.1, 0.2, and 0.3 (20, 37, and 50 percent opacity) are required.
Although calibrated filters with accuracies reported to within
3 percent are available, it is recommended that filter calibrations
be checked with a well-collimated photopic transiussometer of
known linearity prior to use.
2.2 Strip Chart Recorder. Analog str.ip chart recorder \«ith input
voltage range and performance characteristics compatible .with
the measurement system output , r
2.3 Opacity Measurement System An in-stack transnussometer (folded or
single path) with the optical design specifications^designated
below, associated control units and apparatus to keep optical
surfaces clean
3. Definitions
3.1 Measurement System. The total equipment required for the continuous
determination of a pollutant concentration in a source effluent.
The system consists of three major subsystems
62
-------
3.1.1 Sanpling Interface - That portion of t.Te measurement system
that performs ore or more of the.following operations:
delineation, acquisition, transportation, and conditioning of
a sample of the source effluent, or protection of the analyzer
from the effluent
3,1.2 Analyzer - That portion of the system wnich senses the pollu-
tant gas and generates a signal output that is a function of
the pollutant concentration.
3.1.3 Signal Processor - That portion of the measurement system that
processes the analyzer output and provides a display of the
output' signal in terms of pollutant concentration.
3,2 Span. The value of pollutant concentration at which the measure-
ment is set to produce the maximum data display output. For the
purpose of this method, the span shall be set at an opacity of
50 percent for an effluent depth equal to the stack exit diameter
of the source.
3.3 Calibration Error. The difference between the pollutant concen-
tration indicated by the measurement systen and the known values
of a seri'es of test standards. For this method the test standards
are a series of calibrated neutral density filters.
3.4 Zero Drift. The change in measurement system output over a
stated period of time of normal continuous operation when the
pollutant concentration at the tine c£ the measurements is zero,
3.5 Calibration Drift. The change in measurement system output over
a stated period of tine of normal continuous operation when the
pollutant concentration at the time of the -neasurements is the
same known up scale value.
63
-------
3.6 Repeatability, A measure of the measurement system's ability
to give the same output reading(s) upon repeated measurements
*
of the same pollutant concentration(s).
3.7 Response Tiiie. The time interval from a step change in pollutant
concentration in the stack of the source at the input to the
measurement system to the time -at which 95 percent j>f the cor-
responding final value is reached as displayed on the measurement
system data presentation device.
3.8 Operational Period, A minimum period of time over which a
measurement system is expected .to operate within certain per-
formance specifications without unscheduled maintenance, repair,
or adjustment.
3.9 Transmittance. The fraction of incident light that is trans-
mitted through an optical medium of interest,
3.10 Opacity. The fraction of incident light that is attenuated
by ah optical medium of interest. Opacity (0) and transniittance
(T) are related as follows: . $-1
0 = 1 - T •:
3.11 Optical Density. A logarithmic measure of the amount of light
that is attenuated by an optical medium of interest. Optical
density (D) is related to the transntittance and opacity as
follows:
D = -log10T
D = -Iog1() (1-0) '
3.12 Spectral Response. The relative response of a transmissometer
to radiation of different wavelengths.
3.13 Angle of View, The maximum (total) angle of radiation that is
64
-------
seen by tae photo-detector assemoly of an optical transmissomster.
3 14 Angle of Projection. The maximum-(total) -angle of radiation that is
projected by the lamp assembly of an optical transmissometer
3,15 Pathl'engthV "The depth of effluent in the light beam b'etween the
receiver ancf'th'e transmitter of the single pass transpissoneter, or the
depth-of efflnen'C between the transceiver' and reflector of a double pass
trans'nussometer.'
4, Installation Specifications
4.1 Location. The transrcissometer must be located across a section of
duct or stack that will provide a participate flow through the
optical volume of the transroissameter that is representative of the
particulate flow through tne duct or stack.
4.1.1 The transmssometer location shall be downstream from all par-
ticulate control equipment,
4'. 1.2 The transmissometer location shall be located as far from
• • bends and obstructions as practical.
4.1.3 The transmissometer that is located in the duct or stack fol-
lowing a bend shall be installed in the plane of the bend where
Jnpossible
4,1.4 The transmissometer should be installed in the most accessible
location possible.
4.1.5 The transmissometer location in a section of duct or stack
where a representative particulate concentration is in doubt
shall provide an average measure of the opacity of the effluent
in the duct or stack. The location shall be determined bv ex-
' .*• i
amining the opacity profile of the effluent at a series of
positions across the duct or stack while the plant is operating
'i' - ^
65
-------
at full load.
4,2 Slotted Tube, Installations that require the use of a slotted
tube shall use a slotted tube of sufficient size and blackness
so as not to interfere v»ith the free flov» of effluent through
the entire optical volume of the transmissometer or reflect
light into the light detector of the transmissometer.
4.3. Pathler.gth. It is recommended that the pathlength or depth
of effluent for the transiissonieter include the entire width
• or diameter of the duct or stack. Installations using a shorter
pathlength must -use | extra caution in determining the measure-
ment location representative of the particulate flow through
the duct or stack. ;
4.4 Recorder Output. The transmissoweter output shall permit ex-
panded display of the m-stack opacity on a standard 0 to 100
percent scale. In addition, a graph shall be provided with
the installation to show the relation between the standard
0 to 100 percent readout scale and the opacity of the effluent
for a pathlength equal to the stack exit diameter^ ,
The relation fox constructing the graph is:
•log(l - Oi) = Ui/lj) iogC1 - '°2) '
where 1. is the stack exit diameter and 0, is the opacity of
the effluent at the stack exit diameter, 1 is the in-stack
pathlength of the transmissometer, and 0_ is the measured
opacity of the effluent within the transmissometer path.
The opacity standard is based on the opacity of the effluent
66
-------
at the stack exit diameter,
5. Optical Design Specifications
The following optical design specifications shall be met in order that
measurement "system shall be considered acceptable under this method'
PARAMETER "-'••<'•. - SPECIFICATION
a. Spectral response Peak and mean response within
500 to 600 rnn; less that 10%
' of peak response outside 400 to
700 nm
b. Angle of vie"w 5 degrees maximum (total angle)
c. Angle of projection 5 degrees maximum (total angle)
6. Design Specification Data and Test Procedures
6.1 Spectra: Response. Obtain spectral data for detector, lamp,
and filter components used in the -transmissometer from
their respective nanufacturers.
' 6.2 "Angle of View, Set the receiver up as specified by the man-
ufacturer ';' Draw an arc with radius of 3 meters Measure the
receiver response to a small (less than 3 centimeters) non-
directional light source at 5-centimeter intervals on the
arc for 26 centimeters on either side of the detector center-
line. Repeat the test in the vertical direction.
6,3 Angle of Projection,. Set the projector up as specified by
the ".anuf actarer, Draw an arc with radius of 3 meters. Using
67
-------
a small photoelectric light detector (less than 3 centimeters),
measure the light intensity at 5'-centimeter intervals on the
arc for 26 centimeters or. either side of the light source
centerline of projection. Repeat the test in the vertical
direction.
7. Measurement System Performance Specifications
The following performance specifications shall be met in order
that a measurement system shall be considered acceptable under this
method.
PARAMETER
a. Calibration Error
b. Zero Drift (24 hr)
c. Calibration Drift
(24 hr)
d. Response Time
e, Operational Period
SPECIFICATIONS
^10% of test filter value*
.110% of emission standard*
±10% of emission standard*
10 seconds (maximum)
168 hr
'Absolute mean value + 35 percent confidence interval.
8 Performance Specification Test Procedures
8.1 Laboratory Test for Calibration Error, Repeatability, and
Response Tiire-
8.1.1 Set up and calibrate the ineasurejnent system as specified by the
manufacturer's written instructions using a 3-meter pathlength.
Span the instrument for 0 to 50 percent opacity. Insert a
68
-------
range of neutral density filter standards in the transTnissometer
path at the 2,5-meter point. A minimum of three neutral density
filters with nominal opacities of 20, 37, and 50 percent cal-
ibrated within 3 percent must be used Make a total of five
nan-consecutive readings for each filter. Record the
measurement system output readings in percent opacity.
8,1.2 Insert the 30 percent filter in the transmissometer path five
times and record the time required for the system to respond
to 95 percent of final zero and span values,
8.2 Field Test for Zero Drift, Calibration Drift, and Operational Period
8.2.1 Set up and operate the measurement system in accordance with
the manufacturer's written instructions and drawings. Operate
the system for an initial 168 hour conditioning period. During
this period the system should measure the opacity of the
effluent in a normal operational manner.
8.2,2 After completion of this conditioning period, the formal 168-
hour operational test period shall begin. The system shall be
ir.onitorirg the source effluent at all tiroes when not being
zeroed or calibrated. At 24-hour intervals over the specified
operational period, the zero and span of the measurement system
shall be checked according to the manufacturer's written in-
structions. The span value shall not be less than 1.5 tines
the emission standard. After the zero and span check, clean all
optical surfaces open to the effluent, re-align optics and make
any necessary adjustments to the calibration of the system. Zero
and calibration corrections and adjustments are allowed onl> at
24-hour intervals or at such shorter intervals as manufacturer's
written instructions specify. Automatic corrections made bv the
69
-------
measurement system without operator intervention are
allowable at any time. 'During the entire test period, ,
record the values of zero and span opacities before
and after cleaning, aligning, and adjusting the system
at 24-hour intervals.
9, Calculation, Data Analysis, and Reporting
9.1 Procedure for Determination of Mean Values and Confidence In-
teivals,
9.1.1 The riean value of data set is calculated according
to equation F-l.
E Equation F-l
1
i-l
where x. = individual values I = sum of the individual
• " i -•,'.', •• • values
x = mean .value
n = number of data points
9,1.2 The 95 percent confidence interval (two-sided) is cal-
culated according to equation F-2.
/TT V .n fn-1) Equation F-2
• -where IX = SUP of all data points
/"n = square root of the number of data points
tj ,. = t „„ for n samples from a table of
percentages of the t distribution
70
-------
TABLE OF TYPICAL-VALUES FOR t,
1 - «/2
n
2
3
4
5
6
t.975
12.700
4.303
3.182
2.776
2.571
n
7
8
9
10
11
'.975
2.447
2.365
2.306
2.262
2.228
n
12
13
14
15
16
t.975
2.201
2.179
2.160
2.145
2.131
The values in this table are already corrected for n-1 de-
grees of freedom. Use nequal tothe number of samples as
data points.
9.2 Data Analysis and Reporting
"' 9,2.1 Spectral Response. Combine the spectral data obtained
in accordance with Section 6.1 to determine the effective
spectral response of the transmissometer. Report effective
wavelength respond curve and mean response of the trans-
missometer,
9.2.2 Angle of View Using the data obtained in accordance with
Section 6.2, calculate the response of the receiver as a
function of viewing angle in the horizontal and vertical
directions (26 centimeters of arc with a radius of 3 meters
equal 5 degrees), Report relative angle of view curves.
9,2.3 Angle of Projection. Using the data obtained in accordance
with Section 6.5, calculate the response of the photoelectric
71
-------
detector as a function of projection angle in the horizontal
and vertical directions. Report relative angle of projection
curves.
9.2,4 Calibration Error. Using the data from Section 8.1 subtract
the known filter opacity value from the value shown by the -
neasureraent system for each of the 15 readings. Calculate the
mean of the five difference values at each test filter value
and the 95 percent confidence interval according to Equations
F-l and F-2. Report the sum of the absolute mean value and
the 95 percent confidence interval as a percentage of the
test filter value,
9.2.5 Zero Drift. Using the zero concentration values measured
every 24 hours during the field test (Section 8.2),cal-
culate the differences between the zero point after
cleaning, aligning, and adjustment, and the zero value
24 hours later just prior to cleaning, aligning and
adjustment. Calculate the near value of these points and
the confidence interval using Equations c-l and T-2, Pe-
port the sum of the absolute mean value and the 95 percent
confidence interval as a percentage of the omission standard,
9,2,6 Calibration Drift. Using the span ^alue measured every
24. hours during the field test, calculate the differences
between the span value after cleaning, aligning, and
adjustment of 0 and spaa, and the span value 24 hours
later just after cleaning, aligning, and adjustment of 0
72
-------
and before adjustment of span. Calculate the mean
value of these points and the confidence interval
using Equations F-l and F«2« Report the sum of the
absolute mean value and the confidence interval as a
percentage of the emission standard.
9,2.7 Response Time. Using the data from Section 8.1 calculate
the time interval from filter insertion to 95 percent of
the final stable value for all up scale and down scale
traverses. Report the mean of the 10 up scale and dovn
scale test times.
9.2,8 Operational Period. During the 168 hour performance
and operational test period, the measurement system shall
not require any corrective maintenance or repair or re-
placement or adjustment other than that clearly specified
as required in the operation and maintenance manuals as
routine and expected during a one-week period If the
measurement system operated within the specified per-
formance parameters and did not require corrective
maintenance, repair, replacenent, or adjustment other
than specified above, during the 168 hour test period,
the operational period test will be successfully con-
cluded. Failure of the tneasurenent to meet this re-
quiretient shall call for a repetition of the 168 hour
test period. Portions of tne test w.iich were satisfactorily
completed need not be repeated. Failure to meet any per-
fomance specifications shall call for a repetition of
73
-------
the one-week performance test period and that portion of
the testing which is related to the failed specification.
All maintenance and adjustments required shall be re-
corded. Output readings, shall be recorded before and
after all adjustments.
74
-------
TECHNICAL REPORT DATA
(flense read fas&itcnons on the reverse before cc
] BEPORTNO
EPA-650/2-74-013
4 TITLE ANO SUBTITLE
Performance Specifications for Stationary-Source
Monitoring Systems for Gases and Visible Emissions
6 PERFORMING ORGANIZATION CODE
5 REPORT DATI
January 1974
7 AUTHORiS)
John S. Nader
Fredric Jaye
8- PERFORMING ORGANIZATION REPORT NO
William Conner
9 FERFQFMINGORG MMIZAT'ON NAME AND ADDRESS
Chenistry and Physics Laboratory
National Environmental Research Center
Environmental Protection Agency
Research Triangle Park, North Carolina 27711
10 PROGRAM ELEMENT NO
1AA010
11 CONTRACT/GRANT NO
12 SPONSORING AGENCY MAME ANO ADDRESS
13 TYPE OF REPOHT AND PERIOD COVERED
14 SPONSORING AGENCY CODE
IS SUPPLEMENTARY NOTES
16 ABSTRACT
The purpose of this report is to provide a technical basis for the selection of
stationary-source monitors that are required by Federal, State, or local regulations
for emissions. The document identifies performance parameters, gives specifications
and details test procedures to verify the specifications. Examples of the specifica-
tions and test procedures are provided for monitoring systems applied to gases and
visible emissions. Technical dataA utilised for the specifications are based on the
results of laboratory and field studies.--
KEV WORD* AND DOCUMENT ANALYSIS
DESCRIPTORS
b IDENTIFIERS/OPEN ENDED TERMS
c COSATI Field/Group
Emission measurenent
Stationary source monitoring
Performance specifications
Gas emissions monitoring
Visible emissions monitoring
8 OfS~RiBUTJON STATEMENT
Release unlinited
19 SECURITY CLASS (This Report;
Unclassified
20 SECURITY CLASS fThis page/
EPA Form 2220 1 (9 73)
------- |