[Federal Register Volume 60, Number 95 (Wednesday, May 17, 1995)]
[Rules and Regulations]
[Pages 26560-26571]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-11497]
Federal Register / Vol. 60, No. 95 / Wednesday, May 17, 1995 / Rules
and Regulations
[[Page 26560]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 75
[FRL-5203-2]
Acid Rain Program: Continuous Emission Monitoring Rule Technical
Revisions
AGENCY: Environmental Protection Agency (EPA).
ACTION: Interim final rule and request for comments.
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SUMMARY: Title IV of the Clean Air Act (the Act), as amended by the
Clean Air Act Amendments of 1990, authorizes the Environmental
Protection Agency (EPA or Agency) to establish the Acid Rain Program.
The program sets emissions limitations to reduce acidic deposition and
its serious, adverse effects on natural resources, ecosystems,
materials, visibility, and public health. On January 11, 1993, the
Agency promulgated final rules under title IV. Several parties filed
petitions for review of the rules. On April 17, 1995, the EPA and the
parties signed a settlement agreement addressing continuous emission
monitoring (CEM) issues.
In this interim final rule, EPA is amending certain provisions of
the CEM regulations to allow industry to be in compliance in situations
that were not contemplated in the original rulemaking. The interim
final rule allows industry additional flexibility to implement new
provisions immediately that address these unforeseen situations,
reduces the possibility of underestimating emissions, and also allows
the public to comment upon these new provisions.
DATES: Effective Dates. This interim final rule shall become effective
on July 17, 1995. The provisions of Secs. 75.11(a), 75.21(a), and
75.32(a)(3); sections 6.3.1, 6.3.2 and 6.4 of appendix A of part 75;
and section 2.1 of appendix B of part 75 are suspended temporarily from
July 17, 1995 through December 31, 1996. Sections 75.11 (e) and (g),
75.21(f), 75.30 (d) and (e), 75.32(a)(4), 75.55(e), and 75.56(a)(6);
Figure 5 and sections 6.3.3, 6.3.4 and 6.4.1 of appendix A of part 75;
section 2.1.7 of appendix B of part 75; and section 7 of appendix F of
part 75 are temporarily added and are effective from July 17, 1995
through December 31, 1996.
Comment Date. Comments on this interim final rule must be received
on or before June 16, 1995.
ADDRESSES: Any written comments on these interim final rule revisions
must be identified with the Docket No. A-94-16, must be identified as
comments on the interim final rule, and must be submitted in duplicate
to: EPA Air Docket (6102), Environmental Protection Agency, 401 M
Street SW, Washington, DC 20460. The docket is available for public
inspection and copying between 8:30 a.m. and 3:30 p.m., Monday through
Friday, at the address given above. A reasonable fee may be charged for
copying.
FOR FURTHER INFORMATION CONTACT: Margaret Sheppard, Acid Rain Division
(6204J), U.S. Environmental Protection Agency, 401 M Street SW,
Washington, DC 20460, telephone number (202) 233-9180.
SUPPLEMENTARY INFORMATION: All public comments received on the interim
final rule will be addressed in a subsequent final rulemaking notice.
The EPA will not institute a second comment period on this document.
Any parties interested in commenting on this interim final rule should
do so at this time.
For additional information about further revisions to the Acid Rain
monitoring provisions, see the direct final rule published elsewhere in
this Federal Register.
The EPA intends to publish a final rulemaking document as a follow-
up to this interim final rule prior to January 1, 1997 that will
incorporate provisions based upon public comments. At that time, the
sections that are added temporarily by this interim final rule would be
permanently added by the follow-up final rule. Provisions that are
suspended temporarily in this interim final rule would be removed in
the follow-up final rule. If EPA were not to publish a follow-up final
rule prior to January 1, 1997, the sections temporarily added by the
interim final rule would expire and the sections suspended temporarily
by the interim final rule would be effective January 1, 1997.
I. Background
Title IV of the Clean Air Act (CAA or the Act), as amended November
15, 1990, requires the Environmental Protection Agency (EPA or Agency)
to establish an Acid Rain Program to reduce the adverse effects of
acidic deposition. On January 11, 1993, the Agency promulgated final
rules implementing the program, including the General Provisions of the
Permits Regulation and the CEM rule (58 FR 3590-3766). Technical
corrections were published on June 23, 1993 (58 FR 34126) and July 30,
1993 (58 FR 40746-40752). This notice of interim final rulemaking, like
the notice of direct final rulemaking published elsewhere in this issue
of the Federal Register, contains additional technical corrections and
other amendments to address various implementation issues that have
come to light since the final rule was published on January 11, 1993.
The effective date of these interim final amendments will be July 17,
1995.
The EPA has been engaged in settlement discussions with several
parties who challenged certain provisions of the Acid Rain CEM rules
promulgated on January 11, 1993. [See Environmental Defense Fund v.
Browner, No. 93-1203 and consolidated cases, ``Complex'' (D.C. Cir.,
filed March 12, 1993.] Although the parties have been able to reach
agreement on a number of issues, which are addressed in the direct
final rule, some additional issues remain outstanding. These
outstanding issues, unlike the noncontroversial and routine technical
corrections addressed by the direct final rule, may not be considered
noncontroversial and therefore are being addressed separately in this
interim final rule. The issues addressed by this interim final rule
are: (1) A requirement that units with SO2 CEMS burning gaseous
fuels only must use heat input and a default SO2 emission rate or
appendix D methods to determine SO2 emissions instead of an
SO2 CEMS and a flow monitor [Sec. 75.11(e)], (2) the procedure for
assigning proportional flow rates for emissions through multiple stacks
or bypass stacks for purposes of substituting missing data
[Sec. 75.30(e)], (3) the procedure for determining proper operation of
units with add-on controls for purposes of substituting missing data
(Sec. 75.34), (4) clarification of provisions in the January 11, 1993
rule that the unit must be operating while performing certain quality
assurance procedures (appendix A, sections 6.3.1 and 6.3.2; appendix B,
section 2.1 Introductory Text), and (5) the procedures for performing
cycle time tests (appendix A, section 6.4).
In order to allow for necessary changes to the data acquisition and
handling systems (DAHS) required by the revisions to Secs. 75.11(e) and
75.30(e), owners or operators may choose to delay compliance with the
revised provisions regarding use of heat input and a default SO2
emission rate or appendix D methods for units with SO2 CEMS when
burning only gaseous fuels [Sec. 75.11(e)] or with the procedure for
assigning proportional flow rates for emissions through multiple stacks
or bypass stacks for purposes of missing data substitution
[Sec. 75.30(e)] until January 1, 1997. The EPA believes that this will
give utilities time to comment [[Page 26561]] on these issues and EPA
time to respond to these issues in a final rulemaking before the
provisions become required. Furthermore, EPA believes an optional
delayed compliance date for these revised provisions is warranted
because utilities may need time to incorporate these changes into their
DAHS, emissions will be monitored under the current regulations until
the changeover, and emissions affected by these provisions will be
small.
II. EPA Action
Under CAA Section 412(c), not later than January 1, 1995, owners
and operators of Acid Rain affected units must install and operate
CEMS, quality assure the data, and keep records and reports in
accordance with the Acid Rain regulations. Because EPA believes the
revisions published in this rule will improve and enhance the
implementation of the Acid Rain monitoring program, EPA believes it is
necessary that the revisions become effective as soon as possible. Many
of the monitoring provisions in part 75 are interrelated and would be
difficult to separate from other, related provisions and therefore
these technical revisions to the monitoring provisions must be
considered as a whole. For these reasons, EPA is publishing the
noncontroversial revisions through a direct final rulemaking and is
also publishing provisions that may be controversial and on which it
may receive comment through this interim final rulemaking. Both the
direct final rule and the interim final rule will become effective on
the same date. Even though comments may be submitted on these interim
final provisions, EPA believes that it is necessary to include the
interim final revisions in the revised CEM regulation in order to
assure an overall consistent and implementable Acid Rain monitoring
program. Therefore, EPA is issuing these amendments to the CEM
regulation effective at the same time as the direct final amendments
and will take comment on both sets of revisions. Comments on the
interim final provisions must be submitted to Air Docket A-94-16, which
is also the docket for the direct final rulemaking published elsewhere
in this issue of the Federal Register, and must be identified as
comments on the interim final rule to distinguish them from comments on
the direct final provisions. Because the provisions of the direct final
rule and interim final rule are interrelated, the docket contains
supporting material and relevant information for both rulemakings.
As described in the notice of direct final rulemaking, if EPA
receives significant adverse comments on the direct final rule, EPA
will withdraw those portions of the direct final rule upon which
comments are submitted, address the comments, and subsequently issue a
final rule that addresses the withdrawn portions of the direct final
rule. Except for certain specified subsections which will cease to be
in effect as of January 1, 1997, the interim final rule will remain in
effect until EPA publishes a subsequent final rule, following
consideration of comments received in response to the notice of
proposed rulemaking corresponding to this interim final rule. At the
time of that future rulemaking, sections that are temporarily added in
today's interim final rule would be permanently added and would replace
provisions in the current rule that are temporarily suspended.
The EPA has been addressing many technical issues during early
implementation of the Acid Rain monitoring program through issuance of
policy statements interpreting the monitoring provisions of the January
11, 1993 rule, as well as by issuance of technical guidance. Many of
the clarifying policy statements and technical guidance, which are to a
large extent reflected in the direct final rule and interim final rule,
are now being used by utilities for implementation guidance. Therefore,
EPA believes it would be contrary to the public interest to delay the
effectiveness of these monitoring provisions and believes these
technical revisions should be effective immediately. Because EPA
believes it is necessary to issue the technical corrections to the CEMS
regulation as soon as possible and because the revised portions of the
monitoring provisions are integrally interrelated, EPA believes it
necessary for the full complement of revisions to take effect at the
same time. The EPA is therefore invoking the good cause exception under
the Administrative Procedure Act (APA) in not providing an opportunity
for comment before this interim final rule takes effect.1 [See 5
U.S.C. 553(b)(B); see also 42 U.S.C. 7607(d)(1).] Under CAA Section
307(d)(1), subsection 307(d) does not apply in the case of a rule for
which the agency invokes the good cause exception of 5 U.S.C.
553(b)(B). Therefore, CAA Section 307(d) does not apply to this interim
final rule. The EPA believes that notice-and-comment rulemaking prior
to the effective date of the interim final rule would be impracticable
and contrary to the public interest because of the complex and
interrelated nature of the monitoring provisions that make it necessary
to revise all of the CEM provisions in a consistent and integrated way
in order to avoid inconsistency in monitoring requirements and because
of the need to make the technical corrections and amendments available
for use by utilities as soon as possible.
\1\As previously noted however, EPA is providing the public with
an opportunity to comment on EPA's direct final rule and will
withdraw any portions of the direct final rule upon which
significant adverse comments are submitted.
III. Rationale
A. SO2 Monitoring During Combustion of Gas for Units With SO2
CEMS
Some coal-fired units and oil-fired units also combust pipeline
natural gas. Natural gas has a very low sulfur content and will produce
extremely low SO2 concentrations when combusted alone. In order to
monitor these low concentrations accurately, a utility would need to
use an SO2 monitor with a range of a few parts per million (ppm).
At this range, there are no Protocol 1 gases available for
calibrations. Furthermore, it is unlikely that the CEMS would be able
to pass the relative accuracy test at such low levels because it is
difficult to measure extremely small concentrations precisely with
either the reference method or a CEMS. The EPA had concerns about the
accuracy of the SO2 concentration data when measuring natural gas
alone, because of the extremely low concentrations and because of the
difficulty in performing appropriate quality assurance testing. The EPA
decided that it was inappropriate for units to use an SO2 CEMS to
measure emissions from natural gas only. However, a coal-fired, oil-
fired, or gas-fired unit could still use an SO2 CEMS for measuring
SO2 when combusting fuels other than natural gas (or other gaseous
fuel with a sulfur content no greater than natural gas) or when
combusting a combination of fuels.
In order to address this situation, some industry representatives
requested to use the provisions of appendix D of part 75 for
determination of SO2 emissions from natural gas instead of use of
an SO2 CEMS. (See Docket Item II-D-29, Letter from B. Machaver to
S. Jewett, November 30, 1993; Docket Item II-D-30, Log of telephone
conversation on Questions Concerning 40 CFR Part 75 Regulations for
Oil/Gas Fired Title IV Affected Units (Questions provided in November
30, 1993 Memorandum to Susan Jewett), December 7, 1993.) After
consideration, EPA agreed that this [[Page 26562]] would be an
acceptable alternative to using the SO2 CEMS during combustion of
low sulfur gaseous fuel, so long as the utility certifies an excepted
monitoring system under appendix D of part 75 for the measuring of gas.
This requires accuracy testing of a gas flowmeter and testing of the
DAHS. Furthermore, the utility must perform the procedures under
appendix D, with the same fuel sampling, analysis, and fuel flowmeter
quality assurance/quality control (QA/QC) requirements.
Another variant suggested by a utility was to use the default
SO2 emission rate factor of 0.0006 pound per million British
thermal units (lb/mmBtu) for pipeline natural gas that EPA previously
discussed in a policy statement regarding the ``NADB emission rate'' in
appendix D and the heat input calculated by a flow monitor and a
diluent monitor. (See Docket Item II-D-54, Acid Rain CEM (Part 75)
Policy Manual; Docket Item II-D-59, Letter from R. LaBorde, Central
Louisiana Electric Company to J. Winkler, EPA Region VI Re: Requestion
for Clarification, Rodemacher Power Station Unit-1, Rapides Parish, LA,
August 3, 1994). After further consideration, EPA agreed that this also
is acceptable. (See Docket Item II-D-67, Response to R. LaBorde, CLECO,
from J. Hepola, EPA, August 25, 1994.) The owner or operator must
certify the system using the flow monitoring system, the diluent
monitor, and the DAHS as a system for monitoring SO2 emissions.
These monitors must be tested following the QA/QC requirements of
appendix B of part 75. Both of these methods allow utilities to use
provisions that are allowed for estimating the low SO2 emissions
due to combustion of gaseous fuels with a low sulfur content under
appendix D of part 75. The EPA believes that these methods will allow
SO2 accounting with sufficient accuracy for the low emission rate
from combustion of natural gas. These methods are not sufficiently
accurate for combustion of oil or coal because of their higher sulfur
content. Similarly, during periods of co-firing of oil, coal or other
high sulfur fuels, the owner or operator must use the certified
SO2 CEMS.
B. Missing Data Substitution Provisions
1. Missing Data Procedures for Units With Add-On Emission Controls
Many utilities were uncertain of the requirements for substituting
and reporting missing data for units with add-on emission controls. For
instance, the regulation was not clear as to whether or not parametric
data needed to be reported and recorded for these units. Industry also
commented that the possible options for substituting missing data were
unclear for these units. (See Docket Item II-D-3, Discussion Issues for
TU Electric and EPA; Docket Item II-D-4, Draft Meeting Notes for EPA-
Texas Utilities Teleconference, December 7, 1992 ). In response to
these concerns, EPA prepared a policy statement to clarify missing data
substitution procedures for units with add-on emission controls. (See
Docket Item II-D-54, Acid Rain CEM (Part 75) Policy Manual). The EPA
has amended part 75 in part to incorporate these interpretations.
The amendments to part 75 allow four ways of substituting for
missing data. The default option is to substitute the maximum potential
concentration of SO2 or the maximum potential NOX emission
rate when no information on the emission controls is available. A unit
with SO2 add-on emission controls with an inlet monitor may
instead use the maximum SO2 concentration at the scrubber inlet
during the previous 720 quality-assured monitor operating hours. This
option may always be used by a source.
Another option is to develop a site-specific correlation to
determine the removal efficiency of the control equipment. The
designated representative for a unit will petition the Administrator
for use of this correlation instead of following standard missing data
substitution procedures. The requirements for using this correlation as
a missing data substitution method are located in appendix C of part
75. The correlation involves monitoring emission control parameters and
electronically reporting this data for each missing data period to EPA
each quarter. This correlation method may only be used if the
availability or the CEMS at the outlet of the emission controls is 90.0
percent or greater.
A third option is to use the standard missing data procedures and
to keep information on the emission controls at the site. The
parameters listed in appendix C are a guideline of the types of
information that are to be used to verify the add-on emission controls
are operating properly. The EPA considers ``proper operation'' of the
control equipment to require that the removal efficiency is equal to or
greater than that when monitor data is available, such as during the
hours before and after the missing data period. It is not enough to
show that the control device simply is operating. The information that
a utility should keep relates to site-specific equipment. Part 75 does
not require that every single one of those parameters must be kept, nor
does it prohibit the use of other information to verify proper
operation of the emission controls. Also, these records do not have to
be kept electronically. However, the designated representative must
report in the monitoring plan for the unit the range of each parameter
that indicates proper operation of the add-on emission controls. The
EPA or a State air pollution control agency could request to look at
the parametric records or to have them reported at any time to verify
that the add-on emission controls are maintaining emission reductions
and are operating properly, by comparing the data with the range of
each parameter reported in the monitoring plan. In addition, a
designated representative for a source must certify that the emission
controls are properly operating and that the missing data procedures
are not systematically underestimating emissions during the quarter
where the utility uses the standard missing data procedures. This
additional certification is to be reported as part of the designated
representative's certification with each quarterly report.
The fourth and final option for supplying missing data is to use
the standard missing data procedures as in the third option, and then
to petition the Administrator for use of a value more representative of
actual emissions than the maximum SO2 concentration in the
previous 720 hours or the maximum NOX emission rate at the
corresponding load range. As in the existing rule, this is only an
option when monitor data availability is below 90.0 percent, where the
most conservative missing data substitution procedures are required. A
designated representative may petition to substitute with a more
representative value that does not underestimate emissions if
sufficient data exist to demonstrate that the maximum value is an
extreme overestimate, based upon periods of improper operation or non-
operation of the emission controls. This demonstration requires
information such as: CEM data from periods when the add-on emission
controls are operating; unit operating load data; parametric data
indicating proper operation of the add-on emission controls during the
missing data period; and fuel sulfur content. The EPA expects a
``representative value'' to be no less than the maximum hourly value
from when the emission controls were operating during the same lookback
period normally used for an SO2 or NOX CEMS.
The EPA has also made minor changes to indicate that petitions are
submitted by the designated [[Page 26563]] representative, rather than
the owner or operator. This is consistent with the designated
representative's role as the official contact person for EPA for all
submissions.
2. SO2 Concentration Missing Data During Gas Combustion
A utility noted that for a unit that combusts either natural gas
and some oil or natural gas and some coal, SO2 emissions due to
gas combustion are several orders of magnitude smaller than emissions
during combustion of either coal or oil (See II-D-16, Letter from David
Rengert, Niagara Mohawk Power Corporation to Ann Zownir, EPA, May 21,
1993). Therefore, if an SO2 CEMS was not providing quality-assured
data when the unit was combusting only natural gas, the standard
missing data procedures might substitute vastly overestimate SO2
concentration values from combustion of coal or oil. In addition, if
the unit combusts primarily natural gas, these low SO2
concentration values could potentially underestimate emissions when
combusting oil or coal if the 90th percentile and 95th percentile (and
possibly even the maximum value) during the previous 720 quality-
assured monitor operating hours were substituted using all data
collected from all fuels. To address this concern, EPA revised the
missing data procedures to separate SO2 emissions due to
combustion of natural gas and other gaseous fuels with a sulfur content
no greater than that of natural gas. SO2 concentration values
measured by an SO2 monitoring system during combustion of natural
gas only are not kept as part of the historical data that is used to
substitute SO2 concentration data. These values are not used to
provide the average of the hour before and the hour after a missing
data period and are not included in percentile calculations. As a
result, substituted missing data will reflect the fuel being used
during the missing data period.
As was discussed under Section A above, as of January 1, 1997,
SO2 CEMS will no longer be allowed for measuring SO2 during
combustion of natural gas or other gaseous fuels with a sulfur content
no greater than that of natural gas because of the difficulty of
accurately measuring and quality assurance testing at such low
concentrations.
During those times, a utility will either use the heat input from
the flow monitor and diluent monitor and the default SO2 emission
rate for pipeline natural gas of 0.0006 lb/mmBtu according to appendix
F of part 75, or the fuel flow and daily sulfur content of the gaseous
fuel according to appendix D of part 75. The utility should use the
following to fill in missing data if a fuel flowmeter, a flow monitor
or a diluent monitor is not providing quality-assured data. For units
combusting pipeline natural gas using a flow monitor, a diluent monitor
and the default SO2 emission rate, the owner or operator should
follow the missing data procedures for heat input found in Sec. 75.36
of subpart D of part 75. For other units using gas sampling and
analysis and fuel flowmeters, the owner or operator should substitute
using the missing data procedures for sulfur content or fuel flow found
in appendix D of part 75.
Note that these revised procedures are not needed if a unit is co-
firing a high sulfur fuel along with natural gas or other gaseous fuels
with a sulfur content no greater than that of natural gas. In this
case, the concentration will come predominantly from the higher-sulfur
fuel, generally oil or coal. Thus, during periods of co-firing, the
owner or operator should be using the SO2 CEMS or the missing data
procedures in Secs. 75.31 or 75.33 for an SO2 CEMS.
3. Missing Data for Multiple Stacks and Bypass Stacks
The EPA has added a provision to account for missing data
substitution of flow data in the case of multiple stacks or bypass
stacks in Sec. 75.30(e) of today's interim final rule. First, this
revision accounts for the fact that emissions may not flow through a
particular stack during an hour when the unit combusts fuel. To account
for this, EPA has added a provision to the missing data procedures such
that only hours when emissions pass by the monitors on the stack are
included as unit operating hours and as quality-assured monitor
operating hours in calculations of availability and substitute values.
A second provision accounts for the fact that some units may be
able to shift flow between ducts or stacks. If flow from a unit can
shift from one stack to another, such as when flue dampers are moved,
then the correlation between load for the entire unit and flow rate
measured on one stack is no longer accurate. It would be possible to
underestimate flow rate and SO2 mass emissions during use of the
missing data procedures for flow, contrary to EPA's intent for these
missing data procedures. In order to avoid this situation, EPA has
added a provision in today's rule that requires using a substitute
value of the maximum flow rate recorded by the flow monitoring system
at the corresponding load range during the previous 2,160 hours of
quality-assured monitor data when emissions passed through the stack if
the proportion of flow between stacks has changed during that time.
This will avoid potential underestimation that might occur when using
an average flow rate in the corresponding load range. As discussed
above in this notice, owners or operators may choose to delay
compliance with this requirement until January 1, 1997 in order to make
changes to their DAHS and to await implementation of these provisions
until after EPA has addressed all comments on the interim final rule.
In addition, EPA notes that if a utility never changes the flue dampers
so that the proportion of flow is constant, then no changes to the
standard missing data procedures or to their DAHS are necessary.
C. Certification and Quality Assurance Testing
1. Calibration Error Test
The EPA discovered that some CEMS testers were incorrectly
performing the 7-day calibration error test. In the incorrect use of
the procedure, the tester checked the calibration error at the zero
calibration gas level, made automatic adjustments to the monitor data
at that point, checked the calibration error at the high calibration
gas level, and then again made adjustments to the data. The EPA
clarified that a tester should check the calibration error both at the
zero level and the high level before making any adjustments. Both in
the preamble to part 75 (January 11, 1993) and in a public issue paper
on the 7-day calibration error test, EPA stated that this second
interpretation is the correct one. (See Docket Item II-D-27, Issue
Paper on Part 75 Calibration Error Testing for Certification, October
8, 1993; Letter from J. White to D. McNeal, and Response to J. White
from S. Saile, EPA). The EPA has adopted this interpretation of testing
both instrument levels together because instrument errors at the zero
and high levels are not always independent of each other. These interim
amendments to part 75 clarify this provision.
Another related issue associated with the 7-day calibration error
test concerned the kinds of adjustments that could be made.
Requirements of the calibration error tests in 40 CFR part 75 and 40
CFR part 60 could be interpreted as requiring either 7 successive daily
tests or one cumulative 7-day test. The following statements in the
January 11, 1993 rule imply that the 7-day test is cumulative:
Do not make manual adjustments to the monitor setting during the
7-day test. If automatic adjustments are made, conduct the
calibration error test in a way that the [[Page 26564]] magnitude of
the adjustments can be determined and recorded. (section 6.3.1 of
appendix A.)
However, EPA stated in Section V.G(4)(a) of its January 11, 1993
preamble to part 75 that ``the 7-day calibration error test performed
during certification is the same 2-point drift test as the daily
calibration error test'' and referred to 40 CFR part 60, appendix B in
Section V.G(4)(b) (58 FR 3641). Industry generally interprets the
calibration drift test in 40 CFR part 60 to require 7 separate daily
tests, rather than a cumulative test over 7 days. (See Docket Item I-C-
3, Jahnke, James A., Excerpt from Continuous Emission Monitoring, Van
Nostrand Reinhold, New York.) The EPA now clarifies part 75 to state
its original intention that the 7-day calibration error test is a
series of 7 daily calibration error tests. On each day of the test, the
monitor must meet the performance specification of a calibration error
no greater than 2.5 percent of span. Because this is a series of tests,
a tester may not adjust the monitor or monitor data, either manually or
automatically, until the test has been completed at both levels on any
given day. However, the tester may make adjustments between daily
tests, once the previous day's test results have been recorded.
2. Quality Assurance of Data Following Daily Calibration Error Test
During early implementation EPA began developing a series of
policies in order to assist in its evaluation of the acceptability of
data received in quarterly reports. Among these policies concerned the
acceptability of data when a required daily test is not performed. The
Agency initially decided that the absence of information on a test
during a calendar day means that emissions data for that day are not
considered quality-assured. Section 2.1 of appendix B requires daily
assessments, such as calibration error tests and interference checks,
to be performed on each calendar day. Based on this requirement, EPA
initially interpreted data as invalid for a calendar day from midnight
to the time of the next successful daily calibration error test if no
test results were reported. (See Docket Items II-D-56, ETS User
Bulletin #2 and II-D-50, Electronic Data Reporting Supplementary
Instructions, June 29, 1994.)
Some utilities expressed concern that a unit might stop operating
during the middle of a day before the regularly scheduled time for
performing an automated calibration. (See Docket Item II-D-60, Letter
from Gary R. Cline, Pennsylvania Electric Co., to Margaret Sheppard,
EPA, August 1, 1994.) Because the testing procedures require the unit
to operate during all measurements, the utility would be unable to
perform this test and its data would be invalidated beginning at
midnight. Some suggestions from utilities included: allowing
performance of the test while the unit is off-line, treating the data
as quality assured until the time of the next test, and treating the
data as quality-assured prospectively for 24 hours from the previous
test.
The EPA decided that the approach consistent with the regulatory
language that would result in the greatest amount of quality-assured
data while still preserving the requirement for a daily test is to
retain the calendar day requirement for performing each daily test.
However, if a unit stops operating during a calendar day, then data is
still considered quality-assured for 24 clock hours from the previous
day's test. For example, a unit with monitors that are normally
calibrated at 8 a.m. performs the calibration error test at 8 a.m. on
January 11. All 24 hours of data from the monitor for January 11 are
quality-assured. If the unit suddenly ``trips'' and stops operating at
6 a.m. on January 12, the data from midnight until 6 a.m. are also
considered quality-assured. If the unit starts up again at 3 p.m. but
the monitors are not tested between 3 p.m. and midnight, then that
block of data is invalidated. As in the January 11, 1993 rule, today's
rule still requires a calibration error test to be performed with the
unit operating. This is because the readings from the CEMS are affected
by temperature and pressure conditions. (See Docket Item II-D-39, Log
of telephone conversation between Jon Konings, WEPCo, and M. Sheppard,
EPA, on EPA's policy on conducting calibration error test, April 13,
1994.) In order to ensure accurate CEMS measurements for the entire
system and to ensure that this test is performed under controlled
conditions, EPA requires the daily calibration error tests to be
performed while the unit is operating for purposes of quality-assuring
the data and testing the CEMS. (See Docket Item II-D-54, Acid Rain CEM
(Part 75) Policy Manual.)
3. Unit Operation During Testing
This issue is related to provisions of section 6 of appendix A of
part 75 and to the tests performed under appendix B of part 75. Under
the January 11, 1993 rule, section 6.1 of appendix A requires that a
unit be operated during periods when measurements are made for
certification testing. Similarly, section 6.2 indicates that when
performing a linearity check, testers are to conduct each test by
operating the monitor at its normal (unit) operating temperature and
conditions. In this interim rule, EPA further clarifies provisions in
the January 11, 1993 rule, providing that the unit must be operating,
by adding language to sections 6.3.1, 6.3.2, and 6.4 for the
calibration error test and for the cycle time test. These sections are
later cited in appendix B. This language addition clarifies EPA's
intent that a unit must be operating during all monitor testing, both
for initial certification testing and for QA/QC testing.
During the public comment period for the proposed part 75
regulation, some commenters raised this issue. (See Docket A-90-51,
Docket Item IV-D-303, Letter from Nicolson, Rober J., Vice President,
Fossil & Hydro Operations, Consumers Power Company, Comments on Clean
Air Act Amendments--Title IV Part 75 Continuous Emission Monitoring
Rule and Docket A-91-69, Item IV-D-66, Letter from Sullivan, J.J.,
Executive Director, Environmental Programs, PSI Energy, Inc., Comments
on the Proposed Acid Rain Program Rule: 40 CFR Part 72, 73, 75 and 77.)
Under the new source performance standard for subpart Da of 40 CFR part
60 and under the performance specifications in appendix B of 40 part
60, EPA required a unit to operate for 168 hours in a row in order to
perform the 7-day calibration error test for monitors. In part 75, EPA
modified this to allow units to operate only during the periods when
measurements were performed and by allowing operation on nonconsecutive
days. This change was made to account for peaking units, which normally
would not operate for every hour of every day. However, EPA still
required the unit to be operating during testing so that the test will
be performed under the same temperature and pressure conditions as when
monitor readings are taken during the program. (See Docket A-90-69,
Docket Items V-C-1 and V-C-2, Response to Comment Document.)
The test procedures for linearity checks and for calibration error
tests require the entire monitoring system to be tested, rather than
just the analyzer. For example, sections 6.2 and 6.3.1 of appendix A
requires introducing calibration gas through the gas injection port,
which for most systems will be at the probe. The calibration gas must
go through as much of the system as possible, including the probe,
filters, scrubbers, conditioners, and other monitor components for
extractive type monitoring systems, or including all active electronic
and optical components for in situ type monitors.
[[Page 26565]] Monitor responses must come from the DAHS. Thus, the
test is a test of the complete continuous emission monitoring system.
(See Docket Item II-D-68, Memorandum from B. Warren-Hicks, The Cadmus
Group to M. Sheppard, EPA, September 6, 1994). In order to make the
linearity check and calibration error test a true test of the entire
monitoring system, the tests must be performed under the same unit
operating conditions that prevail when the monitor reads emissions to
include in certification test results and in quarterly emissions
reports. The EPA has already stated this policy in question Number
12.17 of its policy guidance manual. (See Docket Item II-D-54, Acid
Rain CEM (Part 75) Policy Manual.) Utilities have also commented on the
significant effects of temperature and pressure conditions upon monitor
readings. (See Docket Items II-D-39, Conversation between J. Konings,
WEPCo and M. Sheppard, EPA:ARD, on EPA's policy on conducting
calibration error test, April 13, 1994; II-D-40, Meeting Notes from EPA
Meeting with J. West of Metropolitan Edison and J. Jahnke of Source
Technology Associates, April 18, 1994.).
The procedures of the relative accuracy test and the cycle time
test require continuous emission monitoring systems and flow monitors
to measure the actual emissions at the stack. Therefore, these tests
can only be performed while the unit is operating.
The EPA does not consider test results to be valid if the test is
performed while the unit is not operating.
Thus, in this interim rule, EPA clarifies that a unit must be
operating when a test is performed in order to provide acceptable
results to meet requirements for certification testing or QA/QC
testing. This is also consistent in a new provision in section 2.1 of
appendix B of part 75. This provision allows data to be considered
valid for 24 hours following the last passed calibration error test if
a unit stops operating on a calendar day before the utility has
performed a calibration error test on that day. However, if a daily
calibration error test were failed or if the daily calibration error
test were performed while the unit is not operating, the data after
that test would not be considered valid.
4. Cycle Time Test
Part 75 included a cycle time/response time test to determine if a
CEMS was capable of drawing down and analyzing a sample frequently
enough to provide an update at least four times an hour. A tester was
required to perform this test on the SO2 pollutant concentration
monitor, the NOX CEMS (in lb/mmBtu), and the CO2 pollutant
concentration monitor. Some testers found the regulatory procedures
unclear as to when a source tester samples stack gas. In addition, EPA
staff realized that some CEMS cannot perform the cycle time/response
time test simultaneously on the NOX and diluent gas components of
the NOX CEMS, because NOX and O2 cannot be kept in the
same bottle for reasons of stability.
As a result of these issues raised during implementation, EPA has
revised the cycle time/response time test to be a cycle time test
patterned after the response time test in Method 20 of appendix A of 40
CFR part 60. A cycle time test is a test to determine the length of
time it takes for a CEM system to draw down a sample of gas, analyze
the sample, achieve a stable reading, and record the new concentration.
More specifically, the cycle time test determines 95 percent of the
length of time for the monitor to go from reading a known concentration
of calibration gas to reading actual stack emissions. (The 95-percent
margin allows for small amounts of error that will prevent a monitor
from reading the labelled value of a calibration gas, even when the
monitor reading is stable.) A tester starts by introducing calibration
gas until the monitor reading is stable. Next, the tester switches the
monitor to reading stack gas emissions. When the monitor response is
stable, the tester notes the time. The DAHS records each value that the
monitor reads and the time of the reading. Once the DAHS has recorded
this stable value, the tester introduces the other calibration gas. The
procedure is repeated, so that the monitor returns to a stable reading
of stack gas and records it. This revised procedure will allow more
time-share monitoring systems to pass the cycle time test than the
earlier cycle time/response time test, because the revised test
eliminates the time it takes for gas to travel from the calibration gas
cylinder to the probe.
Stability is considered to be achieved when the monitor reading
changes by less than 5 percent from the average concentration over a 5-
minute period, or less than 1 percent of the monitor span over 30
seconds. These values were adapted from the response time test found in
Method 20 of appendix A, 40 CFR part 60 for testing of stationary gas
turbines. The EPA made the definition of stability more flexible by
lengthening the time period for averaging concentration from 2 minutes
to 5 minutes, in order to apply to coal-fired boilers, which may
experience less stable loads than stationary gas turbines. Based upon
results from certification tests at Phase I units, EPA believes that
coal-fired units can reliably achieve this definition of stability.
(See Docket Item II-D-75, Analysis of Cycle Time/Response Time Data,
October 3, 1994.)
The longer of the two times going from calibration gas to stack gas
is the cycle time of the component monitor. For a NOX or SO2-
diluent monitoring system, the cycle time is the longer of the two
cycle times for the NOX or SO2 pollutant concentration
monitor and the diluent monitor. Originally, testers were required to
test both component monitors at the same time, which requires injecting
both gases simultaneously. Testing the two component monitors
separately simplifies performing the cycle time test, since calibration
gases do not need to be injected simultaneously. This also resolves the
issues raised during certification testing for Phase I units. In
addition, the revision provides consistency with existing EPA
regulations under 40 CFR part 60.
The EPA has included recordkeeping provisions for this
certification test in Sec. 75.56. Furthermore, the rule amendments
contain an additional figure at the end of appendix A, to complement
the figures for test data and results for other certification tests for
CEMS.
IV. Impact Analyses
The impact analyses required by Executive Orders 12866 and 12875
and by the Regulatory Flexibility Act, the Unfunded Mandates Act and
the Paperwork Reduction Act are found under the notice of direct final
rulemaking in today's Federal Register.
The control numbers assigned to collections of information in
certain EPA regulations by the OMB have been consolidated under 40 CFR
part 9. The EPA finds there is ``good cause'' under Sections 553(b)(B)
and 553(d)(3) of the APA to amend the applicable table in 40 CFR part 9
to display the OMB control number for this rule without prior notice
and comment. Due to the technical nature of the table, further notice
and comment would be unnecessary. For additional information, see 58 FR
18014, April 7, 1993, and 58 FR 27472, May 10, 1993.
List of Subjects in 40 CFR Parts 75
Environmental protection, Air pollution control, Carbon dioxide,
Continuous emission monitors, Electric utilities, Incorporation by
reference, Nitrogen oxides, Reporting and recordkeeping requirements,
Sulfur dioxide.
[[Page 26566]] Dated: April 28, 1995.
Carol M. Browner,
Administrator.
For the reasons set out in the preamble, part 75 of title 40,
chapter I, of the Code of Federal Regulations is amended as follows:
PART 75--CONTINUOUS EMISSION MONITORING
1.-3. The authority citation for part 75 is revised to read as
follows:
Authority: 42 U.S.C. 7601 and 7651k.
4. Section 75.11 is amended by adding a sentence to the end of
paragraph (a) and by adding paragraphs (e) and (g) to read as follows:
Sec. 75.11 Specific provisions for monitoring SO2 emissions
(SO2 and flow monitors).
(a) * * * The provisions in this paragraph are suspended from July
17, 1995 through December 31, 1996.
* * * * *
(e) Units with SO2 continuous emission monitoring systems
during the combustion of gaseous fuel. On or after January 1, 1997, the
owner or operator of a unit with an SO2 continuous emission
monitoring system shall, during any hours in which the unit combusts
only pipeline natural gas or gaseous fuel with a sulfur content no
greater than natural gas, calculate SO2 emissions in accordance
with the following procedures. Prior to January 1, 1997, the owner or
operator of such a unit may calculate SO2 emissions in accordance
with the following procedures.
(1) The owner or operator of a unit with an SO2 continuous
emission monitoring system shall, during any hours in which the unit
combusts only pipeline natural gas, calculate SO2 emissions using
one of the following two methods in lieu of operating and recording
data from the SO2 continuous emission monitoring system:
(i) By using the heat input calculated using a certified flow
monitoring system and a certified diluent monitor, the default SO2
emission rate for pipeline natural gas from appendix D of this part,
and Equation F-23 in appendix F of this part and by certifying this as
a system for monitoring SO2 mass emissions by identification in
the monitoring plan, by tests for the data acquisition and handling
system under Sec. 75.20(c), and by meeting all quality control and
quality assurance requirements in appendix B of this part for a flow
monitor and a diluent monitor; or
(ii) By certifying an excepted monitoring system under appendix D
of this part under Sec. 75.20, by following the procedures for
determining SO2 emissions from combustion of gaseous fuels under
appendix D of this part, by meeting the recordkeeping requirements of
Sec. 75.55, and by meeting all quality control and quality assurance
requirements for fuel flowmeters in appendix D of this part.
(2) During any hours in which the unit combusts only gaseous fuel
with a sulfur content no greater than natural gas other than pipeline
natural gas, the owner or operator shall calculate SO2 mass
emissions by certifying an excepted monitoring system under appendix D
of this part under Sec. 75.20, by using the gas sampling and analysis
and fuel flow procedures of appendix D of this part, by meeting the
recordkeeping requirements of Sec. 75.55, and by meeting all quality
control and quality assurance requirements for fuel flowmeters in
appendix D of this part.
* * * * *
(g) Coal-fired units. The owner or operator shall meet the general
operating requirements in Sec. 75.10 for an SO2 continuous
emission monitoring system and a flow monitoring system for each
affected coal-fired unit while the unit is combusting coal or any fuel
other than natural gas or a gaseous fuel with a sulfur content no
greater than natural gas, except as provided in Sec. 75.16 and in
subpart E of this part.
5. Section 75.21 is amended by adding a sentence to the end of
paragraph (a) and by adding paragraph (f) to read as follows:
Sec. 75.21 Quality assurance and quality control requirements.
(a) * * * The provisions in this paragraph are suspended from July
17, 1995 through December 31, 1996.
* * * * *
(f) Continuous emission monitoring systems. The owner or operator
of an affected unit shall operate, calibrate, and maintain each primary
and redundant backup continuous emission monitoring system used under
the Acid Rain Program according to the quality assurance and quality
control procedures in appendix B of this part. The owner or operator of
an affected unit shall ensure that each non-redundant backup continuous
emission monitoring system used under the Acid Rain Program complies
with the daily and quarterly quality assurance and quality control
procedures in appendix B of this part for each day and quarter that the
system is used to report data. The owner or operator shall perform
quality assurance upon a reference method backup monitoring system
according to the requirements of Method 2, 6C, 7E, or 3A in appendix A
of part 60 of this chapter, instead of the procedures specified in
appendix B of this part. Notwithstanding the provisions of appendix B
of this part, the owner or operator of a unit with an SO2
continuous emission monitoring system is not required to perform daily
or quarterly assessments under appendix B of this part on any day or in
any calendar quarter during which the unit combusts only natural gas or
a gaseous fuel with a sulfur content no greater than natural gas. In
addition, any calendar quarter during which the unit combusts only
natural gas or a gaseous fuel with a sulfur content no greater than
natural gas shall be excluded in determining the calendar quarter,
bypass operating quarter, or unit operating quarter when the next
relative accuracy test audit must be performed for the SO2
continuous emission monitoring system, provided that a relative
accuracy test audit is performed on that system at least once every two
calendar years. The owner or operator of a unit using a certified flow
monitor and a certified diluent monitor and Equation F-23 to calculate
SO2 emissions shall meet all quality control and quality assurance
requirements in appendix B of this part for the flow monitor and the
diluent monitor.
6. Section 75.30 is amended by adding paragraphs (d) and (e) to
read as follows:
Sec. 75.30 General provisions.
* * * * *
(d) On or after January 1, 1997, the owner or operator shall comply
with the provisions of this paragraph. Prior to January 1, 1997, the
owner or operator may comply with the provisions of this paragraph (d)
if also complying with the provisions of Sec. 75.11(e).
(1) Whenever a unit with an SO2 continuous emission monitoring
system combusts only pipeline natural gas and the owner or operator is
using the procedures in section 7 of appendix F of this part to
determine SO2 mass emissions pursuant to Sec. 75.11(e), the owner
or operator shall substitute for missing data from a flow monitoring
system, CO2 diluent monitor or O2 diluent monitor using the
missing data substitution procedures in Sec. 75.36.
(2) Whenever a unit with an SO2 continuous emission monitoring
system combusts gas with a sulfur content no greater than natural gas
or pipeline natural gas and the owner or operator is using the gas
sampling and analysis and fuel flow procedures in appendix D of this
part, to determine SO2 mass emissions pursuant to Sec. 75.11(e),
the owner or operator shall substitute for [[Page 26567]] missing data
using the missing data procedures in appendix D of this part.
(3) The owner or operator shall not use historical data from an
SO2 pollutant concentration monitor to account for SO2
emissions due to combustion of gas during missing data periods. In
addition, the owner or operator shall not include hours when the unit
combusts only natural gas (or a gaseous fuel with sulfur content no
greater than that of natural gas) in the availability calculations in
Sec. 75.32, nor in the calculations of substitute data using the
procedures of either Sec. 75.31 or Sec. 75.33. For the purpose of the
missing data and availability procedures for SO2 pollutant
concentration monitors in Secs. 75.31 through 75.33 only, all hours
during which the unit combusts only natural gas, or a gaseous fuel with
a sulfur content no greater than natural gas, shall be excluded from
the definition of ``monitor operating hour,'' ``quality-assured monitor
operating hour,'' ``unit operating hour,'' and ``unit operating day.''
(e) On or after January 1, 1997, the owner or operator shall comply
with the provisions of this paragraph. Prior to January 1, 1997, the
owner or operator may comply with the provisions of this paragraph.
(1) For monitoring of emissions at a unit with multiple stacks or a
bypass stack, include only those hours when emissions are passing
through the stack or duct in the definitions of ``unit operating hour''
and ``quality-assured monitor operating hour'' for purposes of applying
the missing data and availability procedures in Secs. 75.31 through
75.36 to the monitoring system on that stack or duct.
(2) If the proportion of flow going to each stack from a unit with
multiple stacks or the proportion of flow going to a bypass stack has
changed during the previous 2,160 hours when emissions passed through
that stack, then record the maximum flow rate recorded by the flow
monitoring system at the corresponding load range during the previous
2,160 hours of quality-assured monitor data when emissions passed
through that stack, instead of the value calculated using the missing
data substitution procedures in Sec. 75.31 or Sec. 75.33.
7. Section 75.32 is amended by adding a sentence to the end of
paragraph (a)(3) and adding paragraph (a)(4) to read as follows:
Sec. 75.32 Determination of monitoring data availability for standard
missing data procedure.
(a) * * *
(3) * * * The provisions in this paragraph (a)(3) are suspended
from July 17, 1995 through December 31, 1996.
(4) The owner or operator shall include all unit operating hours,
and all monitor operating hours for which quality-assured data were
recorded by a certified primary monitor, a certified redundant or non-
redundant backup monitor, a reference method for that unit, and from an
approved alternative monitoring system under subpart E of this part
when calculating percent monitor data availability using Equation 8 or
9. The owner or operator shall exclude hours when a unit combusted only
natural gas (or gaseous fuel with the same sulfur content as natural
gas) from calculations of percent monitor data availability for
SO2 pollutant concentration monitors, as provided in
Sec. 75.30(d). No hours from more than three years (26,280 clock hours)
earlier shall be used in Equation 8 or 9. When three years from
certification have elapsed, replace the words ``since certification''
or ``during previous 8,760 unit operating hours'' with ``in the
previous three years'' and replace ``8,760'' with ``total unit
operating hours in the previous three years.''
* * * * *
8. Section 75.34 is revised to read as follows:
Sec. 75.34 Units with add-on emission controls.
(a) The owner or operator of an affected unit equipped with add-on
SO2 and/or NOX emission controls shall use at least one of
the following options:
(1) The owner or operator may use the missing data substitution
procedures as specified for all affected units in Secs. 75.31 through
75.33 for substituting data for each hour where the add-on emission
controls are operating within the proper operation range specified in
the monitoring plan for the unit. The designated representative shall
report the range of add-on emission control operating parameters that
indicate proper operation in the unit's monitoring plan and the owner
or operator shall record data to verify the proper operation of the
SO2 or NOX add-on emission controls during each hour, as
described in paragraph (d) of this section. In addition, under
Sec. 75.64(c) the designated representative shall submit a certified
verification of the proper operation of the SO2 or NOX add-on
emission control for each missing data period at the end of each
quarter.
(2) In addition, the designated representative may petition the
Administrator under Sec. 75.66 to replace the maximum recorded value in
the last 720 quality-assured monitor operating hours with a value
corresponding to the maximum controlled emission rate (an emission rate
recorded when the add-on emission controls were operating) recorded
during the last 720 quality-assured monitor operating hours. For such a
petition, the designated representative must demonstrate that the
following conditions are met: the monitor data availability, calculated
in accordance with Sec. 75.32, for the affected unit is below 90.0
percent and parametric data establish that the add-on emission controls
were operating properly (i.e., within the range of operating parameters
provided in the monitoring plan) during the time period under petition.
(3) The designated representative may petition the Administrator
under Sec. 75.66 for approval of site-specific parametric monitoring
procedure(s) for calculating substitute data for missing SO2
pollutant concentration and NOX emission rate data in accordance
with the requirements of paragraphs (b) and (c) of this section, and
appendix C of this part. The owner or operator shall record the data
required in appendix C of this part, pursuant to Sec. 75.51(b) until
January 1, 1996, or pursuant to Sec. 75.55(b).
(b) For an affected unit equipped with add-on SO2 emission
controls, the designated representative may petition the Administrator
to approve a parametric monitoring procedure, as described in appendix
C of this part, for calculating substitute SO2 concentration data
for missing data periods. The owner or operator shall use the
procedures in Sec. 75.31, Sec. 75.33, or Sec. 75.34(a) for providing
substitute data for missing SO2 concentration data unless a
parametric monitoring procedure has been approved by the Administrator.
(1) Where the monitoring data availability is 90.0 percent or more
for an outlet SO2 pollutant concentration monitor, the owner or
operator may calculate substitute data using an approved parametric
monitoring procedure.
(2) Where the monitor data availability for an outlet SO2
pollutant concentration monitor is less than 90.0 percent, the owner or
operator shall calculate substitute data using the procedures in
Sec. 75.34(a) (1) or (2), even if the Administrator has approved a
parametric monitoring procedure.
(c) For an affected unit with NOX add-on emission controls,
the designated representative may petition the Administrator to approve
a parametric monitoring procedure, as described in appendix C of this
part, in order to calculate substitute NOX emission rate
[[Page 26568]] data for missing data periods. The owner or operator
shall use the procedures in Sec. 75.31 or Sec. 75.33 for providing
substitute data for missing NOX emission rate data prior to
receiving the Administrator's approval for a parametric monitoring
procedure.
(1) Where monitor data availability for a NOX continuous
emission monitoring system is 90.0 percent or more, the owner or
operator may calculate substitute data using an approved parametric
monitoring procedure.
(2) Where monitor data availability for a NOX continuous
emission monitoring system is less than 90.0 percent, the owner or
operator shall calculate substitute data using the procedure in
Sec. 75.34(a) (1) or (2), even if the Administrator has approved a
parametric monitoring procedure.
(d) The owner or operator shall keep records of information as
described in subpart F of this part to verify the proper operation of
the SO2 or NOX emission controls during all periods of
missing data. The owner or operator shall provide these records to the
Administrator or to the EPA Regional Office upon request. Whenever such
records are not provided or such records do not demonstrate that proper
operation of the SO2 or NOX add-on emission controls has been
maintained in accordance with the range of add-on emission control
operating parameters reported in the monitoring plan for the unit, the
owner or operator shall substitute the maximum potential NOX
emission rate, as defined in Sec. 72.2 of this chapter, to report the
NOX emission rate, and either the maximum hourly SO2
concentration recorded by the inlet monitor during the previous 720
quality assured monitor operating hours, if available, or the maximum
potential concentration for SO2, as defined by section 2.1.1.1 of
appendix A of this part, to report SO2 concentration for each hour
of missing data until information demonstrating proper operation of the
SO2 or NOX emission controls is available.
9. Section 75.53 is amended by revising paragraph (d) introductory
text and by adding paragraph (d)(4) to read as follows:
Sec. 75.53 Monitoring plan.
* * * * *
(d) Contents of monitoring plan for specific situations. The
following additional information shall be included in the monitoring
plan for gas-fired or oil-fired units or for units with add-on emission
controls:
* * * * *
(4) For each unit with add-on emission controls:
(i) A list of operating parameters for the add-on emission
controls, including parameters from the list in Sec. 75.55 appropriate
to the particular installation; and
(ii) The range of each operating parameter in the list that
indicates the add-on emission controls are properly operating.
* * * * *
10. Section 75.55 is amended by adding paragraphs (b) and (e) to
read as follows:
Sec. 75.55 General recordkeeping provisions for specific situations.
(a) * * *
(b) Specific parametric data record provisions for calculating
substitute emissions data for units with add-on emission controls. In
accordance with Sec. 75.34, the owner or operator of an affected unit
with add-on emission controls shall either record the applicable
information in paragraph (b)(3) of this section for each hour of
missing SO2 concentration data or NOX emission rate (in
addition to other information), or shall record the information in
paragraph (b)(1) of this section for SO2 or paragraph (b)(2) of
this section for NOX through an automated data acquisition and
handling system, as appropriate to the type of add-on emission
controls:
(1) For units with add-on SO2 emission controls petitioning to
use or using the optional parametric monitoring procedures in appendix
C of this part, for each hour of missing SO2 concentration or
volumetric flow data:
(i) The information required in Sec. 75.54(b) for SO2
concentration and volumetric flow if either one of these monitors is
still operating;
(ii) Date and hour;
(iii) Number of operating scrubber modules;
(iv) Total feedrate of slurry to each operating scrubber module
(gal/min);
(v) Pressure differential across each operating scrubber module
(inches of water column);
(vi) For a unit with a wet flue gas desulfurization system, an
inline measure of absorber pH for each operating scrubber module;
(vii) For a unit with a dry flue gas desulfurization system, the
inlet and outlet temperatures across each operating scrubber module;
(viii) For a unit with a wet flue gas desulfurization system, the
percent solids in slurry for each scrubber module.
(ix) For a unit with a dry flue gas desulfurization system, the
slurry feed rate (gal/min) to the atomizer nozzle;
(x) For a unit with SO2 add-on emission controls other than
wet or dry limestone, corresponding parameters approved by the
Administrator;
(xi) Method of determination of SO2 concentration and
volumetric flow, using Codes 1-15 in Table 3 of Sec. 75.54; and
(xii) Inlet and outlet SO2 concentration values recorded by an
SO2 continuous emission monitoring system and the removal
efficiency of the add-on emission controls.
(2) For units with add-on NOX emission controls petitioning to
use or using the optional parametric monitoring procedures in appendix
C of this part, for each hour of missing NOX emission rate data:
(i) Date and hour;
(ii) Inlet air flow rate (acfh, rounded to the nearest thousand);
(iii) Excess O2 concentration of flue gas at stack outlet
(percent, rounded to nearest tenth of a percent);
(iv) Carbon monoxide concentration of flue gas at stack outlet
(ppm, rounded to the nearest tenth);
(v) Temperature of flue gas at furnace exit or economizer outlet
duct ( deg.F); and
(vi) Other parameters specific to NOX emission controls (e.g.,
average hourly reagent feedrate);
(vii) Method of determination of NOX emission rate using Codes
1-15 in Table 3 of Sec. 75.54; and
(viii) Inlet and outlet NOX emission rate values recorded by a
NOX continuous emission monitoring system and the removal
efficiency of the add-on emission controls.
(3) For units with add-on SO2 or NOX emission controls
following the provisions of Sec. 75.34(a) (1) or (2), for each hour of
missing data record:
(i) Parametric data which demonstrate the proper operation of the
add-on emission controls, as described in the monitoring plan for the
unit (to be maintained on site, and to be submitted upon request from
the Administrator or by an EPA Regional office);
(ii) A flag indicating that the add-on emission controls are
operating with all parameters within the ranges specified in the
monitoring plan or that the add-on emission controls are not operating
properly;
(iii) For units petitioning under Sec. 75.66 for substituting a
representative SO2 concentration during missing data periods, any
available inlet and outlet SO2 concentration values recorded by an
SO2 continuous emission monitoring system; and
(iv) For units petitioning under Sec. 75.66 for substituting a
representative NOX emission rate during missing data periods, any
available inlet and outlet NOX emission rate values recorded by a
[[Page 26569]] NOX continuous emission monitoring system.
* * * * *
(e) Specific SO2 emission record provisions during the
combustion of gaseous fuel. In accordance with the provisions in
Sec. 75.11(e), the owner or operator of a unit with an SO2
continuous emission monitoring system may record the information in
paragraph (c)(3) of this section in lieu of the information in
Secs. 75.54(c)(1) and 75.54(c)(3), for those hours when only pipeline
natural gas or a gaseous fuel with a sulfur content no greater than
natural gas is combusted.
* * * * *
11. Section 75.56 is amended by adding paragraph (a)(6) to read as
follows:
Sec. 75.56 Certification, quality assurance and quality control record
provisions.
(a) * * *
(6) For each SO2, NOX, CO2, or O2 pollutant
concentration monitor, NOx-diluent continuous emission monitoring
system, or SO2-diluent continuous emission monitoring system, the
owner or operator shall record the following information for the cycle
time test:
(i) Component/system identification code;
(ii) Date;
(iii) Start and end times;
(iv) Upscale and downscale cycle times for each component;
(v) Stable start monitor value;
(vi) Stable end monitor value;
(vii) Reference value of calibration gas(es);
(viii) Calibration gas level; and
(ix) Cycle time result for the entire system.
* * * * *
12. Section 75.64 is amended by revising paragraphs (a)(1) and (c)
to read as follows:
Sec. 75.64 Quarterly reports.
(a) * * *
(1) The information and hourly data required in Secs. 75.50 through
75.52 (or Secs. 75.54 through 75.56), no later than the quarterly
report due April 30, 1996), excluding:
(i) Descriptions of adjustments, corrective action, and
maintenance;
(ii) Information which is incompatible with electronic reporting
(e.g., field data sheets, lab analyses, quality control plan);
(iii) Opacity data listed in Sec. 75.50(f) or Sec. 75.54(f);
(iv) For units with SO2 or NOX add-on emission controls
that do not elect to use the approved site-specific parametric
monitoring procedures for calculation of substitute data, the
information in Sec. 75.55(b)(3); and
(v) The information recorded under Sec. 75.56(a)(7) for the period
prior to January 1, 1996.
* * * * *
(c) Compliance certification. The designated representative shall
submit a certification in support of each quarterly emissions
monitoring report based on reasonable inquiry of those persons with
primary responsibility for ensuring that all of the unit's emissions
are correctly and fully monitored. The certification shall indicate
whether the monitoring data submitted were recorded in accordance with
the applicable requirements of this part including the quality control
and quality assurance procedures and specifications of this part and
its appendices, and any such requirements, procedures and
specifications of an applicable excepted or approved alternative
monitoring method. In the event of any missing data periods, the
certification must describe the measures taken to cure the causes for
the missing data periods. For a unit with add-on emission controls, the
designated representative shall also include a certification for all
hours where data are substituted following the provisions of
Sec. 75.34(a)(1), that the add-on emission controls were operating
within the range of parameters listed in the monitoring plan, and that
the substitute values recorded during the quarter do not systematically
underestimate SO2 or NOX emissions, pursuant to Sec. 75.34.
* * * * *
13. Section 75.66 is amended by revising paragraphs (e) and (f) to
read as follows:
Sec. 75.66 Petitions to the Administrator.
* * * * *
(e) Parametric monitoring procedure petitions. The designated
representative for an affected unit may submit a petition to the
Administrator, where each petition shall contain the information
specified in Sec. 75.51(b) (or Sec. 75.55(b), no later than January 1,
1996) for use of a parametric monitoring method. The Administrator will
either:
(1) Publish a notice in the Federal Register indicating receipt of
a parametric monitoring procedure petition;, or
(2) Notify interested parties of receipt of a parametric monitoring
petition.
(f) Missing data petitions for units with add-on emission controls.
The designated representative for an affected unit may submit a
petition to the Administrator for the use of the maximum controlled
emission rate, which the Administrator will approve if the petition
adequately demonstrates that all the requirements in Sec. 75.34(a)(2)
are satisfied. Each petition shall contain the information listed below
for the time period (or data gap) during which the affected unit
experienced the monitor outage that would otherwise result in the
substitution of an uncontrolled maximum value under the standard
missing data procedures contained in subpart D of this part:
(1) Data demonstrating that the affected unit's monitor data
availability for the time period under petition was less than 90.0
percent;
(2) Data demonstrating that the add-on emission controls were
operating properly during the time period under petition (i.e., within
the range of operating parameters for the add-on emission controls in
the monitoring plan for the unit);
(3) A list of the average hourly values for the previous 720
quality-assured monitor operating hours, highlighting both the maximum
recorded value and the value corresponding to the maximum controlled
emission rate; and
(4) An explanation and information on operation of the add-on
emission controls demonstrating that the selected historical SO2
concentration or NOX emission rate does not underestimate the
SO2 concentration or NOX emission rate during the missing
data period.
* * * * *
14. Appendix A to Part 75, Section 6.3 is amended by adding a
sentence to the last paragraph of sections 6.3.1 and 6.3.2 and by
adding section 6.3.3 to read as follows:
Appendix A--Specifications and Test Procedures
* * * * *
6. Certification Tests and Procedures
* * * * *
6.3.1 * * * The provisions in this section are suspended from
July 17, 1995 through December 31, 1996.
6.3.2 * * * The provisions in this section are suspended from
July 17, 1995 through December 31, 1996.
6.3.3 Pollutant Concentration Monitor and CO2 or O2 Monitor
7-day Calibration Error Test
Measure the calibration error of each pollutant concentration
monitor and CO2 or O2 monitor while the unit is operating
once each day for 7 consecutive operating days according to the
following procedures. (In the event that extended unit outages occur
after the commencement of the test, the 7 consecutive unit operating
days need not be 7 consecutive calendar days.) Units using dual span
monitors must perform the calibration error test on both high- and
low-scales of the pollutant concentration monitor.
Do not make manual adjustments to the monitor settings until
after taking measurements at both zero and high
[[Page 26570]] concentration levels for that day during the 7-day
test. If automatic adjustments are made, conduct the calibration
error test in a way that the magnitude of the adjustments can be
determined and recorded. Record and report test results for each day
using the unadjusted concentration or flow rate measured in the
calibration error test prior to making any manual adjustment or
resetting the calibration.
The calibration error tests should be approximately 24 hours
apart (unless the 7-day test is performed over non-consecutive
days). Perform calibration error tests at two concentrations: (1)
Zero-level and (2) high-level, as specified in section 5.2 of this
appendix. In addition, repeat the procedure for SO2 and
NOX pollutant concentration monitors using the low-scale for
units equipped with emission controls or other units with dual span
monitors. Use only NIST traceable reference material, standard
reference material, NIST/EPA-approved certified reference material,
research gas material, Protocol 1 calibration gases certified by the
vendor to be within 2 percent of the label value or zero air
material for the zero level only.
Introduce the calibration gas at the gas injection port, as
specified in section 2.2.1 of this appendix. Operate each monitor in
its normal sampling mode. For extractive and dilution type monitors,
pass the audit gas through all filters, scrubbers, conditioners, and
other monitor components used during normal sampling and through as
much of the sampling probe as is practical. For in situ type
monitors, perform calibration checking all active electronic and
optical components, including the transmitter, receiver, and
analyzer. Challenge the pollutant concentration monitors and
CO2 or O2 monitors once with each gas. Record the monitor
response from the data acquisition and handling system. Using
Equation A-5 of this appendix, determine the calibration error at
each concentration once each day (at 24-hour intervals) for 7
consecutive days according to the procedures given in this section.
Calibration error tests are acceptable for monitor or monitoring
system certification if none of these daily calibration error test
results exceed the applicable performance specifications in section
3.1 of this appendix.
* * * * *
15. Appendix A to part 75, section 6.3.4 is added to read as
follows:
Appendix A--Specifications and Test Procedures
6. Certification Tests and Procedures
* * * * *
6.3.4 Flow Monitor 7-day Calibration Error Test
Measure the calibration error of each flow monitor according to
the following procedures.
Introduce the reference signal corresponding to the values
specified in section 2.2.2.1 of this appendix to the probe tip (or
equivalent), or to the transducer. During the 7-day certification
test period, conduct the calibration error test while the unit is
operating once each unit operating day (as close to 24-hour
intervals as practicable). In the event that extended unit outages
occur after the commencement of the test, the 7 consecutive
operating days need not be 7 consecutive calendar days. Record the
flow monitor responses by means of the data acquisition and handling
system. Calculate the calibration error using Equation A-6 of this
appendix.
Do not perform any corrective maintenance, repair, or
replacement upon the flow monitor during the 7-day certification
test period other than that required in the quality assurance/
quality control (QA/QC) plan required by appendix B of this part. Do
not make adjustments between the zero and high reference level
measurements on any day during the 7-day test. If the flow monitor
operates within the calibration error performance specification
(i.e., less than or equal to 3 percent error each day and requiring
no corrective maintenance, repair, or replacement during the 7-day
test period) the flow monitor passes the calibration error test
portion of the certification test. Record all maintenance activities
and the magnitude of any adjustments. Record output readings from
the data acquisition and handling system before and after all
adjustments. Record and report all calibration error test results
using the unadjusted flow rate measured in the calibration error
test prior to resetting the calibration. Record all adjustments made
during the seven day period at the time the adjustment is made and
report them in the certification application.
* * * * *
16. Appendix A to part 75, is amended by adding a sentence to the
end of section 6.4 and by adding section 6.4.1 to read as follows:
6. Certification Tests and Procedures
* * * * *
6.4 * * * The provisions in this section 6.4 are suspended from
July 17, 1995 through December 31, 1996.
6.4.1 Cycle Time Test
Perform cycle time tests for each pollutant concentration
monitor, and continuous emission monitoring system while the unit is
operating according to the following procedures.
Use a zero-level and a high-level calibration gas (as defined in
section 5.2 of this appendix) alternately. To determine the upscale
elapsed time, inject a zero-level concentration calibration gas into
the probe tip (or injection port leading to the calibration cell,
for in situ systems with no probe). Record the stable starting
monitor value and start time. Next, allow the monitor to measure the
concentration of flue gas emissions until the response stabilizes.
Determine the upscale elapsed time as the time at which 95.0 percent
of the step change is achieved between the stable starting gas value
and the stable ending monitor value. Record the stable ending
monitor value, the end time, and the upscale elapsed time for the
monitor using data acquisition and handling system output. Then
repeat the procedure, starting by injecting the high-level gas
concentration to determine the downscale elapsed time, which is the
time at which 95.0 percent of the step change is achieved between
the stable starting gas value and the stable ending monitor value.
End the downscale test by measuring the concentration of flue gas
emissions. Record the stable starting and ending monitor values, the
start and end times, and the downscale elapsed time for the monitor
using data acquisition and handling system output. A stable value is
equivalent to a reading with a change of less than 1 percent of the
span value for 30 seconds, or a reading with a change of less than 5
percent from the measured average concentration over 5 minutes.
For monitors or monitoring systems that perform a series of
operations (such as purge, sample, and analyze), time the injections
of the calibration gases so they will produce the longest possible
cycle time. Record the span, the zero and high gas concentrations,
the start and end times, the stable starting and ending monitor
values, and the upscale and downscale elapsed times. Report the
slower of the two elapsed times as the cycle time for the analyzer.
(See Figure 5 at the end of this appendix.) For the NOX
continuous emission monitoring system test and SO2-diluent
continuous emission monitoring system test, record and report the
longer cycle time of the two component analyzers as the system cycle
time.
For time-shared systems, this procedure must be done for all
probe locations that will be polled within the same 15-minute period
during monitoring system operations. For cycle time results for a
time-shared system, add together the longest cycle time obtained
from each location. Report the sum of the cycle time at each
location plus the time required for all purge cycles (as determined
by the CEMS manufacturer) for each location as the cycle time for
each and all of those systems. For monitors with dual ranges,
perform the test on the range giving the longest cycle time.
Cycle time test results are acceptable for monitor or monitoring
system certification if none of the cycle times exceed 15 minutes.
* * * * *
17. Appendix A to part 75 is amended by adding Figure 5 at the end
of the appendix to read as follows:
* * * * *
Figure 5--Cycle Time
Date of test-----------------------------------------------------------
Component/system ID#:--------------------------------------------------
Analyzer type----------------------------------------------------------
Serial Number----------------------------------------------------------
High level gas concentration: ______ ppm/% (circle one)
Zero level gas concentration: ______ ppm/% (circle one)
Analyzer span setting: ______ ppm/% (circle one)
Upscale:
Stable starting monitor value: ______ ppm/% (circle one)
Stable ending monitor reading: ______ ppm/% (circle one)
Elapsed time: ______ seconds
Downscale:
Stable starting monitor value: ______ ppm/% (circle one)
[[Page 26571]]
Stable ending monitor value: ______ ppm/% (circle one)
Elapsed time: ______ seconds
Component cycle time= ______ seconds
System cycle time= ______ seconds
* * * * *
18. Appendix B to part 75 is amended by adding a sentence to the
end of section 2.1 and by adding section 2.1.7 to read as follows:
Appendix B--Quality Assurance and Quality Control Procedures
* * * * *
2. Frequency of Testing
2.1 * * * The provisions in this section 2.1 are suspended from
July 17, 1995 through December 31, 1996.
* * * * *
2.1.7 Daily Assessments
For each monitor or continuous emission monitoring system,
perform the following assessments during each day in which the unit
combusts any fuel (hereafter referred to as a ``unit operating
day''), or for a monitor on a bypass stack/duct, during each day
that emissions pass through the by-pass stack or duct. If the unit
discontinues operation or if use of the by-pass stack or duct is
discontinued prior to performance of the calibration error test,
data from the monitor or continuous emission monitoring system may
be considered quality assured prospectively for 24 consecutive clock
hours from the time of successful completion of the previous daily
test performed while the unit is operating. These requirements are
effective as of the date when the monitor or continuous emission
monitoring system completes certification testing.
* * * * *
Appendix F to Part 75--Conversion Procedures
19. Appendix F is amended by adding section 7 to read as follows:
* * * * *
7. Procedures for SO2 Mass Emissions at Units With SO2
Continuous Emission Monitoring Systems During the Combustion of Gaseous
Fuel
Use the following equation to calculate hourly SO2 mass
emissions as allowed for units with SO2 continuous emission
monitoring systems during the combustion of pipeline natural gas
under Sec. 75.11(e). These procedures are optional prior to January
1, 1997 and are required on or after January 1, 1997.
Eh=(0.0006) HI (Eq. F-23)
where,
Eh=Hourly SO2 mass emissions, lb/hr.
0.0006=Default SO2 emission rate for pipeline natural gas, lb/
mmBtu.
HI=Hourly heat input, as determined using the procedures of section
5.2 of this appendix.
[FR Doc. 95-11497 Filed 5-10-95; 3:42 pm]
BILLING CODE 6560-50-P
