Total Mercury and Particulate Continuous Emissions Monitoring Systems; Measurement of Low Level Particulate Emissions; Implementation at Hazardous Waste Combustors; Proposed RuleNotice of Data Availability and Request for Comments

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60 and 63

[FRL-5941-4]

Total Mercury and Particulate Continuous Emissions Monitoring

Systems; Measurement of Low Level Particulate Emissions; Implementation

at Hazardous Waste Combustors; Proposed Rule--Notice of Data

Availability and Request for Comments

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of data availability and request for comments.

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SUMMARY: This announcement is a notice of data availability and

invitation for comment on the following reports pertaining to total

mercury and particulate continuous emissions monitoring systems: DRAFT:

Total Mercury CEMS Demonstration, Summary Table, dated December 1997;

and DRAFT: Particulate Matter CEMS Demonstration, Volume I (with

appendices), dated December 1997. EPA proposed requiring these monitors

for hazardous waste combustors in the hazardous waste combustor

proposed rule published on April 19, 1996. In addition, this document

discusses topics for implementing particulate matter continuous

emissions monitoring systems at hazardous waste combustors.

Readers should note that only comments about new information

discussed in this document will be considered. Issues related to the

April 19, 1996, proposed rule and subsequent documents that are not

directly affected by the documents or data referenced in this Notice of

Data Availability are not open for further comment.

DATES: Written comments on these documents and this document must be

submitted by January 29, 1998.

ADDRESSES: Commenters must send an original and two copies of their

comments referencing Docket Number F-97-CS6A-FFFFF to: RCRA Docket

Information Center, Office of Solid Waste (5305G), U.S. Environmental

Protection Agency Headquarters (EPA, HQ), 401 M Street, SW, Washington,

D.C. 20460. Comments may also be submitted electronically through the

Internet to: [email protected]. Comments in electronic format

should also be identified by the docket number F-97-CS6A-FFFFF. All

electronic comments must be submitted as an ASCII file avoiding the use

of special characters and any form of encryption. Commenters should not

submit electronically any confidential business information (CBI). An

original and two copies of the CBI must be submitted under separate

cover to: RCRA CBI Document Control Officer, OSW (5305W), 401 M Street,

SW, Washington D.C. 20460.

For other information regarding submitting comments electronically,

viewing the comments received, and supporting information, please refer

to the proposed rule (61 FR 17358 (April 19, 1996)). The RCRA

Information Center is located at Crystal Gateway One, 1235 Jefferson

Davis Highway, First Floor, Arlington, Virginia and is open for public

inspection and copying of supporting information for RCRA rules from

9:00 a.m. to 4:00 p.m. Monday through Friday, except for Federal

holidays. The public must make an appointment to view docket materials

by calling (703) 603-9230. The public may copy a maximum of 100 pages

from any regulatory document at no cost. Additional copies cost $0.15

per page.

FOR FURTHER INFORMATION CONTACT: For general information, call the RCRA

Hotline at 1-800-424-9346 or TDD 1-800-553-7672 (hearing impaired)

including directions on how to access some of the documents and data

referred to in this notice electronically. Callers within the

Washington Metropolitan Area must dial 703-412-9810 or TDD 703-412-3323

(hearing impaired). The RCRA Hotline is open Monday-Friday, 9:00 a.m.

to 6:00 p.m., Eastern Time.

The documents referred to in this notice are available over the

Internet. The documents can be accessed by typing the following

universal resource locator (URL):

http://www.epa.gov/epaoswer/hazwaste/combust/cems

This URL provides a home page through which all electronically

available documents can be downloaded. The Technology Transfer Network

(TTN) also provides a link to this page. CEMS information is available

on TTN at the following URL:

http://ttnwww.rtpnc.epa.gov/html/emtic/cem.htm

The home page contains links to the files that are available

electronically. The files are in an executable, compressed format to

facilitate

[[Page 67789]]

downloading. Once extracted, each compressed file may result in more

than one decompressed file. The reports are in Adobe

Acrobat, PDF format. The reader should note that

figures, diagrams, and appendices may not be available electronically

or may only be available in other formats.

For other information regarding the information contained in

Sections I, II, IV, and V of this notice, contact Mr. Scott Postma,

(5302W), Office of Solid Waste, 401 M Street, SW, Washington, D.C.

20460, phone (703) 308-6120, E-MAIL: [email protected]. For

information regarding Section III of this notice, contact Mr. H. Scott

Rauenzahn (5302W), Office of Solid Waste, 401 M Street, SW, Washington,

D.C. 20460, phone (703) 308-8477, e-mail:

[email protected].

SUPPLEMENTARY INFORMATION: On April 19, 1996, EPA proposed revised

standards (herein referred to as ``the proposed rule'') for hazardous

waste combustors (HWCs, i.e., incinerators and cement and lightweight

aggregate kilns that burn hazardous waste). See 61 FR 17358. Comments

received from the public in response to the proposed rule are found in

RCRA docket F-96-RCSP-FFFFF.

A previous notice of data availability (NODA), published on March

21, 1997, gave the public the opportunity to review the Agency's

approach to demonstrating CEMS for HWCs. This previous NODA is herein

referred to as ``the first CEMS NODA'' or ``CEMS NODA 1.'' See 62 FR

13776. Comments received from the public in response to the first CEMS

NODA are found in RCRA docket F-97-CS3A-FFFFF.

Readers should note that a separate docket was established for this

document. See the Addresses section above for more information.

Table of Contents

I. Introduction and Background

II. The Hg CEMS Demonstration Tests

III. The PM CEMS Demonstration Tests

A. PM performance Specification (PS) 11 Levels

1. Revised Specification Levels for the Correlation

Coefficient, Confidence Interval, and Tolerance Interval

2. Data Availability

3. Data Quality Objectives: New Procedures to Appendix F of 40

CFR Part 60

B. Manual Method Accuracy

1. Modification of the Filter Recovery Process

2. Improved Sample Collection

3. Elimination of Contamination

4. Improved Sample Analysis

5. Comparison of M5 and M5i Method Precision

6. Paired Data

C. Transferability of These Demonstration Test Results to Other

HWC Sources

IV. PM CEMS: Implementation and Compliance

A. PM CEMS Compliance Schedule

B. PM CEMS Operating Parameter Limit

1. Introduction

2. Data Excluded from Calculating the PM CEMS Operating

Parameter Limit

3. Determining the Normality of the Data

4. Averaging Periods for the PM CEMS Operating Parameter Limit

5. Options for Calculating the PM CEMS Operating Parameter

Limit

a. Using rank statistics to calculate the PM CEMS-based

operating parameter limit at one, fixed averaging period

b. The traditional standard setting approach

6. Consideration of a Variance Procedure to Project a Higher PM

CEMS Operating Parameter Limit

a. HAPs for which PM control is necessary to ensure compliance

b. Projecting a higher PM CEMS operating parameter limit

considering the ratio of the standard to the measured level of a HAP

c. Ensuring that the higher projected PM CEMS operating

parameter limit does not exceed the MACT PM standard

d. Establishing revised operating parameter limits for the PM

control device corresponding to the higher projected PM CEMS

operating parameter limit

e. Implementing the variance

7. EPA's PM CEMS Testing to Identify a CEMS-Based Emission

Level Achievable by MACT-Controlled Sources

C. RCA Test Frequency

D. Extrapolating PM CEMS Calibration Data

1. Extrapolating Light-Scattering PM CEMS Calibration Data

2. Extrapolation of Beta-gage Calibration Data

E. Need to Calibrate to Twice the Emission Standard

F. Allowing PM CEMS to be Used In-lieu of Method 5 Tests

G. Waivers from the PM CEMS Requirements

1. Waiver of PM and Hg CEMS Requirements for Small On-Site

Incinerators

2. PM CEMS Waiver for Sources with Short Life-Spans

3. Other Sources

V. Other Issues Concerning CEMS and Test Methods for HWCs

A. Performance Specifications for Optional CEMS

B. Stack Sampling Test Methods

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

I. Introduction and Background

In the proposed rule, EPA proposed that continuous emissions

monitoring systems (CEMS) be used for compliance with the HWC total

mercury (Hg) and particulate matter (PM) standards. See 61 FR at 17426

and 17435. To require CEMS for compliance the Agency, among other

things, must determine that the CEMS are commercially available and

have been demonstrated to meet certain performance specifications. To

make these determinations, the Agency tested various Hg and PM CEMS

being marketed in the U.S. and Europe. The first CEMS NODA described

the approach EPA is using to demonstrate the feasibility of PM and Hg

CEMS and requested comment on certain technical issues arising from

this program. This testing is now complete. Today the Agency is

providing notice of an opportunity to comment on the following

documents resulting from these CEMS demonstration test program: DRAFT:

Total Mercury CEMS Demonstration, Summary Table, dated December 1997;

and DRAFT: Particulate Matter CEMS Demonstration, Volume I (with

appendices), dated December 1997.

The remainder of this notice describes important information

bearing upon how the reports' results relate to EPA's approach to

demonstrating Hg and PM CEMS and how PM CEMS could be used for

compliance. Many of these issues were raised by commenters in response

to CEMS NODA 1 and the proposed rule. The reader is referred to the

referenced documents for specific information regarding the Hg and PM

CEMS demonstration test program and the comments cited here.

II. The Hg CEMS Demonstration Tests

EPA seeks comment on the document DRAFT: Total Mercury CEMS

Demonstration, Summary Table, dated December 1997, provided in the

above referenced docket for this NODA. This table summarizes results

from the Hg CEMS demonstration tests EPA conducted.

In summary, the Agency found certain aspects of the testing program

revealed substantial problems regarding the measurement of the Hg CEMS

accuracy and precision. EPA found it difficult to dynamically spike

known amounts of mercury (in the elemental and ionic form) and obtain

manual method and Hg CEMS measurements that agree at the test source.

As a result, the Agency now believes it has not sufficiently

demonstrated the viability of Hg CEMS as a compliance tool at all

hazardous waste combustors and should not require their use.

Nonetheless, EPA still believes Hg CEMS can and will work at some

sources but does not have sufficient confidence that all HWC conditions

are conducive to proper operation of the Hg CEMS tested. Facilities

should have the choice of using Hg CEMS if desired so long as the

[[Page 67790]]

permitting agency approves on a site-specific basis the Hg CEMS and its

site-specific performance specifications. See a related issue in

section V.A. of this NODA regarding the implementation of optional

CEMS.

III. The PM CEMS Demonstration Tests

This section describes the report DRAFT: Particulate Matter CEMS

Demonstration, Volume I (with appendices), dated December 1997,

contained in the docket identified in the Addresses section, above. EPA

issued previous notices asking vendors to participate in this program

(see 61 FR 7232, February 27, 1996) and to allow the public to comment

on the Agency's approach to demonstrating these monitors (see 62 FR

13775, March 21, 1997). Since this could represent the first time EPA

requires PM CEMS for compliance at stationary sources, the technical

discussion contained in this section is expected to have general

applicability beyond sources that burn hazardous waste. In particular,

EPA invites comment from all parties concerning the following documents

attached to this notice: Method 5I for the determination of low level

particulate emissions; Performance Specification 11 for PM CEMS; and

Quality Assurance Requirements for PM CEMS.

A. PM Performance Specification (PS) 11 Levels

In CEMS NODA 1, the Agency stated it intended to loosen the

proposed PM CEMS Performance Specification (PS) 11 to reflect what was

achievable by the monitors during this demonstration test. The test was

designed to be a reasonable worst case investigation of what

performance (relative to the proposed PS11) the monitors could achieve.

Many comments received in response to CEMS NODA 1 stated that the

proposed performance specifications were not sufficiently stringent and

opposed loosening the specification levels.

Concurrent with the Agency's invitation in CEMS NODA 1 to comment

on our approach to demonstrate PM CEMS, EPA determined that much of the

variability in the calibration curves resulted from inaccuracies in

performing the manual method, Method 5 (M5). Since the fundamental

approach in PS11 involves correlating manual method results to PM CEMS

outputs, the PS11 statistical results reflected this variability in the

manual method. Consequently, EPA undertook a systematic effort to

identify and remove this error from the manual method measurement

process. Manual method improvements were developed and observed, and

performance specification results for the PM CEMS improved as a result.

(See a related discussion in section III.B, below, regarding these

improvements to the manual method.)

1. Revised Specification Levels for the Correlation Coefficient,

Confidence Interval, and Tolerance Interval

As a result of comments on CEMS NODA 1, EPA decided to accept a

slightly modified version of the more stringent International Standards

Organization (ISO) specification 10155 for PM CEMS. Four of the five PM

CEMS tested during the PM CEMS demonstration tests were able to meet

all three performance specifications (i.e., those for the correlation

coefficient (r), confidence interval (CI), and Tolerance Interval (TI))

at all three of the emissions levels discussed in the May 2, 1997, NODA

as alternatives to the proposed emissions standards (69 mg/dscm for

cement kilns, 50 mg/dscm for light-weight aggregate kilns, and 34 mg/

dscm for hazardous waste incinerators.) See 62 FR 24212 for a

discussion of those alternative emissions standards. One technology, an

extractive light-scattering technology, did not meet all the

performance specification levels at all of the alternative

standards.1 Since EPA must show that at least one

commercially available PM CEMS can meet the proposed performance

specification, the fact that 4 of the 5 monitors were able to meet

these performance levels under reasonable worst-case test conditions

adequately shows that the modified specification levels are achievable.

The revised performance specification levels are presented in Table 1,

below.

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\1\ This technology did meet 10 of the 14 specification

comparisons.

Table 1: Revised Performance Specifications for PM CEMS

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Confidence Tolerance

Correlation coefficient interval interval

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0.90 10% 25%

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As previously stated, these performance levels are nearly identical

to the ISO specification for PM CEMS. The only major difference between

these and the ISO specification levels is the correlation coefficient,

which is 0.95 in ISO 10155 and 0.90 in the modified PS11. This is

acceptable since the correlation coefficient does not directly relate

to measurement error while the confidence and tolerance intervals

do.2 The revised PS11 also requires that a minimum of 15

runs be used for the calibration while the ISO specification requires

only 9 runs. The ISO specification is also vague regarding the PM

concentration ranges required for a calibration. The revised PS11

stipulates three ranges: 0 to 30, 30 to 60, and 60 to 100% of the

facility's range of PM emissions.

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\2\ The correlation coefficient is defined as the ratio

Sxy divided by the square root of the quantity

Sxx times Syy. Sxy is a measurement

of error as x relates to y, while Sxx and Syy

are a reflection of the range of the data set. As a result, the

correlation coefficient is not as useful a tool to evaluate

measurement error as the correlation and tolerance intervals. This

is particularly true as the correlation coefficient approaches 1.

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2. Data Availability

EPA had proposed that PM CEMS be used at all times that hazardous

waste is in the unit. See 61 FR at 17441. Commenters to the proposed

rule did not view this favorably. They said this proposal is equivalent

to a 100% data availability requirement for PM CEMS. Commenters stated

that this requirement is not achievable since all mechanical devices

fail at some point, often without warning. They said a data

availability requirement in the 85, 90, or 95% range would be more

acceptable. Commenters suggested that when the PM CEMS were not

available, the PM-related operating parameter limits EPA proposed

should be used in place of the PM CEMS.

EPA largely agrees with this comment. The PM CEMS demonstration

tests show that a 100% data availability requirement is not achievable

for all PM CEMS in all instances. The Agency also agrees that when PM

CEMS are not operating, it is reasonable to provide for some back-up

compliance system in lieu of requiring sources to either stop burning

hazardous waste or have a back-up PM CEMS available. The PM APCD

operating parameters proposed in the event there is no PM CEMS

requirement are a good starting point for identifying such a back-up

system. See the discussion later in this section for more information

on this issue.

Based on these demonstration tests and the comments received, EPA

concludes that a 95% data availability requirement is achievable for

most PM CEMS. Therefore, EPA intends that PM CEMS be used 95% of the

time for compliance. However, there are useful technologies that cannot

meet this 95% data availability requirement. This data availability

requirement should be relaxed in certain instances. For instance, beta-

gages did not meet the 95% data availability requirement during the PM

CEMS tests. EPA believes beta-gages, with their relatively superior

[[Page 67791]]

performance and ability to measure PM emissions at truly wet stacks

(i.e., those with entrained water droplets in the stack gas), will be

useful at some sources for compliance. Therefore, EPA will consider an

85% data availability requirement for beta-gage technology PM

CEMS.3 The Agency anticipates other case-by-case

determinations will be made in the future as more is learned about the

performance, benefits, and data availability limitations of other PM

CEMS technologies.

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\3\ One of the beta gage PM CEMS experienced a 74% data

availability during the PM CEMS demonstration test program. Much of

the additional downtime was because no U.S.-based technicians were

fully trained to service this instrument during this program and

parts and personnel had to be brought to the U.S. Once EPA requires

a new technology, such as PM CEMS, the market for that new

technology is expected to mature in the US similar to how one exists

overseas. As a result, data availability will be better than what

was experienced here.

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Finally, EPA believes that increasing the amount of PM data

available will enable sources to improve their understanding and better

define the relationship between operating parameters and emission

levels. EPA is aware of two relevant examples which are described here.

The first one is an ongoing cooperative effort with industry,

regulatory agencies, and the local public. This effort is focused on a

venturi scrubber-controlled lime kiln at a pulp and paper plant where

testing is being conducted to evaluate the feasibility of a predictive

emission monitoring system (PEMS). Following preliminary measurements

and an experimentally designed test matrix, 595 Method 5 runs were

performed over a wide variety of process and scrubber operating

conditions, and PM emission levels. A correlation coefficient above 0.9

was obtained in correlating PM emission levels with 54 operating

parameters. In comparison, use of PM CEMS represents a powerful tool

for accumulating much data at a cost that is far less than performing

hundreds of Method 5 runs. As a result, PM CEMS allow for a cost-

effective way to implement a PM PEMS model than making hundreds of

Method 5 measurements.

The second example directly relates to the first. The Electric

Power Research Institute (EPRI) has already produced a means to

characterize and correlate PM emissions with operating conditions at

coal-fired utility boilers. PM emissions from utility boilers are

similar to HWCs in that their emissions are affected by a complexity of

variations from a number of fuel and feed characteristics, combustor

operations, and electrostatic precipitator (ESP) operations. As in the

lime kiln case mentioned above, use of PM CEMS represents a more

powerful tool for accumulating and correlating vast amounts of PM

emission data with PM-related operating parameters at a cost that is

far less than performing a large number of Method 5 runs.

These two examples, therefore, lead EPA to believe that a PM CEMS

requirement will allow HWC facilities to better define what PM APCD

operating parameter limits correspond to a given PM emissions

concentration. As a result, the Agency encourages HWC facilities to use

PM CEMS data to better define what operating parameters correspond to

compliance with a facility's PM CEMS limit. The site-specific limit is

discussed further in section IV.B. of this notice.

3. Data Quality Objectives: New Procedure 2 to Appendix F of 40 CFR

Part 60

EPA intends to expand the ISO specification to include certain data

quality objectives. For example, PM CEMS routinely and automatically

check and correct their raw outputs to compensate for phenomena such as

``fogging'' of the optics and drift of the measurement signal. A large

and sudden auto correction is indicative of the need to perform

maintenance on the PM CEMS. To address this concern, EPA intends to

include certain data quality objectives such as: The (PM CEMS internal)

calibration drift not exceed 8% during any drift check; the (PM CEMS

internal) calibration drift not exceed more than 4% per day for five

consecutive days; and the automated (PM CEMS internal) calibration

drift adjustment not exceed 2% for five consecutive days.

These data quality criteria would appear in a new Procedure 2 of

Appendix F to 40 CFR part 60. Just as Procedure 1 of Appendix F deals

with data quality objectives for gaseous CEMS for other CAA rules (CEMS

such as NOX and SOX), Procedure 2 would address

data quality objectives for PM CEMS. Procedure 2 would also include the

following data quality objectives: treatment of ``flagged data;'' PM

CEMS automatic zero and calibration span requirements; conduct of the

Absolute Calibration Audit and the quality of the standards used for

these audits; sample volume audit requirements for extractive systems;

relative calibration audit (RCA) requirements; the treatment of audit

failures; how manual method paired data outliers (see the CEMS NODA 1,

62 FR at 13780) are handled; definition of ``out-of-control''

situations; and how facilities are to respond to these ``out-of-

control'' situations. See Procedure 2 (which appears at the end of this

notice) and the draft final PM CEMS Demonstration Test Report for more

information regarding these requirements and Procedure 2.

B. Manual Method Accuracy

One outgrowth of these PM CEMS demonstration tests is that EPA has

made significant improvements in making Method 5 particulate

measurements. As previously mentioned, the calibration process for PM

CEMS involves correlating PM CEMS outputs to manual method results.

High variability in the manual method results will negatively affect

the PS11 calibration statistics. Therefore, one important way to

improve PS11 statistics is to improve the way manual method

measurements are made. These improvements involve the use of a new

Method 5I (M5i) for low level PM emissions. M5i consists of the

following improvements: improved sample collection; elimination of

possible contamination; and improved sample analysis. Each will be

discussed in the following paragraphs. M5i will be instrumental in

correlating PM CEMS outputs to manual method results. EPA also expects

this new method will be preferred in all cases where low level (i.e.,

below 45 mg/dscm [ cents0.02 gr/dscf]) measurements are

required. In practice, this means that M5i is expected to become the

standard method for most HWCs and many other MACT sources. EPA expects

many of the improvements in M5i can and will be implemented whenever

Method 5 (collectively, including Method 5, 5A, ..., 5H) is used to

make particulate measurements.

M5i is almost identical to the traditional M5. Differences are

discussed below. We also present a comparison of the precision of M5i

(which fully implements these improvements) and the traditional M5

(which largely does not use these improvements) and discuss the need

for and handling of paired M5 data.

1. Modification of the Filter Recovery Process

One way M5i differs from the traditional M5 is through the use of a

light-weight and integrated filter and filter assembly that can be

tared and weighed together. This improves M5 by eliminating the filter

recovery step. The filter recovery step can be a significant source of

measurement error at some sources. In some cases as the filter dries,

the filter adheres itself to the filter assembly. Recovery of the

filter then involves scraping the filter off the filter assembly

leaving some of the filter (and sample) on the filter assembly or

otherwise losing it to the environment. In other cases, the filter

recovery

[[Page 67792]]

process can lead to the loss of sample to the environment as light-

weight particles are lost to the air during handling. It can also lead

to contamination of the sample in cases where fugitive dust from the

environment lands on the filter during the recovery step. Simplifying

the recovery step through the use of a light-weight, integrated filter

and assembly addresses these concerns and thereby improves the

reliability of making PM measurements.

One consequence of this improvement, though, is that the filter

used M5i is smaller than that used in the traditional M5 (47 mm

compared to approximately 90 to 100 mm in the traditional M5). This

smaller filter can plug at higher emissions levels. For this reason,

this aspect of M5i may not be implementable at sources with emissions

above 45 mg/dscm (that is, total train catches exceeding 50 mg).

2. Improved Sample Collection

Another important improvement to M5 is to the sample collection

process itself. These improvements include: ensuring that the nozzle is

90 deg. to the direction of flow at each traverse location; and using

Pesticide Grade (i.e., low residue) acetone for probe rinse. Each is

discussed in the following paragraphs. These improvements to the sample

collection process may also be implemented over time into other

versions of Method 5.

Test crews routinely check the ``level'' of the probe only once

during sampling--prior to or at the beginning of the sampling process

itself. As the traverse progresses, the probe can become ``unlevel,''

i.e., it is no longer at a right (90 deg.) angle to the direction flow

in the stack gas. As the angle of the probe departs from 90 deg.,

inconsistent amounts of sample are collected and thereby causes error

in M5 measurements. This can be corrected by applying a level to the

sample probe and checking the level continuously throughout the

traverse. Ensuring that the probe angle is constant and level

throughout the traverse eliminates this potential source of measurement

error.

Finally, residue contained in the acetone used for the probe rinse

is another source of sampling error. Acetone is used for the probe

rinse since it is a solvent that evaporates readily at room

temperatures and thereby allows rapid weighing of the specimen

following sampling. The standard M5 procedures require that acetone

residue blank levels be determined and that reagent-grade acetone in

glass bottles with no more than 0.001% residue be used for probe

rinses. Acetone comes in many grades, including reagent grade,

depending on how the purchaser intends to use the acetone. Some grades

of acetone contain higher levels of residue. This residue remains after

the acetone evaporates and contaminates the probe rinse, making the

``catch'' during the probe rinse greater than what it really is.

Acetone blanks above 0.001% are not allowed by M5, so the acetone

itself must have a concentration of residue no more than this

requirement for the blanks. M5 also requires that the acetone be stored

in glass containers because acetone from metal containers generally

have a high residue blank level. Test crews routinely use reagent-grade

acetone purchased in small, glass containers since large quantity

purchases create a fire safety and storage issue. Though ordered with

the intent of meeting specifications, acetone suppliers often store

bulk, reagent grade acetone in metal containers and transfer this

acetone to glass containers only to ship the small quantities sold.

This means that the residue concentrations found in reagent grade

acetone are often higher than what is allowed by M5. The unallowable

amount of residue from high blank levels would have a negative effect

on the accuracy and precision of M5 results. This can be avoided by

requiring low-residue, Pesticide grade acetone.

3. Elimination of Contamination

In a general sense, eliminating contamination in the filter

handling processes will eliminate potential sources of error.

Contamination can be avoided by: using a portable desiccator for use in

transporting and holding the filters to and on the stack; using glass

plugs on the filter assemblies to keep them ``pure'' prior to and after

sampling; covering the desiccant with a 0.1 micron screen to eliminate

potential external contamination of filter housing during transport;

and handling the filter assemblies with powder free latex gloves. As

previously discussed, contamination in the M5 process will make

measured PM levels appear to be higher than what they truly are. Each

of these steps to eliminate contamination of the sample will ensure

that fugitive particulate from the environment does not contaminate,

thereby inadvertently causing a positive bias to the measured PM

levels.

4. Improved Sample Analysis

Finally, improved sample analysis will help eliminate error in the

Method 5 measurement process. Specific steps to improve M5 sample

analysis include: Elimination of all sources of static charge (such as

those on the operator, beakers, liners, and balance); use of light

weight Teflon beaker liners for gravimetric analysis of the probe

rinse; maintaining the laboratory area at a humidity level of 30% or

less; and putting a covered desiccant container in the balance weighing

chamber. Each is discussed in the following paragraphs.

High, varying levels of static charge typically produce variations

in repeated weighing of susceptible materials such as glass filter

holder assemblies and Teflon beakers (probe rinse catches). The need

for maintaining a relatively dry atmosphere in the analytical room

further exaggerates the negative effect of static charge on the

weighing process. To control and minimize the consequences of static

charge, EPA found it was necessary to preclude any and all aspects of

static electricity. This entailed using: (1) A static-free mat on the

floor area under the desiccator and balance; (2) a small charge-

neutralizer in the desiccator; (3) another small charge-neutralizer in

the weighing chamber of the balance; and (4) a static dissipator

aerosol spray to prevent static buildup on the Teflon beakers. EPA

found it was not possible to consistently reproduce the same weight

results (that is, within 0.5 mg) until all four measures were done.

The particulate, filter assembly, and filter are often hydrophilic

in nature, i.e., they tend to adsorb water from the air. The amount of

water these materials adsorb depends on the amount of water in the air.

The moisture content of air is often quantified in terms of the

relative atmospheric humidity, or what percentage the actual water

concentration of the air is relative to the saturation concentration.

The higher the relative humidity of the air, the more water is

adsorbed. The converse is also true. As a result, if the relative

humidity in the analysis room is high, the amount of water adsorbed

onto the particulate, filter, and assembly becomes variable and it

becomes increasingly difficult to obtain a stable measurement. Ensuring

that the relative humidity in the analysis room remains at a constant,

low level will ensure that the amount of water adsorbed by these

materials remains relatively small and constant. EPA found that

maintaining the relative humidity of the room to below 30% will control

this source of error.4

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\4\ As humidity levels decrease, static charge tends to

increase. The elimination of static charge, previously discussed,

will aid at eliminating this problem.

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To further control and minimize the adverse affects of humidity on

reproducing results in the weighing

[[Page 67793]]

process, a small covered desiccant container was placed in the

balance's weighing chamber. This ensures that the humidity level in the

weighing chamber is consistent with the humidity level in the

desiccator. The desiccant in the weighing chamber dries fugitive air

entering the chamber from the room, preventing the adsorption of room

air humidity on the materials being weighed.

5. Comparison of M5 and M5i Method Precision

M5i has been validated against Method 5.5 It is also

important to quantify the improvements to M5 just discussed. This can

be done by comparing the precision of both methods at each of the three

proposed PM standards: 34, 50, and 69 mg/dscm for hazardous waste

burning incinerators, LWAKs, and cement kilns, respectively. Precision

at the standards is important since measurements at the standard deal

with compliance determinations at facilities. The best estimate of the

standard deviation is presented to represent this precision.

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\5\ Only the filter, extraction, and weighing steps were tested.

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

For M5i, the results presented are the best estimate of the

standard deviation at each of the three proposed emissions standards.

These results are calculated directly from the data obtained during the

PM CEMS demonstration tests. The relative standard deviation (e.g., the

best estimate of the standard deviation at an emissions concentration,

divided by that emissions concentration) for M5i is in all cases less

than 5%.

Historical data from Method 5 was derived from PM concentrations

ranging from 80 to 255 mg/dscm. This data indicates that the relative

standard deviation for M5 is constant at 10%. Therefore, if one were to

multiple the emissions standard by 10%, one can derive the best

estimate of the standard deviation at the three proposed emissions

standards.

Table 2, below, illustrates this comparison and shows that M5i is

an improvement to M5.

Table 2: Comparison of Method 5 and Method 5i Standard Deviations

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

Best estimate of the

standard deviation (mg/

Proposed PM emissions standard (mg/dscm) at 7% dscm)

oxygen -------------------------

Method 5 Method 5i

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

34 3.4 1.67

50 5.0 2.24

69 6.9 2.85

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

6. Paired Data

Throughout most of the PM CEMS demonstration tests, EPA used two

simultaneous Method 5i sampling trains. These two simultaneous trains

are called ``paired trains'' and the paired train data are called

``paired data.'' The average of the paired data from the two trains was

considered the method result. If the ``paired data'' differed by more

than 30% from the method result, EPA eliminated the method result from

the calculation of the calibration.

EPA's experience is that, despite the efforts just discussed to

control method variability, intangibles which are unknown or

unquantifiable can cause variability in M5 (and M5i) measurements.

Since it is important that highly accurate M5 measurements be obtained

for calibrating PM CEMS, these intangibles must be identified in some

way and data affected by these intangibles must be eliminated from the

PM CEMS calibration. The fact that two simultaneously run M5 (or M5i)

measurements do not agree is ample evidence that something in the

sample collection and analysis process was not consistent.

Comments received during the comment period for CEMS NODA 1 stated

that this process would not be allowed if a facility were doing a

calibration for compliance. To address this concern, EPA has

incorporated this outlier procedure in the new Procedure 2 and M5i.

Having this procedure in the regulations will allow facilities to

exclude this type of erroneous data from their PM CEMS calibrations.

Please note that this procedure applies only if paired data are

obtained. Single measurements obtained at different times are not

paired data. Single runs cannot be eliminated by comparing these

results to other single measurements.

EPA strongly encourages facilities to use paired data during their

calibrations. Beyond the ability to eliminate paired data outliers from

the PM CEMS calibration, using the average of two runs as the method

result has a moderating affect on the calibration statistics EPA

calculated and used to base the PS11 revised in today's notice. This

moderating effect improves the PS11 criteria relative to what they

would be if paired data were not used. Some facilities may find it

difficult to obtain a suitable calibration using only single M5

measurements. However, while we encourage using paired data, we are not

requiring paired data for PM CEMS calibrations. This choice can be left

to the facilities to determine what makes the most economic and

technical sense at their site.

C. Transferability of These Demonstration Test Results to Other HWC

Sources

EPA believes this demonstration test program adequately shows that

PM CEMS will meet PS11 at most hazardous waste incinerators, cement

kilns, and light-weight aggregate kilns. These tests were conducted at

a reasonable worst-case facility for performance relative to the

proposed performance specifications6. Therefore, a PM CEMS

should pass the performance measures described in the revised draft

PS11 at most HWC sources. The paragraphs below discuss specific aspects

of PM CEMS and their applicability to each HWC source category.

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\6\ For more on EPA's rationale that this is a reasonable worst-

case test, see CEMS NODA 1 and the PM CEMS Demonstration Test report

sited here.

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For cement kilns, in-situ light scattering PM CEMS are

operationally very similar to continuous opacity monitors (COMs), a

technology employed at these sources for many years. Light-scattering

PM CEMS differ from COMs only in the way they obtain and interpret the

light from the source. As shown in the LaFarge tests,7

though, an informed decision is required to determine what type of in-

situ light-scattering PM CEMS is best suited for these sources. One PM

CEMS used at LaFarge was built with a heated air purge system to blow

cement kiln dust away from and out of the optics of the monitor while

the other was not. The monitor with the heated air purge performed very

well over the course of the tests, though improvements to the Method 5

measurements and a routine cleaning of the optics could have improved

performance. The PM CEMS without the heated air purge suffered

operational difficulty. In addition, PM from cement kilns is mostly

process dust (i.e., raw material). As such, its physical properties are

not significantly affected by changes in waste or fuel feeds.

Accordingly, in-situ light-scattering PM CEMS will pass performance

specifications at cement kilns if an informed decision is made to

[[Page 67794]]

purchase a monitor that is designed to address the dusty environment at

these facilities.

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\7\ See section 2.6.7 of the PM CEMS Demonstration Test Report.

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

EPA believes that LWAKs are very similar to cement kilns relative

to the applicability of PM CEMS, and therefore the conclusions drawn in

the preceding paragraph also apply to LWAKs.

For incinerators, there are certain unique situations which must be

discussed: incinerators with truly wet stacks; incinerators with waste

heat boilers; and mobile incinerators.

As was the case with cement kilns, HWC incinerators with truly wet

stacks (i.e., those with entrained water droplets in the stack gas)

need to make an informed choice regarding what PM CEMS technology they

elect to use. In-situ light-scattering PM CEMS are likely to have

operational difficulty since the water droplets entrained in the stack

gas will be mistaken for particulate. This is a readily accepted source

of error and means that in-situ light-scattering PM CEMS are not a

practical choice for these sources. Beta-gage and certain other light-

scattering PM CEMS, however, are designed with extractive reheat

systems which heat up the extracted gas to above the water condensation

temperature. Incinerator groups are currently working to test these

types of systems to gain first-hand experience and data regarding the

use of PM CEMS at facilities with truly wet stacks. EPA encourages

these tests since they will result in valuable data which can be

communicated to personnel at incinerators with truly wet stacks to

assist their PM CEMS purchasing decisions.

Incinerators equipped with waste heat boilers (WHBs) downstream of

the combustion chamber(s) also require special consideration. Like

boilers, these incinerators blow soot periodically to clean the boiler

tubes. PM emissions will increase and the physical properties

(pertinent to PS11) of the PM may change during periods of soot

blowing. To help address the impact of soot-blowing, sources would be

required to include soot-blowing episodes during a minimum of three

calibration runs. This will ensure that calibration captures the higher

emissions that can occur during soot-blowing, thus minimizing the need

to extrapolate the calibration curve beyond measured values. In

addition, including soot-blowing during calibration runs will enable

the source to determine whether any change in the physical properties

of the PM during soot-blowing has adversely affected the calibration

(i.e., as evidenced by an inability to meet PS 11 when the soot-blowing

runs are included).

EPA requests comment on this approach to address the special

problems that soot-blowing may cause. In particular, EPA seeks the

following information:

--How many incinerators are currently equipped with WHBs? Are sources

likely to remove WHBs to facilitate compliance with the MACT standards

(e.g., D/F)?

--The normal frequency and duration of soot-blowing. Under what

conditions does the frequency and duration of soot-blowing change? How

often does this change(s) occur?

--How do PM emissions for runs that include episodes of soot blowing

compare to runs without soot blowing?

--How does the effect of the APCS, waste and fuel types, and other

relevant factors impact changes to the PM concentrations and physical

properties when one compares PM during soot-blowing and PM at other

times.

The reader should note that EPA intends to promulgate MACT

standards for hazardous waste boilers as part of Phase II of the HWC

rulemaking. EPA intends to address the applicability of PM CEMS to

boilers then. If because of unforeseen reasons EPA provides a PM CEMS

waiver for incinerators with WHBs, EPA would readdress the

applicability of PM CEMS to hazardous waste incinerators with waste

heat boilers in Phase II.

Finally, another class of hazardous waste incinerators are used at

Superfund sites during the clean-up process. These mobile incinerators

have small, limited waste processing capacity and are often trucked to

the site as needed. EPA is concerned that the variability of the feed

to mobile incinerators is beyond what was experienced at the DuPont

facility. As such, a unique calibration might be required for every

clean-up site, which is unnecessarily burdensome. Given the PM CEMS

implementation schedule discussed in section IV.A., below, implementing

PM CEMS at these incinerators may not be feasible, and EPA is

considering whether to waive the PM CEMS requirement for Superfund

mobile incinerators.

If the PM CEMS requirement is waived for certain facilities, the

other, traditional operating parameters discussed in this NODA would be

used instead to document compliance.

IV. PM CEMS: Implementation and Compliance 8

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\8\ The reader should note that HWCs are currently regulated

under RCRA. Sources with a different regulatory history are likely

to have a different compliance regime than the one described here.

One should not assume that the compliance and implementation scheme

described here will necessarily be applied to sources with a

different regulatory history.

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A. PM CEMS Compliance Schedule

Many comments received in response to the proposed rule stated that

facility personnel are not familiar with the operation and maintenance

characteristics of PM CEMS, or how to control their operating

conditions to ensure compliance using PM CEMS. For this and reasons

explained in section IV.B., EPA plans to allow a 12-month phase-in

period before PM CEMS would be used as a compliance parameter. This

section describes this compliance schedule.

Prior to the date PM CEMS would be used for compliance (i.e.,

during the 12-month phase-in period), limits on key PM-related and

other key operating parameters (e.g., metals feedrate) would be used to

ensure compliance with the MACT standards for PM, SVM, and LVM. This

one year phase-in period has four key milestones: The Compliance Date;

the performance Test Date; the Certification of Compliance (CoC) date;

and the Certification of PM CEMS performance date. By the Compliance

Date,9 facilities would determine, using engineering

judgment, the operating parameter limits necessary to ensure compliance

with the standards. These initial operating parameter limits would be

specified in a Precertification of Compliance (Pre-CoC) that would be

submitted to the permitting authority by the Compliance Date. By the

Test Date, which is nominally no later than six months after the

Compliance Date, facilities would have to conduct a performance test to

document compliance with the MACT emissions standards and identify

operating parameter limits based on levels achieved during the test.

Results of the performance tests and these revised operating parameter

limits would be submitted to the permitting authority in a

Certification of Compliance (CoC) nominally no more than nine months

after the Compliance Date. The operating parameter limits in the CoC

would be used as surrogate compliance measures to ensure that the

efficiency of

[[Page 67795]]

the PM control device was maintained at performance test levels until

the one-year anniversary date of the Compliance Date. Beginning at that

time, facilities would start using the PM CEMS and cease using the

operating parameters as their primary operating parameter for PM

control.

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\9\ The Clean Air Act states that the Compliance Date can be no

more than three years after the effective date of the rule (i.e.,

date of publication in the Federal Register), unless a source

obtains an (up to) one-year time extension of the Compliance Date.

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

During this phase-in year, there are important PM CEMS-related

activities being performed. For instance, the PM CEMS, like all other

equipment necessary for compliance with the MACT standards, must be

installed by the Compliance Date. Like all other tests for the rule,

the PM CEMS calibrations and initial certifications (see section 8.3 of

PS11 and section 4 of Procedure 2) must also be performed by the Test

Date.

As discussed in the PM CEMS Demonstration Test Report, the

mathematical characteristics of a light-scattering PM CEMS calibration

curve can be difficult to determine. For this reason, a second

calibration would be required within 9 months of the Compliance Date if

a light-scattering PM CEMS is used. After this second calibration is

performed the source would compare the two calibrations separately to

determine which mathematical model best represents the data. This

information (i.e., the analysis of which mathematical model is best

suited for the calibration at this source and the calibration comprised

of all valid calibration data obtained) would be included in a

Certification of PM CEMS Performance (CoP) submitted within 12 months

after the Compliance Date. (A CoP for beta-gage CEMS would also be

submitted at this time, but would certify performance based on a single

calibration.)

This CoP would also include (for all types of CEMS) the analysis of

CEMS data to identify an achievable CEMS-based PM operating parameter

limit. See section IV.B., below, for more information regarding the PM

CEMS operating parameter limit. On the one-year anniversary of the

Compliance Date, facilities would also cease using the PM control

device operating parameter limits (such as pressure drop across a

fabric filter or total power input to an ESP) and start using the PM

CEMS operating parameter limit as their primary compliance parameter

for the PM control device.

A source using a light-scattering PM CEMS would be required to

perform a third calibration of the PM CEMS within 12 months of the

Compliance Date. The third calibration would verify that the

mathematical model selected by comparing the first two calibrations is

correct. If not, to the approach must be modified based on the new

data. If the model needed to be revised, the source would be required

to recalculate the PM CEMS operating parameter limit considering the 12

months of data following the Compliance Date. If the model did not need

to be revised, the source could elect to recalculate the PM CEMS

operating parameter limit considering the full 12 months of CEMS

recordings. (We request comment on whether all sources required to

perform a third calibration should be required to recalculate the PM

CEMS operating limit even if the calibration curve model did not need

to be revised.) The results of the third calibration,10

reassessment of the calibration model, and recalculation of the PM CEMS

operating parameter limit would be submitted in a second CoP. This

second CoP would be provided to the permitting authority within 15

months of the Compliance Date. Note that this second CoP would not be

required if a source uses a beta-gage type PM CEMS that needs only one

calibration. A source using a PM CEMS that requires only one

calibration (i.e., a beta-gage) would have the option, however, of

submitting a second CoP if it wants to update the PM CEMS operating

parameter limit based on a full year of data.

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

\10\ This would involve the verification that the mathematical

model used for the calibration is correct, a recalculation of the

``master'' calibration comprised of all three calibration curves,

and a revised site-specific PM CEMS operating parameter limit (this

time, using the first 12 months of data).

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

Table 3 summarizes how PM CEMS would be implemented for compliance.

Following this implementation schedule, facilities would be required to

document compliance with the MACT PM standard during periodic

performance testing. As discussed in section IV.F. below, a source

would have the option of using the PM CEMS or the manual method for

this determination. In addition, sources would be required to

recalculate their PM CEMS operating parameter limit based on the

previous year of CEMS data recorded when the source operated within the

operating parameter limits established during the new performance test.

This recalculation of the PM CEMS operating parameter limit is

necessary since the new performance test is likely to result in

numerically different PM-related APCD operating parameters than

resulted from the previous test.11 Facilities would submit

the revised operating parameter limits, including the revised PM CEMS

operating parameter limit, in a CoC describing the results of the new

performance test.

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\11\ If the PM concentration and operating parameter limits

resulting from the subsequent performance test are more stringent

than those from the previous test, the facility would have the

option of not recalculating their PM CEMS operating parameter limit

and continue to operate under the older, more stringent limit.

[[Page 67796]]

Table 3: PM CEMS Compliance Schedule

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

By this date These PM CEMS activities would be performed

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

Compliance date............................. PM CEMS installed

Precertification of Compliance (Pre-CoC) submitted that

establishes PM APCD (and other) operating parameter limits to

ensure compliance with the SVM and LVM (and possibly D/F)

standards based on engineering judgment.

CD + 6 months (the ``Test Date'')........... PM CEMS calibration tests performed during MACT performance test.

Method 5i used to demonstrate compliance with the manual method-

based PM standard.

CD + 9 months............................... Certification of Compliance (CoC) submitted that establishes PM

APCD (and other) operating parameter limits to ensure compliance

with the SVM and LVM (and possibly D/F) standards based on what

levels were determined to correspond to compliance with the

standard during the Performance Test. (These limits supersede

those identified in the Pre-CoC.)

A second calibration of light-scattering PM CEMS is performed.

CD + 12 months.............................. Source identifies calibration curve, calculates the PM CEMS

operating parameter limit (through 9 months), recommends

alternative PM control device operating parameters and their

numerical limits, and submits a Certification of PM CEMS

Performance (CoP).

Source ceases using PM control device operating parameters as the

primary mode of compliance for PM and starts using the PM CEMS.

The operating parameters defined in the CoC are used for

compliance only when the PM CEMS is unavailable.

Source reports initial calibration (composite of all calibrations

through 9 months), PM CEMS-based limit, and revised operating

parameter limits (for use during CEMS malfunctions) to permitting

authority.

A third calibration of light-scattering PM CEMS is performed.

CD + 15 months.............................. Sources using light-scattering PM CEMS revise the calibration

curve if necessary based on the third calibration, recalculate

the PM CEMS operating parameter limit (through 12-months), update

the PM control device operating parameter limits for use during

CEMS malfunctions, and submit a second CoP documenting this

information.

The source starts using the revised operating parameters reported

in the CoP during periods when the PM CEMS is unavailable unless

those alternatives have been disapproved by the permitting

authority.

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

B. PM CEMS Operating Parameter Limit

EPA proposed using site-specific limits on key operating parameters

of the PM control device (e.g., pressure drop across a fabric filter)

to ensure that the device maintained its collection efficiency at

performance test levels. These limits, in combination with other

operating parameter limits (e.g., metals feedrate controls) would

ensure compliance with the semivolatile metal (SVM) and low volatile

metal (LVM) MACT standards. See 61 FR 17376 and 17430 (April 19, 1996).

These operating parameter limits on the PM control device would also

ensure compliance with the MACT PM standard 12, and possibly

the MACT dioxin and furan (D/F) and mercury (Hg) standards if the

source uses activated carbon injection to control these HAPs.

13 The availability of PM CEMS allows the Agency to improve

upon this approach through the use of PM CEMS as the sole PM control

device operating parameter 14. PM CEMS are a more sensitive

and accurate operating parameter than the conventional PM-related

operating parameters now used.

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\12\ The Agency has proposed a MACT PM standard as a surrogate

to control emissions of non-enumerated metals HAPs (i.e., metal HAPs

other than those for which specific standards have been proposed--

Hg, SVM, and LVM). Those non-enumerated HAPs are Sb, Co, Mn, Ni, and

Se.

\13\ The Agency proposed that the site-specific PM limit be a

compliance parameter for the D/F standard irrespective of whether

activated carbon injection was used as a control device. This

requirement was grounded upon EPA's initial view that a significant

amount of D/F (and other heavy organic compounds) are adsorbed onto

particulate. As a result, PM needed to be controlled to ensure

continuous compliance with the D/F standard. The Agency is now

considering comments that significant D/F may not be adsorbed onto

PM. Cement and lightweight kiln PM, in particular, is generally

process dust (i.e., processed raw material). This process dust has

little affinity for adsorbing D/F. However, EPA's ultimate decision

on whether to limit PM on a site-specific basic does not depend on

whether there is a need to control PM at all HWCs for D/F control. A

site-specific PM limit is still needed to ensure compliance with the

SVM and LVM standards at all HWCs. Sources that use activated carbon

injection, howver, would be expected to have a significant amount of

D/F on the PM.

\14\ Note that the MACT standard for PM would continue to be a

manual methods-based standard. See subsection IV.F., below, for

options facilities could have to use PM CEMS for direct compliance

with this PM standard.

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This section describes how PM CEMS would be implemented as an

operating parameter for the SVM, LVM, PM, and possibly D/F and Hg

standards. The reader should note that the proposed MACT standard for

PM is and will continue to be a manual methods-based standard. The

reader is referred to section IV.F., below, for options a facility

could choose to use PM CEMS as a direct indicator of compliance with

the MACT PM standard.

1. Introduction

The PM CEMS operating parameter limit would be determined using the

PM CEMS data obtained during normal operations from the Compliance Date

to the time when the calculation of the operating parameter limit is

performed. Although the PM CEMS would be used as an operating parameter

limit here, an approach to establishing this limit could be very

similar to how EPA establishes national standards from CEMS data. The

municipal waste combustor rule published on February 11, 1991, has an

example of how this is done 15.

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\15\The methods used for establishing CEMS standards in the

February 1991 MWC rule are described in Appendices A and B of EPA

document number EPA-450/3-91-004, dated December 1990. This document

can also be found in the Air Docket, located in the Mall area of EPA

Headquarters, 401 M Street, SW, Washington, DC 20460. It is part of

docket number A-89-08-V-B-3.

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EPA notes that even though the PM CEMS operating parameter limit

and the manual methods-based PM standard are both in units of

particulate concentration, it is likely that the PM CEMS operating

parameter limits will have a different numerical value than the manual

methods-based MACT PM standards. This is because the MACT PM standards

would be based on manual methods testing with no fixed averaging

period. PM CEMS operating parameter limits would have both a fixed

averaging period and a calculated

[[Page 67797]]

numerical limit. As discussed in section 4, below, the numerical value

of a limit or standard is a function of the averaging period. Since it

is likely that the PM MACT standard and the PM CEMS operating parameter

would have different averaging periods, one would expect the numerical

value of the PM CEMS operating parameter limit that indicates

compliance with the MACT standards would differ from the numerical

value of the MACT PM standard.

2. Data Excluded From Calculating the PM CEMS Operating Parameter Limit

Before calculating the PM CEMS operating parameter limit, the PM

CEMS data set must be screened to remove PM CEMS data recorded when the

PM CEMS was not available or the source was out of compliance with the

operating parameter limits established during the CoC.

First, the facility must remove from the data set all PM CEMS data

accumulated while the PM CEMS was not available or not performing

acceptably as defined by the regulations. Examples of the data not

included in the calculation of the PM CEMS operating parameter limit

include data obtained when the PM CEMS was ``out-of-control'' as

defined in Procedure 2 and PS11, periods when the PM CEMS was not

analyzing stack gas (as would happen during calibrations, maintenance,

etc.), and periods when the facility was not in operation.

Next, the facility would further screen the data to exclude times

when the facility was not operated in accordance with the operating

parameter limits resulting from the performance test and reported in

the CoC 16. Note that the CoC operating parameter limits

would supersede the Pre-CoC operating parameter limits for this

screening purpose. Although the Pre-CoC operating parameter limits may

be less stringent than the CoC limits and were valid limits prior to

submitting the CoC, the CoC limits are based on performance testing and

as such show what operating parameter levels reflect compliance with

the standards. The facility must also remove any data collected during

periods of PM APCS upset irrespective of whether the operating

parameter limits were exceeded. 17

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\16\ For simplicity, EPA proposes to exclude data from all

periods in which the facility operated outside of the operating

envelope defined in the CoC irrespective of whether the parameter in

question affects PM control. Defining what operating parameters are

or are not related to PM control would force another layer of

complexity in this step.

\17\ Episodes of high PM emissions caused by periodic, routine

maintenance cycles (e.g., ESP rapping; soot-blowing for waste heat

boiler equipped incinerators, etc.) would not be considered upset

conditions. We request information on how to objectively distinguish

between high PM emissions attributable to PM control device upset

conditions versus normal emissions variability.

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

3. Determining the Normality of the Data

To calculate the PM CEMS operating parameter limit, the CEMS

recordings 18 must be averaged over an appropriate averaging

period. (See the discussion in the following section.) Accordingly,

sources would be required to identify the mathematical model that best

fits the screened CEMS data for purposes of averaging the data. For

example, a log-or exponential fit may better represent a ``normal'' fit

relative to an arithmetic model. To identify which mathematical model

represents the best fit, facilities would calculate the Shapiro-Wilk

Normality test statistic (W) at the 95% confidence level using the data

obtained from the PM CEMS 19. The mathematical model with a

Shapiro-Wilk test statistic closest to one (1) would be the model used

for averaging at the facility. This mathematical model would be used

for all PM CEMS emissions averaging at the facility.

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

\18\ The light-scattering CEMS provide instantaneous data,

recorded every minute as one-minute block averages. Beta-gage CEMS

have sampling periods longer than 1 minute.

\19\ Note that batch CEMS, such as beta-gages, may have sampling

periods longer than 1 minute. In this case, the test statistic would

be performed using the batch results.

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

4. Averaging Periods for the PM CEMS Operating Parameter Limit

Fundamental to any emissions control parameter is the way averaging

affects an emissions standard or limit. At a fixed numerical value, a

standard or limit is more stringent as the averaging period decreases

and less stringent as the averaging period increases because of

emissions variability. In the proposed rule, EPA said that an

appropriate averaging period for PM CEMS would be the length of time it

takes to make three Method 5 runs. The Agency still believes this is an

appropriate point of departure for the averaging period for the PM CEMS

operating parameter limit.

We proposed a 2 hour averaging period for PM CEMS, reasoning that

it would take 40 minutes to accumulate enough PM sample to meet Method

5 requirements for sample ``catch.'' See 61 FR at 17379. Commenters

argued, however, that although it takes 40 minutes to accumulate enough

sample, test crews routinely sample for one hour. In addition, comments

received in response to CEMS NODA 1 said the sampling time for a Method

5 run can vary from 1 to 8 hours. Basing the averaging period for the

PM CEMS operating parameter limit on the length of time it takes to

perform three Method 5 runs would result in an averaging period in the

range of 3 to 24 hours 20. This is still being evaluated.

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\20\ Three to 24 hours is within the range of CEMS averaging

periods EPA typically promulgates. From a broader perspective,

averaging periods vary from regulation to regulation depending on

the analysis of issues pertaining to the technical, policy, and

regulatory history of each particular situation. Therefore, other

source categories may or may not have the same averaging period as

the one established for PM CEMS at HWC, depending on the outcome of

this analysis of issues.

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

5. Options for Calculating the PM CEMS Operating Parameter Limit

As discussed above, the stringency of the standard is a function of

two variables--its numerical limit and the averaging period. Equally

stringent standards would have a higher numerical limit at shorter

averaging period and a lower numerical limit at a longer averaging

period. Thus, to calculate the PM CEMS operating parameter limit, one

of these two variables must be held constant--either the numerical

limit or the averaging period. This section discusses two options for

calculating an achievable PM CEMS operating parameter limit by defining

the averaging period. EPA investigated ways to define the numerical

limit and allow facilities to calculate the averaging period associated

with that numerical limit, but found these alternatives often resulted

in trial-and-error type calculations and might result in all facilities

having different limits and averaging periods. We believe these

alternatives are too labor intensive and confusing--both for facilities

and the enforcement authority--and rejected this approach. Based on

comments and further analysis, the Agency will prescribe one

methodology in the final rule.

a. Using Rank Statistics to Calculate the PM CEMS-based Operating

Parameter Limit at One, Fixed Averaging Period. Under this approach,

the Agency would establish an averaging period common to all sources

and each source would calculate its PM CEMS operating parameter limit

using rank statistics. (As discussed above, EPA is considering

selecting an averaging period from within the range of three to 24

hours.) The averaging period would be the same for all facilities but

the numerical value of the PM CEMS operating parameter limit would

differ from facility-to-facility based on the historical data obtained

at each facility.

[[Page 67798]]

Using the rank statistics option to calculate the limit would

involve the following steps. First, the facility would take the

screened PM CEMS data (i.e., after non-compliance data has been

removed) and calculate rolling averages sequentially from the

Compliance Date 21 using the best-fit mathematical model and

the averaging period EPA promulgates. The facility would then take the

resulting rolling averages and sort them in order from lowest to

highest. The facility's PM CEMS operating parameter limit would be the

95th percentile highest PM CEMS rolling average, by rank, experienced

during the period the PM CEMS data was accumulated. The 95th percentile

is proposed here because it is the percentile level EPA historically

uses for these types of calculations. EPA could promulgate some other

percentile level, the 90th or 99th for example, if another percentile

level is achievable and better represents good PM control.

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\21\ For simplicity, we believe it is best for facilities to

ignore periods when the CEMS recorded data which was screened out

and calculate the rolling averages as if the remaining data occurred

sequentially. EPA specifically requests comment on this approach.

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

This rank statistics option is easier to implement, relative to the

other options. It also would result in a PM CEMS operating parameter

limit that is in the range of actual emissions experienced by the

facility (i.e., as opposed to statistically projected emissions) and

demonstrated by the facility to be achievable over time. Since the

limit for all sources would be based on an averaging period that would

be fixed in the rulemaking, the limit would be easier to enforce as

well.

b. The Traditional Standard Setting Approach. Another approach the

Agency is considering to determine the PM CEMS operating parameter

limit is to use the way EPA has established CEMS-based standards in the

past. This approach involves calculating the average and standard

deviation of the data set and projecting an emissions level associated

with the data. As discussed in the MWC rule, EPA calculated

``continuous compliance levels'' for each source using the equation,

below.

where: y=x+K*5

y = the continuous compliance level;

``x-bar'' = the sample average

k = a constant associated with the averaging period and one

exceedance per year; and

s = the sample standard deviation.

This option has some benefits and weaknesses. As discussed, it

reflects a procedure EPA has previously used to establish CEMS-based

standards. It would also result in every facility having the same

averaging period and thus making it easier to track and enforce.

However, more complicated statistics are involved. EPA also compares

emissions from more than one facility when it uses this approach to set

standards and would be unable to oversee the application of this

approach on a site-specific basis. As a result, this approach may be

unworkable as a way to establish a PM CEMS operating parameter limit.

6. Consideration of a Variance Procedure to Project a Higher PM CEMS

Operating Parameter Limit

As discussed previously in today's notice, the PM CEMS operating

parameter limit would be based on CEMS recordings during the nine

months after the Compliance Date during those periods of time that the

source was operating within the operating parameter limits established

during the performance test (i.e., the operating parameter limits

established in the Certification of Compliance (CoC)). Comments

received in response to the proposed rule questioned the need to

establish PM-related operating parameters based on the performance test

if: (1) PM emissions measured using manual methods during the

performance test were well below the PM MACT standard; and (2)

emissions of HAPs (i.e., SVM, LVM, and possibly Hg, and D/F) for which

PM would be used as an operating parameter limit were well below their

MACT standards. Commenters were concerned that, although their sources

may readily achieve the MACT PM standard, it may be difficult

22 or expensive to ensure that performance test PM levels

are representative of the full range of levels achieved during

operations. The same situation could occur with the PM CEMS operating

parameter limit just discussed. Infrequent exceedances of the PM CEMS

operating parameter limit might or might not be an indication that the

SVM, LVM, Hg, D/F, or PM MACT emission standards have been exceeded.

Accordingly, commenters recommended that the rule allow sources to

project higher PM-related operating parameters based on how much

performance test emissions for these HAPs were below their MACT

standards.

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\22\ For example, some PM control devices are so over-designed

that it is difficult to force them to operate at elevated PM levels

for the duration of a performance test.

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EPA agrees in theory that establishing the PM CEMS operating

parameter limit considering performance test operations (i.e.,

historical CEMS data when the source operated within the CoC operating

parameter limits) could result in an overly conservative operating

parameter for PM control at sources with low PM and low HAPs that

require PM control to ensure compliance. To address the concerns

expressed in the comments received on the proposed rule, the Agency is

considering a variance procedure to establish an higher projected PM

CEMS operating parameter limit.

The variance procedure would allow facilities with very low

concentrations of PM and HAPs requiring PM control for compliance to

increase their PM CEMS operating parameter limit (derived from

operations within the CoC operating parameter limits). The factor used

to increase the PM CEMS operating parameter limit could be defined as

the ratio of the MACT standards for which PM control is required to

assure compliance, to the performance test levels of those HAPs. To

ensure that the source is still be in compliance with the MACT PM

standard, the same ratio would be calculated for the PM standard to the

unadjusted PM CEMS operating parameter limit. This approach is based on

the principle that, at a facility which has experienced no changes in

facility operations, the ratio of emissions of HAPs which require PM

control to ensure compliance to the PM concentration in the stack is

either constant or decreases as PM increases. In addition, revised

(i.e., less stringent) traditional operating parameter limits for the

PM control devices corresponding to the higher projected PM CEMS

operating parameter limit could be established based on historical

operating data at levels near the higher projected PM CEMS operating

parameter limit.

For illustration, an example follows. Assume that a hazardous waste

incinerator has low metals in the feed and uses a HEPA filter for PM

control. Further assume that: This incinerator's measured metals

emissions during the performance test were 10 g/dscm and 7

g/dscm for SVM and LVM, respectively; that the PM

concentration measured during the performance test was 5 g/

dscm; for simplicity that PM control is not required to assure

compliance with the D/F and Hg standards; the unadjusted PM CEMS

operating parameter limit is 15 mg/dscm; and from the HWC NODA

published on May 2, 1997, that the promulgated standards are 100

g/dscm, 55 g/dscm, and 34 mg/dscm for SVM, LVM, and

PM, respectively. The ratio of the standard to the measured levels are

10 and 7.8 for SVM and LVM. For PM,

[[Page 67799]]

the ratio is 6.8. The unadjusted PM CEMS operating parameter limit

would be increased by a factor of 6.8 since the ratio calculated for PM

has the lowest numerical value.

a. HAPs for which PM control is necessary to ensure compliance. PM

would be used as an operating parameter limit for semivolatile metals

(SVM), low volatility metals (LVM), and if activated carbon is used,

dioxin and furan (D/F) and mercury (Hg). See 61 FR 17422 and 17430

(April 19, 1996). Although the Agency is reconsidering whether PM is an

appropriate operating parameter to ensure compliance with the D/F

standard in some cases,23 PM would be an appropriate

operating parameter if activated carbon injection were used to control

D/F or mercury. This is because D/F and mercury adsorb onto the

activated carbon, and as PM emissions increase, emissions of activated

carbon with adsorbed D/F and mercury increase.

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\23\ The Agency is considering comments that significant D/F may

not be adsorbed on emitted PM in all cases. Cement and lightweight

kiln PM, in particular, is generally process dust (i.e., raw

material) that has little affinity for absorbing D/F.

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

b. Projecting a higher PM CEMS operating parameter limit

considering the ratio of the standard to the measured level of a HAP.

The variance would be based on the principle that, as PM emissions

increase, the ratio of emissions of each HAP for which PM is an

operating parameter limit (i.e., SVM, LVM, and possibly D/F and Hg) to

PM emissions either is constant or decreases. Thus, the PM CEMS

operating parameter limit derived from operations within the CoC

operating parameter limits could be increased without exceeding the

MACT standards for those HAPs by a factor considering the ratio of the

standard for each of those HAPs to the performance test level of each

HAP.

LVM are generally not volatilized in the combustion chamber and

thus are evenly distributed over all sizes of particulates. Thus, as PM

emissions increase, the ratio of LVM emissions to PM emissions will be

constant.

SVM are generally volatilized during combustion and condense

preferentially on small particulates prior to (or in) the PM control

device. Thus for many PM control devices, as PM emissions increase, the

ratio of larger particulates to smaller particulates increases, and the

ratio of SVM emissions to total particulate emissions decreases (i.e.,

because the larger particulates have a lower concentration of SVM). For

emission control trains where PM particle size may remain constant with

an increase in PM emissions, the ratio of SVM emissions to PM emissions

would remain constant.

D/F and Hg are adsorbed onto the surface of carbonaceous

particulates (e.g., activated carbon). Smaller particulates have a

larger surface area per mass of particulate than larger particulates,

and thus D/F and Hg concentrations would be higher for smaller

particulates. Thus, similar to SVM, as PM emissions increase and the

ratio of larger particulates to smaller particulates increases, the

ratio of D/F and Hg emissions to total particulate emissions should

decrease (i.e., because the larger particulates have a lower

concentration of D/F and Hg).

The PM CEMS operating parameter limit derived from performance test

operations (i.e., calculated from historical CEMS data when the source

operated within the regulations) could be increased without exceeding

(theoretically) the MACT standards for SVM, LVM, and possibly D/F and

Hg by the ratio of the standard for each of those HAPs to the

performance test level of each HAP. It would be reasonably

conservative, however, to project the higher PM operating parameter

limit by the ratio of some fraction of the standard for those HAPs to

the performance test level of each HAP. This fraction of the standard

would need to allow for adequate flexibility for sources with low PM

and HAPs for which PM control is required while ensuring that the

standards are being met continuously. A specific percentage of the

standard within the range of reasonable values--50% to 100%-- could be

selected and would be appropriate given the uncertainty of projecting a

PM operating limit that is a primary compliance measure for several

MACT emissions standards. EPA believes choosing 75% of the standard as

the basis for calculating the ratio is a reasonable balance of these

issues. The percentage that would be appropriate is a point of interest

for the Agency.

Given that the PM CEMS operating parameter limit is a compliance

measure for SVM, LVM, and possibly D/F and Hg the allowable higher

projected PM CEMS operating parameter limit would be the lowest of the

values projected for each of these standards. For example, if the

projected PM CEMS operating parameter limit based on the ratio of 75%

of the SVM standard to the SVM performance test level was lower than

the PM CEMS operating parameter limit projections for LVM (and possibly

D/F and Hg), then the SVM-projected PM CEMS operating parameter limit

would be used to ensure that the SVM standard was not exceeded at the

higher projected PM operating parameter limit.

The Agency is concerned, however, about increasing the PM CEMS

operating parameter limit itself by the ratios discussed above. This is

because the limit would be established at the upper end of the range of

actual CEMS readings, or perhaps at levels that statistically exceed

what would be expected. See above discussion of options for calculating

the PM CEMS operating parameter limit. It may be more appropriate to

project the higher limit using the following options.

Under option 1, the ratio determined above would be applied to the

average PM emissions over time determined by the PM CEMS instead of

applying the ratio directly to the unadjusted PM CEMS limit itself. The

product of the ratio and the average PM emissions would then be

subtracted from the average emissions to determine the correction to

the PM CEMS operating parameter limit. This correction would then be

added to the PM CEMS operating parameter limit to determine the revised

PM CEMS operating parameter limit. Using the example described above

and assuming average PM CEMS emissions are 2 mg/dscm, the lowest ratio

(6.8 for PM) would be multiplied by the average PM emissions (2x6.8 =

13.6) and the average emissions would be subtracted from this product

(13.6-2). This difference (11.6) would be added to the PM CEMS

operating parameter limit to obtain the revised PM CEMS operating

parameter limit.

Under option 2, the PM CEMS recordings during the performance test

would be analyzed to calculate a PM CEMS operating parameter limit and

that limit would be increased by the factor defined by the ratio

discussed above (e.g., 6.8 in the first example). This approach would

ensure that infrequent high PM episodes that occurred over months of

CEMS operations would not be driving a PM CEMS limit that was then

projected further upward using the factors discussed above (unless

those high PM episodes actually occurred during the performance test).

Given the truncated emissions database (i.e., the performance test) for

calculating the higher projected limit under this option, however, the

limit may in fact be lower than the limit normally calculated from the

full CEMS emissions database (i.e., without attempted to project a

higher limit). In this case, the limit which is numerically higher

would be used.

The Agency requests information on which approach would be more

appropriate for projecting a higher PM CEMS operating parameter limit.

c. Ensuring that the higher projected PM CEMS operating parameter

limit

[[Page 67800]]

does not exceed the MACT PM standard. The PM CEMS operating parameter

limit would also be used to ensure compliance with the MACT PM

standard. We reiterate that the PM CEMS operating parameter limit is

not a measure of the emissions standard--the emissions standard is

defined in the rule as being measured by using manual methods--it is

instead an operating parameter limit used to ensure compliance with the

applicable standards. As discussed in section 1, above, it is likely

that due to several factors the PM CEMS operating parameter would have

a different numerical value that the MACT PM standard.

One reason for different numerical values is the use of different

techniques (i.e., one is manual methods based while the other is CEMS-

based) to determine a PM emissions value. The use of a manual method

test to determine a value is only a limited-time (e.g., 3 to 24 hours

every five years) measure of emissions, whereas a CEMS is a continuous

measure of emissions (e.g., 1 minute readings all the

time). Although the manual method will likely be a measure of ``high-

end'' PM emissions during performance testing, it may not account for

all potential variability during normal operations. The use of a CEMS

to monitor PM emissions is a way to continuously measure the

variability of (both low and high) PM emissions, inherent in any

engineered system.

Additionally, different values may be a result of the different

averaging periods stated for manual methods-based PM standard and the

PM CEMS operating parameter limit. See section 4, above, for a

discussion of the interrelationship between a numerical value of a

limit or standard and the averaging period. Having a PM CEMS operating

parameter limit with a different, possibly higher, numerical limit is

permissible and does not negate the value of the PM CEMS operating

parameter, provided there is reasonable correlation between the

operating parameter and the MACT PM standard. This section explains how

EPA would ensure that the numerically larger, revised PM CEMS operating

parameter limit would not violate the national PM standard.

Ensuring that the higher projected PM CEMS operating parameter

limit does not exceed the MACT PM standard is complicated by the fact

that the PM operating parameter limit would be CEMS-based while the

MACT PM standard would be manual method-based. Nonetheless, compliance

with the MACT PM standard can be ensured by limiting the increase in

the PM CEMS operating parameter limit (i.e., the projected PM CEMS

operating parameter limit divided by the limit prior to projection) to

the ratio of the MACT PM standard to the performance test PM level on a

manual method basis. Given that projections rather than measured values

would be used to ensure compliance with a standard, it may be prudent

to limit the increase in the projected PM CEMS operating parameter

limit to the ratio of 75% of the MACT PM standard to the performance

test PM level. A conservative factor of 75% is within the range of

reasonable values the Agency could have selected--50% to 100%.

Regarding the specific percentage EPA chooses, the reader is referred

to the previous discussion regarding the percentage EPA chooses for the

HAP standards that require PM control to ensure compliance.

Using the example from above and making the same assumptions, the

ratios would be calculated using 75 /dscm, 41/dscm,

and 26 mg/dscm in the numerator for SVM, LVM, and PM. These values are

75% of the standards for incinerators EPA discussed in the May 2, 1997,

HWC NODA. The resulting rations would be 7.5, 5.9, and 5.1. Since the

ratio calculated for PM is the lowest, ratio used to determine the

revised PM CEMS operating parameter limit would be 5.1.

d. Establishing Revised Operating Parameter Limits for the PM

Control Device Corresponding to the Higher Projected PM CEMS Operating

Parameter Limit. Ideally, PM control device operating parameter limits

(e.g, pressure drop across a fabric filter) should be established to

ensure compliance with the higher projected PM CEMS operating parameter

limit for compliance purposes while the CEMS is malfunctioning. Absent

these revised (i.e., less stringent) operating parameter limits, the

source would be required to: (1) Comply with the more stringent

operating parameter limits established during the performance test that

correspond to the original PM CEMS operating parameter limit; or (2)

ensure that a back-up CEMS is always available.

The Agency is considering an approach to establish revised

operating parameter limits for the PM control device corresponding to

operations at the higher projected PM CEMS operating parameter limit.

Under this approach, the source would analyze the historical operating

parameter values during those periods of time that PM emissions were

close to the higher projected PM CEMS operating parameter limit. Issues

that must be addressed, include: (1) What range of PM CEMS operating

parameter limit values should be considered to develop the database for

PM control device operating parameter values; and (2) how should the

database be analyzed to identify appropriate limits.

It may be appropriate to establish the revised PM control device

operating parameter limits based on the 90th percentile of values that

occur when PM levels are within 75% of the higher projected PM CEMS

operating parameter limit. This would help ensure that a significant

data set was available for evaluation and that the limits were not

based on the most lenient values recorded. This is important because

the higher projected PM CEMS operating parameter limit is likely to be

well beyond the calibration curve. 24

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\24\ A source would be allowed to operate infrequently at levels

approaching a higher, projected PM CEMS operating parameter limit

that is beyond the calibration curve. If, however, a source operates

for prolonged periods at levels above the calibration curve, it must

perform Method 5 tests at those higher concentrations and include

those higher PM levels in the POM CEMS calibration. See discussion

on extrapolating PM CEMS calibration data elsewhere in today's

notice.

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

Based on further analysis, the Agency may consider other approaches

to define an appropriate data set of PM control device operating limits

and identify appropriate limits (e.g., considering a different

percentage of the historical data and/or basing the limit on a

different percentile of data). Alternatively, the Agency may conclude

that these approaches to revise the performance test-based operating

parameter limits would be too complicated or difficult for regulatory

officials to oversee, or that it would be difficult to confirm

compliance with the standards. In this event, sources would be required

to continue to comply with the PM control device operating parameter

limits established during the performance test when the CEMS

malfunctions even though the PM CEMS operating parameter limit has been

projected upward under procedures discussed above.

e. Implementing the Variance. Sources requesting the variance to

project a higher PM CEMS operating parameter limit would include the

request with the Certification of PM CEMS Performance (CoP) that would

be submitted within 12 months after the Compliance Date. The variance

request must include documentation of the analyses described above to

identify the higher projected PM CEMS operating parameter limit and the

revised, PM control device operating parameters associated with the

higher projected PM

[[Page 67801]]

operating parameter limit. Sources would be allowed to comply with the

higher projected PM CEMS operating parameter limit immediately upon

submitting the CoP. Regulatory officials would have three months to

review the variance request, however, and to notify the source of

intent to disapprove the higher projected PM CEMS operating parameter

limit (or the associated revised PM control device operating parameter

limits for use during CEMS malfunctions). In such cases, the regulatory

officials would provide the basis of their initial decision and provide

the source with an opportunity to present, within 30 calendar days,

additional information before final action on the variance.

7. EPA's PM CEMS Testing Program to Identify a CEMS-Based Emission

Level Achievable by MACT-Controlled Sources

The Agency is undertaking an additional PM CEMS testing program to

identify CEMS-based emission levels that are achievable by hazardous

waste combustors (i.e., hazardous waste burning incinerators, cement

kilns, and lightweight aggregate kilns) using MACT control. The testing

is scheduled to begin in December 1997 and results should be analyzed

by December 1998. The Agency is working with representatives of the

regulated community to identify one source in each of the three source

categories that is using MACT control and that would be likely to

define the most achievable level (i.e., considering average PM

emissions and emissions variability) for MACT-controlled sources.

Although these test results will not be used as part of the final

rule, the data will be valuable to permitting authorities and the

regulated community as a PM CEMS emission benchmark that is achievable

using MACT controls. Permitting authorities could use the data to

identify sources that appear to have established an anomalously high

CEMS-based PM operating parameter limit, and as a framework within

which to review Certifications of Performance in a cost-effective

manner. Likewise, sources wanting to ensure that their facility is

operating in a manner representative of MACT control could use this

information to see if their CEMS-based PM operating parameter limits

are below the levels that MACT sources show are achievable using MACT

control.

C. RCA Test Frequency

In the proposed rule, EPA said that facilities would be required to

perform relative calibration audits (RCAs) on their PM CEMS every 18

months. This testing interval would be relaxed to 30 months for small

on-site incinerators. These time intervals coincided with the proposed

Performance Test intervals. If these tests can be performed at the same

time as the performance tests, cost savings can be realized by the

facility relative to what the costs would be if the tests were not

conducted at the same time. As a result of the analysis of comments on

the performance test frequency, the Agency is considering requiring all

facilities to conduct comprehensive performance tests every five (5)

years. Therefore, we prefer that RCA tests be performed every five

years.

One of the goals of the PM CEMS Demonstration Test program was to

quantitatively define what RCA frequency is appropriate for PM CEMS.

Unfortunately, variability in the manual method masks any error that

can be identified as being caused by drift in the PM CEMS over time.

Therefore, we are unable to use the PM CEMS data from the demonstration

tests to extrapolate to an appropriate re-test frequency \25\.

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\25\ In fact as method accuracy improved, the PM CEMS

calibration statistics got better over time. Extrapolating this data

would lead to erroneous conclusion that no retesting is ever needed,

since the PM CEMS calibration keeps getting better.

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Lacking these long-term data, it is important to look at what is

done in other countries to qualitatively determine this RCA test

frequency. The United Kingdom (UK) requires that retesting be conducted

at least every year, and in Germany testing is required every 3 to 5

years. The RCA test frequency could therefore reasonably be between one

and five years. The UK, though, heavily relies on manual methods

testing--so much so that they believe using gas bottles is cost

prohibitive for gaseous (e.g., NOx and SOx) CEMS

testing and rely on manual methods testing instead. EPA is inclined to

believe that the German's longer retest frequency is more consistent

with our regulatory framework.

D. Extrapolating PM CEMS Calibration Data

One-minute or batch PM CEMS readings during the course of

operations are likely to occasionally exceed the highest M5i

calibration point during the course of PM CEMS use. This is because the

manual method results used to derive the calibration are (nominally)

one hour block averages of emissions over the sampling period while the

PM CEMS readings are averages of emissions on the order of minutes. See

section 4, above, regarding the interrelationship the numerical limits

of a standard or limit and its associated averaging period. In

addition, emissions variability within the sampling period of M5 is not

likely to represent the full range of emissions variability over all

periods of PM CEMS operation. Therefore, a system is needed to allow

the extrapolation of data beyond the calibration curve.

The revised calibration and implementation scheme described in

today's notice (i.e., multiple calibrations (for light-scattering PM

CEMS) over the full range of emissions at the facility) will result in

a calibration from which some reasonable and limited extrapolation is

reasonable. Therefore, the Agency proposes to allow the calibration

curve to be used for measurements up to 25% more than the maximum M5

\26\ measurement observed during the calibration. (This will be

referred to as the ``125% point.'') Beyond this point (125% of the

highest M5 measurement) EPA is concerned that extrapolating the

calibration data might lead to false compliance determinations.

Therefore, some environmentally conservative approach must be employed.

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\26\ In this context, M5 is meant to refer to all the methods

(Method 5, Method 5A, . . ., Method 5I) used to calibrate PM CEMS.

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

Note that the ability to extrapolate beyond the calibration curve

in no way would mitigate the facility's requirement to calibrate over

its full range of PM emissions. If a facility experiences continuous

periods of PM emissions beyond the calibration curve, it would be

obligated to perform tests to capture these data into the calibration

curve. For example, a facility may determine that it occasionally has

several continuous hours of PM CEMS readings which are greater than the

125% point. Several continuous hours are enough time to conduct a M5

test, so the facility would be obligated to conduct M5 tests at this

emissions level and include these data in the calibration curve used at

the facility. EPA requests comment on how long a period of sustained

operations at emissions levels greater than the 125% point would be

necessary to require these additional calibration data points.

1. Extrapolating Light-Scattering PM CEMS Calibration Data

If it is necessary to extrapolate beyond the 125% point, an

environmentally conservative approach would consist of determining the

slope of the calibration curve at the 125% point and have the

calibration continue with a slope equal to or greater than the slope of

the curve at the 125% point. For example if the

[[Page 67802]]

curve is a log-normal relation, the slope of the curve at the 125%

point would be positive, but less than the slope of a straight line

that would also describe the correlation between method results and PM

CEMS outputs. Therefore, if a log-normal relationship best describes

the calibration curve, facilities should extrapolate beyond the 125%

point using a straight line beyond the 125% point. The slope of the

straight line would be the slope of the log-normal curve, taken from

the points on the calibration curve associated with the lowest M5

measurement and the 125% point.

If the calibration curve is best described by a straight line

arithmetic fit, then extrapolating beyond this 125% point would depend

on the slope of any quadratic fit of the data. If the quadratic curve

slopes negative at higher values of PM CEMS outputs, then the straight

line defined by the calibration would be used to extrapolate beyond the

125% point. If the quadratic fit slopes positive at higher values of PM

CEMS outputs, then the quadratic fit would be used beyond the 125%

point.

Finally, if the calibration curve is a quadratic fit, then the

quadratic fit can be used to extrapolate all data \27\.

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\27\ Note: If the slope of the quadratic fit is ever less than

zero for values of PM CEMS output above what was measured by the

manual method (that is, it ever has a negative slope), this

indicates that the correlation between M5 measurements and PM CEMS

output is not represented by a quadratic fit and that another

mathematical model should be used.

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2. Extrapolation of Beta-gage Calibration Data

For Beta-gage PM CEMS, extrapolating beyond the 125% point would

involve continuing the straight line defined by its linear calibration

equation. Beta-gage PM CEMS apparently are not sensitive to particle

changes in the physical characteristics of particulate, as the light-

scattering PM CEMS are. Therefore, a straight-line fit best represents

the calibration for beta-gage PM CEMS at all times.

E. Need to Calibrate to Twice the Emissions Standard

One issue raised by commenters during the comment period for the

proposed rule was EPA's proposal that facilities calibrate the PM CEMS

to twice the emissions limit. Commenters raised concerns that

facilities might not be able to emit PM at a concentration equal to

twice the standard. They also said this aspect of the proposal in

essence asks facilities to violate the emission standard and could lead

to an enforcement action against the facility. Commenters also had

concerns that facility personnel may not be sufficiently familiar with

the various process and APCD factors to acceptably calibrate the PM

CEMS over the full range of operations experienced at the facility.

Each of these points are discussed in the following paragraphs.

EPA agrees that it would be difficult for many facilities to emit

PM at any prescribed level. Many facilities have redundancies in their

PM APCDs to such an extent that emitting to the emissions limit may be

problematic. However to have accurate PM CEMS measurements, facilities

need to calibrate the PM CEMS over the full range of emissions

experienced at the facility. As a result, it would be necessary to

require facilities to calibrate the PM CEMS over the full range of

operations, including PM emissions. This would eliminate the

prescriptive nature of how high the calibration needs to be while still

addressing the issue that the site-specific calibration of PM CEMS

covers the broad range of PM emissions experienced at the facility.

EPA does not agree, however, that this approach could cause

facilities to violate the manual method MACT PM standard. The PM

standard would be defined as the average of three manual method

measurements. Any single run above the standard would not be a

violation by itself. Average emissions over the calibration would be

below the standard for a source equipped with MACT controls. Therefore,

we expect that sources would be able to calibrate PM CEMS at levels

higher than the PM emissions standard and still remain in compliance

with the standard. If this is not practical, however, EPA may consider

a waiver of the manual method PM standard during periods of calibrating

(and performing RCA tests of) the PM CEMS. The need to obtain and audit

an accurate calibration at and above the PM standard may override any

concerns about high short-term PM emissions. EPA would want to limit

the frequency and duration of calibration runs that exceed the

standard, however. We request comment regarding how such limits could

be implemented. One way this could occur is to require that sources

request in the performance test plan approval to exceed the standard

during calibration. Approval to exceed the standard would only be

required if the average of all PM CEMS calibration runs is greater than

the PM standard.

The revised draft PS 11 states that different PM levels should be

obtained by varying process conditions or, alternatively, by adjusting

the APC system. It is relatively silent in presenting a well-defined

protocol with guidelines on how EPA expects calibration tests to be

performed. This is because individual sources should know best how to

vary their PM emissions. For instance, inserting a throttle plate in

lieu of one (or several) bags in a baghouse and varying the opening of

the throttle plate(s) is likely an effective way to vary PM

concentration for the calibration at a facility equipped with a

baghouse. Varying power to an ESP and simulating various failure modes

(such as lowering the temperature in the ESP to cause condensation on

the plates) is likely vary PM sufficiently for the calibration at

sources equipped with an ESP.

The experience gained during the PM CEMS Demonstration tests

suggests that one can obtain a suitable range of emissions by varying

process conditions that affect inlet PM loading to the last in a series

of PM APCDs and adjusting the performance of that last APCD. Exactly

how this is accomplished at a given facility will vary and depend on

the waste fed to the unit, how the facility is designed and operated,

and in what order the APCDs are configured. Therefore, the language in

the revised PS11 is adequate. More prescriptive language may not work

in most cases.

Finally, EPA, will be working with industry representatives to

develop approaches to better describe how calibration tests should be

performed at individual HWC facilities. EPA expects to provide this

information in a technical implementation guide.

F. Allowing PM CEMS to be Used In-lieu of Method 5 Tests

Although the PM CEMS would be required only as an operating

parameter, EPA intends to allow facilities to voluntarily elect to use

the PM CEMS for compliance with manual methods-based PM standards.

Using the PM CEMS for compliance is expected to provide a cost savings

to the facility since the facility would not have to conduct periodic

Method 5 tests to document compliance with PM standards. Instead a

facility could elect to use the PM CEMS measurements during these

periodic tests. This would be acceptable if the facility uses the block

average of the PM CEMS readings during the M29 tests for the SVM and

LVM standards as the particulate ``method result.''

G. Waivers from the PM CEMS Requirements

In the proposed rule, EPA requested comment on waiving the PM and

Hg CEMS requirement for small, on-site incinerators. See 61 FR at

17439. Upon

[[Page 67803]]

further consideration, EPA has identified other classes of incinerators

where a PM CEMS requirement may be impractical. If the PM CEMS

requirement is waived for a given source, the facility would have to

comply with operating parameter limits to assure compliance for PM. Of

course, a facility could always elect to use a PM CEMS for compliance

even if a waiver procedure is promulgated for that facility.

1. Waiver of PM and Hg CEMS Requirements for Small On-site Incinerators

EPA is considering whether to waive the PM and Hg CEMS requirements

for small, on-site incinerators (SOSI). See the proposed rule, 61 FR at

17439. If a waiver is promulgated, a SOSI would be required to use

existing operating parameters in lieu of a PM CEMS to document

compliance with the PM, SVM, and LVM standards.

2. PM CEMS Waiver for Sources With Short Life-Spans

Given the PM CEMS compliance schedule discussed in section IV.A,

above, facilities with short, fixed life-spans raise several issues.

For instance, certain government-run incinerators are constructed for

the purposes of destroying waste that is too hazardous to transport

off-site. These incinerators often have short life spans (ranging from

months to a few years) and are constructed to fulfill the requirements

of a consent decree, memorandum of understanding (MOU), or other

legally binding enforcement agreement. For example the Department of

Defense (DoD), acting under a MOU with EPA, may construct an

incinerator to destroy nerve-gas agents that are too hazardous to

transport. When this activity is complete, the MOU would obligate DoD

to dismantle and destroy the incinerator.

It does not seem practical to mandate that these facilities use PM

CEMS if they will be in service for less than, or slightly longer than,

the implementation schedule just discussed. Therefore, EPA is

considering a waiver of the PM CEMS requirement for HWCs operating

under a legally binding agreement that ensures the source will stop

burning hazardous waste within three years of the Compliance Date.

EPA could likewise grant a waiver from the PM CEMS requirement for

facilities with short life-spans that lack the legally binding

agreement discussed above. However, EPA is concerned that without a

legally binding agreement to cease operations, the Agency lacks

certainty that operations will cease by a prescribed date. For this

reason, EPA would consider a waiver for other facilities that plan to

cease operations within the first year of compliance with the HWC

regulations, that is, prior to the need to use PM CEMS as the operating

parameter for PM control. Facilities that operate after the first year

would need to have PM CEMS installed, calibrated, meet data

availability requirements, determine the PM CEMS operating parameter

limit, and use the PM CEMS as the primary operating parameter for PM

control.

3. Other Sources

As discussed in section III.C. of this NODA, EPA may be unable to

determine whether the results of the PM CEMS demonstration test can be

transferred to two classes of incinerators: Those with waste heat

boilers and mobile incinerators. See section III.C. for more

information.

V. Other Issues Concerning CEMS and Test Methods for HWCs

A. Performance Specifications for Optional CEMS

In the proposed rule, EPA proposed other performance specifications

for multi-metals, hydrochloric acid (HCl), and chlorine gas

(Cl2) CEMS. These performance specifications were proposed

as PS10, 13, and 14, respectively. Based on what EPA has learned during

the course of demonstrating PM and Hg CEMS, EPA expects not to

promulgate the draft performance specifications (PS) for these CEMS at

the time of the HWC final rule. As discussed in section II of today's

notice, EPA does not plan to promulgate a PS for total mercury (Hg)

CEMS either. The Agency has not tested MM and Cl2 CEMS to

determine what performance is achievable by the CEMS. Hg CEMS have not

been demonstrated as a compliance tool for universal application to all

HWCs. EPA has tested HCl CEMS in preparation for the medical waste

incinerator rulemaking but did not require the use of HCl CEMS in that

rulemaking (see discussion starting at 62 FR 48360, September 15, 1997)

and does not believe requiring HCl CEMS for the HWC rulemaking is

appropriate either (see 61 FR at 17433).

Instead, EPA will consider enabling sources to demonstrate these

CEMS on a site-specific basis and to develop performance levels for the

CEMS as part of the demonstration. The Agency's only concern is that

the CEMS be proven to be a better and more reliable indicator of

compliance for the HAP or standard than the requirements specified in

the regulations. This approach is now being used to demonstrate a

multi-metals CEMS at the Von Roll incinerator in East Liverpool, Ohio.

EPA intends to accumulate the CEMS demonstration results and

experience and will share that information with permitting authorities

and sources wishing to document compliance with CEMS. Since the HCl

CEMS have been demonstrated by EPA, we believe the HCl CEMS performance

specification could more easily be used as a point of departure for

implementing HCl CEMS at a given facility.

B. Stack Sampling Test Methods

Another question is whether EPA should simplify the task of

determining the appropriate manual method tests to be used for

compliance. Currently, stack sampling and analysis methods for HWCs are

(with a few exceptions) located in RCRA's SW-846 for compliance with

the BIF and incinerator rules, and in 40 CFR part 60, Appendix A for

compliance with the NSPS and other air rules. Facilities could be

required to perform two identical tests, one for compliance with MACT

or RCRA and one for compliance with other air rules, using identical

test methods simply because one method is an ``SW-846'' method and the

other an ``air method.''

Stack test methods HWCs use for compliance should be found in one

place to facilitate compliance. EPA intends to reference 40 CFR part

60, Appendix A, when it requires a specific stack-sampling test method.

A few SW-846 methods do not have equivalents in 40 CFR part 60,

Appendix A, namely the VOST and semi-VOST methods. In these few cases,

EPA would continue to refer to these SW-846 methods as well.

This discussion only affects stack sampling methods and has no

affect on feedstream sampling and analysis.

Dated: December 19, 1997.

Matt Hale,

Acting Director, Office of Solid Waste.

Appendix I--Method 5i

Method 5I--Determination of Low Level Particulate Matter Emissions From

Stationary Sources

1. Applicability and Principal

1.1 Applicability. This method applies to the determination of

low level particulate matter (PM) emissions from stationary sources

and facilities performing calibrations or calibration audits of

particulate matter continuous emission monitors as specified in the

regulations. The method is effective for total train catches of 50

mg or less. The minimum detection limit for this method can be

determined by repeatedly collecting and analyzing blank samples. A

blank sample is a sample of blank air collected and analyzed

[[Page 67804]]

in the normal manner. The limit of detection can be calculated by

collecting and analyzing seven blank samples and then calculating an

estimate of the sample standard deviation of these blanks. The limit

of detection would be three times the estimated sample standard

deviation.

1.2 Principal. The PM is withdrawn isokinetically from the

source and collected on a 47 mm glass fiber filter maintained at a

temperature of 120 deg. 14 deg.C (248 deg.

25 deg.F). The PM mass, which includes any material that

condenses at or above the filtration temperature, is determined

gravimetrically after the removal of uncombined water.

2. Apparatus

2.1 Sampling Train. The sampling train configuration is the

same as shown in Method 5, Figure 5-1. The sampling train consists

of the following components: Pitot Tube, Probe liner Differential

Pressure Gauge, Filter Heating System, Condenser, Metering System,

Barometer, and Gas Density Determination Equipment. Same as Method

5, Sections 2.1.2 to 2.1.4, 2.1.6 and 2.1.7 to 2.1.10, respectively.

2.1.1 Probe Nozzle. Same as Method 5, Sections 2.1.1 with the

exception that it is constructed of Borosilicate or quartz glass

tubing with sharp, tapered leading edge.

2.1.2 Filter Holder. The filter holder for this sampling train

is constructed of Borosilicate or quartz glass front cover designed

to hold a 47 mm glass fiber filter, with a stainless steel filter

support, a silicone rubber or Viton O-ring and Teflon tape seal. The

holder design will provide a positive seal against leakage from the

outside or around the filter. The filter holder assembly fits into a

stainless steel filter holder and attaches immediately at the outlet

of the probe (or cyclone, if used). The tare weight of the filter,

Borosilicate or quartz glass, stainless steel filter support,

silicone rubber or Viton O-ring and Teflon tape seal will not exceed

31 grams. The filter holder is designed to use a 47 mm glass fiber

filter meeting the criteria in section 3.1.1 of Method 5. Figure 5I-

1 presents a schematic of the filter holder system. These units are

commercially available.

2.1.3 Glass Plugs and Clamps. Once the filter holder has been

assembled, desiccated and tared it is critical that the filter be

isolated from any external sources of contamination. This can be

accomplished by covering the leak-free ground glass or O-ring socket

on the front half glass filter cover with a Borosilicate or quartz

ground glass plug. The plug shall be secured in place with the

appropriate sized laboratory impinger clamp or any system that can

ensure a leak-free fitting. It is beneficial to place the glass plug

on the inlet socket as soon as the unit is assembled, however do not

tare the assembly with the plug in place, as this will increase the

tare weight introducing additional error into the final weighings.

2.2 Sample Recovery. Is the same as Method 5 for: Glass Sample

Storage Containers, Graduated Cylinder and/or Balance, Plastic

Storage Containers, Funnel and Rubber Policeman (Method 5 sections

2.2.3, 2.2.5--2.2.8, respectively) with the following exceptions:

2.2.1 Probe-Liner and Probe-Nozzle Brushes. Teflon

and nylon bristle brushes with stainless steel wire handles, should

be used to clean the probe. The probe brush shall have extensions

(at least as long as the probe) of Nylon, Teflon, or

similarly inert material. The brushes shall be properly sized and

shaped to brush out the probe liner and nozzle.

2.2.2 Wash Bottles--Two. Teflon wash bottles are

recommended however, polyethylene wash bottles may be used at the

option of the tester. It is recommended that acetone not be stored

in polyethylene bottles for longer than a month.

2.2.3 Sample Holder: A portable carrying case with clean

compartments of sufficient size to accommodate each filter assembly.

The filters shall be able to lay flat with the stainless steel

filter support placed down in the compartment. This system should

have an air tight seal to prevent contamination to the filters

during transport to and from the field. It is recommended that

desiccant be used in this case. The desiccant, if used, is housed in

a container that is capped with a 0.1 micron screen to ensure that

no dust particles can contaminate the outside of the filter housings

during transport.

2.3 Analysis. The same as Method 5 for sections 2.3.2-2.3.7

with the following exception:

2.3.1 Teflon Liner: Teflon liners are used for the

analysis of the probe and nozzle particulate catch. The liners are

washed with soap (Alconox or similar low residue laboratory soap)

and water. Each liner is then rinsed with DI Water followed by an

acetone (low residue) rinse. The static charge on the liners is

removed using an anti-static rinse and then the liners are oven

dried and desiccated.

3. Reagents

3.1 Sampling. The reagents used in sampling are the same as

Method 5 for: Silica Gel, Water, Crushed Ice, Sample Recovery

Reagents, and Desiccant (sections 3.1.2-3.1.5, 3.2-3.3.2) with the

following exceptions:

3.1.1 Filters. 47 mm Glass fiber filters, without organic

binder, exhibiting at least 99.95 percent efficiency (2 or SO3, the filter material

must be of a type that is unreactive to SO2 or

SO3. Citation 10 in the Bibliography for Method 5, may be

used to select the appropriate filter.

3.1.2 Stopcock Grease. Stopcock grease cannot be used with this

sampling train. It is recommended that the sampling train be

configured with glass joints, using o-ring seals or screw-on

connectors with Teflon sleeves, or similar.

3.1.3 Acetone. Pesticide grade or equivalent low residue type

Acetone is used for the recovery of particulate matter from the

probe and nozzle.

3.1.4 Latex Gloves. Disposable, powder free, latex surgical

gloves are used for all handling of the filter housings at all

times.

4. Procedure

4.1 Sampling. The complexity of this method is such that, in

order to obtain reliable results, testers should be trained and

experienced with the test procedures. The sampling procedures are

the same as Method 5 for: Preliminary Determinations, Leak-Check

Procedures, Particulate Train Operation (sections 4.1.2, 4.1.4,

4.1.5 respectively ) with the following exceptions:

4.1.1 Pretest Preparation. Is the same as Method 5, section

4.1.1 with the following exception: Label filter supports prior to

loading filters into the holder assembly. This can be accomplished

with a diamond scribe. As an alternative, label the shipping

container compartments (glass or plastic) and keep the filter holder

assemblies in these compartments at all times except during sampling

and weighing. Using the powder free latex surgical gloves (surgical

gloves must be used at all times when handling the filter holder

assemblies). Place the Viton O-ring on the back of the

filter housing in the O-ring grove. Place a 47mm glass fiber filter

on the O-ring with the face down. Place a stainless steel filter

holder against the back of the filter. Carefully wrap \1/4\ inch

wide Teflon tape one time around the outside of the

filter holder overlapping the stainless steel filter support by

approximately \1/8\ inch. Gently brush the Teflon tape

down on the back of the stainless steel filter support. Desiccate

the filter holder assemblies at 205.6 deg. C

(6810 deg. F) and ambient pressure for at least 24 hours

and weigh at intervals of at least 6 hours to a constant weight,

i.e., 0.5 mg change from previous weighing; record results to the

nearest 0.1 mg. During each weighing the filter holder assemblies

must not be exposed to the laboratory atmosphere for a period

greater than 2 minutes and a relative humidity above 30 percent.

Alternatively (unless otherwise specified by the Administrator), the

filters holder assemblies may be oven dried at 105 deg. C (220 deg.

F) for 2 to 3 hours, desiccated for 2 hours, and weighed.

4.1.2 Same as Method 5, section 4.1.2.

4.1.3 Preparation of Collection Train. Is the same as Method 5,

section 4.1.3 with the following exception: During preparation and

assembly of the sampling train, keep all openings where

contamination can occur covered until just prior to assembly or

until sampling is about to begin. Using clean disposable powder free

latex surgical gloves, place a labeled (identified) and weighed

filter holder assembly in the stainless holder for the assembly.

Then place this whole unit in the Method 5 hot box and attach it to

the probe using clean standard connectors. Do not use any stopcock

grease.

4.2 Sample Recovery. Proper cleanup procedure begins as soon as

the probe is removed from the stack at the end of the sampling

period. Allow the probe to cool. When the probe can be safely

handled, wipe off all external particulate matter near the tip of

the probe nozzle and place a cap over it to prevent losing or

gaining particulate matter. Do not cap off the probe tip tightly

while the sampling train is cooling down as this would create a

vacuum in the filter holder, thus drawing water from the impingers

into the filter holder. Before

[[Page 67805]]

moving the sample train to the cleanup site, remove the probe from

the sample train and cap the open outlet of the probe. Be careful

not to lose any condensate that might be present. Cap the filter

inlet using a standard ground glass plug and secure the cap with an

impinger clamp. Remove the umbilical cord from the last impinger and

cap the impinger. If a flexible line is used between the first

impinger or condenser and the filter holder, disconnect the line at

the filter holder and let any condensed water or liquid drain into

the impingers or condenser. Transfer the probe and filter-impinger

assembly to the cleanup area. This area should be clean and

protected from the wind so that the chances of contaminating or

losing the sample will be minimized. Save a portion of the acetone

used for cleanup of the probe and nozzle as a blank. Take 200 ml of

this acetone directly from the wash bottle being used and place it

in a glass sample container labeled ``acetone blank.'' Inspect the

train prior to and during disassembly and note any abnormal

conditions. Treat the samples as follows:

Container No. 1. Carefully remove the filter holder assembly

from the Method 5 hot box and place it in the transport case. Use a

pair of clean disposable powder free latex surgical gloves to handle

the filter holder assembly. If the transport case is being used to

identify and track the filter holder assemblies the entire transport

container will need to be of sufficient size and shape to fit in the

desiccator at the laboratory. It is important to ensure that the

assemblies have cooled sufficiently to prevent the surgical gloves

from melting on the filter holder assembly.

Container No. 2. Same as Method 5 Container No. 2 with the

exception that it is recommended that only glass sample containers

be used for collection of the sample from the probe and nozzle to

minimize the potential for background contamination.

Container No. 3. Same as Method 5 Container No. 3.

4.3 Analysis. Same as Method 5 section 4.3 with the following

exceptions:

Container No. 1. Same as Method 5 Section 4.3 Container No. 1

with the following exception: Use disposable powder free latex

surgical gloves to remove each of the filter holder assemblies from

the desiccator or transport container.

Container No. 2. Same as Method 5 Section 4.3 Container No. 2

with the following exception: It is recommended that the contents of

Container 2 be transferred to a 250 ml beaker with a Teflon\ liner

or similar container that has a minimal tare weight prior to

bringing to dryness.

Container No. 3. Same as Method 5 Section 4.3 Container No. 3

4.4 Quality Control Procedures. The Quality Control Procedures

used in sampling are the same as Method 5 for: Meter Orifice Check

and Calibrated Critical Orifice (sections 4.4.1--4.4.2).

5. Calibration.

The Calibration Procedures used are the same as Method 5: Probe

Nozzle, Pitot Tube, Metering System, Probe Heater Calibration,

Temperature Gauges, Leak Check of Metering System Shown in Method 5

Figure 5-1, Barometer (sections 5.1--5.7).

6. Calculations

The Calculations used are the same as Method 5 for:

Nomenclature, Average Dry Gas Meter Temperature and Average Orifice

Pressure Drop, Dry Gas Volume, Volume of Water Vapor, Acetone Blank

Concentration, Total Particulate Weight, Particulate Concentration,

Conversion Factors, Isokinetic Variation, Acceptable Results, Stack

Gas Velocity and Volumetric Flow Rate (sections 6.1--6.13).

7. Alternative Procedures

The Alternative Procedures used are the same as Method 5 for:

Dry Gas Meter as a Calibration Standard, Critical Orifices As

Calibration Standards, (sections 7.1--7.2).

8. Bibliography

The Bibliography used is the same as Method 5.

BILLING CODE 6560-50-P

[[Page 67806]]

[GRAPHIC] [TIFF OMITTED] TP30DE97.028

BILLING CODE 6560-50-C

[[Page 67807]]

Appendix II--Performance Specification 11

PERFORMANCE SPECIFICATION 11--Specifications and test procedures for

particulate matter continuous emission monitoring systems in stationary

sources.

211.0 Scope and Application

1.1 Analyte. Particulate matter as defined and determined by

the Reference Method--Method 5 or Method 5I.

1.2 Applicability.

1.2.1 This specification is for evaluating the acceptability of

particulate matter (PM) continuous emission monitoring systems

(CEMS) at the time of or soon after installation and whenever

specified in the regulations. The CEMS may include, for certain

stationary sources, (a) a diluent monitor (i.e., O2, CO,

or other CEMS specified in the applicable regulation), which must

meet its own performance specifications found in this appendix, (b)

auxiliary monitoring equipment to allow measurement, determination,

or input of the gas temperature, pressure, moisture content, and/or

dry volume of stack effluent sampled, and (c) an automatic sampling

system.

This performance specification requires site specific

calibration of the PM CEMS response against manual gravimetric

Reference Method measurements. Procedures for extrapolating results

beyond the range of particulate mass loadings used to develop the

calibration are found in the applicable regulations. A new

calibration may be required if conditions at the facility change and

result in conditions which are unrepresentative of the previous

calibration (i.e., changes in emission control system, concentration

of PM emitted, or feed inputs to the device). Since the validity of

the calibration may be affected by changes in the physical

properties of the particulate (such as density, index of refraction,

and size distribution), the limitations of the CEMS used should be

evaluated with respect to these possible changes on a site specific

basis.

1.2.2 This specification is not designed to evaluate the

installed CEMS performance over an extended period of time nor does

it identify specific calibration techniques and auxiliary procedures

to assess CEMS performance. The source owner or operator, however,

is responsible to properly calibrate, maintain, and operate the

CEMS. The Administrator may require, under Section 114 of the Act,

the operator to conduct CEMS performance evaluations at other times

besides the initial test to evaluate the CEMS performance. See

Appendix F to Part 60--Procedure 2, Quality Assurance Requirements

For Particulate Matter Continuous Emission Monitoring Systems Used

For Compliance Determination.

2.0 Summary of Performance Specification.

Procedures for establishing the CEMS calibration are outlined in

this performance specification. CEMS installation and measurement

location specifications, equipment specifications, performance

specifications, and data reduction procedures are also included.

Conformance of the CEMS with the Performance Specifications is

determined.

3.0 Definitions

3.1 Batch Sampling means the technique of sampling the stack

effluent continuously and concentrating the pollutant in some

capture medium. The capture medium is moved periodically for

analysis after sufficient time has elapsed to concentrate the

pollutant to levels detectable by the analyzer. Continuous sampling

is ensured by sampling (either on a different part of the capture

medium or a different capture medium) while analysis is being

performed on a previous sample.

3.2 Calibration Drift (CD) means the difference in the CEMS

output readings from the established reference value after a stated

period of operation during which no unscheduled maintenance, repair,

or manual adjustment took place.

3.3 Calibration means the site-specific correlation between the

CEMS output and the PM mass concentration measured by the Reference

Method.

3.4 Calibration Standard means a reference material that

produces a known and unchanging response when presented to the

pollutant analyzer portion of the CEMS, and used to calibrate the

drift or response of the analyzer.

3.5 Centroidal Area means a concentric area that is

geometrically similar to the stack or duct cross section and is no

greater than 1 percent of the stack or duct cross sectional area.

3.6 Confidence Interval means the interval defined by equations

13 and 23 of this performance specification with upper and lower

limits within which the CEMS response calibration relation lies with

a given level of confidence.

3.7 Continuous Emission Monitoring System (CEMS) means the

total equipment required for the determination of particulate matter

mass concentration in units of the emission standard. The sample

interface, pollutant analyzer, diluent analyzer, other auxiliary

data monitor(s) and data recorder are the major subsystems of the

CEMS.

3.8 Correlation coefficient means that portion of the

statistical evaluation that measures how well the CEMS and Reference

Method calibration relation data fit the regression line as defined

by equation 16 of this performance specification.

3.9 Data Recorder means that portion of the CEMS that provides

a permanent record of the analyzer output and the final PM

concentration result in units of the emission standard. The data

recorder may provide automatic data reduction and CEMS control

capabilities.

3.10 Diluent Analyzer and Other Auxiliary Data Monitor(s) (if

applicable) means that portion of the CEMS that sense or otherwise

provide the diluent gas (such as O2 or CO, as specified

by the applicable regulations), temperature, pressure, and/or

moisture content, and generates an output proportional to the

diluent gas concentration or data property.

3.11 Linear Calibration means a CEMS response which is linear

relative to the measured PM concentration produced by the Reference

Method.

3.12 Path CEMS means a CEMS that measures particulate matter

mass concentrations along a path across the stack or duct cross

section which is representative of results of the cross-sectional PM

concentrations produced by the Reference Method.

3.13 Point CEMS means a CEMS that measures particulate matter

mass concentrations either at a single point, or over a small fixed

volume or path, which is representative of the cross-sectional PM

concentrations produced by the Reference Method.

3.14 Pollutant Analyzer means that portion of the CEMS that

senses the particulate matter concentration and generates a

proportional output.

3.15 Quadratic Calibration Relation means a CEMS response which

has a second order equation to define its relationship to the

measured PM concentration produced by the Reference Method.

3.16 Reference Method. The Reference Method for particulate

measurements is those methods collectively known as Method 5, found

in Appendix A of 40 CFR Part 60. Unless other variants are specified

in the regulations, Method 5 shall be used for total train catches

exceeding 50 mg (i.e., emissions concentrations of more than 45 mg/

dscm). Method 5I shall be used for total train catches of less than

or equal to 50 mg (i.e., emissions concentrations of 45 mg/dscm or

less). If variants other than Method 5I are used, care should be

taken to follow the general procedures described in Method 5I to aid

in the elimination of measurement error. Other Reference Methods may

be applicable, such as Method 1, 3, or 4. Methods other than Method

5 are referred to in this specification individually by name.

3.17 Representative Results means the results consistent with

the acceptance criteria found in section 13.2 of this specification.

3.18 Response Time means the time interval between the start of

a step change in the system input and the time when the pollutant

analyzer output reaches 95 percent of the final value.

3.19 Sample Interface means that portion of the CEMS used for

one or more of the following: sample acquisition, sample delivery,

sample conditioning, or protection of the monitor from the effects

of the stack effluent.

3.20 Span Value means the upper limit of the CEMS measurement

range. The span value shall be documented by the CEMS manufacturer

with laboratory data.

3.21 Tolerance Interval means the interval with upper and lower

limits within which are contained a specified percentage of the

population with a given level of confidence as defined by equation

14 of this performance specification.

3.22 Zero Drift (ZD) means the difference in the CEMS output

readings for zero input after a stated period of operation during

which no unscheduled maintenance, repair, or adjustment took place.

4.0 Interferences

In the Reference Method a representative sample of particulate

is collected on a filter maintained at a temperature in the range

[[Page 67808]]

specified by the method, and includes any material that deposits in

sample delivery and condenses at or above this filtration

temperature after removal of any combined water. Consequently,

condensible water droplets or condensible acid gas aerosols (i.e.,

those with condensation temperatures above those specified by the

method) at the measurement location can be interferences for PM CEMS

if the necessary precautions are not systematically met.

Interferences may develop for CEMS installed downstream of a wet air

pollution control system or any other conditions that produce flue

gases which are normally or occasionally saturated with water or

acid gases prior to release to the atmosphere. For such conditions,

the CEMS must extract and heat a representative sample of the flue

gas for measurement to simulate results produced by the Reference

Method. Independent of the CEMS measurement technology and

extractive technique, a configuration simulating the Reference

Method is required to assure that: (1) there is no formation or

deposition of particulate in sample delivery from the stack or duct;

and (2) the pollutant analyzer portion of the CEMS measures only

native particulate. Performance of a CEMS design configured to

eliminate interferences with condensible water and/or acid gases

must be documented by the CEMS manufacturer (see Section 6.1.3 of

this performance specification for specific equipment heating

requirements). In-situ CEMS measurement technologies that are not

free of interferences from any condensible constituent in the flue

gas are prohibited in stack or duct flue gas conditions which are

normally or occasionally saturated with water or acid gases.

5.0 Safety

The procedures required under this performance specification may

involve hazardous materials, operations, site conditions, and

equipment. This performance specification does not purport to

address all of the safety problems associated with these procedures.

It is the responsibility of the user to establish appropriate safety

and health practices and determine the applicable regulatory

limitations prior to performing these procedures. The CEMS users'

manual and materials recommended by the Reference Method should be

consulted for specific precautions to be taken.

6.0 Equipment and Supplies

6.1 CEMS Equipment Specifications

6.1.1 Data Recorder Scale. The CEMS data recorder output range

must include zero and a high level value. The high level value is

chosen by the source owner or operator and is defined as follows:

6.1.1.1 For a CEMS installed to measure emissions as required

with an applicable regulation, the high level value between 1.5

times the emission standard and the span value specified in the

applicable regulation is adequate.

6.1.1.2 Alternative high-level values may be used, provided the

source can measure emissions throughout the full range of emissions

concentrations experienced by the facility.

6.1.1.3 The data recorder output must be established so that the

high level value would read between 90 and 100 percent of the data

recorder full scale. (This scale requirement may only be applicable

to analog data recorders.) The zero and high level calibration gas,

filter, or other appropriate media values should be used to

establish the data recorder scale.

6.1.1.4 The high level value must be equal to the span value. If

a lower high level value is used, the CEMS must have the capability

of providing multiple outputs with different high level values (one

of which is equal to the span value) or be capable of automatically

changing the high level value as required (up to the span value)

such that the measured value does not exceed 95 percent of the high

level value.

6.1.1.5 Span. The span of the instrument shall be sufficient to

determine the highest concentration of pollutant at the facility.

The span value shall be documented by the CEMS manufacturer with

laboratory data.

6.1.2 The CEMS design should also allow daily determination and

recording of calibration drift at the zero and high-level values. If

this is not possible or practical, the design must allow these

determinations and recordings to be conducted at a low-level (zero

to 20 percent of the high-level value) and at a value between 50 and

100 percent of the high-level value. In special cases, the

Administrator may approve a single-point calibration drift

determination.

6.1.3 Specification for Saturated Flue Gas. For a CEMS installed

downstream of a wet air pollution control system such that the flue

gases are normally or occasionally saturated with water, then the

CEMS must have equipment to extract and heat a representative sample

of the flue gas for measurement so that the pollutant analyzer

portion of the CEMS measures only dry particulate. Heating shall be

sufficient to raise the temperature of the extracted flue gas to

above the water condensation temperature and shall be maintained at

all times and at all points in the sample line from where the flue

gas is extracted to and including the pollutant analyzer.

Performance of a CEMS design configured in this manner must be

documented by the CEMS manufacturer.

6.2 Sampling and Response Time. The CEMS shall sample the stack

effluent continuously or intermittently for batch sampling CEMS.

Averaging time, the number of measurements in an average, the

minimum sampling time, and the averaging procedure for reporting and

determining compliance shall conform with those specified in the

applicable emission regulation.

6.2.1 Response Time. The response time of the CEMS should not

exceed 2 minutes to achieve 95 percent of the final stable value

(except for Batch CEMS: see 6.2.2). The response time shall be

documented and provided by the CEMS manufacturer. Any changes in the

response time following installation shall be documented and

maintained by the facility.

6.2.2 Response Time for Batch CEMS. The response time

requirement of Section 6.2.1 does not apply to batch CEMS. Instead

it is required that the response time, which is the equivalent to

the cycle time, be no longer than one tenth of the averaging period

for the applicable standard or no longer than fifteen minutes,

whichever is greater. In addition, the delay between the end of the

sampling time and reporting of the sample analysis shall be no

greater than three minutes. Any changes in the response time

following installation shall be documented and maintained by the

owner or operator.

6.2.3 Sampling Time for Batch CEMS. Sampling is required to be

continuous except during brief pauses when the collected pollutant

on the capture media is being moved for analysis and the next

capture medium starts sampling. In addition, the sampling time

should be no less than thirty-five percent of the averaging period

for the applicable standard or no less than thirty-five percent of

the response time.

6.3 Other equipment and supplies, as needed by the applicable

Reference Method(s) (see Section 8.4.2 of this Performance

Specification) or as specified by the CEMS manufacturer, may be

required.

7.0 Reagents and Standards

7.1 Reference Gases, Optical filters, or other technology-

appropriate reference media. As specified by the CEMS manufacturer

for internal calibration (i.e., to adjust drift or response) of the

CEMS. These need not be certified but shall be documented by the

manufacturer to give results consistent with this performance

specification.

7.2 Reagents and Standards. May be required as needed by the

applicable Reference Method(s) (see Section 8.4.2) of this

performance specification).

8.0 Performance Specification Test Procedure

8.1 Installation and Measurement Location Specifications.

8.1.1 CEMS Installation. Install the CEMS at an accessible

location downstream of all pollution control equipment where the

particulate matter mass concentrations measurements are

representative or can be corrected to be representative of the total

emissions as determined by the Reference Method from the affected

facility or at the measurement location cross section. It is

important to select a representative measurement point(s) or path(s)

for monitoring in location(s) that the CEMS will pass the

calibration test (see Section 8.4). If the cause of failure to meet

the calibration relation test is determined to be the measurement

location and a satisfactory correction technique cannot be

established, the Administrator may require the CEMS to be relocated.

Suggested measurement locations and points or paths that are most

likely to provide data that will meet the calibration requirements

are listed below.

8.1.2 Measurement Location. It is suggested that the measurement

location be: (1) at least eight equivalent diameters downstream from

the nearest flow disturbance, such as a control device, point of

pollutant generation, bend, expansion, contraction in the stack/

duct, point of discharge, or other point at which a change of

pollutant concentration or gas streamlines may occur; and (2) at

least two equivalent

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diameter upstream from the effluent exhaust or a flow disturbance.

8.1.2.1 Point CEMS. It is suggested that the measurement point

be: (1) no less than 30% of the stack or duct diameter from the

stack or duct wall; or (2) within or centrally located over the

centroidal area of the stack or duct cross section.

8.1.2.2 Path CEMS. It is suggested that the effective

measurement path be : (1) totally within the inner area bounded by a

line 30 percent of the stack/duct diameter from the stack or duct

wall; (2) have at least 70 percent of the path within the inner 50

percent of the stack or duct cross sectional area; or (3) be

centrally located over any part of the centroidal area.

8.1.3 Reference Method Measurement Location and Traverse Points.

8.1.3.1 Select, as appropriate: (1) an accessible Reference

Method measurement point at least eight equivalent diameters

downstream from the nearest flow disturbance, such as a control

device, point of pollutant generation, bend, expansion, contraction

in the stack or duct discharge point, or other point at which a

change of pollutant concentration or gas flow direction may occur;

and (2) at least two equivalent diameters upstream from the flow

disturbance, such as the effluent exhaust. When pollutant

concentration changes are due solely to diluent leakage (e.g., air

heater leakages) and pollutants and diluents are simultaneously

measured at the same location, a half diameter may be used in lieu

of two equivalent diameters. The CEMS and Reference Method locations

need not be the same so long as the Reference Method is placed at a

location specified by the method and the CEMS output is

representative of pollutant emissions determined by the Reference

Method.

8.1.3.2 Select traverse points that assure acquisition of

representative samples over the stack or duct cross section.

Selection of traverse points to determine the representativeness of

the measurement location should be made according to 40 CFR part 60,

Appendix A, Method 1, Section 2.2 and 2.3.

8.2 Pretest Preparation. Install the CEMS, prepare the

Reference Method test site according to the specifications in

Section 8.1, and prepare the CEMS for operation according to the

manufacturer's written instructions.

8.3 Calibration Drift Test Procedure.

8.3.1 CD test Period. While the affected facility is operating

more than 50 percent of normal load, or as specified in an

applicable Subpart, determine the magnitude of the CD once each day

(at 24-hour intervals) for 7 consecutive days according to the

procedure given in Sections 8.3.2 and 8.3.3.

8.3.2 The purpose of the CD measurement is to verify the

ability of the CEMS to conform to the established CEMS calibration

used for determining the emission concentration or emission rate.

Therefore, if periodic automatic or manual adjustments are made to

the CEMS zero and calibration settings, conduct the CD test

immediately before these adjustments, or conduct it in such a way

that the CD can be determined.

8.3.3 Conduct the CD test at the two points specified in

Section 6.1.2. Introduce to the CEMS the reference gases, optical

filters, or other suitable calibration reference media (these need

not be certified). Record the CEMS response and subtract this value

from the reference value.

8.4 Calibration Test Procedure

8.4.1 Calibration Test Period. Conduct the calibration test

according to the procedure given in Sections 8.4.2 through 8.4.7

while the affected facility is operating at more than 50 percent of

normal load or as specified in an applicable Subpart. The

calibration test may be conducted during the CD test period.

8.4.2 Reference Methods. Unless otherwise specified in an

applicable Subpart of the regulations, Method 3B, 4, and 5I, or

other approved alternatives, are the Reference Methods for diluent

(O2), moisture, and PM, respectively. Method 5 should be

used instead of Method 5I if PM emissions exceed 45 mg/dscm (0.02

gr/dscf).

8.4.3 Sampling Strategy for Reference Method tests. Conduct the

Reference Method tests in such a way that they will yield results

representative of the emissions from the source and can be

correlated to the CEMS data. Conduct the diluent (if applicable),

moisture, (if needed), and PM measurements simultaneously. In order

to correlate the CEMS and Reference Method data properly, make sure

the time from the CEMS data recorder and the time instrument used

for the Reference Method agree and note the beginning and end of

each Reference Method test period of each run (including the exact

time of day) on the CEMS chart recordings or other permanent record

of output. Make two sample traverses for a total of at least 60

minutes, sampling for an equal time at each traverse point (see

Section 8.1.3.2 for discussion of traverse points). The use of

paired Method 5I (or Method 5 as appropriate) trains (that is,

simultaneously traversing across two 90 deg.-opposed axes) is

recommended to improve and assure data quality.

Note: At times, CEMS calibration tests may be conducted during

new source performance standards, performance tests or other

compliance tests subject to the Clean Air Act or other statutes,

such as the Resource Conservation and Recovery Act. In these cases,

Reference Method results obtained during CEMS calibration test may

be used to determine compliance as long as the source and test

conditions are consistent with the applicable regulations.

8.4.4 Number of Runs in a Calibration Relation Test. Conduct a

minimum of 15 runs each consisting of simultaneous CEMS and

Reference Method measurements sets.

Note: More than 15 sets of CEMS and Reference Method measurement

sets may be performed. If this option is chosen, certain test

results may be rejected so long as the total number of test results

used to determine the calibration relation is greater than or equal

to 15. However, all data must be reported, including the rejected

data. The basis for rejecting data must be explicitly stated in: (1)

The Reference Method, this Performance Specification, or Procedure

2; or (2) the site's QA plan approved by the Administrator.

8.4.5 Structure of Tests. CEMS calibration tests shall be

carried out by making simultaneous CEMS and Reference Method

measurement sets at three (or more) different levels of PM mass

concentrations over the full range of operations experienced by the

facility, including emissions. Three (or more) sets of measurements

shall be obtained at each level. The different levels of PM mass

concentration should be obtained by varying process or PM control

device conditions as much as the process allows. If it is not

possible or practical to obtain PM measurement at the standard, it

is recommended that at least six measurement sets be performed at

the maximum PM emission level achievable to produce the most

accurate and representative results. This will help obtain the

smallest confidence and tolerance intervals at the maximum emission

level. Irrespective of the extent of the range, the three PM

concentration levels developed in the calibration tests must be

distributed over the complete operating range experienced by the

facility, and at least three of the minimum 15 measured data points

must lie within each of the following levels:

Level 1: 0 to 30% of the maximum PM concentration;

Level 2: 30 to 60% of the maximum PM concentration; and

Level 3: 60 to 100% of the maximum PM concentration.

8.4.6 Correlation of Reference Method and CEMS Data. If

necessary, adjust the CEMS outputs and Reference Method test data to

the same time. Determine the integrated (arithmetic average) CEMS

output over each Reference Method test period. Consider system

response time, if important, and confirm that the pair of results

are on a consistent moisture, temperature, and diluent concentration

basis. Adjust the Reference Method results to ensure they are on the

same basis as the CEMS measurements. Depending on the particular

CEMS measurement conditions, the CEMS and Method 5I (or Method 5

where applicable) correlations are based on either:

(a) Actual in-stack conditions and actual PM concentrations for

in-situ CEMS in mg/acm (i.e., account for the in-stack temperature,

pressure, and moisture),

(b) Actual CEMS measurement conditions for extractive CEMS in

mg/acm (i.e., account for the elevated temperature of the extracted

flue gas if heated), or

(c) Dry standard conditions and corresponding PM concentrations

in mg/dscm (i.e., do not correct the Reference Method results if the

CEMS outputs are on the same temperature and moisture basis as the

Reference Method). Calculate the appropriate PM concentrations as

specified by CEMS manufacturer using the applicable equations in

Section 12.0.

8.4.7 Calculate the correlation coefficient, confidence

interval, and tolerance interval for the complete set of CEMS/RM

data according to the procedures in Section 12.0.

8.5 Number of Calibration Tests

Because of the need to develop a calibration curve

representative of the facility/APC system, the following strategy

will ensure that the calibration curve facilities develop adequately

corresponds to measured PM concentrations:

Perform the initial calibration test and develop a correlation

within the time period

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specified in the applicable regulation. For CEMS with measurement

technologies insensitive to changes in PM properties (e.g., Beta-

gage), this would be the only calibration test required.

For CEMS with measurement technologies sensitive to PM property

changes (e.g., Light-scattering), perform a second calibration

within the time period specified in the applicable regulation.

Compare the results of the two calibrations to determine what type

of mathematical model (e.g., arithmetic, log-normal, or quadratic)

best correlates with measured PM concentrations. The calibration for

the facility is a composite of both sets of calibration data.

Perform a third calibration test within the time period specified in

the applicable regulation. Compare the third calibration to the

first two. If this calibration relation confirms the findings of the

original two calibrations, then this is the last calibration test to

be performed. The final cali

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