Amendments to Standards of Performance for New Stationary Sources; Monitoring Requirements

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[AD-FRL-4507-6]

Amendments to Standards of Performance for New Stationary

Sources; Monitoring Requirements

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule and notice of public hearing.

-----------------------------------------------------------------------

SUMMARY: Revisions are proposed to the monitoring requirements of

subpart A and to performance specification 1 (PS-1) of appendix B.

Today's action proposes revisions to clarify and update requirements

for source owners and operators who must install and use continuous

stack or duct opacity monitoring equipment. Today's action also

proposes amendments regarding design and performance validation

requirements for continuous opacity monitoring system (COMS) equipment

in appendix B, PS-1. These amendments to subpart A and PS-1 will not

change the affected facilities' applicable emission standards or

requirement to monitor. The amendments will: (1) clarify owner and

operator and monitor vendor obligations, (2) reaffirm and update COMS

design and performance requirements, and (3) provide EPA and affected

facilities with equipment assurances for carrying out effective

monitoring.

A public hearing will be held, if requested, to provide interested

persons an opportunity for oral presentation of data, views, or

arguments concerning the proposed rule.

DATES: Comments. Comments must be received on or before January 24,

1995.

Public Hearing. If anyone contacts EPA requesting to speak at a

public hearing by December 16, 1994, a public hearing will be held on

December 27, 1994 beginning at 10 a.m. Persons interested in attending

the hearing should call the contact person mentioned under ADDRESSES to

verify that a hearing will be held.

Request to Speak at Hearing. Persons wishing to present oral

testimony at the public hearing must contact EPA by December 5, 1994.

ADDRESSES: Comments. Comments should be submitted (in duplicate if

possible) to: Air Docket Section (LE-131), Attention: Docket No. A-91-

07, U.S. Environmental Protection Agency, 401 M Street, SW.,

Washington, DC 20460.

Public Hearing. If anyone contacts EPA requesting a public hearing,

it will be held at EPA's Office of Emission Measurement Laboratory

Building, Research Triangle Park, North Carolina. Persons interested in

attending the hearing or wishing to present oral testimony should

contact Mr. Solomon O. Ricks, Emission Measurement Branch (MD-19),

Technical Support Division, U.S. Environmental Protection Agency,

Research Triangle Park, North Carolina 27711, telephone number (919)

541-3576.

Docket. A docket, No. A-91-07, containing information relevant to

this rulemaking, is available for public inspection between 8:30 a.m.

and noon and 1:30 p.m. and 3:30 p.m., Monday through Friday, at EPA's

Air Docket Section, room M-1500, First Floor, Waterside Mall, 401 M

Street, SW., Washington, DC 20460. A reasonable fee may be charged for

copying.

FOR FURTHER INFORMATION CONTACT: For information concerning the

standard, contact Mr. Solomon Ricks at (919) 541-5242, Emission

Measurement Branch, Technical Support Division (MD-19), U.S.

Environmental Protection Agency, Research Triangle Park, North Carolina

27711.

SUPPLEMENTARY INFORMATION: The following outline is provided to aid in

reading the preamble to the proposed method.

I. Introduction

II. Summary of Proposed Revision

A. Design

B. Demonstration of Design

C. Performance Specifications

III. Administrative Requirements

A. Public Hearing

B. Docket

C. Office of Management and Budget Reviews

D. Regulatory Flexibility Act Compliance

I. Introduction

These revisions to subpart A and PS-1 will apply to all continuous

opacity monitors installed for purposes of monitoring opacity, as

required in the Code of Federal Regulations (CFR). These requirements

may also apply to stationary sources located in a State, District,

Reservation, or Territory that has adopted these requirements into its

implementation plan.

The PS-1, Specifications and Test Procedures for Opacity Continuous

Emission Monitoring Systems in Stationary Sources, was first

promulgated in the Federal Register (40 FR 64250) on October 6, 1975. A

subsequent revision to this specification was promulgated in the

Federal Register March 30, 1983 (48 FR 13322). These specification

revisions for COMS's are based on information obtained by EPA from

additional experience with the procedures since that promulgated

revision. Prior to today's action, the proposal was distributed for

comment to a review group of EPA Regional Offices and a State agency.

In addition, EPA solicited input from opacity monitor manufacturers and

concerned industries. The EPA considered comments from these sources

and incorporated additional changes.

The specifications, in total, shall apply to all COMS's installed

or replaced after the date of promulgation. All COMS that have been

installed prior to the date of promulgation of these revisions would

not be subject to these revisions unless replaced or specifically

required to comply. Following promulgation, a source owner, operator,

or manufacturer will be subject to these PS's if installing a new COMS,

relocating a COMS, replacing a COMS, recertifying a COMS that has

undergone substantial refurbishing (in the opinion of the enforcing

agency), or has been specifically required to recertify the COMS with

these revisions.

The COMS, which met PS-1 prior to these revisions, may not meet

today's proposed specifications. Alternative designs or procedural

modifications to PS-1, approved by the Administrator prior to the

proposal of these revisions, are not applicable to monitors subject to

these revisions. However, source owners and operators, as well as

manufacturers, may apply or reapply per Sec. 60.11(i) to the

Administrator for alternatives to these PS's.

II. Summary of Proposed Revisions

Today's action proposes to restructure and clarify PS-1. The

proposal restructures organization of the specification and delineation

of responsibilities to demonstrate conformance with design, location,

and performance requirements.

Opacity monitoring system technology works in the following way:

light with specific spectral characteristics is projected from a lamp

through the effluent in the stack or duct, and the intensity of the

projected light is then measured by a sensor. The projected light is

attenuated because of absorption and scatter by the particulate matter

in the effluent; the percentage of light attenuated is defined as the

opacity of the emission. Transparent stack emissions that do not

attenuate light have a transmittance of 100 percent or an opacity of

zero percent. Opaque stack emissions that attenuate all of the light

have a transmittance of zero percent or an opacity of 100 percent. The

opacity measured at the location of the COMS is corrected for

differences in measurement pathlength from stack or vent exit

conditions and reported as the facility's opacity emission.

A. Design

The design requirements, as promulgated March 30, 1983, continue to

be required. The following additional and upgraded requirements are

being proposed:

1. The optical alignment device, used to assure that the system is

optically aligned, must clearly indicate misalignment before the

2 percent opacity shift allowed by the design performance limit

occurs. Therefore, systems with subjective observation indicators,

e.g., ``top-dead-center,'' may not comply. Manufacturer evaluations,

conducted in 1989 and 1990, found that several manufacturers were

revising their alignment devices to clearly indicate misalignment.

However, 1992 evaluations have identified a continuing problem of

clearly depicting misalignment. Specifically, a COMS was placed in zero

alignment, yet, the alignment sight directions would have indicated

that it was misaligned. Realignment in this instance could have caused

a negative bias in future recordings.

2. In addition, in 1992, EPA observed COMS responses over different

distances for the COMS alignment test and concluded that the alignment

check should be done at the installation pathlength and not at 8

meters, as currently required by PS-1. This is also a practice of the

manufacturers due to specific aperture, objective lens, and

installation pathlength requirements. Because the alignment check and

performance test are considered installation pathlength specific and

because of the Agency's need to assure clarity in the misalignment, the

optical alignment test is now required at the site of the installation.

This will provide an opportunity for the enforcing agency and source

owner or operator to evaluate and establish clarity in the depiction of

misalignment.

3. The angle of view (AOV) and angle of projection (AOP)

specifications have been revised. Defined as the angle that contains

all of the photopic radiation either detected or projected by the COMS,

the calumniation of the light beam has been reduced to a maximum total

of 4 degrees. From 1989 to 1992 time period, EPA observed the AOV and

AOP testing, conducted by 10 major manufacturers of COMS sold in the

United States, and concluded that the AOV and AOP should be reduced

from the current 5 degrees to 4 degrees. This change also reflects

manufacturers' improvement in the instruments.

4. The COMS must provide a means to simulate a zero and upscale

calibration value in order to check the COMS transmitter/receiver

calibration. The calibration checking system shall include, at the same

time, all the optical and electromechanical equipment used in the

normal measurement mode. The checking system will measure and provide a

permanent record of the COMS calibration status. The COMS's, which

conduct zero and upscale calibration drift (CD) assessments without

simultaneously checking all the components actively used in normal day-

to-day opacity measurement, are deemed to deviate from the proposed

specifications. The Agency recognizes that some existing dual-path

COMS's do not include the reflector in the daily zero and span check.

However, these COMS's have been, and will continue to be, an accepted

exception to the simultaneous check requirement.

5. The COMS shall provide operators visual or audible alarms for

exceeding PS-1, operation specification, equipment failures, and

effluent opacity standards.

6. The COMS shall provide an automated means to assess and record

accumulated automatic zero compensations on a 1-hour and 24-hour basis.

The 1-hour is specifically required only during a specific 24-hour

period of the operational test period. The 24-hour assessment and

recording of the 24-hour accumulated CD is a continual requirement of

the system.

7. The automatic compensation for dirt accumulation on the window

surfaces of the COMS requires including the compensation allowance in

the 4 percent opacity tolerance for zero CD adjustment. The measurement

for determining compensation shall be conducted on those surfaces that

are directly in line with the light beam used to measure the effluent

opacity. In addition, only those optical surfaces, directly in the

light beam path under normal operation to measure opacity, may be

compensated for dust accumulation. The EPA has determined that systems

that attempt to measure dust accumulation in locations, other than the

measurement path of the normally transmitted measurement light beam or

assume equal and uniform dust accumulations on unmeasured surfaces

(e.g., reflectors), could result in unacceptable negative biases in

opacity measurements. Those automatic dust compensation systems that

meet the optical path assessment criteria may demonstrate and petition

the Administrator for an increase in compensation to 20 percent opacity

adjustment.

8. Providing a means to independently audit the COMS will be

required of all new and replacement COMS's. Manufacturers of COMS's,

meeting the March 30, 1983 specifications, have routinely incorporated

this performance check allowance into their designs. In addition, the

proposed specifications recognize and allow for the use of a ``zero-

jig.'' This apparatus, which must have a unique serial number specific

to the installed COMS, may be used to conduct performance check audits

as well as for zero calibrations of the COMS transmitter/receiver

(dual-path systems) during installation.

9. The COMS must automatically correct opacity emissions measured

at the COMS installation location to the emission outlet pathlength.

The capability to automatically display and record the pathlength

correction factor (PLCF) changes must be incorporated into the COMS

design.

B. Demonstration of Design

The proposed demonstration of design conformance requirements of

PS-1 have evolved from historical observation of the current required

demonstrations. Such demonstrations have customarily been done by COMS

manufacturers due to their unique capabilities at the manufacturing

locations. The EPA believed this to be appropriate in 1983 when it

allowed the source owner or operator to obtain a Manufacturer's

Certificate of Conformance (MCOC) rather than conducting design

performance testing at the source. The EPA, then and now, continues to

hold the source owner and operator responsible for the overall

demonstration that the COMS meets all of PS-1 requirements. Today's

proposed specification requires COMS manufacturers to conduct the

design specification testing required in section 6.0, Design

Specification Verification Procedure. However, this does not relieve

the source owners or operators from demonstrating compliance with

applicable COMS requirements. Manufacturers of COMS's are encouraged,

although not required, to seek an EPA evaluation of their design

specification demonstration procedures for each model of COMS marketed

as conforming with these specifications. The evaluation will provide

competitive advantages to successful demonstrations as well as

providing purchaser assurances of initial conformance to regulatory

requirements. The activity is expected to reduce retrofit and

corrective costs potentially encountered with nonconforming systems.

The evaluation will also ensure that COMS's manufactured outside the

United States (U.S.), for subsequent sale in the U.S., perform testing

in the U.S. prior to sale.

The design specification testing requirements assume that apparatus

used to conduct demonstrations is proper. Adequately rugged apparatus

will assure the accuracy and rigor required at the specification

frequency. The testing requirements for demonstrating conformance with

the design specifications assume that the testing apparatus, used to

conduct such tests, were properly chosen, adequately rugged, and

sufficiently accurate. The 1989-1990 evaluation of procedures,

conducted by the COMS manufacturers, found a broad spectrum of

sophistication in demonstration apparatus. The detection limits of some

equipment, used in the manufacturers' procedures, were found to be a

limiting factor in the conduct of some tests. If manufacturers'

operations are not sufficiently precise, accurate, or permanent,

evaluations may indicate problems in repeatability.

The 1983 monitor selection process for design demonstration testing

did not clearly specify how to select a monitor if the manufacturing

operation was not continuous or did not include large inventories. Most

COMS manufacturing operations are likely to use off-the-shelf or

imported components, and the COMS's are constructed and shipped as

orders are received. Large inventories generally do not exist, and

production is demand-based. Today's proposed monitor selection process

revises the 1983 process to recognize some of these typical

manufacturing operations. The proposal requires that each COMS

installed, pursuant to the requirements of an applicable standard, have

a serial number assigned by the manufacturer. (Note: If a zero-jig is

manufactured and provided for the COMS model type, a unique serial

number for the zero-jig, corresponding to the installed COMS serial

number, is required.) The proposed model selection process of section

6, Design Specification Verification Procedure, specifies that the COMS

(per model) selection will be based on a randomly-selected COMS

produced during the month or a randomly-selected COMS per 20 such

monitors produced, whichever is more frequent.

If 20 or more COMS's of a particular model are produced in a month,

the manufacturer shall randomly select a COMS of that model from that

month's production for conducting the design conformance tests in

sections 6.2 through 6.6. Otherwise, the manufacturer shall select a

COMS with a serial number in a distinct lot of 20 monitors of that

model produced, or to be produced, and shall test that COMS for

demonstrating conformance with the design specifications.

The proposed specification does not require additional sampling and

testing upon the finding of nonconformance with the design

requirements. Upon such finding, however, the specification requires

the manufacturer to notify all sources who have purchased that model of

COMS if the COMS was manufactured since the model's last successful

demonstration of conformance. The manufacturer must send a copy of all

such notifications to EPA.

The design specification demonstration incorporates other

requirements.

1. An outline of an example of a MCOC is provided to give direction

on the presentation of supporting documentation for performance

demonstration tests.

2. The current specifications do not require verification of

supporting COMS component conformance documentation, such as lamp

emissivity, which is used for the construction of a spectral response

curve. Also, the 1983 specifications did not put any limit on the valid

time period for certain supporting demonstrations such as development

of the spectral response curve. As a result, some MCOC's now reflect 5-

year old data. The 1989-1990 evaluations of the COMS manufacturers

identified incorrect calculation procedures as well as inclusion of a

component that caused an unacceptable COMS response. The manufacturer

in the latter case, who calculated the response curve, was unaware that

the component's characteristics had changed.

The proposed PS's require the manufacturer to measure the spectral

response curve of the COMS. The specifications will no longer allow the

manufacturer, or source owner or operator, to calculate the spectral

response curve from lamp emissivity, detector response, and filter

characteristics. The EPA has identified two acceptable systems and

procedures for measuring the COMS spectral response curve at 10 nm

intervals from 300 to 800 nm. Information, provided by the

manufacturers, indicates that this requirement is not overly

burdensome. This information is necessary because, from this

information, both the peak and mean spectral response can be accurately

determined.

3. The AOV and AOP tests have been clarified and reaffirmed in the

specification. Note that no alternative procedures have been approved

for the AOV and AOP, even though manufacturers may be using

alternatives. The specification clearly states that alternative

procedures require approval by the Administrator. Therefore, source

owners and operators must obtain approvals of an alternative procedure

prior to seeking a site-specific COMS approval.

C. Performance Specifications

The major change to the PS-1 demonstrations from the 1983

specification occurs in section 7, Performance Specification

Verification Procedures. The proposal requires that testing be

conducted at the affected facility. Current practices have allowed

verification tests to be conducted at the COMS manufacturers' facility.

However, the 1983 specifications intended verification testing to be

performed at the affected facility to ensure that the entire COMS

system was evaluated for the specific installation. The current

practices have resulted in excluding the data recording portion of the

system used at the installation under normal measurement conditions

and, thereby, limiting assessment of the COMS for the specific

installation. For this reason, the proposed specification clarifies

where the required PS-1 testing of section 7 is to be conducted.

The proposal also simplifies procedures for calibration attenuator

selection. The COMS's have been typically required to demonstrate a

certain degree of calibration error over a range of emissions specified

as the span value. This span value may or may not correspond to the

actual instrument range (0 to 100 percent opacity). The primary concern

of COMS data users is the capability of the instrument to measure

accurately opacities at, or near the applicable standard. Once the

opacity level exceeds the standard, the magnitude of the emissions

tends to be of lesser concern than the duration of the operation.

Therefore, the proposal includes selection of appropriate attenuators

and calibration error test for the applicable opacity emission

standard.

The specifications recognize the need to set a surrogate emission

limit for purposes of conducting the calibration error test. This is

due to the fact that some authorities set opacity limitations of zero

percent, and the specification must assess calibration accuracy and

linearity around the standard. Attenuator opacity values are specified

in terms of optical density (or transmittance) which exhibits a

logarithmic relationship to opacity. Because of the nonlinear nature of

this relationship, COMS calibration at high opacity values becomes more

difficult. At the low opacity emission limitations of current

regulations, e.g., 20 percent, the nonlinear relationship of opacity

and optical density is not severe and is within the error specification

in this proposal. Therefore, a surrogate limit for purposes of the

calibration error test would continue to assure acceptable COMS

accuracy, even though the actual emission limitation was below the

surrogate value. Consequently, where emission standards have been set

at 10 percent opacity or less, the proposal specifies a surrogate 10

percent opacity limit for purposes of conducting the calibration error

test. The EPA contacted attenuator manufacturers who indicated that

certifiable low opacity, i.e., 2 percent opacity (98 percent

transmittance) attenuators, necessary to comply with the required

testing, are available.

Where dual standards are specified, e.g., a 10-percent opacity

limitation with an allowance for one 6-minute period in an hour not to

exceed 40 percent opacity, the calibration error test must be conducted

over the full range of standards. The test may be conducted as a three-

point calibration error test over the range, i.e., 10 to 40 percent

opacity, or separate three-point calibration error tests around each

requirement.

The proposal describes procedures for setting the instrument zero

and upscale calibration values and zero alignment. The proposal

specifies that a check of the adequacy of the zero setting with the

alignment must be made. If discrepancies between measured values exist,

they should be resolved prior to stack installation. At this time (if

part of the system), the zero-jig zero setting also should be adjusted

to coincide with the instrument zero for the monitor pathlength,

recorded and permanently set.

The 1983 specifications did not specify the use of secondary

instruments to establish secondary attenuators for calibration error

tests. Today's specification provides a procedure for qualifying a

secondary instrument. The conditioning period has been incorporated

into the operational test period. The operational test period is now a

336-hour test period during which the maintenance and operational

restrictions, that were required of both conditioning and operational

periods in the 1983 specifications, still apply. An additional test has

been included to address short-term diurnal fluctuations in COMS's

opacity output readings. This 1-hour drift test and specification are

designed to assess and limit the amount of zero and upscale calibration

value drifts due to operational conditions occurring during a 24-hour

period.

III. Administrative Requirements

A. Public Hearing

In accordance with section 307(d)(5) of the Clean Air Act as

amended by Public Law 101-549, the Clean Air Act Amendments of 1990, a

public hearing will be held, if requested, to discuss the proposed

revisions to subpart A and appendix B. Persons wishing to make oral

presentations should contact EPA at the address given in the ADDRESSES

section of this preamble. Oral presentations will be limited to 15

minutes each. Any member of the public may file a written statement

with the EPA before, during, or within 30 days after the hearing.

Written statements should be addressed to the Air Docket Section

address given in the ADDRESSES section of this preamble.

A verbatim transcript of the hearing and written statements will be

available for public inspection and copying during normal working hours

at EPA's Air Docket Section in Washington, D.C. (see ADDRESSES section

of this preamble).

B. Docket

The docket is an organized and complete file for all information

submitted or otherwise considered by EPA in the development of this

proposed rulemaking. The principal purposes of the docket are: (1) to

allow interested parties to identify and locate documents so that they

can effectively participate in the rulemaking process, and (2) to serve

as the record in case of judicial review (except for interagency review

materials) [Clean Air Act Section 307(d)(7)(A)].

C. Office of Management and Budget Review

Due to the timing of review which was pre-Executive Order 12866 (58

FR 51735; October 4, 1993), this NPRM underwent Executive Order 12291

Review. Under Executive Order 12291, EPA must judge whether a

regulation is ``major'' and, therefore, subject to the requirement of a

regulatory impact analysis. This rulemaking is not major because it

will not have an annual effect on the economy of $100 million or more;

it will not result in a major increase in costs or prices; and there

will be no significant adverse effects on competition, employment,

investment, productivity, innovation, or on the ability of U.S.-based

enterprises to compete with foreign-based enterprises in domestic or

export markets.

D. Regulatory Flexibility Act Compliance

Pursuant to section 605(b) of the Regulatory Flexibility Act, 5

U.S.C. 605(b), the Administrator certifies that this rule will not have

a significant impact on a substantial number of small entities because

no additional cost will be incurred by such entities. The requirements

of the proposal reaffirm the existing requirements for demonstrating

conformance with the COMS PS's. Small entities will be affected to the

same degree that they are affected under existing requirements.

This rule does not contain any information collection requirements

subject to the Office of Management and Budget review under the

Paperwork Reduction Act of 1980, 44 U.S.C. 3501 et seq.

List of Subjects in 40 CFR Part 60

Environmental protection, Air pollution control, Particulate

matter.

Dated: November 8, 1994.

Carol M. Browner,

Administrator.

The EPA proposes that 40 CFR part 60 be amended as follows:

1. The authority citation for part 60 continues to read as follows:

Authority: 42 U.S.C. 7401, 7411, 7414, 7416, and 7601.

Subpart A--[Amended]

2. Section 60.13 is amended by revising paragraph (d)(1) to read as

follows:

Sec. 60.13 Monitoring requirements.

* * * * *

(d)(1) Owners and operators of continuous emission monitoring

systems (CEMS's) installed in accordance with the provisions of this

part, shall automatically check the zero (or low level value between 0

and 20 percent of span value) and span (50 to 100 percent of span

value) calibration drifts (CD's) at least once daily. For CEMS's used

to measure opacity in accordance with the provisions of this part,

owners and operators shall automatically, intrinsic to the continuous

opacity monitoring system (COMS), check the zero and upscale

calibration drifts at least once daily. For a particular COMS, the

acceptable range of zero and upscale calibration materials shall be as

defined in the applicable version of PS-1 in appendix B of this part.

Where an opacity standard of 10 percent or less, corrected to stack

exit conditions, has been specified, a surrogate 10 percent opacity

standard shall be used for determining the daily calibration values for

the drift assessments required above. The zero and upscale value shall,

as a minimum, be adjusted whenever either the 24-hour zero drift or the

24-hour span drift exceeds two times the limit of the applicable PS in

appendix B. The system must allow the amount of the excess zero and

span drift to be recorded and quantified whenever specified. For

COMS's, the optical surfaces, exposed to the effluent gases, shall be

cleaned prior to performing the zero and span drift adjustments, except

for systems using automatic zero adjustments. The optical surfaces

shall be cleaned when the cumulative automatic zero compensation

exceeds 4 percent opacity.

* * * * *

Appendix B--[Amended]

3. Appendix B to part 60 is amended by revising Performance

Specification 1 to read as follows:

Appendix B to Part 60--Performance Specifications

* * * * *

Performance Specification 1--Specifications and Test Procedures for

Continuous Opacity Monitoring Systems in Stationary Sources

1. Applicability and Principle

1.1 Applicability.

1.1.1 This specification contains requirements for the design,

performance, and installation of instruments for continuous opacity

monitoring systems (COMS's) and data computation procedures for

evaluating the acceptability of a COMS. Certain design requirements

and test procedures, established in this specification, may not

apply to all instrument designs proposed for installation after the

effective date of these specifications. In such instances, approval

for the use of alternative design requirements and test procedures

shall be obtained from the Administrator prior to a demonstration of

conformance with these specifications.

1.1.2 Performance Specification 1 (PS-1) applies to COMS's

installed on or after the effective date which is the date of

promulgation of these specifications. The COMS's installed prior to

the effective date are required to comply with the provisions and

requirements of PS-1 as promulgated on March 30, 1983 (48 FR 13322).

1.1.3 A COMS installed before the effective date of these

specifications need not be re-tested to demonstrate compliance with

these PS's unless specifically required by regulatory action other

than the promulgation of PS-1. If a COMS installed prior to the

effective date is replaced or relocated, this PS-1 shall apply to

the COMS replacement or as relocated.

1.2 Principle.

1.2.1 The opacity of particulate matter in stack emissions is

continuously monitored and corrected to a stack exit pathlength by a

measurement system, based upon the principle of transmissometry.

Light, having specific spectral characteristics, is projected from a

lamp through the effluent in the stack or duct, and the intensity of

the projected light is measured by a sensor. The projected light is

attenuated because of absorption and scatter by the particulate

matter in the effluent; the percentage of visible light energy

attenuated is defined as the opacity of the emission.

1.2.2 This specification establishes specific design,

performance, and installation criteria for the COMS. Prior to

installation, source owners and operators must provide verification

that the COMS has met the design specifications. Prior to

installation, it is recommended that the COMS installation location

be reviewed and approved by the appropriate regulatory authority.

Then, the owner and operator calibrates, installs, and operates the

COMS for a specified test period. During this specified test period,

the COMS is further evaluated to determine conformance with PS-1.

2. Definitions

2.1 Angle of Projection (AOP). The angle that contains all of

the radiation projected from the lamp assembly of the analyzer at a

level of greater than 2.5 percent of the peak illuminance.

2.2 Angle of View (AOV). The angle that contains all of the

radiation detected by the photodetector assembly of the analyzer at

a level greater than 2.5 percent of the peak detector response.

2.3 Calibration Drift (CD). The difference in the COMS output

readings from the upscale calibration value after a stated period of

normal continuous operation during which no unscheduled maintenance,

repair, or adjustment took place.

2.4 Calibration Error. The difference between the opacity

values indicated by the COMS and the known values of a series of

calibration attenuators (filters or screens).

2.5 Centroid Area. A concentric area that is geometrically

similar to the stack or duct cross-section and is no greater than 1

percent of the stack or duct cross-sectional area.

2.6 Continuous Opacity Monitoring System. The total equipment

required for the determination of opacity. The system consists of

the following major subsystems:

2.6.1 Analyzer. That portion of the installed COMS that senses

the pollutant and generates an output that is a function of the

opacity.

2.6.2 Data Recorder. That portion of the installed COMS that

provides a permanent record of the analyzer output in terms of

opacity. The data recorder may include automatic data reduction

capabilities.

2.6.3 Sample Interface. That portion of the installed COMS that

protects the analyzer from the effects of the stack effluent and

aids in keeping the optical surfaces clean.

2.7 External Audit Device. The inherent design, equipment, or

accommodation of the COMS allowing the independent assessment of

system calibration and operation. An adequate design shall permit

the use of external (i.e., not intrinsic to the instrument) neutral

density filters to assess monitor operation.

2.8 External Zeroing Device (Zero-Jig). An external, removable

device for simulating or checking the cross-stack zero alignment of

the COMS.

2.9 Full Scale. The maximum data display output of the COMS.

For purposes of recordkeeping and reporting, full scale shall be

greater than 80 percent opacity.

2.10 Mean Spectral Response. The mean response wavelength of

the wavelength distribution for the effective spectral response

curve of the transmissometer.

2.11 Opacity. The fraction of incident light that is attenuated

by an optical medium. Opacity (Op) and transmittance (Tr) are

related by: Op=1-Tr.

2.12 Operational Test Period. A period of time (336 hours)

during which the COMS is expected to operate within the established

PS's without any unscheduled maintenance, repair, or adjustment.

2.13 Optical Density. A logarithmic measure of the amount of

incident light attenuated. Optical Density (OD) is related to the

transmittance and opacity as follows: OD = -log10 (1-Op).

2.14 Pathlength. The depth of effluent in the light beam

between the receiver and the transmitter of a single-pass trans-

missometer, or the depth of effluent between the transceiver and

reflector of a double-pass transmissometer. Three pathlengths are

referenced by this specification as follows:

2.14.1 Emission Outlet Pathlength. The pathlength (depth of

effluent) at the location where emissions are released to the

atmosphere. For noncircular outlets, D = (2LW)/(L + W), where L is

the length of the outlet and W is the width of the outlet. Note that

this definition does not apply to positive pressure baghouse outlets

with multiple stacks, side discharge vents, ridge roof monitors,

etc.

2.14.2 Installation Pathlength. The installation flange-to-

flange distance.

2.14.3 Monitoring Pathlength. The effective depth of effluent

(the distance over which the light beam is actually evaluating the

stack effluent) measured by the COMS at the installation location.

Monitoring pathlength is to be used for the optical alignment,

response, and calibration error tests of section 7 and calculation

of the pathlength correction factor (PLCF). The effective depth of

effluent measured by the COMS must be equal to or greater than 90

percent of the distance between duct or stack walls.

2.15 Peak Spectral Response. The wavelength of maximum

sensitivity of the transmissometer.

2.16 Primary Attenuators. Primary attenuators are those

calibrated by the National Institute of Standards and Technology

(NIST).

2.17 Response Time. The amount of time it takes the COMS to

display on the data recorder 95 percent of a step change in opacity.

2.18 Secondary Attenuators. Secondary attenuators are those

calibrated against primary attenuators according to procedures in

section 7.1.3.

2.19 Transmissometer. That portion of the installed COMS that

includes the sample interface and the analyzer.

2.20 Transmittance. The fraction of incident light that is

transmitted through an optical medium.

2.21 Upscale Calibration Value. The opacity value at which a

calibration check of the COMS is performed by simulating an upscale

opacity condition as viewed by the receiver. An opacity value

(corrected for pathlength) that is 150 to 190 percent of the

applicable opacity standard.

2.22 Zero Calibration Value. A value at which a calibration

check of the COMS is performed by simulating a zero opacity

condition as viewed by the receiver. An opacity value (corrected for

pathlength) that is 0 to 10 percent of the applicable opacity

standard.

2.23 Zero Drift. The difference in the COMS output readings

from the zero calibration value after a stated period of normal

continuous operation during which no unscheduled maintenance,

repair, or adjustment took place.

2.24 Zero and Upscale Calibration Value Attenuator System. An

inherent system of the COMS which can be an automatic electro-

mechanical and filter system for simulating both a zero and upscale

calibration value, providing an assessment and record on the

calibration of the instrument. Optical filters or screens with

neutral spectral characteristics, or other device that produces a

zero or an upscale calibration value shall be used.

3. Apparatus

3.1 Continuous Opacity Monitoring System. A COMS that meets the

design and PS's of PS-1, including a suitable data recorder, such as

an analog strip chart recorder or other suitable device (e.g.,

digital computer) with an input signal range compatible with the

analyzer output.

3.2 Calibration Attenuators. Minimum of three. These

attenuators must be optical filters with neutral spectral

characteristics selected and calibrated according to the procedures

in sections 7.1.2 and 7.1.3 and of sufficient size to attenuate the

entire light beam received by the detector of the COMS.

3.3 Calibration Spectrophotometer. A laboratory

spectrophotometer meeting the following minimum design

specifications:

------------------------------------------------------------------------

Parameter Specification

------------------------------------------------------------------------

Wavelength range................... 300-800 nm.

Detector angle of view............. 10

percent of the average opacity value measured at the location

meeting the installation criteria in section 4.2, and the difference

between any two average opacity values is less than 2 percent

opacity (absolute). To conduct this demonstration, simultaneously

measure the opacities at the two locations or paths for a minimum

period of time (e.g., 180-minutes) covering the range of normal

operating conditions and compare the results. The opacities of the

two locations or paths may be measured at different times, but must

represent the same process operating conditions. Alternative

procedures for determining acceptable locations may be used if

approved by the Administrator.

4.4 Slotted Tube. For COMS that uses a slotted tube, the

slotted tube must be of sufficient size and orientation so as not to

interfere with the free flow of effluent through the entire optical

volume of the COMS photodetector. The manufacturer must also present

information in the certificate of conformance that the slotted tube

minimizes light reflections. As a minimum, this demonstration shall

consist of laboratory operation of the COMS both with, and without

the slotted tube in position. The slotted portion must meet the

monitoring pathlength requirements of 2.14.3.

5. Design Specifications

5.1 Design Specifications. The COMS shall comply with the

following design specifications:

5.1.1 Peak and Mean Spectral Responses. The peak and mean

spectral responses must occur between 500 nm and 600 nm. The

response at any wavelength below 400 nm or above 700 nm shall be

less than 10 percent of the peak spectral response.

5.1.2 Angle of View. The total AOV shall be no greater than 4

degrees.

5.1.3 Angle of Projection. The total AOP shall be no greater

than 4 degrees.

5.1.4 Optical Alignment Sight. Each analyzer must provide some

method for visually determining that the instrument is optically

aligned. The method provided must be capable of clearly indicating

that the unit is misaligned when an error of no greater than

2 percent opacity occurs due to misalignment at the

installation monitoring pathlength. Instruments that are capable of

providing a clear path zero check while in operation on a stack or

duct with effluent present, and while maintaining the same optical

alignment during measurement and calibration, need not meet this

requirement (e.g., some ``zero pipe'' units). The owner and operator

shall insure that the COMS manufacturer's written procedures and the

certificate of conformance depict the correct alignment and the

misalignment corresponding to a 2 percent opacity shift

as viewed using the alignment sight.

5.1.5 Simulated Zero and Upscale Calibration System. Each

analyzer must include a calibration system for simulating a zero and

upscale calibration value. This calibration system must provide, as

a minimum, a simultaneous system check of all of the active analyzer

internal optics, all active electronic circuitry including the

primary light source (lamp) and photodetector assembly, and electro-

mechanical systems used during normal measurement operation.

5.1.6 Automatic Zero and Upscale Value Compensation Indicator

and Alarm. The COMS shall provide an automated means for determining

and recording the actual amount of 24-hour zero compensation on a

daily basis. The COMS also shall provide an alarm (visual or

audible) when a 4 percent opacity zero compensation has

been exceeded. This indicator shall be at a location which can be

seen or heard by the operator (e.g., process control room) and

accessible to the operator (e.g., the data output terminal).

5.1.6.1 During the operational test period, the COMS also must

provide a means for determining and automatically recording the

actual amount of upscale calibration value compensation at specified

1-hour intervals so that the actual 1-hour upscale calibration value

shift can be determined (see section 7.2.3).

5.1.6.2 If the COMS has a feature that provides automatic zero

compensation for dirt accumulation on exposed optical and mechanical

surfaces, the compensation allowance for dust may be included up to

20 percent opacity. For all other systems, the dirt accumulation on

exposed optical and mechanical surfaces are limited to 4 percent

opacity zero compensation allowance of section 5.1.6. The

determination of dirt accumulation on all surfaces exposed to the

effluent being measured shall include only those surfaces in the

direct path of the measuring light beam under normal opacity

measurement. The dust accumulation must actually be measured.

5.1.7 External Calibration Filter Access. The COMS must be

designed to accommodate an independent assessment of the total

systems response to audit filters. An adequate design shall permit

the use of external (i.e., not intrinsic to the instrument) neutral

density filters to assess monitor operation. This system may include

an external audit zero-jig as identified in section 3.0.

5.1.8 Pathlength Correction Factor. The COMS shall display and

record all opacity values corrected to the emission outlet

pathlength. Equations 1-7 or 1-8 may be used. The system must be

capable of independent display of the PLCF and automatically record

any changes made to the PLCF.

5.1.9 External Fault Indicator. The installed COMS must provide

a means to automatically alert the owner or operator when a

component or performance parameter has failed or been exceeded

(e.g., projector lamp failure, zero or CD operation, purge air

blower failure, data recorder failure). Indicator lights or alarms

must be visible or audible to the operator(s).

5.1.10 Data recorder resolution. The data recorder and data

acquisition system shall record and display opacity values to 0.5

percent opacity.

Table 1-1.--COMS Design Specifications

1. Peak spectral response.

2. Mean spectral response.

3. Angle of view.

4. Angle of projection.

5. Optical alignment sight.

6. Simulated zero and upscale calibration system.

7. Automated zero compensation recording and indicating system.

8. Automated upscale calibration compensation recording and indicating

system.

9. External calibration filter access.

10. Pathlength correction factor recording and indicating system.

6. Design Specifications Verification Procedures

These procedures apply to all instruments installed for purposes

of complying with opacity monitoring requirements (see section 1.1,

Applicability). The source owner or operator is responsible for the

overall COMS performance demonstration required by the applicable

standards. As an alternative, the COMS manufacturer may conduct the

COMS design verification procedures called for in this section and

provide to the source owner or operator a Manufacturer's Certificate

of Conformance (MCOC). These procedures shall be conducted,

detailed, and the results submitted in the MCOC (section 9.5) as an

integral part of each COMS demonstration required by the applicable

standards. In order to assure that the design and procedures to

demonstrate conformance with this section coincide with the design

procedures as stated in the MCOC, the manufacturer is encouraged to

seek an evaluation by the Administrator of the manufacturer's

conformance demonstration practices. The procedures to demonstrate

conformance with this section may require modification to

accommodate instrument designs. All procedural modifications

required to demonstrate conformance with the specifications of this

section must be approved, in writing, by the Administrator. The

owner and operator or the manufacturer, as appropriate, shall obtain

any approvals of modifications to the specifications of this section

before regulatory agency review and acceptance of the overall COMS

performance evaluations.

Each analyzer design shall be selected as follows, in order to

demonstrate conformance with the design specifications of sections

5.1.1 to 5.1.10. The MCOC, section 9.5, for all instruments subject

to this specification shall detail the demonstration procedures as

follows:

6.1 Selection of Analyzer. For conducting the performance test

in sections 6.2 through 6.6, the manufacturer shall randomly select

(1) a COMS model from each month's production, or (2) a COMS model

with a serial number in a distinct lot of 20 such monitors produced,

whichever is more frequent.

6.2 Spectral Response. The owner and operator, or manufacturer,

shall conduct a laboratory measurement of the instrument's spectral

response curve. The procedures of this laboratory evaluation are

subject to approval of the Administrator and shall be provided to

the Administrator upon request. The owner and operator or

manufacturer, shall measure, develop, and report the effective

spectral response curve of the COMS at 10 nm intervals. Determine

and report in the MCOC the peak spectral response wavelength, the

mean spectral response wavelength using equation 1-9, and the

maximum response at any wavelength below 400 nm and above 700 nm

expressed as a percentage of the peak response.

6.3 Angle of View. In the laboratory, set up the COMS detector

as specified by the manufacturer's written instructions. Draw a

circular arc with the center of the circle located at the centroid

of a plane described by the COMS photodetector housing which the

radiation from the nondirectional light source first encounters. The

arc shall have a radius of 3 meters in the horizontal plane of the

COMS photodetector housing. Using a small (less than 3 cm)

nondirectional light source, measure and record the COMS receiver

response as the light is moved at each 5-cm interval on the arc for

30 cm on either side of the COMS detector centerline. Identify the

point on the arc furthest from the centerline which corresponds to

the point where 2.5 percent of the peak COMS detector response is

recorded. Repeat the test in the vertical direction. Then, for both

the horizontal and vertical directions, calculate the response of

the COMS detector as a function of viewing angle (26 cm of arc with

a radius of 3 cm equals 5 degrees), report relative angle of view

curves, and determine and report the angle of view.

6.4 Angle of Projection. In the laboratory, set up the COMS

light source as specified by the manufacturer's written

instructions. Draw a circular arc with the center of the circle

located at the centroid of a plane described by the last part of the

COMS lamp assembly housing encountered by the light radiation

projected from the light assembly. The arc shall have a radius of 3

meters in the horizontal plane of the COMS lamp assembly housing.

Using a small (less than 3 cm) photoelectric light detector, measure

and record the COMS light intensity as the photoelectric light

detector is moved at each 5-cm interval on the arc for 30 cm on

either side of the centerline of the light source projection. Repeat

the test in the vertical direction.

Then, for both the horizontal and vertical directions, calculate

the response of the photoelectric detector as a function of the

projection angle (26 cm of arc with a radius of 3 m equals 5

degrees). Identify the point on the arc furthest from the centerline

at which a light intensity of 2.5 percent of the peak light

intensity of the COMS light source is recorded, report the relative

angle of projection curves, and determine and report the angle of

projection.

6.5 Unacceptable Findings. Whenever a manufacturer finds that a

COMS model does not conform to any of the requirements of this

section, the manufacturer shall notify and provide the findings to

all source owners or operators that have received or installed such

nonconforming COMS models manufactured after the date of the

previous successful conformance demonstration. The manufacturer

shall also submit copies of such notifications to the U.S.

Environmental Protection Agency, Director, Stationary Source

Compliance Division (EN-341W), 401 M Street, S.W., Washington, D.C.

20460.

7. Performance Specifications Verification Procedure

The owner and operator shall perform following procedures and

tests on each COMS that conforms to the design specifications (Table

1-1) to determine conformance with the specifications of Table 1-2.

The tests described in sections 7.1.1, 7.1.4, and 7.1.5, shall be

conducted at the affected facility, in a dust-free environment,

before installing the measurement portion of the COMS system on the

stack or duct. These tests are to be performed using the entire COMS

system, including the data recording component normally used during

monitoring.

Table 1-2.--Performance Specifications

------------------------------------------------------------------------

Parameter Specifications

------------------------------------------------------------------------

Calibration errora................. 3 percent opacity.

Response time...................... 10 seconds.

Operational test periodb........... 336 hours.

Zero drift (24-hour)a.............. 2 percent opacity.

Calibration drift (24-hour)........ 2 percent opacity.

Zero drift (1-hour)................ 2 percent opacity.

Calibration drift (1-hour)......... 2 percent opacity.

------------------------------------------------------------------------

aExpressed as the sum of the absolute value of the mean and the absolute

value of the confidence coefficient.

bDuring the operational test period, the COMS must not require any

corrective maintenance, repair, replacement, or adjustment other than

that clearly specified as routine and required in the operation and

maintenance manuals.

7.1 Preliminary Adjustments and Tests.

7.1.1 Equipment Preparation.

7.1.1.1 Set up and calibrate the COMS for the monitoring

pathlength to be used in the installation as specified by the

manufacturer's written instructions. For this specification, the

monitoring pathlength distance (depth of effluent at the

installation location) specified in engineering drawings must be

verified. The owner and operator shall, following the manufacturer's

instructions, adjust the PLCF signal to yield opacity results based

on the emission outlet pathlength.

7.1.1.2 Under a clear path condition and at the required

monitoring pathlength, align the instrument using the optical sight

and set the instrument actual zero response. As part of this

alignment, include tilting the reflector unit (detector unit for

single pass instruments) on its axis until the point of maximum

instrument response is obtained. Check and record the instrument

alignment with the alignment sight. Deviations in alignment must be

rectified prior to proceeding with the following performance tests.

7.1.1.3 Optical Alignment Sight. At the monitoring pathlength,

align, zero, and span the instrument. Insert an attenuator of 8 to

15 percent actual opacity into the monitoring pathlength.

7.1.1.3.1 Single Path Monitors. Using the optical alignment

site, record and report the visual depiction of alignment prior to

misalignment. Slowly misalign the COMS light assembly unit by

tilting it in the vertical plane until a 2 percent

opacity shift is obtained by the data recorder. Then, following the

manufacturer's written instructions, check the alignment.

Misalignment should be clearly discernable. Record and report the

visual depiction of misalignment as viewed using the optical

alignment sight. Realign the instrument and record the visual

depiction of alignment. Repeat this test for lateral misalignment of

the light source unit. Realign the instrument and follow the same

procedure for checking misalignment of the COMS detector unit.

7.1.1.3.2 Dual Path Monitors. Using the optical alignment site,

record and report the visual depiction of alignment prior to

misalignment. Slowly misalign the COMS transceiver unit (combined

light source and detector unit) by tilting it in the vertical plane

until a 2 percent opacity shift is obtained by the data

recorder. Then, following the manufacturer's written instructions,

check the alignment. Misalignment should be clearly discernable.

Record and report the visual depiction of misalignment as viewed

using the optical alignment sight. Realign the COMS and record and

report the visual depiction of alignment. Repeat this test for

lateral misalignment of the transceiver unit. As an alternative to

the lateral misalignment of the transceiver unit, a lateral

misalignment of the reflector unit may be performed.

7.1.1.4 Simulated Zero and Calibration Value Check. Adjust,

record, and report the COMS zero alignment response so that the

simulated zero output equals the COMS actual clear path zero output

established for the monitoring pathlength. Measure and record the

indicated upscale calibration value. The upscale calibration value

reading must be within the required opacity range (see Definition

2.21).

7.1.2 Calibration Attenuator Selection.

7.1.2.1 Based on the required opacity standard, select a

minimum of three calibration attenuators (low-, mid-, and high-

level) based on the following formulas in Table 1-3:

Table 1-3.--Required Calibration Attenuator Values

Low level--20 to 60 percent of the opacity standard.

Mid level--80 to 120 percent of the opacity standard.

High level--150 to 200 percent of the opacity standard.

7.1.2.2 Calculate the attenuator values required to obtain a

system response equivalent to the applicable values in the ranges

specified in table 1-2 using equation 1-1. Select attenuators having

the values closest to those calculated by equation 1-1. A series of

filters with actual opacity values relative to the values calculated

are commercially available.

TP25NO94.000

Where:

OP1=Nominal opacity value of required

low-, mid-, or high-range calibration attenuators.

OP2=Desired attenuator opacity value from Table 1-2 at the span

required by the applicable subpart.

L1=Monitoring pathlength.

L2=Emission outlet pathlength.

7.1.3 Attenuator Calibration.

7.1.3.1 Primary Attenuators. Attenuators are designated as

primary in one of two ways:

7.1.3.1.1 They are calibrated by NIST; or

7.1.3.1.2 They are calibrated on a 6-month frequency through

the assignment of a luminous transmittance value in the following

manner:

7.1.3.1.2.1 Use a spectrophotometer meeting the specifications

of section 3.6 to calibrate the required filters. The

spectrophotometer calibration must be verified through use of a NIST

930D Standard Reference Material (SRM). The SRM 930D consists of

three (3) neutral density glass filters and a blank, each mounted in

a cuvette. The wavelengths and temperature to be used in the

calibration are listed on the NIST certificate that accompanies the

reported values. Determine and record a transmittance of the SRM

values at the NIST wavelengths (three filters at five wavelengths

each for a total of 15 determinations). A percent difference shall

be calculated between the NIST certified values and the

spectrophotometer response. At least 12 of the 15 differences (in

percent) shall be within 0.5 percent of the NIST SRM

values. No one value shall have a difference of 1.0

percent. Failure to achieve these criteria identifies a need to

recalibrate the SRM or service the spectrophotometer.

7.1.3.1.2.2 Scan the filter to be tested and the NIST blank

from wavelength 380 to 780 nm, and record the spectrophotometer

percent transmittance responses at 10 nm intervals. The sequence of

testing is: blank filter, tested filter, tested filter rotated 90

degrees in the plane of the filter, blank filter. Calculate the

average transmittance at each 10 nm interval. If any pair of the

tested filter transmittance values (for the same filter and

wavelength) differ by more than 0.25 percent, rescan the

tested filter. Failure to achieve this tolerance shall prevent the

use of the filter in the calibration tests of the COMS.

7.1.3.1.2.3 Correct the tested filter transmittance values by

dividing the average tested filter transmittance by the average

blank filter transmittance at each 10 nm interval.

7.1.3.1.2.4 Calculate the weighted tested filter transmittance

by multiplying the transmittance value by the corresponding response

factor shown in table 1-4, to obtain the Source C Human Eye

Response.

Table 1-4--Source C, Human Eye Response Factor

------------------------------------------------------------------------

Wavelength Weighting Wavelength Weighting

nanometers factora nanometers factora

------------------------------------------------------------------------

380.............. 0 590 6627

390.............. 0 600 5316

400.............. 2 610 4176

410.............. 9 620 3153

420.............. 37 630 2190

430.............. 122 640 1443

440.............. 262 650 886

450.............. 443 660 504

460.............. 694 670 259

470.............. 1058 680 134

480.............. 1618 690 62

490.............. 2358 700 29

500.............. 3401 720 14

510.............. 4833 720 6

520.............. 6462 730 3

530.............. 7934 740 2

540.............. 9194 750 1

550.............. 9832 760 1

560.............. 9841 770 0

570.............. 9147 780 0

580.............. 7992 ................. ................

------------------------------------------------------------------------

aTotal of weighting factors=100,000.

7.1.3.1.2.5 Calculate, record and report the luminous

transmittance value of the filter as follows:

TP25NO94.001

Where:

LT=Luminous transmittance

T=Weighted tested filter transmittance.

7.1.3.1.3 Recalibrate the Primary Attenuators Used for the

Required Calibration Error Test Quarterly. Recalibrates semi-

annually if the primary attenuators are used only for quarterly

calibration of secondary attenuators.

7.1.3.2 Secondary Attenuators. Calibrate the secondary

attenuators, if used to conduct COMS calibration error tests,

monthly. The filter calibration may be conducted using a laboratory-

based transmissometer calibrated as follows:

7.1.3.2.1 Use at least three primary filters of nominal

luminous transmittance 50, 70 and 90 percent, calibrated as

specified in section 7.1.3.1, to calibrate the laboratory-based

transmissometer. Using linear regression through zero opacity,

determine and record the slope of the calibration line. The slope of

the calibration line shall be between 0.99 and 1.01, and the

laboratory-based transmissometer reading for each primary filter

shall not deviate by more than 2 percent from the exact

linear regression line. If the calibration of the laboratory-based

transmissometer yields a slope or individual readings outside the

specified ranges, secondary filter calibrations shall not be

performed. Determine the source of the variations (either

transmissometer performance or changes in the primary filters) and

repeat the transmissometer calibration before proceeding with the

attenuator calibration.

7.1.3.2.2 Immediately following the laboratory-based

transmissometer calibration, insert the secondary attenuators and

determine and record the percent effective opacity value per

secondary attenuator from the calibration curve (linear regression

line).

7.1.4 Calibration Error Test. Insert the calibration

attenuators (low-, mid-, and high-level) into the light path between

the transceiver and reflector (or transmitter and receiver) at a

point where the effluent will be measured; i.e., do not place the

calibration attenuator in the instrument housing. While inserting

the attenuator, assure that the entire beam received by the detector

will pass through the attenuator and that the attenuator is inserted

in a manner which minimizes interference from the reflected light.

The placement and removal of the attenuator shall be such that an

integrated measurement of opacity is conducted over the averaging

time of the standard found in the applicable subpart. Make a total

of five nonconsecutive readings for each filter using the data

recording system to be used at the installation. Record the

monitoring system output readings in percent opacity on the data

sheet (see example figure 1-6). Subtract the ``path adjusted''

calibration attenuator values from the measurement system recorder

responses (the ``path adjusted'' calibration attenuator values are

calculated using equation 1-7 or 1-8). Calculate the arithmetic mean

difference, standard deviation, and confidence coefficient of the

five tests at each attenuator value using equations 1-3, 1-4, and 1-

5 (sections 8.1 to 8.3). Calculate the sum of the absolute value of

the mean difference and the absolute value of the confidence

coefficient for each of the three test attenuators. Report these

three values as the calibration error.

7.1.5 System Response Test. Using the high-range calibration

attenuator, alternately insert the filter five times and remove it

from the transmissometer light path. For each filter insertion and

removal, record the amount of time required for the COMS to display

on the primary data recorder 95 percent of the final step change in

opacity. Specifically, for a filter insertion, the owner or operator

shall record the time it takes to reach 95 percent of the final,

steady upscale reading; for filter removal, the time it takes for

the display reading to fall to 5 percent of the initial upscale

opacity reading (see example figure 1-7). Calculate the mean time of

the five upscale and five downscale tests. Report the greater value

as the COMS response time.

7.1.6 Data Recorder Resolution. Review the output from the

calibration error test; the COMS data recorder shall provide output

capable of being resolved into 0.5 percent opacity increments.

7.2 Preliminary Field Adjustments. Install the COMS on the

affected facility according to the manufacturer's written

instructions and the specifications in section 4, and perform the

following preliminary adjustments:

7.2.1 Optical and Zero Alignment. When the facility is not in

operation, optically align the light beam of the transmissometer

upon the optical surface located across the duct or stack (i.e., the

reflector or photodetector, as applicable) in accordance with the

manufacturer's instructions; verify the alignment with the optical

alignment sight. Under clear stack conditions, verify the zero

alignment (performed in section 7.1.1) by assuring that the

monitoring system zero response for the installation zero check

coincides with the instrument actual zero measured by the COMS as

set for the monitor pathlength prior to installation. Record these

values. Adjust the instrument actual zero response, if necessary,

and only if a clear stack condition exists. Then, after the affected

facility has been started up and the effluent stream reaches normal

operating temperature, recheck the optical alignment. If the optical

alignment has shifted, realign the optics. Note: Careful

consideration should be given to whether a ``clear stack'' condition

exists. The stack shall be monitored and the data output

(instantaneous real-time basis) examined to determine whether

fluctuations from zero opacity are occurring before a clear stack

condition is assumed to exist. Check and record the upscale

calibration value.

7.2.2 Optical and Zero Alignment (Alternative Procedure). The

procedure given in section 7.2.1 is the preferred procedure and

should be used whenever possible. However, if the facility is

operating and a zero stack condition cannot practicably be obtained,

use the zero alignment obtained during the preliminary adjustments

(section 7.1.1.2) before installing the COMS on the stack. After

completing all the preliminary adjustments and tests required in

section 7.1, install the system at the source and align the optics,

i.e., align the light beam from the transmissometer upon the optical

surface located across the duct or stack in accordance with the

manufacturer's instruction. Verify the alignment with the optical

alignment sight. The zero alignment conducted in this manner must be

verified and adjusted, if necessary, the first time a clear stack

condition is obtained after the operation test period has been

completed.

7.3 Operational Test Period. Prior to conducting the

operational testing, the owner and operator, or the manufacturer as

appropriate, should have successfully completed all prior testing of

the COMS. After completing all preliminary field adjustments

(section 7.2), operate the COMS for an initial 336-hour test period

while the source is operating. Except during times of instrument

zero and upscale calibration checks, the owner and operator must

ensure that they analyze the effluent gas for opacity and produce a

permanent record of the COMS output. During this period, the owner

and operator may not perform unscheduled maintenance, repair, or

adjustment. The owner or operator may perform zero and calibration

adjustments, exposed optical and other CEMS surface cleaning, and

optical realignment only at 24-hour intervals. Automatic zero and

calibration adjustments, made by the COMS without operator

intervention or initiation, are allowable at any time. During the

operational test period, record all adjustments, realignments, and

exposed surface cleaning. At the end of the operational test period,

verify and record that the COMS optical alignment is correct. If the

operational test period is interrupted because of source breakdown,

continue the 336-hour period following resumption of source

operation. If the test period is interrupted because of COMS

failure, record the time when the failure occurred, after the

failure is corrected, the 336-hour period and tests are restarted.

During the operational test period, perform the following test

procedures:

7.3.1 Zero Calibration Drift Test. At the outset of the 336-

hour operational test period and at each 24-hour period, record the

initial (Reference A) zero calibration value and upscale calibration

value (UC Value), see example format figure 1-8. These values are

the initial 336-hour value established during the optical and zero

alignment procedure (see section 7.2.1). After each 24-hour

interval, check and record the COMS zero response reading before any

cleaning and adjustment. Perform the zero and upscale calibration

adjustments, exposed optical and other instrument surface cleaning,

and optical realignment only at 24-hour intervals (or at such

shorter intervals as the manufacturer's written instructions

specify). If shorter intervals of zero and span adjustment are

conducted, record the drift adjustment. However, adjustments and

cleaning must be performed when the accumulated zero calibration or

upscale CD exceeds the 24-hour drift specification (2

percent opacity). From the initial and final zero readings,

calculate the zero drift for each 24-hour period. Then, calculate

the arithmetic mean, standard deviation, and confidence coefficient

of the 24-hour zero drift and the 95 percent confidence interval

using equations 1-3, 1-4, and 1-5. Calculate the sum of the absolute

value of the mean and the absolute value of the confidence

coefficient, and report this value as the 24-hour zero drift. At the

conclusion of the 336-hour operational test period, record and

report the 336-hour accumulated drift.

7.3.2 Upscale Calibration Drift Test. At each 24-hour interval,

after the zero calibration value has been checked and any optional

or required adjustments have been made, check and record the COMS

response to the upscale calibration value established under the

optical and zero alignment procedure of section 7.2.1. The upscale

calibration value established in section 7.2.1 shall be used each

24-hour period. From the initial and final upscale readings,

calculate the upscale calibration value drift for each 24-hour

period. Then, calculate the arithmetic mean, standard deviation, and

confidence coefficient of the 24-hour CD and the 95 percent

confidence interval using equations 1-3, 1-4, and 1-5. Calculate the

sum of the absolute value of the mean and the absolute value of the

confidence coefficient, and report this value as the 24-hour

calibration value drift. At the conclusion of the 336-hour

operational test period, record and report the 336-hour accumulated

drift.

7.3.3 Calibration Stability Test. Immediately following or

during, the operational test period, conduct a calibration stability

test over a 24-hour period. During this period, there will be no

unscheduled maintenance, repair, adjustment, zero and calibration

adjustments, exposed optical and other instrument surface cleaning,

or optical realignment performed. Record the initial zero and

upscale calibration opacity values and operate the monitor in a

normal manner. After each 1-hour period, record the monitor adjusted

zero and upscale opacity values. Subtract the initial zero and

upscale calibration values from each 1-hour adjusted value and

record the difference. None of these differences shall exceed +2

percent opacity. Figure 1-8 may be used for the recording of the

results of this test.

7.3.4 Retesting. If the COMS fails to meet the specifications

for the tests conducted under the operational test period, make the

necessary corrections and restart the opera- tional test period.

Depending on the correction made, it may be necessary to repeat some

or all design and other preliminary tests.

8. Equations

8.1 Arithmetic Mean. Calculate the mean of a set of data as

follows:

where:

TP25NO94.002

n = Number of data points.

n

xi = Algebraic sum of the individual measurements,

xi. i=1

8.2 Standard Deviation. Calculate the standard deviation

Sd as follows:

TP25NO94.003

8.3 Confidence Coefficient. Calculate the 2.5 percent error

confidence coefficient (one-tailed), CC, as follows:

TP25NO94.004

Where:

t0.975 = t-value (see table 1-5).

8.4 Error. Calculate the error (i.e., calibration error, zero

drift, and CD), Er, as follows:

TP25NO94.005

Table 1-5.--T-Values

------------------------------------------------------------------------

na t0.975

------------------------------------------------------------------------

2............................................................ 12.706

3............................................................ 4.303

4............................................................ 3.182

5............................................................ 2.776

6............................................................ 2.571

7............................................................ 2.447

8............................................................ 2.365

9............................................................ 2.306

10........................................................... 2.262

11........................................................... 2.228

12........................................................... 2.201

13........................................................... 2.179

14........................................................... 2.160

15........................................................... 2.145

16........................................................... 2.131

------------------------------------------------------------------------

aThe values in this table are already corrected for n-1 degrees of

freedom. Use n equal to the number of individual values.

8.5 Conversion of Opacity Values for Monitor Pathlength to

Emission Outlet Pathlength. When the monitor pathlength is different

from the emission outlet pathlength, use either of the following

equations to convert from one basis to the other (this conversion

may be automatically calculated by the monitoring system):

TP25NO94.006

TP25NO94.007

Where:

Op1 = Opacity of the effluent based upon L1.

Op2 = Opacity of the effluent based upon L2.

L1 = Monitor pathlength.

L2 = Emission outlet pathlength.

OD1 = Optical density of the effluent based upon L1.

OD2 = Optical density of the effluent based upon L2.

8.6 Mean Response Wavelength. Calculate the mean of the

effective spectral response curve from the individual responses,

gi, at the wavelength values, Li, as follows:

TP25NO94.008

Where:

Li = The wavelength at which the response gi is calculated

at 20 nm intervals.

gi = The value of the response at Li.

9. Reporting

Report the following (summarize in tabular form where

appropriate):

9.1 General Information.

a. Facility being monitored.

b. Person(s) responsible for operational and conditioning test

periods and affiliation.

c. Instrument manufacturer.

d. Instrument model number.

e. Instrument serial number.

f. Month/year manufactured.

g. Schematic of monitoring system measurement path location.

h. System span value, percent opacity.

i. Emission outlet pathlength, meters.

j. Monitoring pathlength, meters.

k. System span value, percent opacity.

l. Upscale calibration value, percent opacity.

m. Calibrated attenuator values (low-, mid-, and high-range),

percent opacity.

9.2 Design Specification Test Results.

a. Peak spectral response, nm.

b. Mean spectral response, nm.

c. Response above 700 nm, percent of peak.

d. Response below 400 nm, percent of peak.

e. Total angle of view, degrees.

f. Total angle of projection, degrees.

g. Serial number, month/year of manufacturer for unit actually

tested to show design conformance.

9.3 Performance Specification Test Results.

a. Results of optical alignment sight test (if required; see

section 7.1.1.3). The owner and operator shall, in the testing

report, include diagrams indicating the operator's view through the

optical alignment system as depicted during the alignment tests

specified in section 7.1.1.3.

b. Attenuator Calibration. Provide documentation demonstrating

compliance with the requirements for the calibration of primary

attenuators (see section 7.1.3.1). If secondary attenuators (see

section 7.1.3.2) are used, provide documentation listing the

calibration results for the laboratory-based transmissometer, dates

of the latest secondary filter calibrations, and the results of the

secondary filter calibrations. When the primary filter calibration

of section 7.1.3.1. is conducted by the filter manufacturer or by an

independent laboratory, the owner or operator shall include in the

report a statement, from the filter calibration laboratory or

manufacturer, certifying the filter luminous transmittance values

and that the procedures of section 7.1.3.1 have been followed.

c. Calibration Error Test.

(1) Report the required upscale opacity range and indicated

upscale opacity calibration value, as determined in section 7.1.1.4.

(2) Identify the low-, mid-, and high-level calibration

opacities, as determined in section 7.1.2.1.

(3) Present the data and results of the calibration error test

in the format of figure 1-6; all information required by figure 1-6

shall be supplied.

d. System Response Test. Present the data and results of the

system response test in the format of figure 1-7.

e. Zero and Calibration Drift (CD) Tests. In the format of

figure 1-8:

i. Identify the 24-hour zero drift, percent opacity,

ii. Identify the 24-hour CD, percent opacity,

iii. Identify any lens cleaning, clock time,

iv. Identify all optical alignment adjustments, clock time.

9.4 Statements Provide a statement that the operational test

period was completed according to the requirements of section 7.2.

In this statement, include the time periods during which the

operational test period was conducted.

9.5 Manufacturer's Certificate of Conformance (MCOC). The MCOC

must include the results of each test performed for the COMS(s)

sampled under section 6.1. The MCOC also shall specify the date of

testing according to sections 6.2 through 6.4, the COMS monitor

type, serial number, and the intended installation and purchaser of

the tested COMS. Section 9.5.1 identifies the minimally acceptable

information to be submitted by the manufacturer with the

certification of conformance.

9.5.1 Outline of Certificate of Conformance.

a. Instrument Description and Summary of Test Results. The

manufacturer shall supply the results of section 6 tests (spectral

response curve measurement information, angle of view, angle of

projection).

b. Test Procedures. The manufacturer shall supply a complete

description of the test equipment, procedures, and calculations used

in obtaining the results listed in Part I of the certificate. Any

procedures not conforming to those specified in section 6 or 7, must

be clearly noted. Required supporting documentation for each test

(listed below) and any necessary letters demonstrating approval of

the alternate procedure by the Administrator shall appear in the

appropriate section of Part III.

c. Supporting Documentation. Include here any information,

besides the procedural descriptions of Part II, which is necessary

for verification of compliance with sections 5 and 6. In each

section, provide letters demonstrating approval of the alternate

procedures listed in Part II, if necessary.

(1) Spectral Response. Provide the date of testing, measurement

data, and results of the latest calibration performed on the

instrument used in the measurement.

(2) Angle of View. Include the results of testing. Provide

letters demonstrating approval of alternate methods, if necessary.

(3) Angle of Projection. Include the results of testing. Provide

letters demonstrating approval of alternate methods, if necessary.

(4) Verification of Compliance with Additional Design

Specifications. The owner and operator or manufacturer shall provide

diagrams and operational descriptions of the instrument which

demonstrate conformance with the requirements of sections 5.1.5,

5.1.7, 5.1.8, 5.1.9, and 5.1.10.

9.6 Appendix. Provide the data tabulations and calculations for

any of the above demonstrations.

10. Bibliography

1. Experimental Statistics. Department of Commerce. National

Bureau of Standards Handbook 91. Paragraph 3-3.1.4. 1963. 3-31 p.

2. Performance Specifications for Stationary Source Monitoring

Systems for Gases and Visible Emissions, EPA-650/2-74-013, January

1974, U.S. Environmental Protection Agency, Research Triangle Park,

NC.

3. Koontz, E.C., Walton, J. Quality Assurance Programs for

Visible Emission Evaluations. Tennessee Division of Air Pollution

Control. Nashville, TN. 78th Meeting of the Air Pollution Control

Association. Detroit, MI. June 16-21, 1985.

4. Evaluation of Opacity CEMS Reliability and Quality Assurance

Procedures. Volume 1. U.S. Environmental Protection Agency. Research

Triangle Park, NC. EPA-340/1-86-009a.

5. Nimeroff, I. ``Colorimetry Precision Measurement and

Calibration.'' NBS Special Publication 300. Volume 9. June 1972.

6. Technical Assistance Document: Performance Audit Procedures

for Opacity Monitors. U.S. Environmental Protection Agency. Research

Triangle Park, NC. EPA-600/8-87-025. April 1987.

[FR Doc. 94-28973 Filed 11-23-94; 8:45 am]

BILLING CODE 6560-50-P