[Code of Federal Regulations]
[Title 40, Volume 9]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR63.8]

[Page 40-47]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES--Table of Contents
 
                      Subpart A--General Provisions
 
Sec. 63.8  Monitoring requirements.

    (a) Applicability. (1) The applicability of this section is set out 
in Sec. 63.1(a)(4).
    (2) For the purposes of this part, all CMS required under relevant 
standards shall be subject to the provisions of this section upon 
promulgation of performance specifications for CMS as specified in the 
relevant standard or otherwise by the Administrator.
    (3) [Reserved]
    (4) Additional monitoring requirements for control devices used to 
comply with provisions in relevant standards of this part are specified 
in Sec. 63.11.
    (b) Conduct of monitoring. (1) Monitoring shall be conducted as set 
forth in this section and the relevant standard(s) unless the 
Administrator--
    (i) Specifies or approves the use of minor changes in methodology 
for the specified monitoring requirements and procedures (see 
Sec. 63.90(a) for definition); or
    (ii) Approves the use of an intermediate or major change or 
alternative to any monitoring requirements or procedures (see 
Sec. 63.90(a) for definition).
    (iii) Owners or operators with flares subject to Sec. 63.11(b) are 
not subject to the requirements of this section unless otherwise 
specified in the relevant standard.
    (2)(i) When the emissions from two or more affected sources are 
combined before being released to the atmosphere, the owner or operator 
may install an applicable CMS for each emission stream or for the 
combined emissions streams, provided the monitoring is sufficient to 
demonstrate compliance with the relevant standard.
    (ii) If the relevant standard is a mass emission standard and the 
emissions from one affected source are released to the atmosphere 
through more than one point, the owner or operator must install an 
applicable CMS at each emission point unless the installation of fewer 
systems is--
    (A) Approved by the Administrator; or
    (B) Provided for in a relevant standard (e.g., instead of requiring 
that a CMS be installed at each emission point before the effluents from 
those points are channeled to a common control device, the standard 
specifies that only one CMS is required to be installed at the vent of 
the control device).
    (3) When more than one CMS is used to measure the emissions from one 
affected source (e.g., multiple breechings, multiple outlets), the owner 
or operator shall report the results as required for each CMS. However, 
when one CMS is used as a backup to another CMS, the owner or operator 
shall report the results from the CMS used to meet the monitoring 
requirements of this part. If both such CMS are used during a particular 
reporting period to meet the monitoring requirements of this part, then 
the owner or operator shall report the results from each CMS for the 
relevant compliance period.

[[Page 41]]

    (c) Operation and maintenance of continuous monitoring systems. (1) 
The owner or operator of an affected source shall maintain and operate 
each CMS as specified in this section, or in a relevant standard, and in 
a manner consistent with good air pollution control practices.(i) The 
owner or operator of an affected source must maintain and operate each 
CMS as specified in Sec. 63.6(e)(1).
    (ii) The owner or operator must keep the necessary parts for routine 
repairs of the affected CMS equipment readily available.
    (iii) The owner or operator of an affected source must develop and 
implement a written startup, shutdown, and malfunction plan for CMS as 
specified in Sec. 63.6(e)(3).
    (2)(i) All CMS must be installed such that representative measures 
of emissions or process parameters from the affected source are 
obtained. In addition, CEMS must be located according to procedures 
contained in the applicable performance specification(s).
    (ii) Unless the individual subpart states otherwise, the owner or 
operator must ensure the read out (that portion of the CMS that provides 
a visual display or record), or other indication of operation, from any 
CMS required for compliance with the emission standard is readily 
accessible on site for operational control or inspection by the operator 
of the equipment.
    (3) All CMS shall be installed, operational, and the data verified 
as specified in the relevant standard either prior to or in conjunction 
with conducting performance tests under Sec. 63.7. Verification of 
operational status shall, at a minimum, include completion of the 
manufacturer's written specifications or recommendations for 
installation, operation, and calibration of the system.
    (4) Except for system breakdowns, out-of-control periods, repairs, 
maintenance periods, calibration checks, and zero (low-level) and high-
level calibration drift adjustments, all CMS, including COMS and CEMS, 
shall be in continuous operation and shall meet minimum frequency of 
operation requirements as follows:
    (i) All COMS shall complete a minimum of one cycle of sampling and 
analyzing for each successive 10-second period and one cycle of data 
recording for each successive 6-minute period.
    (ii) All CEMS for measuring emissions other than opacity shall 
complete a minimum of one cycle of operation (sampling, analyzing, and 
data recording) for each successive 15-minute period.
    (5) Unless otherwise approved by the Administrator, minimum 
procedures for COMS shall include a method for producing a simulated 
zero opacity condition and an upscale (high-level) opacity condition 
using a certified neutral density filter or other related technique to 
produce a known obscuration of the light beam. Such procedures shall 
provide a system check of all the analyzer's internal optical surfaces 
and all electronic circuitry, including the lamp and photodetector 
assembly normally used in the measurement of opacity.
    (6) The owner or operator of a CMS that is not a CPMS, which is 
installed in accordance with the provisions of this part and the 
applicable CMS performance specification(s), must check the zero (low-
level) and high-level calibration drifts at least once daily in 
accordance with the written procedure specified in the performance 
evaluation plan developed under paragraphs (e)(3)(i) and (ii) of this 
section. The zero (low-level) and high-level calibration drifts must be 
adjusted, at a minimum, whenever the 24-hour zero (low-level) drift 
exceeds two times the limits of the applicable performance 
specification(s) specified in the relevant standard. The system shall 
allow the amount of excess zero (low-level) and high-level drift 
measured at the 24-hour interval checks to be recorded and quantified 
whenever specified. For COMS, all optical and instrumental surfaces 
exposed to the effluent gases must be cleaned prior to performing the 
zero (low-level) and high-level drift adjustments; the optical surfaces 
and instrumental surfaces must be cleaned when the cumulative automatic 
zero compensation, if applicable, exceeds 4 percent opacity. The CPMS 
must be calibrated prior to use for the purposes of complying with this 
section. The CPMS must be checked daily for indication that the system 
is responding. If

[[Page 42]]

the CPMS system includes an internal system check, results must be 
recorded and checked daily for proper operation.
    (7)(i) A CMS is out of control if--
    (A) The zero (low-level), mid-level (if applicable), or high-level 
calibration drift (CD) exceeds two times the applicable CD specification 
in the applicable performance specification or in the relevant standard; 
or
    (B) The CMS fails a performance test audit (e.g., cylinder gas 
audit), relative accuracy audit, relative accuracy test audit, or 
linearity test audit; or
    (C) The COMS CD exceeds two times the limit in the applicable 
performance specification in the relevant standard.
    (ii) When the CMS is out of control, the owner or operator of the 
affected source shall take the necessary corrective action and shall 
repeat all necessary tests which indicate that the system is out of 
control. The owner or operator shall take corrective action and conduct 
retesting until the performance requirements are below the applicable 
limits. The beginning of the out-of-control period is the hour the owner 
or operator conducts a performance check (e.g., calibration drift) that 
indicates an exceedance of the performance requirements established 
under this part. The end of the out-of-control period is the hour 
following the completion of corrective action and successful 
demonstration that the system is within the allowable limits. During the 
period the CMS is out of control, recorded data shall not be used in 
data averages and calculations, or to meet any data availability 
requirement established under this part.
    (8) The owner or operator of a CMS that is out of control as defined 
in paragraph (c)(7) of this section shall submit all information 
concerning out-of-control periods, including start and end dates and 
hours and descriptions of corrective actions taken, in the excess 
emissions and continuous monitoring system performance report required 
in Sec. 63.10(e)(3).
    (d) Quality control program. (1) The results of the quality control 
program required in this paragraph will be considered by the 
Administrator when he/she determines the validity of monitoring data.
    (2) The owner or operator of an affected source that is required to 
use a CMS and is subject to the monitoring requirements of this section 
and a relevant standard shall develop and implement a CMS quality 
control program. As part of the quality control program, the owner or 
operator shall develop and submit to the Administrator for approval upon 
request a site-specific performance evaluation test plan for the CMS 
performance evaluation required in paragraph (e)(3)(i) of this section, 
according to the procedures specified in paragraph (e). In addition, 
each quality control program shall include, at a minimum, a written 
protocol that describes procedures for each of the following operations:
    (i) Initial and any subsequent calibration of the CMS;
    (ii) Determination and adjustment of the calibration drift of the 
CMS;
    (iii) Preventive maintenance of the CMS, including spare parts 
inventory;
    (iv) Data recording, calculations, and reporting;
    (v) Accuracy audit procedures, including sampling and analysis 
methods; and
    (vi) Program of corrective action for a malfunctioning CMS.
    (3) The owner or operator shall keep these written procedures on 
record for the life of the affected source or until the affected source 
is no longer subject to the provisions of this part, to be made 
available for inspection, upon request, by the Administrator. If the 
performance evaluation plan is revised, the owner or operator shall keep 
previous (i.e., superseded) versions of the performance evaluation plan 
on record to be made available for inspection, upon request, by the 
Administrator, for a period of 5 years after each revision to the plan. 
Where relevant, e.g., program of corrective action for a malfunctioning 
CMS, these written procedures may be incorporated as part of the 
affected source's startup, shutdown, and malfunction plan to avoid 
duplication of planning and recordkeeping efforts.
    (e) Performance evaluation of continuous monitoring systems--(1) 
General. When required by a relevant standard, and at any other time the 
Administrator may require under section 114 of

[[Page 43]]

the Act, the owner or operator of an affected source being monitored 
shall conduct a performance evaluation of the CMS. Such performance 
evaluation shall be conducted according to the applicable specifications 
and procedures described in this section or in the relevant standard.
    (2) Notification of performance evaluation. The owner or operator 
shall notify the Administrator in writing of the date of the performance 
evaluation simultaneously with the notification of the performance test 
date required under Sec. 63.7(b) or at least 60 days prior to the date 
the performance evaluation is scheduled to begin if no performance test 
is required.
    (3)(i) Submission of site-specific performance evaluation test plan. 
Before conducting a required CMS performance evaluation, the owner or 
operator of an affected source shall develop and submit a site-specific 
performance evaluation test plan to the Administrator for approval upon 
request. The performance evaluation test plan shall include the 
evaluation program objectives, an evaluation program summary, the 
performance evaluation schedule, data quality objectives, and both an 
internal and external QA program. Data quality objectives are the pre-
evaluation expectations of precision, accuracy, and completeness of 
data.
    (ii) The internal QA program shall include, at a minimum, the 
activities planned by routine operators and analysts to provide an 
assessment of CMS performance. The external QA program shall include, at 
a minimum, systems audits that include the opportunity for on-site 
evaluation by the Administrator of instrument calibration, data 
validation, sample logging, and documentation of quality control data 
and field maintenance activities.
    (iii) The owner or operator of an affected source shall submit the 
site-specific performance evaluation test plan to the Administrator (if 
requested) at least 60 days before the performance test or performance 
evaluation is scheduled to begin, or on a mutually agreed upon date, and 
review and approval of the performance evaluation test plan by the 
Administrator will occur with the review and approval of the site-
specific test plan (if review of the site-specific test plan is 
requested).
    (iv) The Administrator may request additional relevant information 
after the submittal of a site-specific performance evaluation test plan.
    (v) In the event that the Administrator fails to approve or 
disapprove the site-specific performance evaluation test plan within the 
time period specified in Sec. 63.7(c)(3), the following conditions shall 
apply:
    (A) If the owner or operator intends to demonstrate compliance using 
the monitoring method(s) specified in the relevant standard, the owner 
or operator shall conduct the performance evaluation within the time 
specified in this subpart using the specified method(s);
    (B) If the owner or operator intends to demonstrate compliance by 
using an alternative to a monitoring method specified in the relevant 
standard, the owner or operator shall refrain from conducting the 
performance evaluation until the Administrator approves the use of the 
alternative method. If the Administrator does not approve the use of the 
alternative method within 30 days before the performance evaluation is 
scheduled to begin, the performance evaluation deadlines specified in 
paragraph (e)(4) of this section may be extended such that the owner or 
operator shall conduct the performance evaluation within 60 calendar 
days after the Administrator approves the use of the alternative method. 
Notwithstanding the requirements in the preceding two sentences, the 
owner or operator may proceed to conduct the performance evaluation as 
required in this section (without the Administrator's prior approval of 
the site-specific performance evaluation test plan) if he/she 
subsequently chooses to use the specified monitoring method(s) instead 
of an alternative.
    (vi) Neither the submission of a site-specific performance 
evaluation test plan for approval, nor the Administrator's approval or 
disapproval of a plan, nor the Administrator' failure to approve or 
disapprove a plan in a timely manner shall--
    (A) Relieve an owner or operator of legal responsibility for 
compliance with any applicable provisions of this

[[Page 44]]

part or with any other applicable Federal, State, or local requirement; 
or
    (B) Prevent the Administrator from implementing or enforcing this 
part or taking any other action under the Act.
    (4) Conduct of performance evaluation and performance evaluation 
dates. The owner or operator of an affected source shall conduct a 
performance evaluation of a required CMS during any performance test 
required under Sec. 63.7 in accordance with the applicable performance 
specification as specified in the relevant standard. Notwithstanding the 
requirement in the previous sentence, if the owner or operator of an 
affected source elects to submit COMS data for compliance with a 
relevant opacity emission standard as provided under Sec. 63.6(h)(7), 
he/she shall conduct a performance evaluation of the COMS as specified 
in the relevant standard, before the performance test required under 
Sec. 63.7 is conducted in time to submit the results of the performance 
evaluation as specified in paragraph (e)(5)(ii) of this section. If a 
performance test is not required, or the requirement for a performance 
test has been waived under Sec. 63.7(h), the owner or operator of an 
affected source shall conduct the performance evaluation not later than 
180 days after the appropriate compliance date for the affected source, 
as specified in Sec. 63.7(a), or as otherwise specified in the relevant 
standard.
    (5) Reporting performance evaluation results. (i) The owner or 
operator shall furnish the Administrator a copy of a written report of 
the results of the performance evaluation simultaneously with the 
results of the performance test required under Sec. 63.7 or within 60 
days of completion of the performance evaluation if no test is required, 
unless otherwise specified in a relevant standard. The Administrator may 
request that the owner or operator submit the raw data from a 
performance evaluation in the report of the performance evaluation 
results.
    (ii) The owner or operator of an affected source using a COMS to 
determine opacity compliance during any performance test required under 
Sec. 63.7 and described in Sec. 63.6(d)(6) shall furnish the 
Administrator two or, upon request, three copies of a written report of 
the results of the COMS performance evaluation under this paragraph. The 
copies shall be provided at least 15 calendar days before the 
performance test required under Sec. 63.7 is conducted.
    (f) Use of an alternative monitoring method.--(1) General. Until 
permission to use an alternative monitoring procedure (minor, 
intermediate, or major changes; see definition in Sec. 63.90(a)) has 
been granted by the Administrator under this paragraph (f)(1), the owner 
or operator of an affected source remains subject to the requirements of 
this section and the relevant standard.
    (2) After receipt and consideration of written application, the 
Administrator may approve alternatives to any monitoring methods or 
procedures of this part including, but not limited to, the following:
    (i) Alternative monitoring requirements when installation of a CMS 
specified by a relevant standard would not provide accurate measurements 
due to liquid water or other interferences caused by substances within 
the effluent gases;
    (ii) Alternative monitoring requirements when the affected source is 
infrequently operated;
    (iii) Alternative monitoring requirements to accommodate CEMS that 
require additional measurements to correct for stack moisture 
conditions;
    (iv) Alternative locations for installing CMS when the owner or 
operator can demonstrate that installation at alternate locations will 
enable accurate and representative measurements;
    (v) Alternate methods for converting pollutant concentration 
measurements to units of the relevant standard;
    (vi) Alternate procedures for performing daily checks of zero (low-
level) and high-level drift that do not involve use of high-level gases 
or test cells;
    (vii) Alternatives to the American Society for Testing and Materials 
(ASTM) test methods or sampling procedures specified by any relevant 
standard;
    (viii) Alternative CMS that do not meet the design or performance 
requirements in this part, but adequately demonstrate a definite and 
consistent

[[Page 45]]

relationship between their measurements and the measurements of opacity 
by a system complying with the requirements as specified in the relevant 
standard. The Administrator may require that such demonstration be 
performed for each affected source; or
    (ix) Alternative monitoring requirements when the effluent from a 
single affected source or the combined effluent from two or more 
affected sources is released to the atmosphere through more than one 
point.
    (3) If the Administrator finds reasonable grounds to dispute the 
results obtained by an alternative monitoring method, requirement, or 
procedure, the Administrator may require the use of a method, 
requirement, or procedure specified in this section or in the relevant 
standard. If the results of the specified and alternative method, 
requirement, or procedure do not agree, the results obtained by the 
specified method, requirement, or procedure shall prevail.
    (4)(i) Request to use alternative monitoring procedure. An owner or 
operator who wishes to use an alternative monitoring procedure must 
submit an application to the Administrator as described in paragraph 
(f)(4)(ii) of this section. The application may be submitted at any time 
provided that the monitoring procedure is not the performance test 
method used to demonstrate compliance with a relevant standard or other 
requirement. If the alternative monitoring procedure will serve as the 
performance test method that is to be used to demonstrate compliance 
with a relevant standard, the application must be submitted at least 60 
days before the performance evaluation is scheduled to begin and must 
meet the requirements for an alternative test method under Sec. 63.7(f).
    (ii) The application must contain a description of the proposed 
alternative monitoring system which addresses the four elements 
contained in the definition of monitoring in Sec. 63.2 and a performance 
evaluation test plan, if required, as specified in paragraph (e)(3) of 
this section. In addition, the application must include information 
justifying the owner or operator's request for an alternative monitoring 
method, such as the technical or economic infeasibility, or the 
impracticality, of the affected source using the required method.
    (iii) The owner or operator may submit the information required in 
this paragraph well in advance of the submittal dates specified in 
paragraph (f)(4)(i) above to ensure a timely review by the Administrator 
in order to meet the compliance demonstration date specified in this 
section or the relevant standard.
    (iv) Application for minor changes to monitoring procedures, as 
specified in paragraph (b)(1) of this section, may be made in the site-
specific performance evaluation plan.
    (5) Approval of request to use alternative monitoring procedure.
    (i) The Administrator will notify the owner or operator of approval 
or intention to deny approval of the request to use an alternative 
monitoring method within 30 calendar days after receipt of the original 
request and within 30 calendar days after receipt of any supplementary 
information that is submitted. If a request for a minor change is made 
in conjunction with site-specific performance evaluation plan, then 
approval of the plan will constitute approval of the minor change. 
Before disapproving any request to use an alternative monitoring method, 
the Administrator will notify the applicant of the Administrator's 
intention to disapprove the request together with--
    (A) Notice of the information and findings on which the intended 
disapproval is based; and
    (B) Notice of opportunity for the owner or operator to present 
additional information to the Administrator before final action on the 
request. At the time the Administrator notifies the applicant of his or 
her intention to disapprove the request, the Administrator will specify 
how much time the owner or operator will have after being notified of 
the intended disapproval to submit the additional information.
    (ii) The Administrator may establish general procedures and criteria 
in a relevant standard to accomplish the requirements of paragraph 
(f)(5)(i) of this section.
    (iii) If the Administrator approves the use of an alternative 
monitoring method for an affected source under

[[Page 46]]

paragraph (f)(5)(i) of this section, the owner or operator of such 
source shall continue to use the alternative monitoring method until he 
or she receives approval from the Administrator to use another 
monitoring method as allowed by Sec. 63.8(f).
    (6) Alternative to the relative accuracy test. An alternative to the 
relative accuracy test for CEMS specified in a relevant standard may be 
requested as follows:
    (i) Criteria for approval of alternative procedures. An alternative 
to the test method for determining relative accuracy is available for 
affected sources with emission rates demonstrated to be less than 50 
percent of the relevant standard. The owner or operator of an affected 
source may petition the Administrator under paragraph (f)(6)(ii) of this 
section to substitute the relative accuracy test in section 7 of 
Performance Specification 2 with the procedures in section 10 if the 
results of a performance test conducted according to the requirements in 
Sec. 63.7, or other tests performed following the criteria in Sec. 63.7, 
demonstrate that the emission rate of the pollutant of interest in the 
units of the relevant standard is less than 50 percent of the relevant 
standard. For affected sources subject to emission limitations expressed 
as control efficiency levels, the owner or operator may petition the 
Administrator to substitute the relative accuracy test with the 
procedures in section 10 of Performance Specification 2 if the control 
device exhaust emission rate is less than 50 percent of the level needed 
to meet the control efficiency requirement. The alternative procedures 
do not apply if the CEMS is used continuously to determine compliance 
with the relevant standard.
    (ii) Petition to use alternative to relative accuracy test. The 
petition to use an alternative to the relative accuracy test shall 
include a detailed description of the procedures to be applied, the 
location and the procedure for conducting the alternative, the 
concentration or response levels of the alternative relative accuracy 
materials, and the other equipment checks included in the alternative 
procedure(s). The Administrator will review the petition for 
completeness and applicability. The Administrator's determination to 
approve an alternative will depend on the intended use of the CEMS data 
and may require specifications more stringent than in Performance 
Specification 2.
    (iii) Rescission of approval to use alternative to relative accuracy 
test. The Administrator will review the permission to use an alternative 
to the CEMS relative accuracy test and may rescind such permission if 
the CEMS data from a successful completion of the alternative relative 
accuracy procedure indicate that the affected source's emissions are 
approaching the level of the relevant standard. The criterion for 
reviewing the permission is that the collection of CEMS data shows that 
emissions have exceeded 70 percent of the relevant standard for any 
averaging period, as specified in the relevant standard. For affected 
sources subject to emission limitations expressed as control efficiency 
levels, the criterion for reviewing the permission is that the 
collection of CEMS data shows that exhaust emissions have exceeded 70 
percent of the level needed to meet the control efficiency requirement 
for any averaging period, as specified in the relevant standard. The 
owner or operator of the affected source shall maintain records and 
determine the level of emissions relative to the criterion for 
permission to use an alternative for relative accuracy testing. If this 
criterion is exceeded, the owner or operator shall notify the 
Administrator within 10 days of such occurrence and include a 
description of the nature and cause of the increased emissions. The 
Administrator will review the notification and may rescind permission to 
use an alternative and require the owner or operator to conduct a 
relative accuracy test of the CEMS as specified in section 7 of 
Performance Specification 2.
    (g) Reduction of monitoring data. (1) The owner or operator of each 
CMS must reduce the monitoring data as specified in paragraphs (g)(1) 
through (5) of this section.
    (2) The owner or operator of each COMS shall reduce all data to 6-
minute averages calculated from 36 or more data points equally spaced 
over each 6-minute period. Data from CEMS for

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measurement other than opacity, unless otherwise specified in the 
relevant standard, shall be reduced to 1-hour averages computed from 
four or more data points equally spaced over each 1-hour period, except 
during periods when calibration, quality assurance, or maintenance 
activities pursuant to provisions of this part are being performed. 
During these periods, a valid hourly average shall consist of at least 
two data points with each representing a 15-minute period. 
Alternatively, an arithmetic or integrated 1-hour average of CEMS data 
may be used. Time periods for averaging are defined in Sec. 63.2.
    (3) The data may be recorded in reduced or nonreduced form (e.g., 
ppm pollutant and percent O2 or ng/J of pollutant).
    (4) All emission data shall be converted into units of the relevant 
standard for reporting purposes using the conversion procedures 
specified in that standard. After conversion into units of the relevant 
standard, the data may be rounded to the same number of significant 
digits as used in that standard to specify the emission limit (e.g., 
rounded to the nearest 1 percent opacity).
    (5) Monitoring data recorded during periods of unavoidable CMS 
breakdowns, out-of-control periods, repairs, maintenance periods, 
calibration checks, and zero (low-level) and high-level adjustments must 
not be included in any data average computed under this part. For the 
owner or operator complying with the requirements of 
Sec. 63.10(b)(2)(vii)(A) or (B), data averages must include any data 
recorded during periods of monitor breakdown or malfunction.

[59 FR 12430, Mar. 16, 1994, as amended at 64 FR 7468, Feb. 12, 1999; 67 
FR 16603, Apr. 5, 2002]