6560-50-P

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2010-0873; FRL xxxx-x]

RIN 2060-AH23

Quality Assurance Requirements for Continuous Opacity Monitoring 

Systems at Stationary Sources

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final rule.

SUMMARY: The EPA is taking direct final action to establish quality 

assurance and quality control (QA/QC) procedures for continuous 

opacity monitoring systems (COMS) used to demonstrate continuous 

compliance with opacity standards in federally enforceable 

regulations. This action is necessary because we do not currently 

have QA/QC procedures for COMS. This action would require COMS used 

to demonstrate continuous compliance to meet these procedures

(referred to as Procedure 3).

DATES: This rule is effective on [Insert date 60 days from date of 

publication in the Federal Register] without further notice, unless 

the EPA receives adverse comment by [Insert date 30 days from date of 

publication in the Federal Register]. If the EPA receives adverse 

comment, we will publish a timely withdrawal in the Federal Register

informing the public that the rule will not take effect.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQOAR-2010-0873 by one of the following methods:
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 www.regulations.gov: Follow the on-line instructions for 

submitting comments.

 Email: a-and-r-docket@epa.gov.

 Fax: (202) 566-9744.

 Mail: Attention Docket ID No. EPA-HQ-OAR-2010-0873, 

Environmental Protection Agency, Mailcode: 2822T, 1200 

Pennsylvania Ave., NW, Washington, DC 20460. 

 Hand Delivery: The EPA Docket Center, EPA West, Room 3334, 1301 

Constitution Ave., NW, Washington, DC 20460. Such deliveries are 

only accepted during the Docket’s normal hours of operation, and 

special arrangements should be made for deliveries of boxed 

information. 

Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-2010-

0873. The EPA’s policy is that all comments received will be included 

in the public docket without change and may be made available online 

at www.regulations.gov, including any personal information provided, 

unless the comment includes information claimed to be Confidential 

Business Information (CBI) or other information whose disclosure is 

restricted by statute. Do not submit information that you consider to 

be CBI or otherwise protected through www.regulations.gov or email. 

The www.regulations.gov website is an “anonymous access” system, 

which means the EPA will not know your identity or contact 

information unless you provide it in the body of your comment. If you 

send an email comment directly to the EPA without going through 
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www.regulations.gov, your email address will be automatically 

captured and included as part of the comment that is placed in the 

public docket and made available on the Internet. If you submit an 

electronic comment, the EPA recommends that you include your name and 

other contact information in the body of your comment and with any 

disk or CD-ROM you submit. If the EPA cannot read your comment due to 

technical difficulties and cannot contact you for clarification, the 

EPA may not be able to consider your comment. Electronic files should 

avoid the use of special characters, any form of encryption, and be 

free of any defects or viruses. For additional information about the 

EPA’s public docket, visit the EPA Docket Center homepage at 

http://www.epa.gov/epahome/dockets.htm.

Docket: All documents in the docket are listed in the 

www.regulations.gov index. Although listed in the index, some 

information is not publicly available, e.g., CBI or other information 

whose disclosure is restricted by statute. Certain other material, 

such as copyrighted material, will be publicly available only in hard 

copy. Publicly available docket materials are available either 

electronically in www.regulations.gov or in hard copy at the

Procedure 3 - Quality Assurance Requirements for Continuous Opacity 

Monitoring Systems at Stationary Sources Docket, EPA/DC, EPA West, 

Room 3334, 1301 Constitution Ave., NW, Washington, DC. The Docket 

Facility and Public Reading Room are open from 8:30 a.m. to 4:30 

p.m., Monday through Friday, excluding legal holidays. The telephone 
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number for the Air Docket is (202) 566-1742, and the telephone number 

for the Public Reading Room is (202) 566-1744. 

FOR FUTHER INFORMATION CONTACT: Ms. Lula H. Melton, U.S. EPA, Office 

of Air Quality Planning and Standards, Air Quality Assessment 

Division, Measurement Technology Group (Mail Code: E143-02), Research 

Triangle Park, NC 27711; telephone number: (919) 541-2910; fax 

number: (919) 541-0516; email address: melton.lula@epa.gov.

SUPPLEMENTARY INFORMATION: 

Table of Contents

I. General Information

A. Why is the EPA using a direct final rule?

B. Does this action apply to me?

C. Where can I obtain a copy of this action?

D. Judicial Review

II. This Action

III. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and 

Executive Order 13563: Improving Regulation and Regulatory 

Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination with 

Indian Tribal Governments 

G. Executive Order 13045: Protection of Children from 

Environmental Health Risks and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations that 

Significantly Affect Energy Supply, Distribution, or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income 

Populations

K. Congressional Review Act

I. General Information

A. Why is the EPA using a direct final rule?
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The EPA is publishing this rule without a prior proposed rule 

because we view this as a non-controversial action and anticipate no 

adverse comment. This action establishes QA/QC procedures for COMS

used to demonstrate continuous compliance with opacity standards in 

federally enforceable regulations. We believe that these QA/QC 

procedures are reasonable and that they can be met by any wellmaintained and operated COMS. Furthermore, the procedures were 

developed based on input provided by the affected parties. On May 8, 

2003, we published a proposed rule to codify QA/QC procedures for 

COMS (i.e., Procedure 3). Due to other priorities, we did not 

finalize Procedure 3, but public comments received on the proposal 

have been considered in this action. This rule also takes into 

account changes in technology since 2003.

In the “Proposed Rules” section of this Federal Register, we are 

publishing a separate document that will serve as the proposed rule 

if relevant adverse comments are received on this direct final rule. 

We will not institute a second comment period on this action. Any 

parties interested in commenting, must do so at this time. For 

further information about commenting on this rule, see the ADDRESSES

section of this document. If the EPA receives adverse comment, we 

will publish a timely withdrawal in the Federal Register informing 

the public that this direct final rule will not take effect. We would 

address all public comments in any subsequent final rule based on the 

proposed rule.

B. Does this action apply to me?
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Procedure 3 applies to COMS used to demonstrate continuous 

compliance with opacity standards in federally enforceable 

regulations.

C. Where can I obtain a copy of this action?

In addition to being available in the docket, an electronic copy 

of this rule will also be available on the Worldwide Web (www) 

through the Technology Transfer Network (TTN). Following the 

Administrator’s signature, a copy of the final rule will be placed on 

the TTN’s policy and guidance page for newly proposed or promulgated 

rules at http://www.epa.gov/ttn/oarpg. The TTN provides information 

and technology exchange in various areas of air pollution control. A 

redline strikeout document that compares this final rule to the 

proposed rule has also been added to the docket.

D. Judicial Review

Under section 307(b)(1) of the Clean Air Act (CAA), judicial 

review of this direct final rule is available by filing a petition 

for review in the United States Court of Appeals for the District of 

Columbia Circuit by [Insert date 60 days from date of publication in 

the Federal Register]. Under section 307(d)(7)(B) of the CAA, only an 

objection to this direct final rule that was raised with reasonable 

specificity during the period for public comment can be raised during 

judicial review. Moreover, under section 307(b)(2) of the CAA, the 

requirements that are the subject of this direct final rule may not 

be challenged later in civil or criminal proceedings brought by the 

EPA to enforce these requirements.
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II. This Action

This direct final rule codifies Procedure 3 in 40 CFR part 60,

Appendix F. Procedure 3 establishes QA/QC procedures for COMS used to 

demonstrate continuous compliance with opacity standards in federally 

enforceable regulations. More specifically, Procedure 3 provides 

requirements for daily instrument zero and upscale drift checks, 

daily status indicator checks, quarterly performance audits, annual 

zero alignment audits, and corrective action for malfunctioning COMS. 

On May 8, 2003, we published a proposed rule to codify Procedure 3. 

However, due to other priorities, we did not finalize Procedure 3 

after the comment period ended July 7, 2003. Public comments received 

on the May 8, 2003, proposal have been considered in this action. 

III. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory Planning and Review and 

Executive Order 13563: Improving Regulation and Regulatory Review

This action is not a “significant regulatory action” under the 

terms of Executive Order 12866 (58 FR 51735, October 4, 1993) and is 

therefore not subject to review under Executive Orders 12866 and 

13563 (76 FR 3821, January 21, 2011).

B. Paperwork Reduction Act

This action does not impose an information collection burden

under the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 

et seq. Burden is defined at 5 CFR 1320.3(b). These quality assurance 

procedures do not add information collection requirements beyond 

those currently required under the applicable regulations. 
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C. Regulatory Flexibility Act 

The Regulatory Flexibility Act (RFA) generally requires an 

agency to prepare a regulatory flexibility analysis of any rule 

subject to notice and comment rulemaking requirements under the 

Administrative Procedure Act or any other statute unless the agency 

certifies that the rule will not have a significant economic impact 

on a substantial number of small entities. Small entities include 

small businesses, small organizations, and small governmental 

jurisdictions.

For purposes of accessing the impacts of this rule on small

entities, small entity is defined as: (1) a small business as 

defined by the Small Business Administration’s (SBA) regulations at 

13 CFR 121.201; (2) a small governmental jurisdiction that is a 

government of a city, county, town, school district or special 

district with a population of less than 50,000; and (3) a small 

organization that is any not-for-profit enterprise which is 

independently owned and operated and is not dominant in its field.

After considering the economic impacts of this rule on small 

entities, I certify that this action will not have a significant 

economic impact on a substantial number of small entities. This final 

rule will not impose any requirements on small entities. This action 

establishes QA/QC procedures for COMS used to demonstrate continuous

compliance with opacity standards as specified in federally 

enforceable regulations and does not impose additional regulatory

requirements on sources.
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D. Unfunded Mandates Reform Act

This rule does not contain a federal mandate that may result in 

expenditures of $100 million or more for State, local, and tribal 

governments, in the aggregate, or the private sector in any one year. 

Rules establishing quality assurance requirements impose no costs 

independent from national emission standards which require their use, 

and such costs are fully reflected in the regulatory impact 

assessment for those emission standards. Thus, this rule is not 

subject to the requirements of sections 202 or 205 of UMRA.

This rule is also not subject to the requirements of section 203 

of UMRA because it contains no regulatory requirements that might 

significantly or uniquely affect small governments. This action 

simply establishes QA/QC procedures for COMS used to demonstrate 

continuous compliance with opacity standards as specified in 

federally enforceable regulations.

E. Executive Order 13132: Federalism

This action does not have federalism implications. It will not 

have substantial direct effects on the states, on the relationship 

between the national government and the states, or on the 

distribution of power and responsibilities among the various levels 

of government, as specified in Executive Order 13132. This action 

establishes QA/QC procedures for COMS used to demonstrate continuous 

compliance with opacity standards as specified in federally 

enforceable regulations. Thus, Executive Order 13132 does not apply 

to this action. 
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F. Executive Order 13175: Consultation and Coordination with 

Indian Tribal Governments

This action does not have tribal implications, as specified in 

Executive Order 13175 (65 FR 67249, November 9, 2000). This action 

establishes QA/QC procedures for COMS used to demonstrate continuous 

compliance with opacity standards as specified in federally 

enforceable regulations. It does not add any emission limits and does 

not affect pollutant emissions or air quality. Thus, Executive Order 

13175 does not apply to this action.

G. Executive Order 13045: Protection of Children from 

Environmental Health Risks and Safety Risks

The EPA interprets EO 13045 (62 FR 19885, April 23, 1997) as 

applying only to those regulatory actions that concern health or 

safety risks, such that the analysis required under section 5-501 of 

the EO has the potential to influence the regulation. This action is 

not subject to EO 13045 because it does not establish an 

environmental standard intended to mitigate health or safety risks.

H. Executive Order 13211: Actions Concerning Regulations that 

Significantly Affect Energy Supply, Distribution, or Use

This action is not subject to Executive Order 13211 (66 FR 28355

(May 22, 2001)) because it is not a significant regulatory action 

under Executive Order 12866.

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and 

Advancement Act of 1995 (“NTTAA”), Public Law No. 104-113, 12(d) (15 
Page 11 of 33

U.S.C. 272 note) directs the EPA to use voluntary consensus standards 

in its regulatory activities unless to do so would be inconsistent 

with applicable law or otherwise impractical. Voluntary consensus 

standards are technical standards (e.g., materials specifications, 

test methods, sampling procedures, and business practices) that are 

developed or adopted by voluntary consensus standards bodies. NTTAA 

directs the EPA to provide Congress, through OMB, explanations when 

the agency decides not to use available and applicable voluntary 

consensus standards.

This action does not involve technical standards. Therefore, the 

EPA did not consider the use of any voluntary consensus standards. 

J. Executive Order 12898: Federal Actions to Address Environmental 

Justice in Minority Populations and Low-Income Populations

Executive Order (EO) 12898 (59 FR 7629 (Feb. 16, 1994)) 

establishes federal executive policy on environmental justice. Its 

main provision directs federal agencies, to the greatest extent 

practicable and permitted by law, to make environmental justice part 

of their mission by identifying and addressing, as appropriate, 

disproportionately high and adverse human health or environmental 

effects of their programs, policies, and activities on minority 

populations and low-income populations in the United States. 

The EPA has determined that this direct final rule will not have 

disproportionately high and adverse human health or environmental 

effects on minority or low-income populations because it does not 

affect the level of protection provided to human health or the 
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environment. This rule does not relax the control measures on sources 

regulated by the rule and, therefore, will not cause emissions 

increases from these sources.

K. Congressional Review Act

The Congressional Review Act, 5 U.S.C. 801 et seq., as added by 

the Small Business Regulatory Enforcement Fairness Act of 1996, 

generally provides that before a rule may take effect, the agency 

promulgating the rule must submit a rule report, which includes a 

copy of the rule, to each House of the Congress and to the 

Comptroller General of the United States. The EPA will submit a 

report containing this rule and other required information to the 

U.S. Senate, the U.S. House of Representatives, and the Comptroller 

General of the United States prior to publication of the rule in the 

Federal Register. A major rule cannot take effect until 60 days after 

it is published in the Federal Register. This action is not a “major 

rule” as defined by 5 U.S.C. 804(2). This rule will be effective 

[insert date 60 days from date of publication in the Federal 

Register].
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Quality Assurance Requirements for Continuous Opacity Monitoring 

Systems at Stationary Sources

List of Subjects in 40 CFR Part 60

Air pollution control, Environmental protection, Continuous 

opacity monitoring.

____________________

Dated: 

____________________

Lisa P. Jackson,

Administrator.
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For the reasons stated in the preamble, title 40, chapter I of the 

Code of Federal Regulations is amended as follows:

Part 60 – [AMENDED]

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

Authority: 42 U.S.C. 7401 et seq.

2. Appendix F of part 60 is amended by adding Procedure 3 to read as 

follows:

Appendix F to Part 60 – Quality Assurance Procedures

* * * * *

Procedure 3 – Quality Assurance Requirements for Continuous Opacity 

Monitoring Systems at Stationary Sources

1.0 What are the Purpose and Applicability of Procedure 3?

The purpose of Procedure 3 is to establish quality assurance and 

quality control (QA/QC) procedures for continuous opacity monitoring 

systems (COMS). Procedure 3 applies to COMS used to demonstrate 

continuous compliance with opacity standards in federally enforceable 

regulations.

1.1 What are the data quality objectives of Procedure 3? The 

overall data quality objective (DQO) of Procedure 3 is the generation 

of valid and representative opacity data. Procedure 3 specifies the 

minimum requirements for controlling and assessing the quality of 

COMS data submitted to us or the delegated regulatory agency. 

Procedure 3 requires you to perform periodic evaluations of a COMS 

performance and to develop and implement QA/QC programs to ensure 

that COMS data quality is maintained. 
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1.2 What is the intent of the QA/QC procedures specified in 

Procedure 3? Procedure 3 is intended to establish the minimum QA/QC 

requirements to verify and maintain an acceptable level of quality of 

the data produced by COMS. It is presented in general terms to allow 

you to develop a program that is most effective for your 

circumstances.

1.3 When must I comply with Procedure 3? You must comply with 

Procedure 3 after your COMS has been initially certified.

2.0 What are the Basic Functions of Procedure 3? 

The basic functions of Procedure 3 are assessment of the quality 

of your COMS data and control and improvement of the quality of the 

data by implementing QC requirements and corrective actions. 

Procedure 3 provides requirements for:

(1) Daily instrument zero and upscale drift checks, as well as,

daily status indicators checks;

(2) Quarterly performance audits which include the following 

assessments:

(i) Optical alignment,

(ii) Calibration error,

(iii) Zero compensation; and

(3) Annual zero alignment.

Sources that consistently achieve quality assured data may request a 

semi-annual audit frequency by submitting the request in writing to 

the Administrator.

3.0 What Special Definitions Apply to Procedure 3? 
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The definitions in Procedure 3 include those provided in 

Performance Specification 1 (PS-1) of Appendix B and ASTM D 6216-98,

03, 07 and the following additions.

3.1 Out-of-control periods. Out-of-control periods mean that one 

or more COMS parameters falls outside of the acceptable limits 

established by this rule.

(1) Daily Assessments. Whenever the calibration drift (CD) exceeds 

twice the specification of PS-1, the COMS is out-of-control. The 

beginning of the out-of-control period is the time corresponding to 

the completion of the daily calibration drift check. The end of the 

out-of-control period is the time corresponding to the completion of 

appropriate adjustment and subsequent successful CD assessment.

(2) Quarterly and Annual Assessments. Whenever an annual zero 

alignment or quarterly performance audit indicates noncompliance with 

the criteria established in paragraphs (2) and (3) of section 10.4, 

the COMS is out-of-control. The beginning of the out-of-control 

period is the time corresponding to the completion of the performance 

audit indicating noncompliance. The end of the out-of-control period 

is the time corresponding to the completion of appropriate corrective 

actions and the subsequent successful audit (or, if applicable, 

partial audit).

4.0 What Interferences Must I Avoid? 

Opacity cannot be measured accurately in the presence of water 

droplets. Thus, COMS opacity compliance determinations cannot be made 
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when water droplets are present, such as downstream of a wet scrubber 

without a reheater or at other saturated flue gas locations. 

5.0 What Do I Need to Know to Ensure the Safety of Persons Using 

Procedure 3? 

People using Procedure 3 may be exposed to hazardous materials, 

operations and equipment. Procedure 3 does not purport to address all 

of the safety issues associated with its use. It is your 

responsibility to establish appropriate health and safety practices

and determine the applicable regulatory limitations before performing 

this procedure. You should consult the COMS user’s manual for 

specific precautions to take.

6.0 What Equipment and Supplies Do I Need? 

The equipment and supplies that you need are specified in PS-1.

7.0 What Reagents and Standards Do I Need? 

The reagents and standards that you need are specified in PS-1.

8.0 What Sample Collection, Preservation, Storage, and Transport are 

Relevant to This Procedure? [Reserved]

9.0 What Quality Control Measures Are Required by This Procedure for 

my COMS? 

You must develop and implement a QC program for your COMS. Your 

QC program must, at a minimum, include written procedures which 

describe in detail complete step-by-step procedures and operations 

for the activities in paragraphs (1) through (4):

(1) Procedures for performing drift checks, including both zero 

and upscale drift and the status indicators check,
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(2) Procedures for performing quarterly performance audits,

(3) A means of checking the zero alignment of the COMS, and

(4) A program of corrective action for a malfunctioning COMS. The 

corrective action must include, at a minimum, the requirements 

specified in section 10.5.

9.1 What QA/QC documentation must I have? You are required to 

keep the QA/QC written procedures on record and available for 

inspection by us, the State, and/or local enforcement agencies for 

the life of your COMS or until you are no longer subject to the 

requirements of this procedure.

9.2 What are the consequences of failing QC audits? Your QC 

procedures are deemed to be inadequate or your COMS incapable of 

providing quality data if you fail two consecutive annual audits, two

consecutive quarterly audits, or five consecutive daily checks. If 

this occurs, you must either revise your QC procedures or repair or 

replace the COMS to correct the deficiencies causing the audit 

failures. If you determine that your COMS requires extensive repairs, 

you may use a substitute COMS provided the substitute meets the 

requirements in section 10.6.

10.0 What Calibration and Standardization Procedures Must I Perform 

for My COMS? 

(1) You must perform routine system checks to ensure proper 

operation of system electronics and optics, light and radiation 

sources and detectors, electric or electro-mechanical systems, and 

general stability of the system calibration. 
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(2) You must subject your COMS to a performance audit to include 

checks of the individual COMS components and factors affecting the 

accuracy of the monitoring data at least once per calendar quarter. 

(3) At least annually, you must perform a zero alignment by 

comparing the COMS simulated zero to the actual clear path zero. The 

simulated zero device produces a simulated clear path condition or 

low-level opacity condition, where the energy reaching the detector 

is between 90 and 110 percent of the energy reaching the detector 

under actual clear path conditions.

10.1 What routine system checks must I perform on my COMS? 

Necessary components of the routine system checks will depend on the

design details of your COMS. At a minimum, you must verify the system 

operating parameters listed in paragraphs (1) through (3) of this 

section on a daily basis. Some COMS may perform one or more of these 

functions automatically or as an integral portion of unit operations; 

other COMS may perform one or more of these functions manually.

(1) You must check the zero drift to ensure stability of your COMS 

response to the simulated zero device. The simulated zero device, an 

automated mechanism within the transmissometer that produces a 

simulated clear path condition or low-level opacity condition, is 

used to check the zero drift. You must, at a minimum, take corrective 

action on your COMS whenever the daily zero drift exceeds twice the 

applicable drift specification in PS-1. 

(2) You must check the upscale drift to ensure stability of your 

COMS response to the upscale drift value. The upscale calibration 
Page 20 of 33

device, an automated mechanism (employing a filter or reduced 

reflectance device) within the transmissometer that produces an 

upscale opacity value is used to check the upscale drift. You must, 

at a minimum, take corrective action on your COMS whenever the daily 

upscale drift check exceeds twice the applicable drift specification 

in PS-1.

(3) You must, at a minimum, check the status indicators, data 

acquisition system error messages, and other system self-diagnostic 

indicators. You must take appropriate corrective action based on the 

manufacturer’s recommendations when the COMS is operating outside 

preset limits. All COMS data recorded during periods in which the 

fault status indicators are illuminated are to be considered invalid.

10.2 What are the quarterly auditing requirements for my COMS? At 

a minimum, the parameters listed in paragraphs (1) through (3) of 

this section must be included in the quarterly performance audit. 

(1) For units with automatic zero compensation, you must determine 

the zero compensation for the COMS. The value of the zero 

compensation applied at the time of the audit must be calculated as 

equivalent opacity and corrected to stack exit conditions according 

to the procedures specified by the manufacturer. The compensation 

applied to the effluent recorded by the monitor system must be 

recorded.

(2) You must conduct a three-point calibration error test of the 

COMS. For either calibration error test method identified below, 

three neutral density filters meeting the requirements of PS-1 must 
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be placed in the COMS light beam path for at least three 

nonconsecutive readings. All monitor responses must then be 

independently recorded from the COMS permanent data recorder. 

Additional guidance for conducting this test is included in section 

8.1(3)(ii) of PS-1. The low-, mid-, and high-range calibration error 

results must be computed as the mean difference and 95 percent 

confidence interval for the difference between the expected and 

actual responses of the monitor as corrected to stack exit 

conditions. The equations necessary to perform the calculations are 

found in section 12.0 of PS-1. For the calibration error method, you 

must use the external audit device. You must confirm that the 

external audit device produces a zero value within one percent 

opacity. 

(3) You must check the optical alignment of the COMS. The optical 

alignment should be checked when the stack temperature is ± 50

percent of the typical operating temperature in degrees Farenheit.

10.3 What are the annual auditing requirements for my COMS? 

(1) You must perform the primary zero alignment method under clear 

path conditions. The COMS may be removed from its installation and 

setup under clear path conditions or, if the process is not operating 

and the monitor path is free of particulate matter, the zero 

alignment may be conducted at the installed site. Determining if the 

monitor path is free of particulate matter can be accomplished by, 

but is not limited to, the following procedure: (1) observe the 

instantaneous or one-minute average opacity for at least two hours 
Page 22 of 33

prior to the clear path adjustment; (2) open the reflector or 

detector housing and observe the projected light beam and look for 

the presence of forward scattered light (halo-effect); (3) if the 

beam observation reveals no perceptible particulate, and the 2-hour 

readings do not vary more than ± 3 percent opacity, adjust the clear 

path zero based on the lowest opacity reading recorded during the 2-

hour period. There must be no adjustments to the monitor other than 

the establishment of the proper monitor path length and correct 

optical alignment of the COMS components. You must record the COMS 

response to a clear condition and to the COMS’s simulated zero 

condition as percent opacity corrected to stack exit conditions. For 

a COMS with automatic zero compensation, you must disconnect or 

disable the zero compensation mechanism or record the amount of 

correction applied to the COMS’s simulated zero condition. The 

response difference in percent opacity to the clear path and 

simulated zero conditions must be recorded as the zero alignment 

error. You must adjust the COMS’s simulated zero device to provide 

the same response as the clear path condition as specified in 

paragraph (3) of section 10.0. You must perform the zero alignment 

audits with the COMS off the stack at least every three years.

(2) As an alternative, monitors capable of allowing the 

installation of an external zero device (commonly referred to as

zero-jig) may use the device for the zero alignment provided that:

(1) the zero-jig setting has been established for the monitor path 

length and recorded for the specific COMS by comparison of the COMS 
Page 23 of 33

responses to the installed zero-jig and to the clear path condition,

and (2) the zero-jig is demonstrated to be capable of producing a 

consistent zero response when it is repeatedly (i.e., three 

consecutive installations and removals prior to conducting the final 

zero alignment check) installed on the COMS. This can be demonstrated 

by either the MCOC or actual on-site performance. The zero-jig 

setting must be permanently set at the time of initial zeroing to the 

clear path zero value and protected when not in use to ensure that 

the setting equivalent to zero opacity does not change. The zero-jig 

response must be checked and recorded prior to initiating the zero 

alignment. If the zero-jig setting has changed, you must remove the 

COMS from the stack in order to reset the zero-jig. If you employ a 

zero-jig, you must perform the zero alignment audits with the COMS 

off the stack at least every three years. If the zero-jig is adjusted 

within the three-year period, you must perform the zero alignment 

with the COMS off the stack no later than three years from the date 

of adjustment.

(3) The procedure in section 6.8 of ASTM D 6216-98, 03, 07 is 

allowed.

(4) Other alternatives that verify that the zero optical 

adjustment is ± 3 percent opacity are also allowed.

10.4 What are my limits for excessive audit inaccuracy? Unless 

specified otherwise in the applicable subpart, the criteria for 

excessive inaccuracy are listed in paragraphs (1) through (4). 
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(1) What is the criterion for excessive zero or upscale drift? 

Your COMS is out-of-control if either the zero drift check or upscale 

drift check exceeds twice the applicable drift specification in PS-1

for any one day.

(2) What is the criterion for excessive zero alignment? Your COMS 

is out-of-control if the zero alignment error exceeds 2 percent 

opacity.

(3) What is the criterion to pass the quarterly performance audit?

Your COMS is out-of-control if the results of a quarterly performance 

audit indicate noncompliance with the following criteria:

(i) The optical alignment misalignment error exceeds 3 percent 

opacity,

(ii) The zero compensation exceeds 4 percent opacity, or

(iii) The calibration error exceeds 3 percent opacity.

(4) What is the criterion for data capture? The data capture will 

be considered insufficient if your COMS fails to obtain valid opacity 

data for at least 95 percent of your operating hours per calendar 

quarter, considering COMS downtime for all causes (e.g., monitor 

malfunctions, data system failures, preventative maintenance, unknown 

causes, etc.) except for downtime associated with routine zero and 

upscale checks and QA/QC activities required by this procedure. 

Whenever less than 95 percent of the valid data averages are 

obtained, you must either: 

(i) Perform additional QA/QC activities as deemed necessary to 

ensure acceptable data capture, or
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(ii) Determine if the COMS is functioning properly. If your COMS 

is malfunctioning, you may use a substitute COMS until repairs are 

made, provided the substitute meets the requirements in section 10.6.

10.5 What corrective action must I take if my COMS is 

malfunctioning? You must have a corrective action program in place to 

address the repair and/or maintenance of your COMS. There are four 

classes of maintenance and repair procedures to be considered as

described in paragraphs (1) through (4) of this section. They may be 

performed at the manufacturer’s facility, a service provider’s 

facility, the user’s instrument laboratory, or at the stack/duct at 

the discretion of the owner/operator and within the recommendation of 

the manufacturer. They must be performed by persons either skilled 

and/or trained in the operation and maintenance of the analyzer. 

After the repair/maintenance of your COMS, you must ensure that the 

COMS is still in compliance with PS-1. Table 17-1 outlines the tests 

required to maintain PS-1 certification.

(1) Routine/Preventative Maintenance. Routine/preventative 

maintenance includes the routine replacement of consumables, cleaning 

of optical surfaces, and adjustment of monitor operating parameters 

as needed to maintain normal operation. Replacement of consumables 

that have the possibility of adversely affecting the performance of 

an analyzer may cause the nature of the maintenance procedure to fall 

within one of the classifications described below.

(2) Measurement Non-Critical Repairs. Measurement non-critical 

repairs include repair and/or replacement of standard non-critical 
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components, the unique characteristics of which do not materially 

affect the performance of the monitor. These components include, but 

are not limited to, resistors, capacitors, inductors, transformers, 

semiconductors, such as discrete components and integrated circuits, 

brackets and machined parts (not associated with internal optical 

components), cabling and connectors, electro mechanical components,

such as relays, solenoids, motors, switches, blowers, pressure/flow 

indicators, tubing, indicator lights, software with the same version 

and/or revision level, glass windows (uncoated or anti-reflection 

coated, but with no curvature), lenses with mounts where such mounts 

are not adjustable as installed, circuit boards where such boards are 

interchangeable and without unique adjustments (except offset and 

gain adjustments) for the specific analyzer of the same model, with 

such repairs to include the maintenance procedures required to ensure 

that the analyzer is appropriately setup.

(3) Primary Measurement Light Source. Repair or replace the 

primary measurement light source.

(4) Measurement Critical Repairs. Measurement critical repairs 

include repair and/or replacement of measurement sensitive 

components, the unique characteristics of which may materially affect 

the performance of the monitor. These components include, but are not 

limited to, optical detectors associated with the opacity 

measurement/reference beam(s), spectrally selective optical filters, 

beam splitters, internal zero and/or upscale reference reflective or 

transmissive materials, electro optical light switches, retro 
Page 27 of 33

reflectors, adjustable apertures used on external zero devices or 

reflectors, lenses which have an adjustable mount, circuit boards 

which are not completely interchangeable and/or require unique 

adjustments for the specific analyzer, with such repairs to include 

the maintenance procedures required to ensure that the analyzer is 

appropriately setup.

(5) Rebuilt or Refurbished Analyzers. Rebuilt or refurbished 

analyzers include analyzers for which a major sub-assembly has been 

replaced or multiple lesser sub-assemblies with different revision 

levels from the original have been replaced and/or modified. This 

also includes major changes to the analyzer measurement detection and 

processing hardware or software. 

10.6 What requirements must I meet if I use a substitute 

opacity monitor? In the event that your certified opacity monitor has 

to be removed for extended service, you may install a temporary 

replacement monitor to obtain required opacity emissions data

provided that:

(1) The temporary monitor has been certified according to ASTM D 

6216-98, 03, 07 for which a manufacturer’s certificate of conformance 

(MCOC) has been provided;

(2) The use of the temporary monitor does not exceed 720 hours (30 

days) of operation per year as a replacement for a fully certified 

opacity monitor. After that time, the analyzer must complete a full 

certification according to PS-1 prior to further use as a temporary 

replacement monitor. Once a temporary replacement monitor has been 
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installed and required testing and adjustments have been successfully 

completed, it cannot be replaced by another temporary replacement 

monitor to avoid the full PS-1 certification testing required after 

720 hours (30 days) of use;

(3) The temporary monitor has been installed and successfully 

completed an optical alignment assessment and status indicator 

assessment;

(4) The temporary monitor has successfully completed an off-stack 

clear path zero assessment and zero calibration value adjustment 

procedure;

(5) The temporary monitor has successfully completed an 

abbreviated zero and upscale drift check consisting of seven zero and 

upscale calibration value drift checks which may be conducted within 

a 24-hour period with not more than one calibration drift check every 

three hours and not less than one calibration drift check every 25 

hours. Calculated zero and upscale drift requirements are the same as 

specified for the normal PS-1 certification;

(6) The temporary monitor has successfully completed a three-point 

calibration error test;

(7) The upscale reference calibration check value of the new 

monitor has been updated in the associated data recording equipment;

(8) The overall calibration of the monitor and data recording 

equipment has been verified; and 

(9) The user has documented all of the above in the maintenance 

log or in other appropriate permanently maintained records.
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10.7 When do out-of-control periods begin and end? The out-ofcontrol periods are as specified in section 3.1.

10.8 What are the limitations on the use of my COMS data 

collected during out-of-control periods? During the period your COMS 

is out-of-control, you may not use your COMS data to calculate 

emission compliance or to meet minimum data capture requirements in 

this procedure or the applicable regulation.

10.9 What are the QA/QC reporting requirements for my COMS? You 

must report the accuracy results from section 10.0 for your COMS at 

the interval specified in this procedure or the applicable 

regulation. You must report the drift and accuracy information as a 

Data Assessment Report (DAR), and include one copy of this DAR for 

each quarterly audit with the report of emissions required under the 

applicable regulation. An example DAR is provided in Procedure 1, 

Appendix F of this part.

10.10 What minimum information must I include in my DAR? At a 

minimum, you must include the information listed in paragraphs (1) 

through (5) of this section in the DAR.

(1) Your name and address,

(2) Identification and location of your COMS(s), 

(3) Manufacturer, model, and serial number of your COMS(s),

(4) Assessment of COMS data accuracy/acceptability and date of 

assessment as determined by a performance audit described in section 

10.0. If the accuracy audit results show your COMS to be out-ofcontrol, you must report both the audit results showing your COMS to 
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be out-of-control and the results of the audit following corrective 

action showing your COMS to be operating within specifications, and 

(5) Summary of all corrective actions you took when you determined 

your COMS was out-of-control.

10.11 Where and how long must I retain the QA data that this 

procedure requires me to record for my COMS? You must keep the 

records required by this procedure for your COMS onsite and available 

for inspection by us, the State, and/or the local enforcement agency 

for the period specified in the regulations requiring the use of 

COMS.

11.0 What Analytical Procedures Apply to this Procedure? [Reserved]

12.0 What Calculations and Data Analysis Must I Perform for My COMS?

The calculations required for the performance audit are in section 

12.0 of PS-1. 

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

16.1 Performance Specification 1-Specifications and Test 

Procedures for Continuous Opacity Monitoring Systems in Stationary 

Sources, 40 CFR part 60, Appendix B.

16.2 ASTM D 6216-98, 03, 07-Standard Practice for Opacity 

Monitor Manufacturers to Certify Conformance with Design and 

Performance Specifications, American Society for Testing and 

Materials (ASTM).
Page 31 of 33

17.0 What Tables, Diagrams, Flowcharts, and Validation Data are 

Relevant to This Procedure?
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17.1. Table 17-1 Diagnostic Tests Required after Various Repairs.

Description 

of Event

Optical 

Alignment

Optical 

alignment 

indicator 

assessment 

(Note 

1)

Zero 

calibration 

check

Clear 

path 

(offstack) 

zero 

assessment 

(Note 

3)

Upscale 

calibration 

check

Calibration 

error 

check

Fault 

status 

indicator 

check

Averaging 

period 

calculation and 

recording

7-day 

zero 

and 

upscale 

drift 

check 

(Note 

2)

Recertify 

per 

PS-1

New 

MCOC 

per 

ASTM D 

6216-

98, 07

Comments

(1)Replace or 

repair 

components 

described as 

routine 

and/or 

preventative 

maintenance.

x --- x --- x --- x --- --- --- --- Includes replacement 

of blower, cleaning

optical surfaces, 

resetting adjustable 

parameters to maintain 

normal performance, 

etc.

(2)Replace or 

repair 

primary 

measurement 

light.

x X x x x x x --- --- --- --- Light source 

uniformity and 

position are key 

source to many 

performance 

parameters. 

(3) Replace 

or repair 

components 

which are 

measurement 

non-critical.

x --- x --- x x --- --- --- --- See text description, 

section 10.5(2).

(4) Replace 

or repair 

components 

which are 

measurement 

critical.

x X x x x x x --- x --- --- See test description,

section 10.5(3).

(5) Replace 

or repair 

components 

which are 

measurement 

critical but 

do not 

involve 

optical or 

electrooptical 

components.

--- --- x --- x x x X --- --- --- Includes changes of 

components involving 

data acquisition and 

recording.
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(6) Rebuild 

or

substantially 

refurbish the 

analyzer.

--- --- --- --- --- --- --- --- --- x --- See text description, 

section 10.5(4).

(7) Change 

to, or 

addition of, 

analyzer 

components 

which may 

affect MCOCspecified 

performance 

parameters.

--- --- --- --- --- --- --- --- --- x x Significant changes 

which are not part of 

the MCOC-designated 

configuration.

Notes: (1) Optical alignment indicator assessment requires the operator to verify during an off the 

stack clear path zero assessment that the beam is centered on the reflector/retro reflector when the 

alignment indicator indicates on-axis centered alignment. If not, the analyzer optical train must be 

adjusted until this condition is met.

(2) 7-day zero and upscale drift assessment. Opacity measurement data recorded prior to completion 

of the 7-day drift test will be considered as valid provided that the first 7-day drift test is 

successful, that it is completed within 14 days of completion of the repair, and that other QA 

requirements are met during this time period.

(3) Requires verification of the external zero-jig response, or recalibration of the same, after 

the off-stack clear path zero has been re-established.