51494 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Parts 60, 72 and 75 

[EPA–HQ–OAR–2007–0164, FRL–8459–8] 

RIN 2060–AO01 

Two Optional Methods for Relative 

Accuracy Test Audits of Mercury 

Monitoring Systems Installed on 

Combustion Flue Gas Streams and 

Several Amendments to Related 

Mercury Monitoring Provisions 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Direct final rule. 

SUMMARY: EPA is taking direct final 

action on two optional methods for 

relative accuracy audits of mercury 

monitoring systems installed on 

combustion flue gas streams and several 

amendments to related mercury 

monitoring provisions. This action 

approves two optional mercury (Hg) 

emissions test methods for potential use 

in conjunction with an existing 

regulatory requirement for Hg emissions 

monitoring, as well as several revisions 

to the mercury monitoring provisions 

themselves. This action is in regard to 

the testing and monitoring requirements 

for mercury specified in the Federal 

Register on May 18, 2005. Since that 

publication, EPA has received 

numerous comments concerning the 

desirability of EPA evaluating and 

allowing use of the measurement 

techniques addressed in the two 

optional methods in lieu of the methods 

identified in the cited Federal Register 

publication, as they can produce equally 

acceptable measures of the relative 

accuracy achieved by Hg monitoring 

systems. This action allows use of these 

two optional methods entirely at the 

discretion of the owner or operator of an 

affected emission source in place of the 

two currently specified methods. This 

direct final rule also amends 

Performance Specification 12A by 

adding Methods 30A and 30B to the list 

of reference methods acceptable for 

measuring Hg concentration and the Hg 

monitoring provisions of May 18, 2005, 

to reflect technical insights since gained 

by EPA which will help to facilitate 

implementation including clarification 

and increased regulatory flexibility for 

affected sources. 

DATES: This rule is effective on 

November 6, 2007 without further 

notice, unless EPA receives adverse 

comment by October 9, 2007. If EPA 

receives adverse comment, EPA will 

publish a timely withdrawal in the 

Federal Register informing the public 

that some or all of the amendments in 

this rule will not take effect. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–HQ– 

OAR–2007–0164, by one of the 

following methods: 

• www.regulations.gov. Follow the 

on-line instructions for submitting 

comments. 

• E-mail: a-and-r-docket@epa.gov. 

• Fax: (202) 566–9744. 

• Mail: Two Optional Methods for 

Relative Accuracy Test Audits of 

Mercury Monitoring Systems Installed 

on Combustion Flue Gas Streams and 

Several Amendments to the Related 

Mercury Monitoring Provisions, 

Environmental Protection Agency, 

Mailcode: 2822T, 1200 Pennsylvania 

Avenue, NW., Washington, DC 20460. 

Please include a total of two copies. 

• Hand Delivery: EPA Docket Center, 

1301 Constitution Avenue, NW., EPA 

Headquarters Library, Room 3334, EPA 

West Building, Washington, DC 20460. 

Such deliveries are only accepted 

during the Docket’s normal hours of 

operation, and special arrangements 

should be made for deliveries of boxed 

information. 

Instructions: Direct your comments to 

Docket ID No. EPA–HQ–OAR–2007– 

0164. EPA’s policy is that all comments 

received will be included in the public 

docket without change and may be 

made available online at 

www.regulations.gov, including any 

personal information provided, unless 

the comment includes information 

claimed to be Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Do not submit information that you 

consider to be CBI or otherwise 

protected through www.regulations.gov 

or e-mail. The www.regulations.gov Web 

site is an ‘‘anonymous access’’ system, 

which means EPA will not know your 

identity or contact information unless 

you provide it in the body of your 

comment. If you send an e-mail 

comment directly to EPA without going 

through www.regulations.gov, your email address will be automatically 

captured and included as part of the 

comment that is placed in the public 

docket and made available on the 

Internet. If you submit an electronic 

comment, EPA recommends that you 

include your name and other contact 

information in the body of your 

comment and with any disk or CD–ROM 

you submit. If EPA cannot read your 

comment due to technical difficulties 

and cannot contact you for clarification, 

EPA may not be able to consider your 

comment. Electronic files should avoid 

the use of special characters, any form 

of encryption, and be free of any defects 

or viruses. For additional information 

about EPA’s public docket, visit the EPA 

Docket Center homepage at http:// 

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

Docket: All documents in the docket 

are listed in the www.regulations.gov 

index. Although listed in the index, 

some information is not publicly 

available, e.g., CBI or other information 

whose disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, will be publicly 

available only in hard copy. Publicly 

available docket materials are available 

either electronically in 

www.regulations.gov or in hard copy at 

the Two Optional Methods for Relative 

Accuracy Audits of Mercury Monitoring 

Systems Installed on Combustion Flue 

Gas Streams Air and Radiation Docket, 

EPA/DC, EPA West Building, EPA 

Headquaters Library, Room 3334, 1301 

Constitution Avenue, NW., Washington, 

DC. The Public Reading Room is open 

from 8:30 a.m. to 4:30 p.m., Monday 

through Friday, excluding legal 

holidays. The telephone number for the 

Public Reading Room is (202) 566–1744, 

and the telephone number for the Air 

and Radiation Docket is (202) 566–1742. 

FOR FURTHER INFORMATION CONTACT: 

Either Mr. William Grimley, Office of 

Air Quality Planning and Standards, Air 

Quality Assessment Division, 

Measurement Technology Group (E143– 

02), EPA, Research Triangle Park, NC 

27711, telephone (919) 541–1065, 

facsimile number (919) 541–0516, email address: grimley.william@epa.gov 

or Ms. Robin Segall, Office of Air 

Quality Planning and Standards, Air 

Quality Assessment Division, 

Measurement Technology Group (E143– 

02), EPA, Research Triangle Park, NC 

27711, telephone (919) 541–0893, 

facsimile number (919) 541–0516, email address: segall.robin@epa.gov. 

SUPPLEMENTARY INFORMATION: 

I. Why is EPA using a Direct Final 

Rule? 

EPA is publishing this rule without a 

prior proposed rule because we view 

this as a noncontroversial action and 

anticipate no adverse comment. The 

most important benefit of direct final 

rulemaking for this action is to provide: 

(1) Additional reference method 

options, and (2) judicious revisions to 

mercury monitoring provisions 

specified in the Federal Register on 

May 18, 2005 that, if successful, relieve 

affected facilities of uncertainty 

regarding final emission monitoring 

requirements and certification details as 

opposed to waiting through a 

potentially protracted proposal/final 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51495 

rulemaking process. Insofar as the two 

methods are concerned, EPA believes 

that they contain the necessary elements 

to generate acceptable data quality 

without being unduly burdensome. 

Through experience gained from 

developing existing performance based 

methods and trading rules, EPA has 

learned to identify test method criteria 

significant to effective rule 

implementation. EPA believes each of 

the two methods adopted in this action 

contain adequate specific criteria and 

procedures essential to the accurate 

measurement of Hg emissions, without 

adversely compromising the goals of 

performance-based methodology. EPA 

will continue to support and advance 

the principles and practicality of these 

methods by adding detailed method 

application information to facilitate 

their use to the Web site www.epa.gov/ 

airmarkets/ as it becomes available. 

Since use of either of these methods is 

not mandatory, but optional, there 

should be no objection to their 

availability. Regarding the amendments 

to the Hg emission monitoring 

provisions of 40 CFR parts 72 and 75, 

these amendments reflect EPA’s 

increased technical understanding since 

the May 18, 2005 rulemaking. However, 

in the ‘‘Proposed Rules’’ section of 

today’s Federal Register, we are 

publishing a separate document that 

will serve as the proposed rule to 

approve provisions, if any, of this direct 

final rule that receive relevant adverse 

comments on this direct final rule. We 

will not institute a second comment 

period on this action. Any parties 

interested in commenting must do so at 

this time. For further information about 

commenting on this rule, see the 

ADDRESSES section of this document. 

If EPA receives adverse comment on 

one or more distinct provisions of this 

rulemaking, we will publish a timely 

withdrawal in the Federal Register 

indicating which provisions we are 

withdrawing and informing the public 

that those provisions will not take 

effect. The provisions that are not 

withdrawn will become effective on the 

date set out above, notwithstanding 

adverse comment on any other 

provision. We would address all public 

comments in a subsequent final rule 

based on the proposed rule. 

II. Does This Action Apply to Me? 

Regulated Entities. The regulated 

categories and entities affected by this 

direct final rule include: 

Category NAICSa Examples of regulated entities 

Industry ............................................ 221112 Fossil fuel-fired electric utility steam generating units. 

Federal government ......................... b 221122 Fossil fuel-fired electric utility steam generating units owned by the Federal government. 

State/local governments .................. b 221122 Fossil fuel-fired electric utility steam generating units owned by municipalities. 

Tribal governments .......................... 921150 Fossil fuel-fired electric utility steam generating units in Indian country.

a North American Industry Classification System. 

bFederal, State, or local government-owned and operated establishments are classified according to the activity in which they are engaged. 

This table is not intended to be 

exhaustive, but rather provides a guide 

for readers regarding entities likely to be 

affected by this direct final rule. If you 

have any questions regarding the 

applicability of this direct final rule to 

a particular entity, consult either the air 

permit authority for the entity or your 

EPA regional representative as listed in 

40 CFR 63.13. 

III. Where Can I Obtain a Copy of This 

Action? 

In addition to being available in the 

docket, an electronic copy of this direct 

final rule is also available on the World 

Wide Web through the Technology 

Transfer Network (TTN). Following 

signature, a copy of this direct final rule 

will be posted on the TTN’s policy and 

guidance page for newly proposed or 

promulgated rules at the following 

address: http://www.epa.gov/ttn/oarpg. 

The TTN provides information and 

technology exchange in various areas of 

air pollution control. 

IV. How Is This Document Organized? 

The information presented in this 

preamble is organized as follows: 

I. Why Is EPA Using a Direct Final Rule? 

II. Does This Action Apply to Me? 

III. Where Can I Obtain a Copy of This 

Action? 

IV. How Is This Document Organized? 

V. Background 

VI. This Action 

VII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

B. Paperwork Reduction Act 

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act 

E. Executive Order: 13132: Federalism 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

and Safety Risks 

H. Executive Order 13211: Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use 

I. National Technology Transfer and 

Advancement Act 

J. Executive Order 12898: Federal Actions 

To Address Environmental Justice in 

Minority Populations and Low-Income 

Populations 

K. Congressional Review Act 

V. Background 

On May 18, 2005, in the preamble of 

the Clean Air Mercury Rule (CAMR) (70 

FR 28608), EPA stated its intention to 

propose and promulgate an 

instrumental reference method as an 

alternative to the use of ASTM Method 

D6784–02 (the Ontario Hydro Method) 

to perform Relative Accuracy Test 

Audits (RATAs) of Hg continuous 

emission monitoring systems (CEMS) 

and sorbent trap monitoring systems 

used to monitor Hg emissions from coalfired power plants. 

In comments on the proposed CAMR, 

commenters had two primary objections 

to the use of the Ontario Hydro Method 

as the reference test method for RATAs. 

Some expressed concern that the 

complexity of this wet chemical method 

could lead to results that would cause 

a properly functioning Hg CEMS to fail 

a RATA. Other commenters noted that, 

unlike instrumental reference methods 

used to audit CEMS for SO2 and NOX

that provide real-time values, test 

results from the Ontario Hydro Method 

can take weeks to be received from the 

laboratory. Commenters stated that this 

time lag can lead to implementation 

problems with regard to both missing 

data and emissions reporting. 

Since the CAMR was promulgated, 

EPA has proposed changes to 40 CFR 

part 75, which would allow the use of 

EPA Method 29, with enhanced qualityassurance procedures, as an alternative 

Hg reference method (71 FR 49257; 

August 22, 2006). Although Method 29 

is somewhat simpler than the Ontario 

Hydro Method and is more familiar to 

stack testers and State regulatory 

agencies, it is also a wet chemistry 

method and is, therefore, subject to the 

same limitations that make the Ontario 

Hydro method less than optimal for 

RATA testing. 

In view of these considerations, EPA 

believes that for RATA testing, an 

instrumental Hg reference method 


jlentini on PROD1PC65 with RULES2
51496 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

would be preferable to both the Ontario 

Hydro Method and to Method 29. An 

instrumental method would provide 

real-time data that would best facilitate 

implementation of a mercury cap and 

trade program. Therefore, this action 

approves a performance-based 

instrumental reference method for 

measuring Hg emission concentrations. 

Another commenter to the proposed 

CAMR recommended that the sorbent 

trap monitoring approach, now 

specified in 40 CFR part 75, appendix 

K, be considered for use as a reference 

method. Although EPA did not commit 

to establishing a sorbent trap reference 

method at the time of CAMR 

promulgation, stakeholder interest in 

this methodology has increased 

significantly. In an August 22, 2006 

Federal Register notice, EPA solicited 

comment on the use of sorbent trap 

technology for Hg reference method 

testing, and numerous supportive 

comments were received. In view of 

this, we initiated a review of available 

historical test data where concurrent 

measurements of Hg concentration were 

made with sorbent trap systems and 

either the Ontario Hydro Method or 

Method 29. These data, taken together 

with additional supporting data from 

recent field tests that were performed 

after the CAMR was promulgated, 

suggest that using the sorbent trap 

methodology for Hg reference method 

testing is viable. The Hg sorbent trap 

approach is less onerous to use than 

either Ontario Hydro or Method 29, and 

although it does not measure real-time 

Hg concentrations, a thermal technique 

can be used to analyze the samples on 

the same day that they are collected, 

facilitating RATA testing in the context 

of a cap and trade program. Therefore, 

this action also approves a sorbent trap 

reference method for Hg, as an 

alternative to the Ontario Hydro Method 

and Method 29. 

This direct final rule also includes 

several carefully considered 

amendments to the Hg emission 

monitoring provisions of 40 CFR parts 

72 and 75. EPA believes these 

amendments will facilitate 

implementation of the CAMR by 

clarifying portions of that rule and by 

providing added regulatory flexibility to 

the affected sources. 

VI. This Action 

This direct final rule allows for the 

earliest possible use of two optional 

reference test methods for measuring 

total vapor phase mercury emissions 

from stationary sources as well as 

several related amendments to the Hg 

monitoring provisions of the CAMR. 

Both an instrumental test method and a 

sorbent trap test method for 

measurement of total vapor phase 

mercury emissions are being added to 

Appendix A–8 of 40 CFR part 60 as 

approved alternatives to the Ontario 

Hydro Method and EPA Method 29 to 

perform RATAs of installed mercury 

monitoring systems. The two methods 

are discussed below, and the related 

amendments are explained in detail 

later in this section. 

The first method being added to 

appendix A–8 of 40 CFR part 60 today 

is titled ‘‘Method 30A—Determination 

of Total Vapor Phase Mercury Emissions 

from Stationary Sources (Instrumental 

Analyzer Procedure).’’ In Method 30A, a 

sample of the effluent gas is 

continuously extracted and conveyed to 

an analyzer capable of measuring the 

total vapor phase Hg concentration. 

Elemental and oxidized mercury (i.e., 

Hg0 and Hg∂2) may be measured 

separately or simultaneously but, for 

purposes of this method, total vapor 

phase Hg is the sum of Hg0 and Hg∂2. 

Method 30A provides test programspecific verification of method 

performance using a dynamic spiking 

approach, coupled with other 

performance criteria, which include 

system calibration, interference testing, 

and system integrity/drift checks. The 

dynamic spiking requirement, which is 

a gaseous ‘‘method of standard 

additions,’’ is the only part of Method 

30A not parallel to the routinely applied 

instrumental reference methods used to 

perform relative accuracy testing of 

CEMS for SO2 and NOX. The dynamic 

spiking procedure is included in 

Method 30A to characterize 

measurement bias for Hg, which can be 

highly reactive on a site-specific basis 

(i.e., for each emissions sample matrix), 

with recovery criteria set to ensure that 

the bias is held to a minimal level. All 

performance requirements of Method 

30A must be met for the data to be 

considered valid. The availability of an 

instrumental reference method for Hg 

testing is consistent with the approach 

EPA has taken in the successful Acid 

Rain and NOX Budget emissions trading 

programs. 

Method 30A is performance based in 

keeping with the criteria established 

under our Notice of Intent to Implement 

Performance Based Measurement 

Systems for Environmental Monitoring 

(62 FR 52098, October 6, 1997). Use of 

the performance-based measurement 

approach will allow for continued 

development and application of new, 

improved, and more cost-effective Hg 

measurement technologies while 

ensuring the collection of data of known 

quality. 

Based on EPA’s experience in 

conducting test programs to evaluate the 

procedures and performance criteria 

included in Method 30A, EPA 

recognizes that although prototypes of 

all equipment needed to perform this 

method have been successfully 

demonstrated in the field, at present the 

equipment needed to follow all 

procedures required by the method is 

commercially available only on a 

limited basis, and is being further 

refined. One of the issues of greatest 

concern in the development of an 

instrumental reference method for Hg 

has been the design of the sampling 

probe. Most of the commerciallyavailable probes suitable for Hg 

measurement are very heavy (over 100 

lbs.) making it difficult to move the 

probe from point-to-point and port-toport for Hg stratification testing and/or 

sample traverses. Much progress is 

being made in probe redesign. One 

manufacturer has recently developed a 

probe that weighs less than 40 lbs., 

samples at significantly lower flow 

rates, and is suitable for dynamic 

spiking. Additional field testing of this 

probe and others currently under 

development is underway, and EPA 

plans to continue to actively encourage 

equipment development and evaluation. 

To encourage the use of Method 30A, 

including further development of the 

supporting equipment, which we 

believe will eventually enable source 

testers to perform Hg monitoring system 

RATAs more efficiently and will 

become the reference method of choice 

for many testing companies and affected 

sources, we are deferring the 

requirement for implementation of the 

dynamic spiking and Hg stratification 

test procedures until January 1, 2009. 

EPA believes this deferral is reasonable 

because Hg monitoring data reported to 

EPA in 2009 will not be used in the 

trading of Hg allowances, as allowance 

accounting under the CAMR does not 

begin until 2010. Source testers are 

encouraged to use this time to acquire 

the necessary equipment and familiarize 

themselves with these procedures. Also, 

for all emissions test programs and 

RATAs performed under CAMR prior to 

January 1, 2009, we are allowing either: 

(1) A 12-point traverse for sulfur dioxide 

(SO2) to be substituted for a 12-point Hg 

traverse, in cases where stratification 

testing is used to determine the 

appropriate number and location of the 

reference method sampling points, or (2) 

use of the alternate three-point traverse 

line (0.4, 1.2, and 2.0 meters from the 

stack wall) as specified in section 

8.1.3.2 of Performance Specification 2 

(40 CFR part 60, appendix B). We 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51497 

believe that in the short-term, these 

temporary deferrals will encourage the 

application of Method 30A and will 

help affected CAMR sources meet the 

January 1, 2009 deadline for initial 

certification of the required Hg 

monitoring systems. Several additional 

Method 30A development 

considerations are worthy of note. A 

preliminary draft of Method 30A was 

first available for public consideration 

on an EPA Web site (www.epa.gov/ttn/ 

emc/) on February 28, 2006. Since that 

time, EPA and several stakeholder 

groups have evaluated the various 

technical aspects of the method. Based 

on the combined laboratory and field 

observations, EPA has been able to 

simplify several procedural 

requirements that we believe are 

essential to the method. The dynamic 

spiking requirement (for test programspecific verification of measurement 

system data quality) has been reduced to 

only a pretest requirement. The 

interference test has been made 

optional. The three-point system 

calibration error test using Hg∂2 has 

been streamlined to a system integrity 

check using a zero gas and a single 

upscale Hg∂2 gas. Another change has 

been to relax the Hg0 calibration error 

specification from 2 percent to 5 percent 

of span, in recognition of the fact that 

this procedure is a check of the entire 

measurement system, as well as the 

current knowledge regarding the 

uncertainty of NIST traceable standards. 

EPA does plan, however, to reconsider 

this specification relaxation as more 

field data become available. A final 

consideration in development of 

Method 30A has been the requirement 

for calibration with both Hg0 and Hg∂2. 

Some stakeholders have recommended 

that we eliminate the Hg0 calibration 

and rely solely on the Hg∂2 calibration. 

EPA, however, believes this approach 

would not be adequate, because if only 

Hg∂2 were used, instrument calibration 

response adjustment could compensate 

for an unknown amount of converter 

inefficiency, which would then result in 

an inaccurate total mercury 

measurement in situations where Hg0 is 

an appreciable fraction of the total stack 

gas Hg. 

The second method being added to 

appendix A–8 of 40 CFR part 60 today 

is titled ‘‘Method 30B—Use of Sorbent 

Traps to Measure Total Vapor Phase 

Mercury Emissions from Coal-Fired 

Combustion Sources.’’ In Method 30B, a 

sample of the effluent gas is 

continuously drawn through a series of 

tubes containing activated carbon or 

another sorbent material. After 

sampling, the tubes are sealed. The Hg 

captured by the sorbent is then either: 

(1) Thermally desorbed and analyzed; or 

(2) the tubes are transferred to a 

laboratory for extraction of Hg and 

analysis. Like Method 30A, Method 30B 

is a performance-based method and 

contains performance specifications and 

procedures for hardware selection and 

calibration, sorbent spiking, and 

analytical recovery/analysis which 

allow for development and application 

of new, improved, and more costeffective Hg measurement technologies 

while still ensuring the collection of 

data of known quality. In particular, 

Method 30B contains five key 

measurement performance tests 

designed to ensure: (1) Selection of a 

sorbent and analytical technique 

combination capable of quantitative 

collection and analysis of gaseous Hg, 

(2) collection during field testing of 

enough Hg on each sorbent trap to be 

reliably quantified, and (3) adequate 

performance of the method for each test 

program. 

In considering development of a 

sorbent trap-based reference method, 

EPA has reviewed historical emissions 

data where sorbent trap measurement 

systems were operated concurrently 

with either the Ontario Hydro Method 

or Method 29 (40 CFR part 60, appendix 

A–8). EPA has also conducted several 

field test evaluations of sorbent trap 

systems versus the Ontario Hydro 

Method in collaboration with the 

Electric Power Research Institute (EPRI). 

Based on these efforts, we have 

concluded that a sorbent trap-based 

technique coupled with appropriate 

performance criteria and QA procedures 

can provide Hg emissions data of 

quality comparable to that produced by 

the Ontario Hydro Method. Data 

supporting this conclusion are 

presented in the docket, EPA–HQ–

OAR–2007–0164. 

As we have done for Method 30A, for 

Method 30B emission tests and RATAs 

performed prior to January 1, 2009, we 

are allowing either: (1) A 12-point 

traverse for sulfur dioxide (SO2) to be 

substituted for a 12-point Hg traverse for 

the stratification testing used to 

determine the number and location of 

the reference method sampling points, 

or (2) use of the alternate three-point 

traverse line (0.4, 1.2, and 2.0 meters 

from the stack wall) as specified in 

section 8.1.3.2 of Performance 

Specification 2 (40 CFR part 60, 

appendix B). We also intend to extend 

this temporary deferral of mercury 

stratification testing to application of 

the Ontario Hydro Method and Method 

29. EPA believes this deferral is 

reasonable because Hg monitoring data 

reported to EPA in 2009 will not be 

used in the trading of Hg allowances, as 

allowance accounting under the CAMR 

does not begin until 2010. 

This direct final rule also amends 

Performance Specification 12A of 

appendix B to part 60 by adding 

Methods 30A and 30B to the list of 

reference methods acceptable for 

relative accuracy testing of Hg emissions 

monitoring systems. Once this direct 

final rule becomes effective, the 

reference methods acceptable for Hg 

measurement in Performance 

Specification 12A will include Methods 

29, 30A, 30B, and ASTM D6784–02. 

With today’s action, EPA is taking the 

opportunity to include several 

considered revisions to the Hg emission 

monitoring provisions of 40 CFR parts 

72 and 75 as described in detail below. 

EPA is including these revisions in this 

direct final rule because we believe that 

they will facilitate implementation of 

the Hg monitoring under CAMR. 

First, § 75.81(a) is being revised to 

confirm that the Hg CEMS and sorbent 

trap monitoring systems required under 

subpart I of part 75 are to measure the 

total vapor phase mass concentration of 

Hg in the flue gas, including both the 

elemental and oxidized forms of Hg, 

expressed in units of micrograms per 

standard cubic meter (μg/scm). 

Although it is generally understood that 

total vapor phase Hg is the regulated 

pollutant under CAMR, it recently was 

brought to EPA’s attention that subpart 

I of part 75 does not explicitly state that 

Hg monitoring systems only need to 

measure total vapor phase Hg. The 

amended language in § 75.81(a) clarifies 

this. 

Second, paragraph (i) in § 75.15 is 

being revised and a new paragraph 

(d)(2)(ix) is being added to § 75.20, to 

codify the rules for using optional nonredundant (‘‘cold’’) backup Hg 

monitoring systems and like-kind 

replacement Hg analyzers, when the 

primary Hg monitoring system is unable 

to provide quality-assured data. For the 

other types of monitoring systems 

required by part 75, these monitoring 

options have been in place since May 

1999 (see 64 FR 28597, May 26, 1999). 

Today’s action simply extends these 

provisions to Hg monitoring systems. 

Through the years, the regulated 

community has found these backup 

monitoring options to be beneficial, in 

that they minimize the use of missing 

data substitution procedures during 

outages of the primary monitoring 

system. 

In particular, § 75.20(d)(2)(ix) 

specifies that a non-redundant backup 

Hg monitoring system can either be a Hg 

CEMS or a sorbent trap monitoring 

system. The non-redundant backup Hg 


jlentini on PROD1PC65 with RULES2
51498 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

1On August 22, 2006, EPA proposed to amend 

Appendix K to allow the data from a pair of sorbent 

traps to be validated in cases where the third 

section spike recovery from only one of the traps 

meets the percent recovery specifications (see 71 FR 

49275). EPA proposed to allow the results from the 

trap that meets the specifications to be used for 

reporting, provided that a single trap adjustment 

factor (STAF) of 1.222 is applied. EPA is evaluating 

the comments received on this proposal and 

expects to publish the final rule in the summer of 

2007. 

monitoring system must be initially 

certified at each unit or stack location 

where it will be used, in accordance 

with § 75.20(d)(2)(i). For a nonredundant backup Hg CEMS, all of the 

initial certification tests specified in 

§ 75.20(c)(1) are required, except for the 

7-day calibration error test. However, for 

ongoing quality assurance (QA), a RATA 

is required only once every two years (8 

calendar quarters), as specified in 

§ 75.20(d)(2)(vi). For a non-redundant 

backup sorbent trap monitoring system, 

a RATA is required for initial 

certification, and once every two years 

thereafter for ongoing QA. 

When a certified non-redundant 

backup Hg CEMS or a like-kind 

replacement Hg analyzer is brought into 

service, a three-point linearity check 

with elemental Hg standards and a 

single-point system integrity check will 

be required. Alternatively, a three-level 

system integrity check may be 

performed instead of these two tests. 

When a certified non-redundant backup 

sorbent trap monitoring system is 

brought into service, only the routine 

sampling and QA procedures of § 75.15 

and appendix K of part 75 will be 

required. 

Each non-redundant backup Hg 

monitoring system and each like-kind 

replacement Hg analyzer will be subject 

to the applicable ongoing QA 

requirements, restrictions and 

conditions specified in § 75.20(d)(2). For 

certified non-redundant backup Hg 

CEMS and like-kind replacement Hg 

analyzers, the weekly system integrity 

checks described in section 2.6 of 

appendix B of 40 CFR part 75 will also 

be required as long as the system or 

analyzer remains in service, unless the 

daily calibration error tests of the 

analyzer are done using NIST-traceable 

oxidized Hg standards. 

Third, a new paragraph (k) is being 

added to § 75.15 that: (1) Clarifies that, 

when the RATA of an appendix K 

sorbent trap monitoring system is 

performed, the type of sorbent material 

used in the appendix K sorbent traps 

must be the same as that used for daily 

operation of the appendix K monitoring 

system, and (2) allows the appendix K 

traps used during RATA testing to be 

smaller than the traps used for daily 

operation of the appendix K monitoring 

system. This change will be particularly 

advantageous at very low Hg 

concentrations as it will facilitate 

shorter RATA test run times. Parallel 

changes are being made to section 6.5.7 

of appendix A of part 75 to be consistent 

with the provisions of § 75.15(k). 

Section 6.5.7 currently requires the 

appendix K sorbent traps used for the 

RATA to be the same size as the traps 

used for daily operation of the appendix 

K monitoring system. 

Fourth, today’s action revises a 

number of sections of part 75, appendix 

K, pertaining to the use of sorbent trap 

monitoring systems. EPA is 

withdrawing the requirement to use the 

percentage recovery of the elemental Hg 

spike in section 3 of each sorbent trap 

to adjust or ‘‘normalize’’ the Hg mass 

collected in sections 1 and 2 of the trap. 

The requirement to spike the third 

section of each trap is being retained 

and data from each pair of traps must 

still be invalidated if either or both 

spike recovery percentages fall outside 

the acceptable limits;1 however, the 

results of the spike recoveries will no 

longer be used to adjust the Hg mass 

collected in the first two sections of the 

traps. EPA is making this rule change 

based on an analysis of recent spike 

recovery data from long-term appendix 

K field demonstrations. Although the 

vast majority of the spike recoveries in 

these studies have been within the 

currently acceptable limits of 75 to 125 

percent, the requirement to normalize 

based on spike recovery could affect 

data precision. For a given pair of traps, 

if one spike recovery was high (e.g., 110 

percent) and the other one low (e.g., 90 

percent), normalization of the Hg mass 

collected in the first two trap sections 

using third section spike recoveries 

could make it difficult for a pair of 

sorbent traps to meet the relative 

deviation (RD) specifications in 

appendix K. In the example cited, 

normalization of the data would cause 

the Hg concentrations measured by the 

traps to be adjusted by 10 percent in 

opposite directions, i.e., one upward 

and one downward. Thus, two Hg 

concentrations that may have been in 

close agreement without normalization 

now might not be able to meet the RD 

specifications. In view of this, EPA has 

concluded that evaluating the spike 

recovery data on a pass/fail basis 

instead of using the percent recovery 

values to adjust the emissions data is 

more technically sound and is also 

consistent with the way in which the 

results of daily and quarterly QA 

assessments of CEMS are interpreted. 

Regarding the range of acceptable 

third section spike recoveries, EPA is 

not changing the 75 to 125 percent 

acceptance criteria. As previously 

noted, early field experience with 

appendix K monitoring systems has 

demonstrated that spike recoveries 

within this range are achievable. 

However, recent appendix K data 

indicate that more stringent acceptance 

criteria may be justifiable. It appears 

that there has been a marked 

improvement in third section spike 

recovery percentages. Recoveries in the 

range from 85 to 115 percent are 

consistently being achieved. If this trend 

continues, EPA may propose to tighten 

the spike recovery acceptance criteria in 

a future rulemaking. Toward that end, 

EPA will continue to collect and 

evaluate third section spike recovery 

data from appendix K monitoring 

systems in the months ahead. 

To effect these changes to appendix K, 

section 11.5 is being removed and 

reserved; section 10.4 is being revised; 

Equations K–6 and K–7 are being 

redesignated as Equations K–5 and K–6, 

respectively; and the definition of ‘‘M*’’

in redesignated Equation K–5 is being 

revised. 

EPA is also revising appendix K to 

allow the owner or operator to use other 

types of gas flow meters besides the 

conventional dry gas meter (DGM) to 

quantify sample gas volume. Since the 

publication of appendix K (see 70 FR 

28695, May 18, 2005), numerous 

requests have been received from the 

regulated community to allow this 

flexibility. In response to these requests, 

EPA initiated an investigation of the 

feasibility of replacing the DGM in a 

sorbent trap monitoring system with a 

thermal mass flow meter. As a result of 

its investigation, EPA has concluded 

that a properly calibrated thermal mass 

flow meter can be at least as accurate as 

a DGM. The mass flow meter is also a 

more modern technology than the DGM; 

since it has no moving parts, it may be 

more reliable than a DGM for 

continuous duty. 

Having found one type of gas flow 

meter that can measure as accurately as 

a DGM, EPA is persuaded that there 

may be other commercially available gas 

flow meter technologies that are equally 

capable and may be suitable for 

appendix K applications. Accordingly, 

EPA has decided that a performancebased approach, rather than a 

prescriptive one, is more appropriate for 

appendix K gas flow meters. Today’s 

action allows the use of any type of gas 

flow meter that is capable of accurately 

measuring gas volumes to within 2 

percent. 

Section 9.2.2.1 of appendix K now 

requires the manufacturer of the gas 

flow meter to perform all necessary setVerDate Aug<31>2005 18:54 Sep 06, 2007 Jkt 211001 PO 00000 Frm 00006 Fmt 4701 Sfmt 4700 E:\FR\FM\07SER2.SGM 07SER2

jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51499 

up, testing, programming, etc. of the 

meter and to provide any necessary 

instructions so that for the particular 

field application, the meter will give an 

accurate readout of dry gas volume in 

units of standard cubic meters. Then, 

prior to its initial use, the flow meter 

must be calibrated at a minimum of 

three settings covering the expected 

range of sample flow rates for the 

appendix K system. The initial 

calibration may be performed either by 

the manufacturer or by the end user. 

The calibration of the gas flow meter 

must be checked quarterly thereafter, at 

an intermediate flow rate. For mass flow 

meters, the initial three-point 

calibration must be performed by using 

either a compressed gas mixture 

containing CO2, O2, and N2 in 

proportions representative of the stack 

gas composition or by using the actual 

stack gas. However, when the initial 

calibration is done with a compressed 

gas mixture, the mass flow meter may 

not be used until an additional on-site 

calibration check of the flow meter at an 

intermediate flow rate is performed and 

passed, using the actual stack gas. 

To calibrate the gas flow meter, the 

owner or operator may either follow the 

basic procedures in section 10.3 or 

section 16 of Method 5 in appendix 

A–3 of part 60 for calibration of dry gas 

meters, or alternatively, may 

temporarily install a reference gas flow 

meter (RGFM) at the discharge of the 

appendix K monitoring system while 

the monitoring system is in operation 

and make concurrent measurements of 

dry stack gas volume with the RGFM 

and the appendix K gas flow meter. If 

the latter option is chosen, the RGFM 

may either be a gas flow metering device 

that has been calibrated according to 

section 10.3.1 or section 16 of Method 

5 or a NIST-traceable volumetric 

calibration device with an accuracy of 

±1 percent. Note that this alternative 

calibration technique allows required 

QA checks to be performed with little or 

no disruption of the operation of the 

sorbent trap monitoring system. 

Regardless of which calibration 

approach is used, a calibration factor, 

Yi, must be obtained at each tested flow 

rate, where Yi is the ratio of the volume 

measured by the reference meter to the 

volume measured by the flow meter 

being calibrated. For the initial threepoint calibration, the three Yi values 

must be averaged, and each individual 

Yi must be within ± 0.02 of the average 

value. The average value, Y, must then 

be used to correct the gas volumes 

measured by the gas flow meter. For 

single-level calibration checks (e.g., the 

quarterly checks performed for routine 

QA), the Yi value obtained at the tested 

flow rate must be compared with the 

current value of Y. If Yi differs from Y 

by more than 5 percent, a full threepoint recalibration is then required to 

determine a new Y value. 

In this direct final action, the majority 

of the revised rule provisions pertaining 

to gas flow meters can be found in 

sections 5.1.5 and 9.2 of appendix K. 

Minor revisions to sections 7.2.3 and 

7.2.5, Figure K–1, and Table K–1 are 

being made to be consistent with the 

changes to sections 5.1.5 and 9.2. In 

several other places throughout part 75 

and in the definition of ‘‘Sorbent trap 

monitoring system’’ in part 72, the term 

‘‘dry gas meter,’’ when used in reference 

to a sorbent trap monitoring system, is 

being replaced with the more general 

term ‘‘gas flow meter.’’ Revisions to 

section 1.5.2 of appendix B of part 75 

will require the gas flow meter 

calibration procedures and protocols for 

periodic recalibration of reference gas 

flow meters to be included in the QA 

plan for the affected unit. 

This direct final action, which 

approves the use of two optional 

methods (Methods 30A and 30B) for 

determining total vapor phase Hg 

emissions from stationary sources, is 

being taken in response to numerous 

public comments concerning the 

desirability of allowing the use of these 

types of methods to comply with the Hg 

emission monitoring requirements of 

the CAMR for electric utility steam 

generating units. In the May 18, 2005 

final rule (70 FR 28636), we 

summarized the public comments that 

we received regarding the use of an 

instrumental method as an alternative to 

the Ontario Hydro Method specified in 

the proposed CAMR. As noted earlier in 

this preamble, the commenters 

primarily objected to the required use of 

the Ontario Hydro Method as the 

reference method for the RATAs of Hg 

monitoring systems and expressed 

concern about the complexities in the 

method and the amount of time that is 

required to perform the testing and to 

receive the results. Commenters pointed 

out that it could take days to complete 

the testing and weeks to receive the 

results from a laboratory. Commenters 

claimed that for the cap and trade 

program proposed under CAMR, these 

delays could lead to significant 

implementation problems with respect 

to the timely reporting of emissions 

data. Further, if a RATA should be 

failed or invalidated (e.g., if fewer than 

nine test runs meet the relative 

deviation criterion for the paired 

Ontario Hydro trains), data from the Hg 

monitoring system would be invalidated 

from the hour of the failed or 

invalidated test until the hour of 

completion of a successful RATA. 

Conservatively high substitute data 

values would have to be reported during 

that entire time period. In our response 

to those comments in the final CAMR 

rule, we stated that the alternative use 

of an instrumental method for the 

required RATAs of Hg monitoring 

systems and sorbent trap monitoring 

systems is allowed by the final rule but 

is subject to approval by the 

Administrator. We also stated our 

commitment to propose and promulgate 

a Hg instrumental reference method 

once sufficient supporting field test data 

become available. We further stated that 

‘‘A Hg instrumental reference method 

for RATA testing is vastly preferable to 

the Ontario Hydro Method and will 

greatly facilitate the implementation of 

a Hg cap-and-trade program.’’

Since promulgation of CAMR, we 

have continued to communicate with 

stakeholders interested in the Hg 

monitoring requirements of the rule, 

and we have come to more clearly 

understand that it is of great interest to 

the affected entities to have additional 

reference method options available for 

relative accuracy testing of installed Hg 

monitoring systems as soon as possible. 

Accordingly, at the end of 2005, we 

began developing an instrumental test 

method for Hg and solicited feedback 

from the stakeholders on a working draft 

of the method (referred to as PRE–009 

at http://www.epa.gov/ttn/emc/ 

prelim.html). More recently, we have 

been developing a viable sorbent trap 

reference method. These efforts have 

resulted in Methods 30A and 30B. 

The general beneficial impacts of this 

direct final rule to approve the two 

optional Hg test methods and amend 

targeted portions of 40 CFR parts 72 and 

75 include: Allowing affected sources to 

choose the use of an alternative to the 

Ontario Hydro Method without the 

administrative burden of applying for 

Administrator approval on a case-bycase basis; providing the availability of 

real-time RATA results (Method 30A); 

reducing the overall RATA testing 

times; reducing costs relative to the 

Ontario Hydro Method; and providing 

additional flexibility in appendix K 

sorbent trap monitoring and backup 

monitoring approaches. The two 

optional methods being approved by 

this direct final rule are considered to be 

comparable to the Ontario Hydro 

Method in terms of the quality of the 

results produced. Over the last year, 

EPA has collaborated with EPRI and 

some of its members in a number of 

field test programs that have confirmed 

that the instrumental reference method 

approved/established in this notice will 

provide data comparable to or better 


jlentini on PROD1PC65 with RULES2
51500 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

than that of the ‘‘Ontario Hydro 

Method.’’

Assuming we do not receive adverse 

comment on this direct final rulemaking 

and Methods 30A and 30B become final, 

we plan to post information relevant to 

Method 30A and 30B applications and 

equipment advances on EPA’s Web site 

at http://www.epa.gov/airmarkets. 

VII. Statutory and Executive Order 

Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

This action is not a ‘‘significant 

regulatory action’’ under the terms of 

Executive Order (EO) 12866 (58 FR 

51735, October 4, 1993) and is therefore 

not subject to review under the EO. 

B. Paperwork Reduction Act 

This action does not impose an 

information collection burden under the 

provisions of the Paperwork Reduction 

Act, 44 U.S.C. 3501 et seq. Burden 

means the total time, effort, or financial 

resources expended by persons to 

generate, maintain, retain, or disclose or 

provide information to or for a Federal 

agency. This includes the time needed 

to review instructions; develop, acquire, 

install, and utilize technology and 

systems for the purposes of collecting, 

validating, and verifying information, 

processing and maintaining 

information, and disclosing and 

providing information; adjust the 

existing ways to comply with any 

previously applicable instructions and 

requirements; train personnel to be able 

to respond to a collection of 

information; search data sources; 

complete and review the collection of 

information; and transmit or otherwise 

disclose the information. 

An agency may not conduct or 

sponsor, and a person is not required to 

respond to a collection of information, 

unless it displays a currently valid OMB 

control number. The OMB control 

numbers for EPA’s regulations in 40 

CFR are listed in 40 CFR part 9. 

C. Regulatory Flexibility Act 

The Regulatory Flexibility Act (RFA) 

generally requires an agency to prepare 

a regulatory flexibility analysis of any 

rule subject to notice and comment 

rulemaking requirements under the 

Administrative Procedure Act or any 

other statute unless the agency certifies 

that the rule will not have a significant 

economic impact on a substantial 

number of small entities. Small entities 

include small businesses, small 

organizations, and small governmental 

jurisdictions. 

For purposes of assessing the impacts 

of today’s rule on small entities, small 

entity is defined as: (1) A small business 

whose parent company has fewer than 

100 or 1,000 employees, or fewer than 

4 billion kilowatt-hr per year of 

electricity usage, depending on the size 

definition for the affected North 

American Industry Classification 

System code; (2) a small governmental 

jurisdiction that is a government of a 

city, county, town, school district or 

special district with a population of less 

than 50,000; and (3) a small 

organization that is any not-for-profit 

enterprise which is independently 

owned and operated and is not 

dominant in its field. 

After considering the economic 

impacts of today’s direct final rule on 

small entities, I certify that this action 

will not have a significant economic 

impact on a substantial number of small 

entities. This direct final rule will not 

impose any requirements on small 

entities because it does not impose any 

additional regulatory requirements, but 

rather provides clarification and 

additional regulatory flexibilty. 

D. Unfunded Mandates Reform Act 

Title II of the Unfunded Mandates 

Reform Act of 1995 (UMRA), Pub. L. 

104–4, establishes requirements for 

Federal agencies to assess the effects of 

their regulatory actions on State, local, 

and tribal governments and the private 

sector. Under section 202 of the UMRA, 

EPA generally must prepare a written 

statement, including a cost-benefit 

analysis, for proposed and final rules 

with ‘‘Federal mandates’’ that may 

result in expenditures to State, local, 

and tribal governments, in the aggregate, 

or to the private sector, of $100 million 

or more in any one year. Before 

promulgating an EPA rule for which a 

written statement is needed, section 205 

of the UMRA generally requires EPA to 

identify and consider a reasonable 

number of regulatory alternatives and 

adopt the least costly, most costeffective or least burdensome alternative 

that achieves the objectives of the rule. 

The provisions of section 205 do not 

apply when they are inconsistent with 

applicable law. Moreover, section 205 

allows EPA to adopt an alternative other 

than the least costly, most cost-effective, 

or least burdensome alternative if the 

Administrator publishes with the final 

rule an explanation why that alternative 

was not adopted. Before EPA establishes 

any regulatory requirements that may 

significantly or uniquely affect small 

governments, including tribal 

governments, it must have developed 

under section 203 of the UMRA a small 

government agency plan. The plan must 

provide for notifying potentially 

affected small governments, enabling 

officials of affected small governments 

to have meaningful and timely input in 

the development of EPA regulatory 

proposals with significant Federal 

intergovernmental mandates, and 

informing, educating, and advising 

small governments on compliance with 

the regulatory requirements. 

EPA has determined that this direct 

final rule does not contain a Federal 

mandate that may result in expenditures 

of $100 million or more for State, local, 

and tribal governments in the aggregate, 

or to the private sector in any 1 year, nor 

does this rule significantly or uniquely 

impact small governments, because it 

contains no requirements that impose 

new obligations upon them. Thus, this 

direct final rule is not subject to the 

requirements of sections 202 and 205 of 

the UMRA. 

E. Executive Order 13132: Federalism 

Executive Order 13132, entitled 

‘‘Federalism’’ (64 FR 43255, August 10, 

1999), requires EPA to develop an 

accountable process to ensure 

‘‘meaningful and timely input by State 

and local officials in the development of 

regulatory policies that have federalism 

implications.’’ ‘‘Policies that have 

federalism implications’’ is defined in 

the Executive Order to include 

regulations that have ‘‘substantial direct 

effects on the States, on the relationship 

between the national government and 

the States, or on the distribution of 

power and responsibilities among the 

various levels of government.’’

This direct final rule does not have 

federalism implications. It will not have 

substantial direct effects on the States, 

on the relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132. The use of these 

methods is optional on the part of the 

regulated entities listed. Thus, 

Executive Order 13132 does not apply 

to this direct final rule. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

Executive Order 13175, entitled 

‘‘Consultation and Coordination with 

Indian Tribal Governments’’ (65 FR 

67249, November 9, 2000), requires EPA 

to develop an accountable process to 

ensure ‘‘meaningful and timely input by 

tribal officials in the development of 

regulatory policies that have tribal 

implications.’’ This direct final rule 

does not have tribal implications, as 

specified in Executive Order 13175. It 

will not have substantial direct effects 

on tribal governments, on the 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51501 

relationship between the Federal 

government and Indian tribes, or on the 

distribution of power and 

responsibilities between the Federal 

government and Indian tribes. Thus, 

Executive Order 13175 does not apply 

to this final rule. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

and Safety Risks 

Executive Order 13045: ‘‘Protection of 

Children from Environmental Health 

Risks and Safety Risks’’ (62 FR 19885, 

April 23, 1997) applies to any rule that: 

(1) Is determined to be ‘‘economically 

significant’’ as defined under Executive 

Order 12866, and (2) concerns an 

environmental health or safety risk that 

EPA has reason to believe may have a 

disproportionate effect on children. If 

the regulatory action meets both criteria, 

the Agency must evaluate the 

environmental health or safety effects of 

the planned rule on children, and 

explain why the planned regulation is 

preferable to other potentially effective 

and reasonably feasible alternatives 

considered by the Agency. EPA 

interprets Executive Order 13045 as 

applying only to those regulatory 

actions that are based on health or safety 

risks, such that the analysis required 

under section 5–501 of the Order has 

the potential to influence the regulation. 

This rule is not subject to Executive 

Order 13045 because it does not 

establish an environmental standard 

intended to mitigate health or safety 

risks. 

H. Executive Order 13211: Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This rule is not subject to Executive 

Order 13211, ‘‘Actions Concerning 

Regulations That Significantly Affect 

Energy Supply, Distribution, or Use’’ (66 

FR 28355, May 22, 2001) because it is 

not a significant regulatory action under 

Executive Order 12866. 

I. National Technology Transfer 

Advancement Act 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (NTTAA), Public Law No. 

104–113, section 12(d) (15 U.S.C. 272 

note) directs EPA to use voluntary 

consensus standards in its regulatory 

activities unless to do so would be 

inconsistent with applicable law or 

otherwise impractical. Voluntary 

consensus standards are technical 

standards (e.g., materials specifications, 

test methods, sampling procedures, and 

business practices) that are developed or 

adopted by voluntary consensus 

standards bodies. The NTTAA directs 

EPA to provide Congress, through OMB, 

explanations when the Agency decides 

not to use available and applicable 

voluntary consensus standards. This 

rulemaking involves technical 

standards. Consistent with the NTTAA, 

EPA in a previous related rulemaking 

(70 FR 28606, May 18, 2005) identified 

an acceptable VCS for measuring Hg 

emissions. The standard ASTM D6784–

02, Standard Test Method for Elemental, 

Oxidized, Particle-Bound and Total 

Mercury Gas Generated from Coal-Fired 

Stationary sources (Ontario Hydro 

Method) was cited in that final rule for 

measuring Hg emissions. After today’s 

action becomes effective, the Ontario 

Hydro Method will remain an 

acceptable method for measuring Hg 

emissions. 

J. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

Executive Order 12898 (59 FR 7629 

(Feb. 16, 1994)) establishes federal 

executive policy on environmental 

justice. Its main provision directs 

federal agencies, to the greatest extent 

practicable and permitted by law, to 

make environmental justice part of their 

mission by identifying and addressing, 

as appropriate, disproportionately high 

and adverse human health or 

environmental effects of their programs, 

policies, and activities on minority 

populations and low-income 

populations in the United States. 

EPA has determined that this direct 

final rule will not have 

disproportionately high and adverse 

human health or environmental effects 

on minority or low-income populations 

because it does not affect the level of 

protection provided to human health or 

the environment. This direct final rule 

does not affect or relax the control 

measures on sources impacted by this 

rule and therefore will not cause 

emissions increases from these sources. 

K. Congressional Review Act 

The Congressional Review Act, 5 

U.S.C. 801 et seq., as added by the Small 

Business Regulatory Enforcement 

Fairness Act of 1996, generally provides 

that before a rule may take effect, the 

Agency promulgating the rule must 

submit a rule report, which includes a 

copy of the rule, to each House of the 

Congress and to the Comptroller General 

of the United States. EPA will submit a 

report containing this rule and other 

required information to the U.S. Senate, 

the U.S. House of Representatives, and 

the Comptroller General of the United 

States prior to publication of the rule in 

the Federal Register. A major rule 

cannot take effect until 60 days after it 

is published in the Federal Register. 

This action is not a ‘‘major rule’’ as 

defined by 5 U.S.C. 804(2). This rule 

will be effective on November 6, 2007. 

List of Subjects 

40 CFR Part 60 

Environmental protection, 

Administrative practice and procedures, 

Air pollution control, Continuous 

emission monitors, Electric utilities, 

Mercury, Test methods and procedures. 

40 CFR Part 72 

Environmental protection, 

Administrative practice and procedures, 

Air pollution control, Continuous 

emission monitors, Electric utilities, 

Mercury, Test methods and procedures. 

40 CFR Part 75 

Environmental protection, 

Administrative practice and procedures, 

Air pollution control, Continuous 

emission monitors, Electric utilities, 

Mercury, Test methods and procedures. 

Dated: August 17, 2007. 

Stephen L. Johnson, 

Administrator. 

■ For the reasons set out in the 

preamble, title 40, chapter I, parts 60, 

72, and 75 of the Code of Federal 

Regulations are amended as follows: 

PART 60—STANDARDS OF 

PERFORMANCE FOR NEW 

STATIONARY SOURCES 

■ 1. The authority citation for part 60 

continues to read as follows: 

Authority: 42 U.S.C. 7401–7601. 

Appendix A–8 [Amended] 

■ 2. Amend Appendix A–8 by revising 

the heading and adding in numerical 

order Methods 30A and 30B to read as 

follows: 

APPENDIX A–8 TO PART 60—TEST 

METHODS 26 THROUGH 30B 

* * * * * 

Method 30A—Determination of Total Vapor 

Phase Mercury Emissions From Stationary 

Sources (Instrumental Analyzer Procedure) 

1.0 Scope and Application 

What Is Method 30A? 

Method 30A is a procedure for measuring 

total vapor phase mercury (Hg) emissions 

from stationary sources using an 

instrumental analyzer. This method is 

particularly appropriate for performing 

emissions testing and for conducting relative 

accuracy test audits (RATAs) of mercury 

continuous emissions monitoring systems 

(Hg CEMS) and sorbent trap monitoring 

systems at coal-fired combustion sources. 

Quality assurance and quality control 


jlentini on PROD1PC65 with RULES2
51502 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

requirements are included to assure that you, 

the tester, collect data of known and 

acceptable quality for each testing site. This 

method does not completely describe all 

equipment, supplies, and sampling 

procedures and analytical procedures you 

will need but refers to other test methods for 

some of the details. Therefore, to obtain 

reliable results, you should also have a 

thorough knowledge of these additional 

methods which are also found in appendices 

A–1 and A–3 to this part: 

(a) Method 1—Sample and Velocity 

Traverses for Stationary Sources. 

(b) Method 4—Determination of Moisture 

Content in Stack Gases. 

1.1 Analytes. What does this method 

determine? This method is designed to 

measure the mass concentration of total 

vapor phase Hg in flue gas, which represents 

the sum of elemental Hg (Hg0) and oxidized 

forms of Hg (Hg∂2), in mass concentration 

units of micrograms per cubic meter (μg/m3). 

Analyte CAS No. Sensitivity 

Elemental Hg (Hg0) .................................................................... 7439–97–6 Typically <2% of Calibration Span. 

Oxidized Hg (Hg∂2) ................................................................... (Same). 

1.2 Applicability. When is this method 

required? Method 30A is offered as a 

reference method for emission testing and for 

RATAs of Hg CEMS and sorbent trap 

monitoring systems at coal-fired boilers. 

Method 30A may also be specified for other 

source categories in the future, either by New 

Source Performance Standards (NSPS), 

National Emission Standards for Hazardous 

Air Pollutants (NESHAP), emissions trading 

programs, State Implementation Plans (SIP), 

or operating permits that require 

measurement of Hg concentrations in 

stationary source emissions to determine 

compliance with an applicable emission 

standard or limit, or to conduct RATAs of Hg 

CEMS and sorbent trap monitoring systems. 

1.3 Data Quality Objectives (DQO). How 

good must my collected data be? Method 30A 

has been designed to provide data of high 

and known quality for Hg emission testing 

and for relative accuracy testing of Hg 

monitoring systems including Hg CEMS and 

sorbent trap monitoring systems. In these and 

other applications, the principle objective is 

to ensure the accuracy of the data at the 

actual emission levels encountered. To meet 

this objective, calibration standards prepared 

according to an EPA traceability protocol 

must be used and measurement system 

performance tests are required. 

2.0 Summary of Method 

In this method, a sample of the effluent gas 

is continuously extracted and conveyed to an 

analyzer capable of measuring the total vapor 

phase Hg concentration. Elemental and 

oxidized mercury (i.e., Hg0 and Hg∂2) may 

be measured separately or simultaneously 

but, for purposes of this method, total vapor 

phase Hg is the sum of Hg0 and Hg∂2. You 

must meet the performance requirements of 

this method (i.e., system calibration, 

interference testing, dynamic spiking, and 

system integrity/drift checks) to validate your 

data. The dynamic spiking requirement is 

deferred until January 1, 2009. 

3.0 Definitions 

3.1 Calibration Curve means the 

relationship between an analyzer’s response 

to the injection of a series of calibration gases 

and the actual concentrations of those gases. 

3.2 Calibration Gas means a gas standard 

containing Hg0 or HgCl2 at a known 

concentration that is produced and certified 

in accordance with an EPA traceability 

protocol for certification of Hg calibration 

standards. 

3.2.1 Zero Gas means a calibration gas 

with a concentration that is below the level 

detectable by the measurement system. 

3.2.2 Low-Level Gas means a calibration 

gas with a concentration that is 10 to 30 

percent of the calibration span. 

3.2.3 Mid-Level Gas means a calibration 

gas with a concentration that is 40 to 60 

percent of the calibration span. 

3.2.4 High-Level Gas means a calibration 

gas whose concentration is equal to the 

calibration span. 

3.3 Converter means a device that reduces 

oxidized mercury (Hg∂2) to elemental 

mercury (Hg0). 

3.4 Calibration Span means the upper 

limit of valid instrument response during 

sampling. To the extent practicable the 

measured emissions are to be between 10 and 

100 percent of the selected calibration span 

(i.e., the measured emissions should be 

within the calibrated range determined by 

the Low- and High-Level gas standards). It is 

recommended that the calibration span be at 

least twice the native concentration to 

accommodate the dynamic spiking 

procedure. 

3.5 Centroidal Area means the central 

area that has the same shape as the stack or 

duct cross section and is no greater than one 

percent of the stack or duct total crosssectional area. 

3.6 Data Recorder means the equipment 

that permanently records the concentrations 

reported by the analyzer. 

3.7 Drift Check means the test to 

determine the difference between the 

measurement system readings obtained in a 

post-run system integrity check and the prior 

pre-run system integrity check at a specific 

calibration gas concentration level (i.e., zero, 

mid-level, or high-level). 

3.8 Dynamic Spiking means a procedure 

in which a known mass or concentration of 

vapor phase HgCl2 is injected into the probe 

sample gas stream at a known flow rate, in 

order to assess the effects of the flue gas 

matrix on the accuracy of the measurement 

system. 

3.9 Gas Analyzer means the equipment 

that detects the total vapor phase Hg being 

measured and generates an output 

proportional to its concentration. 

3.10 Interference Test means the test to 

detect analyzer responses to compounds 

other than Hg, usually gases present in the 

measured gas stream, that are not adequately 

accounted for in the calibration procedure 

and may cause measurement bias. 

3.11 Measurement System means all of 

the equipment used to determine the Hg 

concentration. The measurement system may 

generally include the following major 

subsystems: sample acquisition, Hg∂2 to Hg0

converter, sample transport, sample 

conditioning, flow control/gas manifold, gas 

analyzer, and data recorder. 

3.12 Native Concentration means the 

total vapor phase Hg concentration in the 

effluent gas stream. 

3.13 NIST means the National Institute of 

Standards and Technology, located in 

Gaithersburg, Maryland. 

3.14 Response Time means the time it 

takes for the measurement system, while 

operating normally at its target sample flow 

rate or dilution ratio, to respond to a known 

step change in gas concentration (from a lowlevel to a high-level gas) and to read within 

5 percent of the stable high-level gas 

response. 

3.15 Run means a series of gas samples 

taken successively from the stack or duct. A 

test normally consists of a specific number of 

runs. 

3.16 System Calibration Error means the 

difference between the measured 

concentration of a low-, mid-, or high-level 

Hg0 calibration gas and the certified 

concentration of the gas when it is 

introduced in system calibration mode. 

3.17 System Calibration Mode means 

introducing the calibration gases into the 

measurement system at the probe, upstream 

of all sample conditioning components. 

3.18 Test refers to the series of runs 

required by the applicable regulation. 

4.0 Interferences 

Interferences will vary among instruments 

and potential instrument-specific spectral 

and matrix interferences must be evaluated 

through the interference test and the dynamic 

spiking tests. 

5.0 Safety 

What safety measures should I consider 

when using this method? 

This method may require you to work with 

hazardous materials and in hazardous 

conditions. You are encouraged to establish 

safety procedures before using the method. 

Among other precautions, you should 

become familiar with the safety 

recommendations in the gas analyzer user’s 

manual. Occupational Safety and Health 

Administration (OSHA) regulations 

concerning use of compressed gas cylinders 

and noxious gases may apply. 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51503 

6.0 Equipment and Supplies 

6.1 What do I need for the measurement 

system? This method is intended to be 

applicable to multiple instrumental 

technologies. You may use any equipment 

and supplies that meet the following 

specifications. 

6.1.1 All wetted sampling system 

components, including probe components 

prior to the point at which the calibration gas 

is introduced, must be chemically inert to all 

Hg species. Materials such as perfluoroalkoxy 

(PFA) TeflonTM, quartz, treated stainless steel 

(SS) are examples of such materials. [Note: 

These materials of construction are required 

because components prior to the calibration 

gas injection point are not included in the 

system calibration error, system integrity, 

and interference tests.] 

6.1.2 The interference, system calibration 

error, system integrity, drift and dynamic 

spiking test criteria must all be met by the 

system used. 

6.1.3 The system must be capable of 

measuring and controlling sample flow rate. 

6.1.4 All system components prior to the 

Hg∂2 to Hg0 converter must be maintained at 

a sample temperature above the acid gas dew 

point. 

6.2 Measurement System Components. 

Figure 30A–1 in Section 17.0 is an example 

schematic of a Method 30A measurement 

system. 

6.2.1 Sample Probe. The probe must be 

made of the appropriate materials as noted in 

Section 6.1.1, heated when necessary (see 

Section 6.1.4), configured with ports for 

introduction of calibration and spiking gases, 

and of sufficient length to traverse all of the 

sample points. 

6.2.2 Filter or Other Particulate Removal 

Device. The filter or other particulate 

removal device is considered to be a part of 

the measurement system, must be made of 

appropriate materials as noted in Section 

6.1.1, and must be included in all system 

tests. 

6.2.3 Sample Line. The sample line that 

connects the probe to the converter, 

conditioning system and analyzer must be 

made of appropriate materials as noted in 

Section 6.1.1. 

6.2.4 Conditioning Equipment. For dry 

basis measurements, a condenser, dryer or 

other suitable device is required to remove 

moisture continuously from the sample gas. 

Any equipment needed to heat the probe, or 

sample line to avoid condensation prior to 

the moisture removal component is also 

required. For wet basis systems, you must 

keep the sample above its dew point either 

by: (1) Heating the sample line and all 

sample transport components up to the inlet 

of the analyzer (and, for hot-wet extractive 

systems, also heating the analyzer) or (2) by 

diluting the sample prior to analysis using a 

dilution probe system. The components 

required to do either of the above are 

considered to be conditioning equipment. 

6.2.5 Sampling Pump. A pump is needed 

to push or pull the sample gas through the 

system at a flow rate sufficient to minimize 

the response time of the measurement 

system. If a mechanical sample pump is used 

and its surfaces are in contact with the 

sample gas prior to detection, the pump must 

be leak free and must be constructed of a 

material that is non-reactive to the gas being 

sampled (see Section 6.1.1). For dilution-type 

measurement systems, an ejector pump 

(eductor) may be used to create a sufficient 

vacuum that sample gas will be drawn 

through a critical orifice at a constant rate. 

The ejector pump may be constructed of any 

material that is non-reactive to the gas being 

sampled. 

6.2.6 Calibration Gas System(s). One or 

more systems may be needed to introduce 

calibration gases into the measurement 

system. A system should be able to flood the 

sampling probe sufficiently to prevent entry 

of gas from the effluent stream. 

6.2.7 Dynamic Spiking Port. For the 

purposes of the dynamic spiking procedure 

described in Section 8.2.7, the measurement 

system must be equipped with a port to allow 

introduction of the dynamic spike gas stream 

with the sample gas stream, at a point as 

close as possible to the inlet of the probe so 

as to ensure adequate mixing. The same port 

used for system calibrations and calibration 

error checks may be used for dynamic 

spiking purposes. 

6.2.8 Sample Gas Delivery. The sample 

line may feed directly to a converter, to a bypass valve (for speciating systems), or to a 

sample manifold. All valve and/or manifold 

components must be made of material that is 

non-reactive to the gas sampled and the 

calibration gas, and must be configured to 

safely discharge any excess gas. 

6.2.9 Hg Analyzer. An instrument is 

required that continuously measures the total 

vapor phase Hg in the gas stream and meets 

the applicable specifications in Section 13.0. 

6.2.10 Data Recorder. A recorder, such as 

a computerized data acquisition and 

handling system (DAHS), digital recorder, 

strip chart, or data logger, is required for 

recording measurement data. 

6.3 Moisture Measurement System. If 

correction of the measured Hg emissions for 

moisture is required (see Section 8.5), either 

Method 4 in appendix A–3 to this part or 

other moisture measurement methods 

approved by the Administrator will be 

needed to measure stack gas moisture 

content. 

7.0 Reagents and Standards 

7.1 Calibration Gases. What calibration 

gases do I need? You will need calibration 

gases of known concentrations of Hg0 and 

HgCl2. Special reagents and equipment may 

be required to prepare the HgCl2 gas 

standards (e.g., a NIST-traceable solution of 

HgCl2 and a gas generator equipped with 

mass flow controllers). 

The following calibration gas 

concentrations are required: 

7.1.1 High-Level Gas. Equal to the 

selected calibration span. 

7.1.2 Mid-Level Gas. 40 to 60 percent of 

the calibration span. 

7.1.3 Low-Level Gas. 10 to 30 percent of 

the calibration span. 

7.1.4 Zero Gas. No detectable Hg. 

7.1.5 Dynamic Spike Gas. The exact 

concentration of the HgCl2 calibration gas 

used to perform the pre-test dynamic spiking 

procedure described in Section 8.2.7 depends 

on the native Hg concentration in the stack 

The spike gas must produce a spiked sample 

concentration above the native concentration, 

as specified in Section 8.2.7.2.2. 

7.2 Interference Test. What reagents do I 

need for the interference test? Use the 

appropriate test gases listed in Table 30A–3 

in Section 17.0 (i.e., the potential interferents 

for the source to be tested, as identified by 

the instrument manufacturer) to conduct the 

interference check. These gases need not be 

of protocol gas quality. 

8.0 Sample Collection 

Emission Test Procedure 

Figure 30A–2 in Section 17.0 presents an 

overview of the test procedures required by 

this method. Since you may choose different 

options to comply with certain performance 

criteria, you must identify the specific 

options and associated frequencies you select 

and document your results in regard to the 

performance criteria. 

8.1 Sample Point Selection. What 

sampling site and sampling points do I 

select? 

8.1.1 When this method is used solely for 

Hg emission testing (e.g., to determine 

compliance with an emission standard or 

limit), use twelve sampling points located 

according to Table 1–1 or Table 1–2 of 

Method 1 in appendix A–1 to this part. 

Alternatively, you may conduct a 

stratification test as described in Section 

8.1.3 to determine the number and location 

of the sampling points. 

8.1.2 When this method is used for 

relative accuracy testing of a Hg CEMS or 

sorbent trap monitoring system, follow the 

sampling site selection and sampling point 

layout procedures for gas monitor RATA 

testing described in the appropriate 

performance specification or applicable 

regulation (e.g., Performance Specification 2, 

section 8.1.3 of appendix B to this part or 

section 6.5.6 of appendix A to part 75 of this 

chapter), with one exception. If you elect to 

perform stratification testing as part of the 

sampling point selection process, perform the 

testing in accordance with Section 8.1.3 of 

this method (see also ‘‘Summary Table of 

QA/QC Requirements’’ in Section 9.0). 

8.1.3 Determination of Stratification. If 

you elect to perform stratification testing as 

part of the sampling point selection process 

and the test results show your effluent gas 

stream to be unstratified or minimally 

stratified, you may be allowed to sample at 

fewer points or at different points than would 

otherwise be required. 

8.1.3.1 Test Procedure. To test for 

stratification, use a probe of appropriate 

length to measure the total vapor phase Hg 

concentration at twelve traverse points 

located according to Table 1–1 or Table 1–

2 of Method 1 in appendix A–1 to this part. 

Alternatively, for a sampling location where 

stratification is expected (e.g., after a wet 

scrubber or at a point where dissimilar gas 

streams are combined together), if a 12-point 

Hg stratification test has been previously 

performed at that location and the results of 

the test showed the location to be minimally 

stratified or unstratified according to the 

criteria in section 8.1.3.2, you may perform 

an abbreviated 3-point or 6-point Hg 

stratification test at the points specified in 


jlentini on PROD1PC65 with RULES2
51504 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

section 6.5.6.2(a) of appendix A to part 75 of 

this chapter in lieu of performing the 12- 

point test. Sample for a minimum of twice 

the system response time (see Section 8.2.6) 

at each traverse point. Calculate the 

individual point and mean Hg 

concentrations. 

8.1.3.2 Acceptance Criteria and Sampling 

Point Location. 

8.1.3.2.1 If the Hg concentration at each 

traverse point differs from the mean 

concentration for all traverse points by no 

more than: (a) ±5 percent of the mean 

concentration; or (b) ±0.2 μg/m3 (whichever 

is less restrictive), the gas stream is 

considered to be unstratified and you may 

collect samples from a single point that most 

closely matches the mean. 

8.1.3.2.2 If the 5 percent or 0.2 μg/m3

criterion in Section 8.1.3.2.1 is not met, but 

the Hg concentration at each traverse point 

differs from the mean concentration for all 

traverse points by no more than: (a)±10 

percent of the mean; or (b)±0.5 μg/m3

(whichever is less restrictive), the gas stream 

is considered to be minimally stratified, and 

you may take samples from three points, 

provided the points are located on the 

measurement line exhibiting the highest 

average Hg concentration during the 

stratification test. If the stack diameter (or 

equivalent diameter, for a rectangular stack 

or duct) is greater than 2.4 meters (7.8 ft), 

locate the three sampling points at 0.4, 1.0, 

and 2.0 meters from the stack or duct wall. 

Alternatively, if a RATA required by part 75 

of this chapter is being conducted, you may 

locate the three points at 4.4, 14.6, and 29.6 

percent of the duct diameter, in accordance 

with Method 1 in appendix A–1 to this part. 

For stack or duct diameters of 2.4 meters (7.8 

ft) or less, locate the three sampling points 

at 16.7, 50.0, and 83.3 percent of the 

measurement line. 

8.1.3.2.3 If the gas stream is found to be 

stratified because the 10 percent or 0.5 μg/m3

criterion in Section 8.1.3.2.2 is not met, then 

either locate three sampling points at 16.7, 

50.0, and 83.3 percent of the measurement 

line that exhibited the highest average Hg 

concentration during the stratification test, or 

locate twelve traverse points for the test in 

accordance with Table 1–1 or Table 1–2 of 

Method 1 in appendix A–1 to this part; or, 

if a RATA required by part 75 of this chapter 

is being conducted, locate six Method 1 

points along the measurement line that 

exhibited the highest average Hg 

concentration. 

8.1.3.3 Temporal Variations. Temporal 

variations in the source Hg concentration 

during a stratification test may complicate 

the determination of stratification. If 

temporal variations are a concern, you may 

use the following procedure to normalize the 

stratification test data. A second Hg 

measurement system, i.e., either an installed 

Hg CEMS or another Method 30A system, is 

required to perform this procedure. Position 

the sampling probe of the second Hg 

measurement system at a fixed point in the 

stack or duct, at least one meter from the 

stack or duct wall. Then, each time that the 

Hg concentration is measured at one of the 

stratification test points, make a concurrent 

measurement of Hg concentration at the fixed 

point. Normalize the Hg concentration 

measured at each traverse point, by 

multiplying it by the ratio of CF,avg to CF, 

where CF is the corresponding fixed-point Hg 

concentration measurement, and CF,avg is the 

average of all of the fixed-point 

measurements over the duration of the 

stratification test. Evaluate the results of the 

stratification test according to section 8.1.3.2, 

using the normalized Hg concentrations. 

8.1.3.4 Stratification Testing Exemption. 

Stratification testing need not be performed 

at a test location where it would otherwise 

be required to justify using fewer sample 

points or different sample points, if the 

owner or operator documents that the Hg 

concentration in the stack gas is expected to 

be 3 μg/m3 or less at the time of a Hg 

monitoring system RATA or an Hg emissions 

test. To demonstrate that a particular test 

location qualifies for the stratification testing 

exemption, representative Hg emissions data 

must be collected just prior to the RATA or 

emissions test. At least one hour of Hg 

concentration data is required for the 

demonstration. The data used for the 

demonstration shall be recorded at process 

operating conditions that closely 

approximate the operating conditions that 

will exist during the RATA or emissions test. 

It is recommended that collection of the 

demonstration data be integrated with the onsite pretest procedures required by the 

reference method being used for the RATA or 

emissions test (whether this method or 

another approved Hg reference method is 

used). Quality-assured data from an installed 

Hg monitoring system may also be used for 

the demonstration. If a particular test 

location qualifies for the stratification testing 

exemption, sampling shall be performed at 

three points, as described in section 8.1.3.2.2 

of this method. The owner or operator shall 

fully document the method used to collect 

the demonstration data and shall keep this 

documentation on file with the data from the 

associated RATA or Hg emissions test. 

8.1.3.5 Interim Alternative Stratification 

Test Procedures. In the time period between 

the effective date of this method and January 

1, 2009, you may follow one of the following 

two procedures. Substitute a stratification 

test for sulfur dioxide (SO2) for the Hg 

stratification test described in section 8.1.3.1. 

If this option is chosen, follow the test 

procedures in section 6.5.6.1 of appendix A 

to part 75 of this chapter. Evaluate the test 

results and determine the sampling point 

locations according to section 6.5.6.3 of 

appendix A to part 75 of this chapter. If the 

sampling location is found to be minimally 

stratified or unstratified for SO2, it shall be 

considered minimally stratified or 

unstratified for Hg. Alternatively, you may 

forgo stratification testing, assume the gas 

stream is minimally stratified, and sample at 

three points as described in section 8.1.3.2.2 

of this method. 

8.2 Initial Measurement System 

Performance Tests. What initial performance 

criteria must my system meet before I begin 

sampling? Before measuring emissions, 

perform the following procedures: 

(a) Interference Test; 

(b) Calibration Gas Verification; 

(c) Measurement System Preparation; 

(d) 3-Point System Calibration Error Test; 

(e) System Integrity Check; 

(f) Measurement System Response Time 

Test; and 

(g) Dynamic Spiking Test. 

8.2.1 Interference Test (Optional). Your 

measurement system should be free of known 

interferences. It is recommended that you 

conduct this interference test of your 

measurement system prior to its initial use in 

the field to verify that the candidate test 

instrument is free from inherent biases or 

interferences resulting from common 

combustion emission constituents. If you 

have multiple measurement systems with 

components of the same make and model 

numbers, you need only perform this 

interference check on one system and you 

may also rely on an interference test 

conducted by the manufacturer on a system 

having components of the same make and 

model(s) of the system that you use. The 

interference test procedure is found in 

Section 8.6 of this method. 

8.2.2 Calibration Gas Verification. How 

must I verify the concentrations of my 

calibration gases? 

8.2.2.1 Cylinder Gas Standards. When 

cylinder gas standards are used for Hg0, 

obtain a certificate from the gas manufacturer 

and confirm that the documentation includes 

all information required by an EPA 

traceability protocol (see Section 16). 

Confirm that the manufacturer certification is 

complete and current. Ensure that the 

calibration gas certifications have not 

expired. 

8.2.2.2 Other Calibration Standards. All 

other calibration standards for HgCl2 and 

Hg0, such as gas generators, must meet the 

requirements of an EPA traceability protocol 

(see Section 16), and the certification 

procedures must be fully documented in the 

test report. 

8.2.2.3 Calibration Span. Select the 

calibration span (i.e., high-level gas 

concentration) so that the measured source 

emissions are 10 to 100 percent of the 

calibration span. This requirement is waived 

for applications in which the Hg 

concentrations are consistently below 1 μg/ 

m3; however, the calibration span for these 

low-concentration applications shall not 

exceed 5 μg/m3. 

8.2.3 Measurement System Preparation. 

How do I prepare my measurement system 

for use? Assemble, prepare, and precondition 

the measurement system according to your 

standard operating procedure. Adjust the 

system to achieve the correct sampling rate 

or dilution ratio (as applicable). Then, 

conduct a 3-point system calibration error 

test using Hg0 as described in Section 8.2.4, 

an initial system integrity check using HgCl2

and a zero gas as described in Section 8.2.5, 

and a pre-test dynamic spiking test as 

described in Section 8.2.7. 

8.2.4 System Calibration Error Test. 

Conduct a 3-point system calibration error 

test before the first test run. Use Hg0

standards for this test. Introduce the low-, 

mid-, and high-level calibration gases in any 

order, in system calibration mode, unless you 

desire to determine the system response time 

during this test, in which case, inject the 

gases such that the high-level injection 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51505 

directly follows the low-level injection. For 

non-dilution systems, you may adjust the 

system to maintain the correct flow rate at 

the analyzer during the test, but you may not 

make adjustments for any other purpose. For 

dilution systems, you must operate the 

measurement system at the appropriate 

dilution ratio during all system calibration 

error checks, and you may make only the 

adjustments necessary to maintain the proper 

ratio. After each gas injection, wait until a 

stable response has been obtained. Record 

the analyzer’s final, stable response to each 

calibration gas on a form similar to Table 

30A–1 in Section 17.0. For each calibration 

gas, calculate the system calibration error 

using Equation 30A–1 in Section 12.2. The 

calibration error specification in Section 13.1 

must be met for the low-, mid-, and highlevel gases. If the calibration error 

specification is not met for all three gases, 

take corrective action and repeat the test 

until an acceptable 3-point calibration is 

achieved. 

8.2.5 System Integrity Check. Perform a 

two-point system integrity check before the 

first test run. Use the zero gas and either the 

mid- or high-level HgCl2 calibration gas for 

the check, whichever one best represents the 

total vapor phase Hg concentration levels in 

the stack. Record the data on a form similar 

to Table 30A–2 in Section 17.0. The system 

integrity check specification in Section 13.2 

must be met for both the zero gas and the 

mid- or high-level gas. If the system integrity 

specification is not met for both gases, take 

corrective action and repeat the test until an 

acceptable system integrity check is 

achieved. 

8.2.6 Measurement System Response 

Time. The measurement system response 

time is used to determine the minimum 

sampling time for each sampling point and 

is equal to the time that is required for the 

measured Hg concentration to increase from 

the stable low-level calibration gas response 

to a value within 5 percent of the stable highlevel calibration gas response during the 

system calibration error test in Section 8.2.4. 

Round off the measured system response 

time to the nearest minute. 

8.2.7 Dynamic Spiking Test. You must 

perform dynamic spiking prior to the first 

test run to validate your test data. The 

purpose of this procedure is to demonstrate 

that the site-specific flue gas matrix does not 

adversely affect the accuracy of the 

measurement system. The specifications in 

Section 13.5 must be met to validate your 

data. If these specifications are not met for 

the pre-test dynamic spiking, you may not 

proceed with the test until satisfactory results 

are obtained. For the time period between the 

effective date of this method and January 1, 

2009, the dynamic spiking requirement is 

waived. 

8.2.7.1 How do I perform dynamic 

spiking? Dynamic spiking is a gas phase 

application of the method of standard 

additions, which involves injecting a known 

quantity of Hg into the measurement system 

upstream of all sample conditioning 

components, similar to system calibration 

mode, except the probe is not flooded and 

the resulting sample stream includes both 

effluent gas and the spike gas. You must 

follow a written procedure that details how 

the spike is added to the system, how the 

spike dilution factor (DF) is measured, and 

how the Hg concentration data are collected 

and processed. 

8.2.7.2 Spiking Procedure Requirements. 

8.2.7.2.1 Spiking Gas Requirements. The 

spike gas must also be a HgCl2 calibration gas 

certified by an EPA traceability protocol. You 

must choose concentrations that can produce 

the target levels while being injected at a 

volumetric flow rate that is ≤20 percent of the 

total volumetric flow rate through the 

measurement system (i.e., sample flow rate 

plus spike gas flow rate). 

8.2.7.2.2 Target Spiking Level. The target 

level for spiking must be 150 to 200 percent 

of the native Hg concentration; however, if 

the native Hg concentration is <1 μg/m3, set 

the target level to add between 1 and 4 μg/ 

m3 Hg∂2 to the native concentration. Use 

Equation 30A–5 in Section 12.5 to calculate 

the acceptable range of spike gas 

concentrations at the target level. Then select 

a spike gas concentration in that range. 

8.2.7.2.3 Spike Injections. You must 

inject spikes in such a manner that the 

spiking does not alter the total volumetric 

sample system flow rate and dilution ratio (if 

applicable). You must collect at least 3 data 

points, and the relative standard deviation 

(RSD) specification in Section 13.5 must be 

met. Each data point represents a single spike 

injection, and pre- and post-injection 

measurements of the native Hg concentration 

(or diluted native concentration, as 

applicable) are required for each spike 

injection. 

8.2.7.2.4 Spike Dilution Factor (DF). For 

each spike injection, DF, the dilution factor 

must be determined. DF is the ratio of the 

total volumetric flow rate of gas through the 

measurement system to the spike gas flow 

rate. This factor must be ≥5. The spiking 

mass balance calculation is directly 

dependent on the accuracy of the DF 

determination. As a result, high accuracy 

total volumetric flow rate and spike gas 

flowrate measurements are required. These 

flow rates may be determined by direct or 

indirect measurement. Calibrated flow 

meters, venturies, orifices or tracer gas 

measurements are examples of potential flow 

measurement techniques. 

8.2.7.2.5 Concentrations. The 

measurement system must record total vapor 

phase Hg concentrations continuously during 

the dynamic spiking procedure. It is possible 

that dynamic spiking at a level close to 200 

percent of the native Hg concentration may 

cause the measured Hg concentration to 

exceed the calibration span value. Avoid this 

by choosing a lower spiking level or by 

recalibration at a higher span. The 

measurements shall not exceed 120 percent 

of the calibration span. The ‘‘baseline’’

measurements made between spikes may 

represent the native Hg concentration (if 

spike gas flow is stopped between injections) 

or the native Hg concentration diluted by 

blank or carrier gas flowing at the same rate 

as the spike gas (if gas flow cannot be 

stopped between injections). Each baseline 

measurement must include at least 4 readings 

or 1 minute (whichever is greater) of stable 

responses. Use Equation 30A–10 or 30A–11 

in Section 12.10 (as applicable) to convert 

baseline measurements to native 

concentration. 

8.2.7.2.6 Recovery. Calculate spike 

recoveries using Equation 30A–7 in Section 

12.7. Mass recoveries may be calculated from 

stable responses based on injected mass 

flows or from integrated response peaks 

based on total mass injected. Calculate the 

mean and RSD for the three (or more) spike 

injections and compare to the specifications 

in Section 13.5. 

8.2.7.2.7 Error Adjustment Option. You 

may adjust the measurement data collected 

during dynamic spiking for the system 

calibration error using Equation 30A–3 in 

Section 12. To do this, perform the initial 

system integrity check prior to the dynamic 

spiking test, and perform another system 

integrity check following the dynamic 

spiking test and before the first test run. If 

you choose this option, you must apply 

Equation 30A–3 to both the spiked sample 

concentration measurement (Css) and the 

baseline or native concentration 

measurement (Cnative), each substituted in 

place of Cavg in the equation. 

8.2.7.3 Example Spiking Procedure Using 

a Hot Vapor Calibration Source Generator. 

(a) Introduce the spike gas into the probe 

using a hot vapor calibration source generator 

and a solution of HgCl2 in dilute HC1 and 

HNO3. The calibrator uses a mass flow 

controller (accurate within 2 percent) to 

measure the gas flow, and the solution feed 

is measured using a top-loading balance 

accurate to 0.01g. The challenges of injecting 

oxidized Hg may make it impractical to stop 

the flow of gas between spike injections. In 

this case, operate the hot vapor calibration 

source generator continuously during the 

spiking procedure, swapping blank solutions 

for HgCl2 solutions when switching between 

spiking and baseline measurements. 

(b) If applicable, monitor the measurement 

system to make sure the total sampling 

system flow rate and the sample dilution 

ratio do not change during this procedure. 

Record all data on a data sheet similar to 

Table 30A–5 in Section 17.0. If the Hg 

measurement system design makes it 

impractical to measure the total volumetric 

flow rate through the system, use a spike gas 

that includes a tracer for measuring the 

dilution factor, DF (see Equation 30A–9 in 

Section 12.9). Allow the measurements to 

stabilize between each spike injection, 

average the pre- and post-injection baseline 

measurements, and calculate the native 

concentration. If this measurement shifts by 

more than 5 percent during any injection, it 

may be necessary to discard that data point 

and repeat the injection to achieve the 

required RSD among the injections. If the 

spikes persistently show poor repeatability, 

or if the recoveries are not within the range 

specified in Section 13.5, take corrective 

action. 

8.2.8 Run Validation. How do I confirm 

that each run I conduct is valid? 

8.2.8.1 System Integrity Checks. 

(a) Before and after each test run, perform 

a two-point system integrity check using the 

same procedure as the initial system integrity 

check described in Section 8.2.5. You may 

use data from that initial system integrity 


jlentini on PROD1PC65 with RULES2
51506 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

check as the pre-run data for the first test run, 

provided it is the most recent system 

integrity check done before the first run. You 

may also use the results of a successful postrun system integrity check as the pre-run 

data for the next test run. Do not make any 

adjustments to the measurement system 

during these checks, other than to maintain 

the target calibration gas flow rate and the 

proper dilution ratio. 

(b) As a time-saving alternative, you may, 

at the risk of invalidating multiple test runs, 

skip one or more integrity checks during a 

test day. Provided there have been no autocalibrations or other instrument alterations, a 

single integrity check may suffice as a postrun check to validate (or invalidate) as many 

consecutive test runs as can be completed 

during a single test day. All subsequent test 

days must begin with a pre-run system 

integrity check subject to the same 

performance criteria and corrective action 

requirements as a post-run system integrity 

check. 

(c) Each system integrity check must meet 

the criteria for system integrity checks in 

Section 13.2. If a post-run system integrity 

check is failed, all test runs since the last 

passed system integrity check are invalid. If 

a post-run or a pre-run system integrity check 

is failed, you must take corrective action and 

pass another 3-point Hg0 system calibration 

error test (Section 8.2.4) followed by another 

system integrity check before conducting any 

additional test runs. Record the results of the 

pre- and post-run system integrity checks on 

a form similar to Table 30A–2 in Section 

17.0. 

8.2.8.2 Drift Check. Using the data from 

the successful pre- and post-run system 

integrity checks, calculate the zero and 

upscale drift, using Equation 30A–2 in 

Section 12.3. Exceeding the Section 13.3 

specification does not invalidate the run, but 

corrective action must be taken and a new 3- 

point Hg0 system calibration error test and a 

system integrity check must be passed before 

any more runs are made. 

8.3 Dilution-Type Systems—Special 

Considerations. When a dilution-type 

measurement system is used, there are three 

important considerations that must be taken 

into account to ensure the quality of the 

emissions data. First, the critical orifice size 

and dilution ratio must be selected properly 

so that the sample dew point will be below 

the sample line and analyzer temperatures. 

Second, a high-quality, accurate dilution 

controller must be used to maintain the 

correct dilution ratio during sampling. The 

dilution controller should be capable of 

monitoring the dilution air pressure, orifice 

upstream pressure, eductor vacuum, and 

sample flow rates. Third, differences between 

the molecular weight of calibration gas 

mixtures, dilution air, and the stack gas 

molecular weight must be considered 

because these can affect the dilution ratio 

and introduce measurement bias. 

8.4 Sampling. 

(a) Position the probe at the first sampling 

point. Allow the system to flush and 

equilibrate for at least two times the 

measurement system response time before 

recording any data. Then, traverse and record 

measurements at all required sampling 

points. Sample at each traverse point for an 

equal length of time, maintaining the 

appropriate sample flow rate or dilution ratio 

(as applicable). For all Hg instrumental 

method systems, the minimum sampling 

time at each sampling point must be at least 

two times the system response time, but not 

less than 10 minutes. For concentrating 

systems, the minimum sampling time must 

also include at least 4 concentration 

measurement cycles. 

(b) After recording data for the appropriate 

period of time at the first traverse point, you 

may move the sample probe to the next point 

and continue recording, omitting the 

requirement to allow the system to 

equilibrate for two times the system response 

time before recording data at the subsequent 

traverse points. You must, however, sample 

at this and all subsequent traverse points for 

the required minimum amount of time 

specified in this section. If you must remove 

the probe from the stack for any reason, you 

must again allow the sampling system to 

equilibrate for at least two times the system 

response time prior to resuming data 

recording. 

(c) If at any point the measured Hg 

concentration exceeds the calibration span 

value, you must at a minimum identify and 

report this as a deviation from the method. 

Depending on the data quality objectives of 

the test, this event may require corrective 

action before proceeding. If the average Hg 

concentration for any run exceeds the 

calibration span value, the run is invalidated. 

8.5 Moisture Correction. If the moisture 

basis (wet or dry) of the measurements made 

with this method is different from the 

moisture basis of either: (1) The applicable 

emission limit; or (2) a Hg CEMS or sorbent 

trap monitoring system being evaluated for 

relative accuracy, you must determine the 

moisture content of the flue gas and correct 

the measured gas concentrations to a dry 

basis using Method 4 in appendix A–3 of this 

part or other appropriate methods, subject to 

the approval of the Administrator. 

8.6 Optional Interference Test Procedure. 

(a) Select an appropriate calibration span 

that reflects the source(s) to be tested and 

perform the interference check at 40 percent 

of the lowest calibration span value 

anticipated, e.g., 10 μg/m3. Alternatively, 

successfully conducting the interference test 

at an absolute Hg concentration of 2 μg/m3

will demonstrate performance for an 

equivalent calibration span of 5 μg/m3, the 

lowest calibration span allowed for Method 

30A testing. Therefore, performing the 

interference test at the 2 μ/m3 level will serve 

to demonstrate acceptable performance for all 

calibration spans greater than or equal to 5 

μg/m3. 

(b) Introduce the interference test gases 

listed in Table 30A–3 in Section 17.0 into the 

measurement system separately or as a 

mixture. The interference test gases HCl and 

NO must be introduced as a mixture. The 

interference test gases must be introduced 

into the sampling system at the probe such 

that the interference gas mixtures pass 

through all filters, scrubbers, conditioners, 

and other components as would be 

configured for normal sampling. 

(c) The interference test must be performed 

using HgCl2, and each interference test gas 

(or gas mixture) must be evaluated in 

triplicate. This is accomplished by measuring 

the Hg response first with only the HgCl2 gas 

present and then when adding the 

interference test gas(es) while maintaining 

the HgCl2 concentration of the test stream 

constant. It is important that the equipment 

used to conduct the interference test be of 

sufficient quality so as to be capable of 

blending the HgCl2 and interference gases 

while maintaining the Hg concentration 

constant. Gas blending system or manifolds 

may be used. 

(d) The duration of each test should be for 

a sufficient period of time to ensure the Hg 

measurement system surfaces are 

conditioned and a stable output is obtained. 

Measure the Hg response of the analyzer to 

these gases in μg/m3. Record the responses 

and determine the overall interference 

response using Table 30A–4 in Section 17.0 

and the equations presented in Section 12.11. 

The specification in Section 13.4 must be 

met. 

(e) A copy of these data, including the date 

completed and a signed certification, must be 

included with each test report. The intent of 

this test is that the interference test results 

are intended to be valid for the life of the 

system. As a result, the Hg measurement 

system should be operated and tested in a 

configuration consistent with the 

configuration that will be used for field 

applications. However, if the system used for 

field testing is not consistent with the system 

that was interference-tested, the interference 

test must be repeated before it is used for any 

field applications. Examples of such 

conditions include, but are not limited to: 

major changes in dilution ratio (for dilution 

based systems), changes in catalyst materials, 

changes in filtering device design or 

materials, changes in probe design or 

configuration, and changes in gas 

conditioning materials or approaches. 

9.0 Quality Control 

What quality control measures must I take? 

The table which follows is a summary of 

the mandatory, suggested, and alternative 

quality assurance and quality control 

measures and the associated frequency and 

acceptance criteria. All of the QC data, along 

with the run data, must be documented and 

included in the test report. 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51507 

SUMMARY TABLE OF QA/QC REQUIREMENTS

Status 1 Process or element QA/QC specification Acceptance criteria Checking frequency 

S ............... Identify Data User ......... ........................................ Regulatory Agency or other primary end user of 

data.

Before designing test. 

M .............. Analyzer Design ............ Analyzer range .............. Sufficiently > high-level gas to allow determination of system calibration error.

S ............... ........................................ Analyzer resolution or 

sensitivity.

< 2.0 % of full-scale range .................................... Manufacturer design. 

S ............... ........................................ Interference response ... Overall response ≤ 3% of calibration span ...........

Alternatively, overall response ≤ 0.3 μg/m3.

M .............. Calibration Gases .......... Traceability protocol ...... Validation of concentration required.

M .............. ........................................ High-level Hg0 gas ........ Equal to the calibration span ................................ Each calibration error 

test. 

M .............. ........................................ Mid-level Hg0 gas .......... 40 to 60% of calibration span ............................... Each calibration error 

test. 

M .............. ........................................ Low-level Hg0 gas ......... 10 to 30% of calibration span ............................... Each calibration error 

test. 

M .............. ........................................ High-level HgCl2 gas ..... Equal to the calibration span ................................ Each system integrity 

check (if it better represents Cnative than 

the mid level gas). 

M .............. ........................................ Mid-level HgCl2 .............. 40 to 60% of calibration span ............................... Each system gas integrity check (if it better 

represents Cnative than 

the high level gas). 

M .............. ........................................ Zero gas ........................ ................................................................................ Each system integrity 

check. 

M .............. ........................................ Dynamic spike gas 

(Cnative ≥ 1 μg/m3).

A high-concentration HgCl2 gas, used to produce 

a spiked sample concentration that is 150 to 

200% of the native concentration.

Pre-test; dynamic spiking not required until 

1/1/09. 

M .............. ........................................ Dynamic spike gas 

(Cnative < 1 μg/m3).

A high-concentration HgCl2 gas, used to produce 

a spiked sample concentration that is 1 to 2 

μg/m3 above the native concentration.

Pre-test; dynamic spiking not required until 

1/1/09. 

S ............... Data Recorder Design ... Data resolution .............. ≤ 0.5% of full-scale ................................................ Manufacturer design. 

M .............. Sample Extraction ......... Probe material ............... Inert to sample constituents (e.g., PFA Teflon, or 

quartz if stack > 500 °F).

Each run. 

M .............. Sample Extraction ......... Probe, filter and sample 

line temperature.

For dry-basis analyzers, keep sample above the 

dew point, by heating prior to moisture removal.

For wet-basis analyzers, keep sample above dew 

point at all times, by heating or dilution.

Each run. 

M .............. Sample Extraction ......... Calibration valve material.Inert to sample constituents (e.g., PFA Teflon or 

PFA Teflon coated).

Each test. 

S ............... Sample Extraction ......... Sample pump material .. Inert to sample constituents .................................. Each test. 

M .............. Sample Extraction ......... Manifold material ........... Inert to sample constituents .................................. Each test. 

M .............. Particulate Removal ...... Filter inertness ............... Pass calibration error check .................................. Each calibration error 

check. 

M .............. System Calibration Performance.System calibration error 

(CE) test.

CE ≤ 5.0 % of the calibration span for the low-, 

mid-or high-level Hg0 calibration gas.

Alternative specification: ≤ 0.5 μg/m3 absolute difference between system response and reference value.

Before initial run and 

after a failed system 

integrity check or drift 

test. 

M .............. System Calibration Performance.System integrity check .. Error ≤ 5.0% of the calibration span for the zero 

and mid- or high-level HgCl2 calibration gas.

Alternative specification: ≤ 0.5 μg/m3 absolute difference between system response and reference value.

Before initial run, after 

each run, at the beginning of subsequent 

test days, and after a 

failed system integrity 

check or drift test. 

M .............. System Performance ..... System response time ... Used to determine minimum sampling time per 

point.

During initial 3-point system calibration error 

test. 

M .............. System Performance ..... Drift ................................ ≤ 3.0% of calibration span for the zero and midor high-level gas.

Alternative specification: ≤ 0.3 μg/m3 absolute difference between pre- and post-run system calibration error percentages..

At least once per test 

day. 

M .............. System Performance ..... Minimum sampling time The greater of two times the system response 

time or 10 minutes. Concentrating systems 

must also include at least 4 cycles.

Each sampling point. 

M .............. System Performance ..... Percentage spike recovery and relative standard deviation.Percentage spike recovery, at the target level: 

100 ± 10%.

Relative standard deviation: ≤ 5 percent ...............

Alternative specification: absolute difference between calculated and measured spike values 

≤ 0.5 μg/m3.

Before initial dynamic 

spiking not required 

until 1/1/09. 


jlentini on PROD1PC65 with RULES2
51508 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

SUMMARY TABLE OF QA/QC REQUIREMENTS—Continued 

Status 1 Process or element QA/QC specification Acceptance criteria Checking frequency 

M .............. Sample Point Selection Number and Location of 

Sample Points.

For emission testing applications, use 12 points, 

located according to Method 1 in appendix A–1 

to this part, unless the results of a stratification 

test allow fewer points to be used.

Prior to first run. 

........................................ ........................................ For Part 60 RATAs, follow the procedures in Performance Specification 2, section 8.1.3, and for 

Part 75 RATAs, follow the procedures in section 6.5.6 of appendix A to Part 75. That is: 

........................................ ........................................ • At any test location, you may use 3 sample 

points located at 16.7, 50.0, and 83.3% of a 

‘‘long’’ measurement line passing through the 

centroidal area; or 

........................................ ........................................ • At any test location, you may use 6 sample 

points along a diameter, located according to 

Method 1 (Part 75 RATAs, only); or 

........................................ ........................................ • At a location where stratification is not expected and the measurement line is > 2.4 m 

(7.8 ft), you may use 3 sample points located 

along a ‘‘short’’ measurement line at 0.4, 1.0, 

and 2.0 m from the stack or duct wall or, for 

Part 75 only, sample points may be located at 

4.4, 14.6, and 29.6% of the measurement line; 

or 

........................................ ........................................ • After a wet scrubber or at a point where dissimilar gas streams are combined, either locate 

3 sample points along the ‘‘long’’ measurement 

line or locate 6 Method 1 points along a diameter (Part 75, only), unless the results of a stratification test allow you to use a ‘‘short’’ 3-point 

measurement line or to sample at a single 

point.

........................................ ........................................ • If it can be demonstrated that stack gas concentration is ≤ 3 μg/m3, then the test site is exempted from stratification testing. Use the 3- 

point ‘‘short’’ measurement line if the stack diameter is > 2.4 m (7.8 ft) and the 3-point ‘‘long’’

line for stack diameters ≤ 2.4 m (7.8 ft).

A ............... Sample Point Selection Stratification Test (see 

Section 8.1.3).

If the Hg concentration 2 at each traverse point 

during the stratification test is: 

• Within ± 5% of mean, use 1-point sampling (at 

the point closest to the mean); or 

• Not within ± 5% of mean, but is within ± 10% of 

mean, use 3-point sampling. Locate points according to Section 8.1.3.2.2 of this method.

Prior to first run. 

........................................ ........................................ Alternatively, if the Hg concentration at each 

point is: 

• Within ± 0.2 μg/m3 of mean, use 1-point sampling (at the point closest to the mean); or 

• Not within ± 0.2 μg/m3 of mean, use 3-point 

sampling. Locate points according to Section 

8.1.3.2.2 of this method.

Prior to 1/1/09, you may 

(1) forgo stratification 

testing and use 3 

sampling points (as 

per Section 8.1.3.2.2) 

or (2) perform a SO2

stratification test (see 

Sections 6.5.6.1 and 

6.5.6.3 of appendix A 

to part 75), in lieu of a 

Hg stratification test. If 

the test location is 

unstratified or minimally stratified for 

SO2, it can be considered unstratified or 

minimally stratified for 

Hg also. 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51509 

SUMMARY TABLE OF QA/QC REQUIREMENTS—Continued 

Status 1 Process or element QA/QC specification Acceptance criteria Checking frequency 

........................................ ........................................ If the Hg concentration is > 10% of the mean at 

any point, then, if the alternative specification 

is not met or if the stack diameter is ≤ 2.4 m 

(7.8 ft): 

• Perform sampling at 12 Method 1 points; or .....

• Sample at 3 points located at 16.7, 50.0 and 

83.3% of the measurement line that exhibited 

the highest average Hg concentration during 

stratification test; or.

• Sample at 6 Method 1 points along the line 

that exhibited the highest average Hg concentration (Part 75 RATAs, only).

On and after 1/1/09, 

only Hg stratification 

tests are acceptable 

for the purposes of 

this method. 

M .............. Data Recording ............. Frequency ...................... Once per cycle ...................................................... During run. 

S ............... Data Parameters ........... Sample concentration 

and calibration span.

All analyzer readings during each run within calibration span.Each run. 

M .............. Data Parameters ........... Sample concentration 

and calibration span.

All analyzer readings during dynamic spiking 

tests within 120% of calibration span.

Each spike injection. 

M .............. Data Parameters ........... Sample concentration 

and calibration span.

Average Hg concentration for the run ≤ calibration span.Each run. 

1 M = Mandatory; S = Suggested; A = Alternative. 

2These may either be the unadjusted Hg concentrations or concentrations normalized to account for temporal variations. 

10.0 Calibration and Standardization 

What measurement system calibrations are 

required? 

Your analyzer must be calibrated with Hg° 

standards. The initial 3-point system 

calibration error test described in Section 

8.2.4 is required before you start the test. 

Also, prior to and following test runs, the 

two-point system integrity checks described 

in Sections 8.2.5 and 8.2.8 are required. On 

and after January 1, 2009, the pre-test 

dynamic spiking procedure described in 

section 8.2.7 is also required to verify that the 

accuracy of the measurement system is 

suitable and not adversely affected by the 

flue gas matrix. 

11.0 Analytical Procedures 

Because sample collection and analysis are 

performed together (see Section 8), additional 

discussion of the analytical procedure is not 

necessary. 

12.0 Calculations and Data Analysis 

You must follow the procedures for 

calculations and data analysis listed in this 

section. 

12.1 Nomenclature. The terms used in the 

equations are defined as follows: 

Bws = Moisture content of sample gas as 

measured by Method 4 in Appendix A–

3 to this part, percent/100. 

Cavg = Average unadjusted Hg concentration 

for the test run, as indicated by the data 

recorder μg/m3. 

Cbaseline = Average Hg concentration measured 

before and after dynamic spiking 

injections, μg/m3. 

Cd = Hg concentration, dry basis, μg/m3. 

Cdif = Absolute value of the difference 

between the measured Hg concentrations 

of the reference HgCl2 calibration gas, 

with and without the individual or 

combined interference gases, μg/m3. 

Cdif avg = Average of the 3 absolute values of 

the difference between the measured Hg 

concentrations of the reference HgCl2

calibration gas, with and without the 

individual or combined interference 

gases, μg/m3. 

Cgas = Average Hg concentration in the 

effluent gas for the test run, adjusted for 

system calibration error, μg/m3. 

Cint = Measured Hg concentration of the 

reference HgCl2 calibration gas plus the 

individual or combined interference 

gases, μg/m3. 

Cm = Average of pre- and post-run system 

integrity check responses for the upscale 

(i.e., mid- or high-level) calibration gas, 

μg/m3. 

Cma = Actual concentration of the upscale 

(i.e., mid- or high-level) calibration gas 

used for the system integrity checks, μg/ 

m3. 

C0 = Average of pre- and post-run system 

integrity check responses from the zero 

gas, μg/m3. 

Cnative = Vapor phase Hg concentration in the 

source effluent, μg/m3. 

Cref = Measured Hg concentration of the 

reference HgCl2 calibration gas alone, in 

the interference test, μg/m3. 

Cs = Measured concentration of a calibration 

gas (zero-, low-, mid-, or high-level), 

when introduced in system calibration 

mode, μg/m3. 

Cspike = Actual Hg concentration of the spike 

gas, μg/m3. 

C*spike = Hg concentration of the spike gas 

required to achieve a certain target value 

for the spiked sample Hg concentration, 

μg/m3. 

Css = Measured Hg concentration of the 

spiked sample at the target level, μg/m3. 

C*ss = Expected Hg concentration of the 

spiked sample at the target level, μg/m3. 

Ctarget = Target Hg concentration of the spiked 

sample, μg/m3. 

CTnative = Measured tracer gas concentration 

present in native effluent gas, ppm. 

CTdir = Tracer gas concentration injected with 

spike gas, ppm. 

CTv = Diluted tracer gas concentration 

measured in a spiked sample, ppm. 

Cv = Certified Hg° or HgCl2 concentration of 

a calibration gas (zero, low, mid, or 

high), μg/m3. 

Cw = Hg concentration measured under moist 

sample conditions, wet basis, μg/m3. 

CS = Calibration span, μg/m3. 

D = Zero or upscale drift, percent of 

calibration span. 

DF = Dilution factor of the spike gas, 

dimensionless. 

I = Interference response, percent of 

calibration span. 

Qprobe = Total flow rate of the stack gas 

sample plus the spike gas, liters/min. 

Qspike = Flow rate of the spike gas, liters/min. 

Ri = Individual injection spike recovery, %;. 

R= Mean value of spike recoveries at a 

particular target level, %;. 

RSD = Relative standard deviation, %;. 

SCE = System calibration error, percent of 

calibration span. 

SCEi = Pre-run system calibration error 

during the two-point system integrity 

check, percent of calibration span. 

SCEf = Post-run system calibration error 

during the two-point system integrity 

check, percent of calibration span. 

12.2 System Calibration Error. Use 

Equation 30A–1 to calculate the system 

calibration error. Equation 30A–1 applies to: 

3–point system calibration error tests 

performed with Hg° standards; and pre- and 

post-run two-point system integrity checks 

performed with HgCl2. 

SCE = C C

CS 100 Eq. 30A-1 s v − ×

12.3 Drift Assessment. Use Equation 

30A–2 to separately calculate the zero and 

upscale drift for each test run. 

D = SCE Eq. 30A-2 SCEf − i

12.3 Effluent Hg Concentration. For each 

test run, calculate Cavg, the arithmetic average 

of all valid Hg concentration values recorded 

during the run. Then, adjust the value of Cavg


jlentini on PROD1PC65 with RULES2ER07SE07.005</MATH> ER07SE07.006</MATH>
51510 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

for system calibration error, using Equation 

30A–3. 

C = (C C ) C C Eq. 30A-3 gas avg 0

m 0

− −

Cma

12.4 Moisture Correction. Use Equation 

30A–4a if your measurements need to be 

corrected to a dry basis. 

C =

1 B Eq. 30A-4a d

w

ws

C

−

Use Equation 30A–4b if your 

measurements need to be corrected to a wet 

basis. 

C C (1 B Eq. 30A-4b w = ×− d ws )

12.5 Dynamic Spike Gas Concentrations. 

Use Equation 30A–5 to determine the spike 

gas concentration needed to produce a spiked 

sample with a certain ‘‘target’’ Hg 

concentration. 

C DF(C C C Eq. 30A-5 target native native

* ) spike = −+

12.6 Spiked Sample Concentration. Use 

Equation 30A–6 to determine the expected or 

theoretical Hg concentration of a spiked 

sample. 

C C ss native

* = +

(C C ) −

DF Eq. 30A-6 spike native

12.7 Spike Recovery. Use Equation 30A–

7 to calculate the percentage recovery of each 

spike. 

R DF C C

C Eq native native

spike

= − +× (C 30A-7 ss ) 100% .

12.8 Relative Standard Deviation. Use 

Equation 30A–8 to calculate the relative 

standard deviation of the individual 

percentage spike recovery values from the 

mean. 

RSD

R

R R

n

Eq

i

i

n

=

−

−

= 100 ∑

1

2

% 1

( )

. 30A-8

12.9 Spike Dilution Factor. Use Equation 

30A–9 to calculate the spike dilution factor, 

using either direct flow measurements or 

tracer gas measurements. 

DF Q

Q

C C

C C Eq probe

spike

Tdir Tnative

Ttv Tnative

= = −

− . 30A-9

12.10 Native Concentration. For spiking 

procedures that inject blank or carrier gases 

(at the spiking flow rate, Qspike) between 

spikes, use Equation 30A–10 to calculate the 

native concentration. 

C C DF

DF Eq native

baseline = −1

. 30A-10

For spiking procedures that halt all 

injections between spikes, the native 

concentration equals the average baseline 

concentration (see Equation 30A–11). 

C C Eq native baseline = . 30A-11

12.11 Overall Interference Response. Use 

equation 30A–12 to calculate the overall 

interference response. 

I

C

CS Eq difavg = × ∑ 100 . 30A-12

Where, for each interference gas (or 

mixture): 

C

C

Eq difavg

dif

=

∑1

3

3

. 30A-13

C C C Eq dif ref = − int . 30A-14


ER07SE07.007</MATH> ER07SE07.008</MATH> ER07SE07.009</MATH> ER07SE07.010</MATH> ER07SE07.011</MATH> ER07SE07.012</MATH> ER07SE07.013</MATH> ER07SE07.014</MATH> ER07SE07.015</MATH> ER07SE07.016</MATH> ER07SE07.017</MATH> ER07SE07.018</MATH> ER07SE07.019</MATH>jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51511 

13.0 Method Performance 

13.1 System Calibration Error Test. This 

specification applies to the 3-point system 

calibration error tests using Hg0. At each 

calibration gas level tested (low-, mid-, or 

high-level), the calibration error must be 

within ±5.0 percent of the calibration span. 

Alternatively, the results are acceptable if | Cs

¥ Cv | ≤0.5 μg/m3. 

13.2 System Integrity Checks. This 

specification applies to all pre- and post-run 

2-point system integrity checks using HgCl2

and zero gas. At each calibration gas level 

tested (zero and mid- or high-level), the error 

must be within ±5.0 percent of the calibration 

span. Alternatively, the results are acceptable 

if | Cs ¥ Cv | ≤0.5 μg/m3. 

13.3 Drift. For each run, the low-level and 

upscale drift must be less than or equal to 3.0 

percent of the calibration span. The drift is 

also acceptable if the pre- and post-run 

system integrity check responses do not 

differ by more than 0.3 μg/m3 (i.e., | Cs post-run

¥ Cs pre-run | ≤0.3 μg/m3). 

13.4 Interference Test. Summarize the 

results following the format contained in 

Table 30A–4. For each interference gas (or 

mixture), calculate the mean difference 

between the measurement system responses 

with and without the interference test gas(es). 

The overall interference response for the 

analyzer that was used for the test (calculated 

according to Equation 30A–12), must not be 

greater than 3.0 percent of the calibration 

span used for the test (see Section 8.6). The 

results of the interference test are also 

acceptable if the sum of the absolute average 

differences for all interference gases (i.e., S 

Cdif avg) does not exceed 0.3 μg/m3. 

13.5 Dynamic Spiking Test. For the pretest dynamic spiking, the mean value of the 

percentage spike recovery must be 100 ±10 

percent. In addition, the relative standard 

deviation (RSD) of the individual percentage 

spike recovery values from the mean must be 

≤5.0 percent. Alternatively, if the mean 

percentage recovery is not met, the results are 

acceptable if the absolute difference between 

the theoretical spiked sample concentration 

(see Section 12.6) and the actual average 

value of the spiked sample concentration is 

≤0.5 μg/m3. 

14.0 Pollution Prevention [Reserved] 

15.0 Waste Management [Reserved] 

16.0 References 

1. EPA Traceability Protocol for 

Qualification and Certification of Elemental 

Mercury Gas Generators, expected 

publication date December 2008, see 

www.epa.gov/ttn/emc. 

2. EPA Traceability Protocol for 

Qualification and Certification of Oxidized 

Mercury Gas Generators, expected 

publication date December 2008, see 

www.epa.gov/ttn/emc. 

3. EPA Traceability Protocol for Assay and 

Certification of Gaseous Calibration 

Standards, expected revision publication 

date December 2008, see www.epa.gov/ttn/ 

emc. 

17.0 Figures and Tables 

BILLING CODE 6560–50–C 


jlentini on PROD1PC65 with RULES2
51512 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 


jlentini on PROD1PC65 with RULES2ER07SE07.020</MATH>
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51513 


jlentini on PROD1PC65 with RULES2ER07SE07.021</MATH>
51514 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 


jlentini on PROD1PC65 with RULES2ER07SE07.022</MATH>
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51515 

TABLE 30A–3.—INTERFERENCE CHECK

GAS CONCENTRATIONS

Potential 

interferent gas 1

Concentration, 

tentative—(balance N2) 

CO2 ...................... 15% ± 1% CO2

CO ........................ 100 ± 20 ppm 

HCl 2 ..................... 100 ± 20 ppm 

NO 2 ...................... 250 ± 50 ppm 

SO2 ....................... 200 ± 20 ppm 

O2 ......................... 3% ± 1% O2

TABLE 30A–3.—INTERFERENCE CHECK

GAS CONCENTRATIONS—Continued 

Potential 

interferent gas 1

Concentration, 

tentative—(balance N2) 

H2O ...................... 10% ± 1% H2O 

Nitrogen ................ Balance 

TABLE 30A–3.—INTERFERENCE CHECK

GAS CONCENTRATIONS—Continued 

Potential 

interferent gas 1

Concentration, 

tentative—(balance N2) 

Other.

1Any of these specific gases can be tested 

at a lower level if the manufacturer has provided reliable means for limiting or scrubbing 

that gas to a specified level. 2 HCl and NO must be tested as a mixture. 


jlentini on PROD1PC65 with RULES2ER07SE07.023</MATH>
51516 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 


jlentini on PROD1PC65 with RULES2ER07SE07.024</MATH>
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51517 


jlentini on PROD1PC65 with RULES2ER07SE07.025</MATH>
51518 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

Method 30B—Determination of Total Vapor 

Phase Mercury Emissions From Coal-Fired 

Combustion Sources Using Carbon Sorbent 

Traps 

1.0 Scope and Application 

What is Method 30B? 

Method 30B is a procedure for measuring 

total vapor phase mercury (Hg) emissions 

from coal-fired combustion sources using 

sorbent trap sampling and an extractive or 

thermal analytical technique. This method is 

only intended for use only under relatively 

low particulate conditions (e.g., sampling 

after all pollution control devices). Quality 

assurance and quality control requirements 

are included to assure that you, the tester, 

collect data of known and acceptable quality 

for each testing program. This method does 

not completely describe all equipment, 

supplies, and sampling and analytical 

procedures you will need, but instead refers 

to other test methods for some of the details. 

Therefore, to obtain reliable results, you 

should also have a thorough knowledge of 

these additional methods which are found in 

Appendices A–1 and A–3 to this part: 

(a) Method 1—Sample and Velocity 

Traverses for Stationary Sources. 

(b) Method 4—Determination of Moisture 

Content in Stack Gases. 

(c) Method 5—Determination of Particulate 

Matter Emissions from Stationary Sources 

1.1 Analytes. What does this method 

determine? This method is designed to 

measure the mass concentration of total 

vapor phase Hg in flue gas, including 

elemental Hg (Hg0) and oxidized forms of Hg 

(Hg∂2), in micrograms per dry standard cubic 

meter (μg/dscm). 

Analyte CAS No. 

Analytical 

range and 

sensitivity 

Elemental Hg 

(Hg 0 ).

7439–97–6 Typically 0.1 

μg/dscm to 

>50 μg/ 

dscm. 

Oxidized Hg 

(Hg∂2).

.................... (Same) 

1.2 Applicability. When is this method 

required? Method 30B is a reference method 

for relative accuracy test audits (RATAs) of 

vapor phase Hg CEMS and sorbent trap 

monitoring systems installed at coal-fired 

boilers and is also appropriate for Hg 

emissions testing at such boilers. It is 

intended for use only under relatively low 

particulate conditions (i.e., sampling after all 

pollution control devices); in cases where 

significant amounts of particle-bound Hg 

may be present, an isokinetic sampling 

method for Hg should be used. Method 30B 

may also be specified by New Source 

Performance Standards (NSPS), National 

Emission Standards for Hazardous Air 

Pollutants (NESHAP), emissions trading 

programs, State Implementation Plans (SIPs), 

and operating permits that require 

measurement of Hg concentrations in 

stationary source emissions, either to 

determine compliance with an applicable 

emission standard or limit, or to conduct 

RATAs of Hg CEMS and sorbent trap 

monitoring systems. 

1.3 Data Quality Objectives (DQO). How 

good must my collected data be? Method 30B 

has been designed to provide data of high 

and known quality for Hg emissions testing 

and for RATA testing of Hg monitoring 

systems, including CEMS and sorbent trap 

monitors. In these and other applications, the 

principal objective is to ensure the accuracy 

of the data at the actual emissions levels and 

in the actual emissions matrix encountered. 

To meet this objective, NIST-traceable 

calibration standards must be used and 

method performance tests are required. 

2.0 Summary of Method 

Known volumes of flue gas are extracted 

from a stack or duct through paired, in-stack 

sorbent media traps at an appropriate flow 

rate. Collection of mercury on the sorbent 

media in the stack mitigates potential loss of 

mercury during transport through a probe/ 

sample line. For each test run, paired train 

sampling is required to determine 

measurement precision and verify 

acceptability of the measured emissions data. 

A field recovery test which assesses recovery 

of an elemental Hg spike to determine 

measurement bias is also used to verify data 

acceptability. The sorbent traps are recovered 

from the sampling system, prepared for 

analysis as needed, and analyzed by any 

suitable determinative technique that can 

meet the performance criteria. 

3.0 Definitions 

3.1 Analytical System is the combined 

equipment and apparatus used to perform 

sample analyses. This includes any 

associated sample preparation apparatus e.g., 

digestion equipment, spiking systems, 

reduction devices, etc., as well as analytical 

instrumentation such as UV AA and UV AF 

cold vapor analyzers. 

3.2 Calibration Standards are the Hg 

containing solutions prepared from NIST 

traceable standards and are used to directly 

calibrate analytical systems. 

3.3 Independent Calibration Standard is 

a NIST traceable standard obtained from a 

source or supplier independent of that for the 

calibration standards and is used to confirm 

the integrity of the calibration standards 

used. 

3.4 Method Detection Limit (MDL) is the 

lowest mass of Hg greater than zero that can 

be estimated and reported by your candidate 

analytical technique. The MDL is statistically 

derived from replicate low level 

measurements near your analytical 

instrument’s detection level. 

3.5 NIST means the National Institute of 

Standards and Technology, located in 

Gaithersburg, Maryland. 

3.6 Run means a series of gas samples 

taken successively from the stack or duct. A 

test normally consists of a specific number of 

runs. 

3.7 Sorbent Trap means a cartridge or 

sleeve containing a sorbent media (typically 

activated carbon treated with iodine or some 

other halogen) with multiple sections 

separated by an inert material such as glass 

wool. These sorbent traps are optimized for 

the quantitative capture of elemental and 

oxidized forms of Hg and can be analyzed by 

multiple techniques. 

3.8 Test refers to the series of runs 

required by the applicable regulation. 

3.9 Thermal Analysis means an analytical 

technique where the contents of the sorbent 

traps are analyzed using a thermal technique 

(desorption or combustion) to release the 

captured Hg in a detectable form for 

quantification. 

3.10 Wet Analysis means an analytical 

technique where the contents of the sorbent 

tube are first leached or digested to 

quantitatively transfer the captured Hg to 

liquid solution for subsequent analysis. 

4.0 Interferences 

Interferences may result from the sorbent 

trap material used as well as from the 

measurement environment itself. The iodine 

present on some sorbent traps may impart a 

negative measurement bias. High levels of 

sulfur trioxide (SO3) are also suspected to 

compromise the performance of sorbent trap 

Hg capture. These, and other, potential 

interferences are assessed by performing the 

analytical matrix interference, Hg0 and HgCl2

analytical bias and field recovery tests. 

5.0 Safety 

What safety measures should I consider 

when using this method? This method may 

require you to work with hazardous materials 

and in hazardous conditions. You are 

encouraged to establish safety procedures 

before using the method. Among other 

precautions, you should become familiar 

with the safety recommendations in the gas 

analyzer user’s manual. Occupational Safety 

and Health Administration (OSHA) 

regulations concerning use of compressed gas 

cylinders and noxious gases may apply. 

5.1 Site Hazards. Prior to applying these 

procedures/specifications in the field, the 

potential hazards at the test site should be 

considered; advance coordination with the 

site is critical to understand the conditions 

and applicable safety policies. At a 

minimum, portions of the sampling system 

will be hot, requiring appropriate gloves, 

long sleeves, and caution in handling this 

equipment. 

5.2 Laboratory Safety. Policies should be 

in place to minimize risk of chemical 

exposure and to properly handle waste 

disposal in the laboratory. Personnel shall 

wear appropriate laboratory attire according 

to a Chemical Hygiene Plan established by 

the laboratory. 

5.3 Reagent Toxicity/Carcinogenicity. 

The toxicity and carcinogenicity of any 

reagents used must be considered. Depending 

upon the sampling and analytical 

technologies selected, this measurement may 

involve hazardous materials, operations, and 

equipment and this method does not address 

all of the safety problems associated with 

implementing this approach. It is the 

responsibility of the user to establish 

appropriate safety and health practices and 

determine the applicable regulatory 

limitations prior to performance. Any 

chemical should be regarded as a potential 

health hazard and exposure to these 

compounds should be minimized. Chemists 

should refer to the Material Safety Data Sheet 

(MSDS) for each chemical used. 

5.4 Waste Disposal. Any waste generated 

by this procedure must be disposed of 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51519 

according to a hazardous materials 

management plan that details and tracks 

various waste streams and disposal 

procedures. 

6.0 Equipment and Supplies 

The following list is presented as an 

example of key equipment and supplies 

likely required to measure vapor-phase Hg 

using a sorbent trap sampling system. It is 

recognized that additional equipment and 

supplies may be needed. Collection of paired 

samples is required. 

6.1 Sorbent Trap Sampling System. A 

typical sorbent trap sampling system is 

shown in Figure 30B–1 in Section 17.0. The 

sorbent trap sampling system shall include 

the following components: 

6.1.1 Sorbent Traps. The sorbent media 

used to collect Hg must be configured in a 

trap with at least two distinct segments or 

sections, connected in series, that are 

amenable to separate analyses. Section 1 is 

designated for primary capture of gaseous Hg. 

Section 2 is designated as a backup section 

for determination of vapor phase Hg 

breakthrough. Each sorbent trap must be 

inscribed or otherwise permanently marked 

with a unique identification number, for 

tracking purposes. The sorbent media may be 

any collection material (e.g., carbon, 

chemically-treated filter, etc.) capable of 

quantitatively capturing and recovering for 

subsequent analysis, all gaseous forms of Hg 

in the emissions from the intended 

application. Selection of the sorbent media 

shall be based on the material’s ability to 

achieve the performance criteria contained in 

this method as well as the sorbent’s vapor 

phase Hg capture efficiency for the emissions 

matrix and the expected sampling duration at 

the test site. The sorbent media must be 

obtained from a source that can demonstrate 

their quality assurance and quality control 

(see Section 7.2). The paired sorbent traps are 

supported on a probe (or probes) and inserted 

directly into the flue gas stream. 

6.1.2 Sampling Probe Assembly. Each 

probe assembly shall have a leak-free 

attachment to the sorbent trap(s). Each 

sorbent trap must be mounted at the entrance 

of or within the probe such that the gas 

sampled enters the trap directly. Each probe/ 

sorbent trap assembly must be heated to a 

temperature sufficient to prevent liquid 

condensation in the sorbent trap(s). Auxiliary 

heating is required only where the stack 

temperature is too low to prevent 

condensation. Use a calibrated thermocouple 

to monitor the stack temperature. A single 

probe capable of operating the paired sorbent 

traps may be used. Alternatively, individual 

probe/sorbent trap assemblies may be used, 

provided that the individual sorbent traps are 

co-located to ensure representative Hg 

monitoring. 

6.1.3 Moisture Removal Device. A 

moisture removal device or system shall be 

used to remove water vapor from the gas 

stream prior to entering dry gas flow 

metering devices. 

6.1.4 Vacuum Pump. Use a leak-tight, 

vacuum pump capable of operating within 

the system’s flow range. 

6.1.5 Gas Flow Meter. A gas flow meter 

(such as a dry gas meter, thermal mass flow 

meter, or other suitable measurement device) 

shall be used to determine the total sample 

volume on a dry basis, in units of standard 

cubic meters. The meter must be sufficiently 

accurate to measure the total sample volume 

to within 2 percent and must be calibrated 

at selected flow rates across the range of 

sample flow rates at which the sampling train 

will be operated. The gas flow meter shall be 

equipped with any necessary auxiliary 

measurement devices (e.g., temperature 

sensors, pressure measurement devices) 

needed to correct the sample volume to 

standard conditions. 

6.1.6 Sample Flow Rate Meter and 

Controller. Use a flow rate indicator and 

controller for maintaining necessary 

sampling flow rates. 

6.1.7 Temperature Sensor. Same as 

Section 6.1.1.7 of Method 5 in Appendix A–

3 to this part. 

6.1.8 Barometer. Same as Section 6.1.2 of 

Method 5 in Appendix A–3 to this part. 

6.1.9 Data Logger (optional). Device for 

recording associated and necessary ancillary 

information (e.g., temperatures, pressures, 

flow, time, etc.). 

6.2 Gaseous Hg0 Sorbent Trap Spiking 

System. A known mass of gaseous Hg0 must 

be either present on or spiked onto the first 

section of sorbent traps in order to perform 

the Hg0 and HgCl2 analytical bias test and the 

field recovery study. Any approach capable 

of quantitatively delivering known masses of 

Hg0 onto sorbent traps is acceptable. Several 

spiking technologies or devices are available 

to meet this objective. Their practicality is a 

function of Hg mass spike levels. For low 

levels, NIST-certified or NIST-traceable gas 

generators or tanks may be suitable. An 

alternative system, capable of delivering 

almost any mass required, makes use of 

NIST-certified or NIST-traceable Hg salt 

solutions (e.g., HgCl2, Hg(NO3)2). With this 

system, an aliquot of known volume and 

concentration is added to a reaction vessel 

containing a reducing agent (e.g., stannous 

chloride); the Hg salt solution is reduced to 

Hg0 and purged onto the sorbent trap using 

an impinger sparging system. When 

available, information on example spiking 

systems will be posted at http:// 

www.epa.gov/ttn/emc. 

6.3 Sample Analysis Equipment. Any 

analytical system capable of quantitatively 

recovering and quantifying total Hg from the 

sorbent media selected is acceptable 

provided that the analysis can meet the 

performance criteria described in this 

method. Example recovery techniques 

include acid leaching, digestion, and thermal 

desorption/direct combustion. Example 

analytical techniques include, but are not 

limited to, ultraviolet atomic fluorescence 

(UV AF), ultraviolet atomic absorption (UV 

AA) with and without gold trapping, and Xray fluorescence (XRF) analysis. 

6.3 Moisture Measurement System. If 

correction of the measured Hg emissions for 

moisture is required (see Section 8.3.3.7), 

either Method 4 in Appendix A–3 to this part 

or other moisture measurement methods 

approved by the Administrator will be 

needed to measure stack gas moisture 

content. 

7.0 Reagents and Standards 

7.1 Reagents and Standards. Only NISTcertified or NIST-traceable calibration 

standards, standard reference materials, and 

reagents shall be used for the tests and 

procedures required by this method. 

7.2 Sorbent Trap Media. The sorbent trap 

media shall be prepared such that the 

material used for testing is of known and 

acceptable quality. Sorbent supplier quality 

assurance/quality control measures to ensure 

appropriate and consistent performance such 

as sorptive capacity, uniformity of 

preparation treatments, and background 

levels shall be considered. 

8.0 Sample Collection and Handling 

This section presents the sample collection 

and handling procedures along with the 

pretest and on-site performance tests 

required by this method. Since you may 

choose different options to comply with 

certain performance criteria, each test report 

must identify the specific options selected 

and document the results with respect to the 

performance criteria of this method. 

8.1 Sample Point Selection. What 

sampling site and sampling points do I 

select? Same as Section 8.1 of Method 30A 

of this appendix. 

8.2 Measurement System Performance 

Tests. What performance criteria must my 

measurement system meet? The following 

laboratory and field procedures and 

associated criteria of this section are 

designed to ensure (1) selection of a sorbent 

and analytical technique combination 

capable of quantitative collection and 

analysis of gaseous Hg, (2) collection of an 

adequate amount of Hg on each sorbent trap 

during field tests, and (3) adequate 

performance of the method for each test 

program: The primary objectives of these 

performance tests are to characterize and 

verify the performance of your intended 

analytical system and associated sampling 

and analytical procedures, and to define the 

minimum amount of Hg (as the sample 

collection target) that can be quantified 

reliably. 

(a) Analytical Matrix Interference Test; 

(b) Determination of Minimum Sample 

Mass; 

(c) Hg0 and HgCl2 Analytical Bias Test; 

(d) Determination of Nominal Sample 

Volume; 

(e) Field Recovery Test. 

8.2.1 Analytical Matrix Interference Test 

and Minimum Sample Dilution. 

(a) The analytical matrix interference test 

is a laboratory procedure. It is required only 

if you elect to use a liquid digestion 

analytical approach and needs to be 

performed only once for each sorbent 

material used. The purpose of the test is to 

verify the presence or absence of known and 

potential analytical matrix interferences, 

including the potential negative bias 

associated with iodine common to many 

sorbent trap materials. The analytical matrix 

interference test determines the minimum 

dilution (if any) necessary to mitigate matrix 

effects on the sample digestate solutions. 

(b) The result of the analytical matrix 

interference test, i.e., the minimum sample 

dilution required (if any) for all sample 


jlentini on PROD1PC65 with RULES2
51520 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

analyses, is used to establish the minimum 

sample mass needed for the Hg0 and HgCl2

analytical bias test and to determine the 

nominal sample volume for a test run. The 

analytical matrix interference test is sorbent 

material-specific and shall be performed for 

each sorbent material you intend to use for 

field sampling and analysis. The test shall be 

performed using a mass of sorbent material 

comparable to the sorbent mass typically 

used in the first section of the trap for 

sampling. Similar sorbent materials from 

different sources of supply are considered to 

be different materials and must be tested 

individually. You must conduct the 

analytical matrix interference test for each 

sorbent material prior to the analysis of field 

samples. 

8.2.1.1 Analytical Matrix Interference 

Test Procedures. Digest and prepare for 

analysis a representative mass of sorbent 

material (unsampled) according to your 

intended laboratory techniques for field 

samples. Analyze the digestate according to 

your intended analytical conditions at the 

least diluted level you intend to use for 

sample analysis (e.g., undiluted, 1 in 10 

dilution, etc.). Determine the Hg 

concentration of the undiluted digestate 

solution. Prepare a series of solutions with a 

fixed final volume containing graduated 

aliquots of the sample digestate and, a fixed 

aliquot of a calibration standard (with the 

balance being Hg-free reagent or H20) to 

establish solutions of varied digestate 

dilution ratio (e.g., 1:2, 1:5, 1:10, 1:100, etc.—

see example in Section 8.2.1.3, below). One 

of these solutions should contain only the 

aliquot of the calibration standard in Hg-free 

reagent or H2O. This will result in a series 

of solutions where the amount of Hg is held 

relatively constant and only the volume of 

digestate diluted is varied. Analyze each of 

these solutions following intended sample 

analytical procedures and conditions, 

determining the concentration for each 

solution. 

8.2.1.2 Analytical Matrix Interference 

Test Acceptance Criteria. Compare the 

measured concentration of each solution 

containing digestate to the measured 

concentration of the digestate-free solution. 

The lowest dilution ratio of any solution 

having a Hg concentration within ±5 percent 

of the digestate-free solution is the minimum 

dilution ratio required for analysis of all 

samples. If you desire to measure the 

digestate without dilution, the ± 5 percent 

criterion must be met at a dilution ratio of 

at least 9:10 (i.e., ≥90% digestate). 

8.2.1.3 Example Analytical Matrix 

Interference Test. An example analytical 

matrix interference test is presented below. 

Additional information on the conduct of the 

analytical matrix interference test will be 

posted at http://www.epa.gov/ttn/emc. 

Determine the most sensitive working range 

for the analyzer to be used. This will be a 

narrow range of concentrations. Digest and 

prepare for analysis a representative mass of 

sorbent material (unsampled) according to 

your intended laboratory techniques for 

sample preparation and analysis. Prepare a 

calibration curve for the most sensitive 

analytical region, e.g., 0.0, 0.5, 1.0, 3.0, 5.0, 

10 ppb. Using the highest calibration 

standard, e.g., 10.0 ppb, prepare a series of 

solutions by adding successively smaller 

increments of the digestate to a fixed volume 

of the calibration standard and bringing each 

solution to a final fixed volume with 

mercury-free deionized water (diH2O). To 2.0 

ml of the calibration standard add 18.0, 10.0, 

4.0, 2.0, 1.0, 0.2, and 0.0 ml of the digestate. 

Bring the final volume of each solution to a 

total volume of 20 ml by adding 0.0, 8.0, 

14.0, 16.0, 17.0, 17.8, and 18.0 ml of diH2O. 

This will yield solutions with dilution ratios 

of 9:10, 1:2, 1:5, 1:10, 1:20, 1:100, and 0:10, 

respectively. Determine the Hg concentration 

of each solution. The dilution ratio of any 

solution having a concentration that is within 

±5 percent of the concentration of the 

solution containing 0.0 ml of digestate is an 

acceptable dilution ratio for analyzing field 

samples. If more than one solution meets this 

criterion, the one with the lowest dilution 

ratio is the minimum dilution required for 

analysis of field samples. If the 9:10 dilution 

meets this criterion, then no sample dilution 

is required. 

8.2.2 Determination of Minimum Sample 

Mass. The minimum mass of Hg that must be 

collected per sample must be determined. 

This information is necessary in order to 

effectively perform the Hg0 and HgCl2

Analytical Bias Test, to estimate target 

sample volumes/sample times for test runs, 

and to ensure the quality of the 

measurements. The determination of 

minimum sample mass is a direct function of 

analytical technique, measurement 

sensitivity, dilutions, etc. This determination 

is required for all analytical techniques. 

Based on the analytical approach you 

employ, you should determine the most 

sensitive calibration range. Based on a 

calibration point within that range, you must 

consider all sample treatments (e.g., 

dilutions) to determine the mass of sample 

that needs to be collected to ensure that all 

sample analyses fall within your calibration 

curve. 

8.2.2.1 Determination of Minimum 

Calibration Concentration or Mass. Based on 

your instrument’s sensitivity and linearity, 

determine the calibration concentrations or 

masses that make up a representative low 

level calibration range. Verify that you are 

able to meet the multipoint calibration 

performance criteria in section 11.0 of this 

method. Select a calibration concentration or 

mass that is no less than 2 times the lowest 

concentration or mass in your calibration 

curve. The lowest point in your calibration 

curve must be at least 5, and preferably 10, 

times the Method Detection Limit (MDL), 

which is the minimum amount of the analyte 

that can be detected and reported. The MDL 

must be determined at least once for the 

analytical system using an MDL study such 

as that found in section 17.0 of the proposed 

amendments to EPA Method 301 (69 FR 

76642, 12/22/2004). 

Note to Section 8.2.2.1: While it might be 

desirable to base the minimum calibration 

concentration or mass on the lowest point in 

the calibration curve, selecting a higher 

concentration or mass is necessary to ensure 

that all analyses of the field samples will fall 

within the calibration curve. Therefore, it is 

strongly recommended that you select a 

minimum calibration concentration or mass 

that is sufficiently above the lowest point of 

the calibration curve (see examples in 

sections 8.2.2.2.1 and 8.2.2.2.2 below). 

8.2.2.2 Determination of Minimum 

Sample Mass. Based on your minimum 

calibration concentration or mass and other 

sample treatments including, but not limited 

to, final digestate volume and minimum 

sample dilution, determine the minimum 

sample mass. Consideration should also be 

given to the Hg levels expected to be 

measured in Section 2 of the sorbent traps 

and to the breakthrough criteria presented in 

Table 9–1. 

8.2.2.2.1 Example Determination of 

Minimum Sample Mass for Thermal 

Desorption Analysis. A thermal analysis 

system has been calibrated at five Hg mass 

levels: 10 ng, 20 ng, 50 ng, 100 ng, 200 ng, 

and shown to meet the calibration 

performance criteria in this method. Based 

on 2 times the lowest point in the calibration 

curve, 20 ng is selected as the minimum 

calibration mass. Because the entire sample 

is analyzed and there are no dilutions 

involved, the minimum sample mass is also 

20 ng. 

Note: In this example, if the typical 

background (blank) Hg levels in section 2 

were relatively high (e.g., 3 to 5 ng), a sample 

mass of 20 ng might not have been sufficient 

to ensure that the breakthrough criteria in 

Table 9–1 would be met, thereby 

necessitating the use of a higher point on the 

calibration curve (e.g., 50 ng) as the 

minimum calibration and sample mass. 

8.2.2.2.2 Example Determination of 

Minimum Sample Mass for Acid Leachate/ 

Digestate Analysis. A cold vapor analysis 

system has been calibrated at four Hg 

concentration levels: 2 ng/L, 5 ng, 10 ng/L, 

20 ng/L, and shown to meet the calibration 

performance criteria in this method. Based 

on 2 times the lowest point in the calibration 

curve, 4 ng/L was selected as the minimum 

calibration concentration. The final sample 

volume of a digestate is nominally 50 ml 

(0.05 L) and the minimum dilution necessary 

was determined to be 1:100 by the Analytical 

Matrix Interference Test of Section 8.2.1. The 

following calculation would be used to 

determine the minimum sample mass. 

Minimum sample mass = (4 ng/L) × (0.05 L) 

× (100) = 20 ng 

Note: In this example, if the typical 

background (blank) Hg levels in section 2 

were relatively high (e.g., 3 to 5 ng), a sample 

mass of 20 ng might not have been sufficient 

to ensure that the breakthrough criterion in 

Table 9–1 would be met, thereby 

necessitating the use of a higher point on the 

calibration curve (e.g., 10 ng/L) as the 

minimum calibration concentration. 

8.2.3 Hg0 and HgCl2 Analytical Bias Test. 

Before analyzing any field samples, the 

laboratory must demonstrate the ability to 

recover and accurately quantify Hg0 and 

HgCl2 from the chosen sorbent media by 

performing the following analytical bias test 

for sorbent traps spiked with Hg0 and HgCl2. 

The analytical bias test is performed at a 

minimum of two distinct sorbent trap Hg 

loadings that will: (1) Represent the lower 

and upper bound of sample Hg loadings for 

application of the analytical technique to the 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51521 

field samples, and (2) be used for data 

validation. 

8.2.3.1 Hg0 and HgCl2 Analytical Bias 

Test Procedures. Determine the lower and 

upper bound mass loadings. The minimum 

sample mass established in Section 8.2.2.2 

can be used for the lower bound Hg mass 

loading although lower Hg loading levels are 

acceptable. The upper bound Hg loading 

level should be an estimate of the greatest 

mass loading that may result as a function of 

stack concentration and volume sampled. As 

previously noted, this test defines the bounds 

that actual field samples must be within in 

order to be valid. 

8.2.3.1.1 Hg0 Analytical Bias Test. 

Analyze the front section of three sorbent 

traps containing Hg0 at the lower bound mass 

loading level and the front section of three 

sorbent traps containing Hg0 at the upper 

bound mass loading level. In other words, 

analyze each mass loading level in triplicate. 

You may refer to Section 6.2 for spiking 

guidance. Prepare and analyze each spiked 

trap, using the same techniques that will be 

used to prepare and analyze the field 

samples. The average recovery for the three 

traps at each mass loading level must be 

between 90 and 110 percent. If multiple 

types of sorbent media are to be analyzed, a 

separate analytical bias test is required for 

each sorbent material. 

8.2.3.1.2 HgCl2 Analytical Bias Test. 

Analyze the front section of three sorbent 

traps containing HgCl2 at the lower bound 

mass loading level and the front section of 

three traps containing HgCl2 at the upper 

bound mass loading level. HgCl2 can be 

spiked as a gas, or as a liquid solution 

containing HgCl2. However the liquid volume 

spiked must be <100 μL. Prepare and analyze 

each spiked trap, using the techniques that 

will be used to prepare and analyze the field 

samples. The average recovery for three traps 

at each spike concentration must be between 

90 and 110 percent. Again, if multiple types 

of sorbent media are to be analyzed, a 

separate analytical bias test is required for 

each sorbent material. 

8.2.4 Determination of Target Sample 

Volume. The target sample volume is an 

estimate of the sample volume needed to 

ensure that valid emissions data are collected 

(i.e., that sample mass Hg loadings fall within 

the analytical calibration curve and are 

within the upper and lower bounds set by the 

analytical bias tests). The target sample 

volume and minimum sample mass can also 

be determined by performing a diagnostic 

test run prior to initiation of formal testing. 

Example: If the minimum sample mass is 

50 ng and the concentration of mercury in 

the stack gas is estimated to be 2 μg/m3 (ng/ 

L) then the following calculation would be 

used to determine the target sample volume: 

Target Sample Volume = (50 ng)/(2 ng/L) = 

25 L 

Note: For the purposes of relative accuracy 

testing of Hg monitoring systems under part 

75 of this chapter and Performance 

Specification 12A in appendix B to this part, 

when the stack gas Hg concentration is 

expected to be very low (<0.5 μg/dscm) you 

may estimate the Hg concentration at 0.5 μg/ 

dscm. 

8.2.5 Determination of Sample Run Time. 

Sample run time will be a function of 

minimum sample mass (see Section 8.2.2), 

target sample volume and nominal 

equipment sample flow rate. The minimum 

sample run time for conducting relative 

accuracy test audits of Hg monitoring 

systems is 30 minutes and for emissions 

testing to characterize an emission source is 

1 hour. The target sample run time can be 

calculated using the following example. 

Example: If the target sample volume has 

been determined to be 25 L, then the 

following formula would be used to 

determine the sampling time necessary to 

acquire 25 L of gas when sampling at a rate 

of 0.4 L/min. 

Sampling time (min) = 25 L / 0.4 L/min = 63 

minutes 

8.2.6 Field Recovery Test. The field 

recovery test provides a test program-specific 

verification of the performance of the 

combined sampling and analytical approach. 

Three sets of paired samples, one of each pair 

which is spiked with a known level of Hg, 

are collected and analyzed and the average 

recovery of the spiked samples is used to 

verify performance of the measurement 

system under field conditions during that test 

program. The conduct of this test requires an 

estimate or confirmation of the stack Hg 

concentrations at the time of testing. 

8.2.6.1 Calculation of Pre-sampling 

Spiking Level. Determine the sorbent trap 

spiking level for the field recovery test using 

estimates of the stack Hg concentration, the 

target sample flow rate, and the planned 

sample duration. First, determine the Hg 

mass expected to be collected in section 1 of 

the sorbent trap. The pre-sampling spike 

must be within 50 to 150 percent of this 

expected mass. 

Example calculation: For an expected stack 

Hg concentration of 5 ug/m3 (ng/L) a target 

sample rate of 0.40 liters/min, and a sample 

duration of 1 hour: 

(0.40 L/min)*(60 min)*(5ng/L) = 120 ng 

A Hg spike of 60 to 180 ng (50–150% of 

120 ng) would be appropriate. 

8.2.6.2 Procedures. Set up two identical 

sampling trains. One of the sampling trains 

shall be designated the spiked train and the 

other the unspiked train. Spike Hg0 onto the 

front section of the sorbent trap in the spiked 

train before sampling. The mass of Hg spiked 

shall be 50 to 150 percent of the mass 

expected to be collected with the unspiked 

train. Sample the stack gas with the two 

trains simultaneously using the same 

procedures as for the field samples (see 

Section 8.3). The total sample volume must 

be within ±20 percent of the target sample 

volume for the field sample test runs. 

Analyze the sorbent traps from the two trains 

utilizing the same analytical procedures and 

instrumentation as for the field samples (see 

Section 11.0). Determine the fraction of 

spiked Hg recovered (R) using the equations 

in Section 12.7. Repeat this procedure for a 

total of three runs. Report the individual R 

values in the test report; the average of the 

three R values must be between 85 and 115 

percent. 

Note to section 8.2.6.2: It is acceptable to 

perform the field recovery test concurrent 

with actual test runs (e.g., through the use of 

a quad probe). It is also acceptable to use the 

field recovery test runs as test runs for 

emissions testing or for the RATA of a Hg 

monitoring system under part 75 of this 

chapter and Performance Specification 12A 

in appendix B to this part, if certain 

conditions are met. To determine whether a 

particular field recovery test run may be used 

as a RATA run, subtract the mass of the Hg0

spike from the total Hg mass collected in 

sections 1 and 2 of the spiked trap. The 

difference represents the mass of Hg in the 

stack gas sample. Divide this mass by the 

sample volume to obtain the Hg 

concentration in the effluent gas stream, as 

measured with the spiked trap. Compare this 

concentration to the corresponding Hg 

concentration measured with the unspiked 

trap. If the paired trains meet the relative 

deviation and other applicable data 

validation criteria in Table 9–1, then the 

average of the two Hg concentrations may be 

used as an emissions test run value or as the 

reference method value for a RATA run. 

8.3 Sampling. This section describes the 

procedures and criteria for collecting the 

field samples for analysis. As noted in 

Section 8.2.6, the field recovery test samples 

are also collected using these procedures. 

8.3.1 Pre-test leak check. Perform a leak 

check of the sampling system with the 

sorbent traps in place. For each of the paired 

sampling trains, draw a vacuum in the train, 

and adjust the vacuum to ∼15′′ Hg; and, using 

the gas flow meter, determine leak rate. The 

leak rate for an individual train must not 

exceed 4 percent of the target sampling rate. 

Once the leak check passes this criterion, 

carefully release the vacuum in the sample 

train, then seal the sorbent trap inlet until the 

probe is ready for insertion into the stack or 

duct. 

8.3.2 Determination of Flue Gas 

Characteristics. Determine or measure the 

flue gas measurement environment 

characteristics (gas temperature, static 

pressure, gas velocity, stack moisture, etc.) in 

order to determine ancillary requirements 

such as probe heating requirements (if any), 

initial sampling rate, moisture management, 

etc. 

8.3.3 Sample Collection 

8.3.3.1 Remove the plug from the end of 

each sorbent trap and store each plug in a 

clean sorbent trap storage container. Remove 

the stack or duct port cap and insert the 

probe(s). Secure the probe(s) and ensure that 

no leakage occurs between the duct and 

environment. 

8.3.3.2 Record initial data including the 

sorbent trap ID, date, and the run start time. 

8.3.3.3 Record the initial gas flow meter 

reading, stack temperature, meter 

temperatures (if needed), and any other 

appropriate information, before beginning 

sampling. Begin sampling and target a 

sampling flow rate similar to that for the field 

recovery test. Then, at regular intervals (≤5 

minutes) during the sampling period, record 

the date and time, the sample flow rate, the 

gas meter reading, the stack temperature, the 

flow meter temperatures (if using a dry gas 

meter), temperatures of heated equipment 

such as the vacuum lines and the probes (if 

heated), and the sampling system vacuum 

readings. Adjust the sampling flow rate as 

necessary to maintain the initial sample flow 


jlentini on PROD1PC65 with RULES2
51522 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

rate. Ensure that the total volume sampled for 

each run is within 20 percent of the total 

volume sampled for the field recovery test. 

8.3.3.4 Data Recording. Obtain and record 

any essential operating data for the facility 

during the test period, e.g., the barometric 

pressure must be obtained for correcting 

sample volume to standard conditions when 

using a dry gas meter. At the end of the data 

collection period, record the final gas flow 

meter reading and the final values of all other 

essential parameters. 

8.3.3.5 Post-Test Leak Check. When 

sampling is completed, turn off the sample 

pump, remove the probe(s) with sorbent traps 

from the port, and carefully seal the end of 

each sorbent trap. Perform another leak check 

of each sampling train with the sorbent trap 

in place, at the maximum vacuum reached 

during the sampling period. Record the 

leakage rates and vacuums. The leakage rate 

for each train must not exceed 4 percent of 

the average sampling rate for the data 

collection period. Following each leak check, 

carefully release the vacuum in the sample 

train. 

8.3.3.6 Sample Recovery. Recover each 

sampled sorbent trap by removing it from the 

probe and sealing both ends. Wipe any 

deposited material from the outside of the 

sorbent trap. Place the sorbent trap into an 

appropriate sample storage container and 

store/preserve in appropriate manner (see 

Section 8.3.3.8). 

8.3.3.7 Stack Gas Moisture 

Determination. If the moisture basis of the 

measurements made with this method (dry) 

is different from the moisture basis of either: 

(1) the applicable emission limit; or (2) a Hg 

CEMS being evaluated for relative accuracy, 

you must determine the moisture content of 

the flue gas and correct for moisture using 

Method 4 in appendix A–3 to this part. If 

correction of the measured Hg concentrations 

for moisture is required, at least one Method 

4 moisture determination shall be made 

during each test run. 

8.3.3.8 Sample Handling, Preservation, 

Storage, and Transport. While the 

performance criteria of this approach provide 

for verification of appropriate sample 

handling, it is still important that the user 

consider, determine, and plan for suitable 

sample preservation, storage, transport, and 

holding times for these measurements. 

Therefore, procedures in ASTM WK223 

‘‘Guide for Packaging and Shipping 

Environmental Samples for Laboratory 

Analysis’’ shall be followed for all samples, 

where appropriate. To avoid Hg 

contamination of the samples, special 

attention should be paid to cleanliness 

during transport, field handling, sampling, 

recovery, and laboratory analysis, as well as 

during preparation of the sorbent cartridges. 

Collection and analysis of blank samples 

(e.g., reagent, sorbent, field, etc.,) is useful in 

verifying the absence or source of 

contaminant Hg. 

8.3.3.9 Sample Custody. Proper 

procedures and documentation for sample 

chain of custody are critical to ensuring data 

integrity. The chain of custody procedures in 

ASTM D4840–99 ‘‘Standard Guide for 

Sampling Chain-of-Custody Procedures’’

shall be followed for all samples (including 

field samples and blanks). 

9.0 Quality Assurance and Quality Control 

Table 9–1 summarizes the QA/QC 

performance criteria that are used to validate 

the Hg emissions data from Method 30B 

sorbent trap measurement systems. 

TABLE 9–1.—QUALITY ASSURANCE/QUALITY CONTROL CRITERIA FOR METHOD 30B 

QA/QC test or specification Acceptance criteria Frequency Consequences if not met 

Gas flow meter calibration (At 3 

settings or points).

Calibration factor (Yi) at each flow 

rate must be within ± 2% of the 

average value (Y).

Prior to initial use and when posttest check is not within ± 5% of 

Y.

Recalibrate at 3 points until the 

acceptance criteria are met. 

Gas flow meter post-test calibration check (Single-point).Calibration factor (Yi) must be 

within ± 5% of the Y value from 

the most recent 3-point calibration.

After each field test. For mass 

flow meters, must be done onsite, using stack gas.

Recalibrate gas flow meter at 3 

points to determine a new value 

of Y. For mass flow meters, 

must be done on-site, using 

stack gas. Apply the new Y 

value to the field test data. 

Temperature sensor calibration ..... Absolute temperature measures 

by sensor within ± 1.5% of a 

reference sensor.

Prior to initial use and before 

each test thereafter.

Recalibrate; sensor may not be 

used until specification is met. 

Barometer calibration ..................... Absolute pressure measured by 

instrument within ± 10 mm Hg 

of reading with a mercury barometer.

Prior to initial use and before 

each test thereafter.

Recalibrate; instrument may not 

be used until specification is 

met. 

Pre-test leak check ........................ ≤ 4% of target sampling rate ........ Prior to sampling .......................... Sampling shall not commence 

until the leak check is passed. 

Post-test leak check ...................... ≤ 4% of average sampling rate ..... After sampling ............................... Sample invalidated.* 

Analytical matrix interference test 

(wet chemical analysis, only).

Establish minimum dilution (if any) 

needed to eliminate sorbent 

matrix interferences.

Prior to analyzing any field samples; repeat for each type of 

sorbent used.

Field sample results not validated. 

Analytical bias test ......................... Average recovery between 90% 

and 110% for Hg0 and HgCl2 at 

each of the 2 spike concentration levels.

Prior to analyzing field samples 

and prior to use of new sorbent 

media.

Field samples shall not be analyzed until the percent recovery 

criteria has been met. 

Multipoint analyzer calibration ....... Each analyzer reading withini 

± 10% of true value and r2

≥ 0.99.

On the day of analysis, before 

analyzing any samples.

Recalibrate until successful. 

Analysis of independent calibration 

standard.

Within ± 10% of true value ........... Following daily calibration, prior to 

analyzing field samples.

Recalibrate and repeat independent standard analysis until 

successful. 

Analysis of continuing calibration 

verification standard (CCVS).

Within ± 10% of true value ........... Following daily calibration, after 

analyzing ≤10 field samples, 

and at end of each set of analyses.

Recalibrate and repeat independent standard analysis, reanalyze samples until successful, if possible; for destructive 

techniques, samples invalidated. 

Test run total sample volume ........ Within ± 20% of total volume sampled during field recovery test.Each individual sample ................. Sample invalidated. 

Sorbent trap section 2 breakthrough.<10% of section 1 Hg mass for 

Hg concentrations > 1 μg/dscm;.

Every sample ................................ Sample invalidated.* 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51523 

TABLE 9–1.—QUALITY ASSURANCE/QUALITY CONTROL CRITERIA FOR METHOD 30B—Continued 

QA/QC test or specification Acceptance criteria Frequency Consequences if not met 

≤ 20% of section 1 Hg mass for 

Hg concentrations ≤ 1 μg/dscm.

Paired sorbent trap agreement ...... ≤ 10% Relative Deviation (RD) 

mass for Hg concentrations > 1 

μg/dscm; 

Every run ...................................... Run invalidated.* 

≤ 20% RD or ≤ 0.2 μg/dscm absolute difference for Hg concentrations ≤ 1 μg/dscm.

Sample analysis ............................. Within valid calibration range 

(within calibration curve).

All Section 1 samples where 

stack Hg concentation is ≥ 0.5 

μg/dscm.

Reanalyze at more concentrated 

level if possible, samples invalidated if not within calibrated 

range. 

Sample analysis ............................. Within bounds of Hg0 and HgCl2

Analytical Bias Test.

All Section 1 samples where 

stack Hg concentration is ≥ 0.5 

μg/dscm.

Expand bounds of Hg0 and HgCl2

Analytical Bias Test; if not successful, samples invalidated. 

Field recovery test ......................... Average recovery between 85% 

and 115% for Hg0.

Once per field test ........................ Field sample runs not validated 

without successful field recovery test. 

* And data from the pair of sorbent traps are also invalidated. 

10.0 Calibration and Standardization 

10.1 Only NIST-certified and NISTtraceable calibration standards (i.e., 

calibration gases, solutions, etc.) shall be 

used for the spiking and analytical 

procedures in this method. 

10.2 Gas Flow Meter Calibration. 

10.2.1 Preliminaries. The manufacturer or 

equipment supplier of the gas flow meter 

should perform all necessary set-up, testing, 

programming, etc., and should provide the 

end user with any necessary instructions, to 

ensure that the meter will give an accurate 

readout of dry gas volume in standard cubic 

meters for this method. 

10.2.2 Initial Calibration. Prior to its 

initial use, a calibration of the gas flow meter 

shall be performed. The initial calibration 

may be done by the manufacturer, by the 

equipment supplier, or by the end user. If the 

flow meter is volumetric in nature (e.g., a dry 

gas meter), the manufacturer or end user may 

perform a direct volumetric calibration using 

any gas. For a mass flow meter, the 

manufacturer, equipment supplier, or end 

user may calibrate the meter using either: (1) 

A bottled gas mixture containing 12 ±0.5% 

CO2, 7 ±0.5% O2, and balance N2 (when this 

method is applied to coal-fired boilers); (2) a 

bottled gas mixture containing CO2, O2, and 

N2 in proportions representative of the 

expected stack gas composition; or (3) the 

actual stack gas. 

10.2.2.1 Initial Calibration Procedures. 

Determine an average calibration factor (Y) 

for the gas flow meter by calibrating it at 

three sample flow rate settings covering the 

range of sample flow rates at which the 

sampling system will be operated. You may 

either follow the procedures in section 10.3.1 

of Method 5 in appendix A–3 to this part or 

in section 16 of Method 5 in appendix A–3 

to this part. If a dry gas meter is being 

calibrated, use at least five revolutions of the 

meter at each flow rate. 

10.2.2.2 Alternative Initial Calibration 

Procedures. Alternatively, you may perform 

the initial calibration of the gas flow meter 

using a reference gas flow meter (RGFM). The 

RGFM may be: (1) A wet test meter calibrated 

according to section 10.3.1 of Method 5 in 

appendix A–3 to this part; (2) a gas flow 

metering device calibrated at multiple flow 

rates using the procedures in section 16 of 

Method 5 in appendix A–3 to this part; or (3) 

a NIST-traceable calibration device capable 

of measuring volumetric flow to an accuracy 

of 1 percent. To calibrate the gas flow meter 

using the RGFM, proceed as follows: While 

the Method 30B sampling system is sampling 

the actual stack gas or a compressed gas 

mixture that simulates the stack gas 

composition (as applicable), connect the 

RGFM to the discharge of the system. Care 

should be taken to minimize the dead 

volume between the gas flow meter being 

tested and the RGFM. Concurrently measure 

dry stack gas volume with the RGFM and the 

flow meter being calibrated for at least 10 

minutes at each of three flow rates covering 

the typical range of operation of the sampling 

system. For each set of concurrent 

measurements, record the total sample 

volume, in units of dry standard cubic meters 

(dscm), measured by the RGFM and the gas 

flow meter being tested. 

10.2.2.3 Initial Calibration Factor. 

Calculate an individual calibration factor Yi

at each tested flow rate from section 10.2.2.1 

or 10.2.2.2 of this method (as applicable) by 

taking the ratio of the reference sample 

volume to the sample volume recorded by 

the gas flow meter. Average the three Yi

values, to determine Y, the calibration factor 

for the flow meter. Each of the three 

individual values of Yi must be within ±0.02 

of Y. Except as otherwise provided in 

sections 10.2.2.4 and 10.2.2.5 of this method, 

use the average Y value from the initial 3- 

point calibration to adjust subsequent gas 

volume measurements made with the gas 

flow meter. 

10.2.2.4 Pretest On-Site Calibration Check 

(Optional). For a mass flow meter, if the most 

recent 3-point calibration of the flow meter 

was performed using a compressed gas 

mixture, you may want to conduct the 

following on-site calibration check prior to 

testing, to ensure that the flow meter will 

accurately measure the volume of the stack 

gas: While sampling stack gas, check the 

calibration of the flow meter at one 

intermediate flow rate setting representative 

of normal operation of the sampling system. 

If the pretest calibration check shows that the 

value of Yi, the calibration factor at the tested 

flow rate, differs from the current value of Y 

by more than 5 percent, perform a full 3- 

point recalibration of the meter using stack 

gas to determine a new value of Y, and 

(except as otherwise provided in section 

10.2.2.5 of this method) apply the new Y 

value to the data recorded during the field 

test. 

10.2.2.5 Post-Test Calibration Check. 

Check the calibration of the gas flow meter 

following each field test at one intermediate 

flow rate setting, either at, or in close 

proximity to, the average sample flow rate 

during the field test. For dry gas meters, 

ensure at least three revolutions of the meter 

during the calibration check. For mass flow 

meters, this check must be performed before 

leaving the test site, while sampling stack 

gas. If a one-point calibration check shows 

that the value of Yi at the tested flow rate 

differs by more than 5 percent from the 

current value of Y, repeat the full 3-point 

calibration procedure to determine a new 

value of Y, and apply the new Y value to the 

gas volume measurements made with the gas 

flow meter during the field test that was just 

completed. For mass flow meters, perform 

the 3-point recalibration while sampling 

stack gas. 

10.3 Thermocouples and Other 

Temperature Sensors. Use the procedures 

and criteria in Section 10.3 of Method 2 in 

Appendix A–1 to this part to calibrate instack temperature sensors and 

thermocouples. Dial thermometers shall be 

calibrated against mercury-in-glass 

thermometers. Calibrations must be 

performed prior to initial use and before each 

field test thereafter. At each calibration point, 

the absolute temperature measured by the 

temperature sensor must agree to within ±1.5 

percent of the temperature measured with the 

reference sensor, otherwise the sensor may 

not continue to be used. 


jlentini on PROD1PC65 with RULES2
51524 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

10.4 Barometer. Calibrate against a 

mercury barometer as per Section 10.6 of 

Method 5 in appendix A–3 to this part. 

Calibration must be performed prior to initial 

use and before each test program, and the 

absolute pressure measured by the barometer 

must agree to within +10 mm Hg of the 

pressure measured by the mercury barometer, 

otherwise the barometer may not continue to 

be used. 

10.5 Other Sensors and Gauges. Calibrate 

all other sensors and gauges according to the 

procedures specified by the instrument 

manufacturer(s). 

10.6 Analytical System Calibration. See 

Section 11.1 of this method. 

11.0 Analytical Procedures 

The analysis of Hg in the field and quality 

control samples may be conducted using any 

instrument or technology capable of 

quantifying total Hg from the sorbent media 

and meeting the performance criteria in this 

method. Because multiple analytical 

approaches, equipment and techniques are 

appropriate for the analysis of sorbent traps, 

it is not possible to provide detailed, 

technique-specific analytical procedures. As 

they become available, detailed procedures 

for a variety of candidate analytical 

approaches will be posted at http:// 

www.epa.gov/ttn/emc. 

11.1 Analytical System Calibration. 

Perform a multipoint calibration of the 

analyzer at three or more upscale points over 

the desired quantitative range (multiple 

calibration ranges shall be calibrated, if 

necessary). The field samples analyzed must 

fall within a calibrated, quantitative range 

and meet the performance criteria specified 

below. For samples suitable for aliquotting, a 

series of dilutions may be needed to ensure 

that the samples fall within a calibrated 

range. However, for sorbent media samples 

consumed during analysis (e.g., when using 

thermal desorption techniques), extra care 

must be taken to ensure that the analytical 

system is appropriately calibrated prior to 

sample analysis. The calibration curve 

range(s) should be determined such that the 

levels of Hg mass expected to be collected 

and measured will fall within the calibrated 

range. The calibration curve may be 

generated by directly introducing standard 

solutions into the analyzer or by spiking the 

standards onto the sorbent media and then 

introducing into the analyzer after preparing 

the sorbent/standard according to the 

particular analytical technique. For each 

calibration curve, the value of the square of 

the linear correlation coefficient, i.e., r2, must 

be ≥0.99, and the analyzer response must be 

within ±10 percent of the reference value at 

each upscale calibration point. Calibrations 

must be performed on the day of the analysis, 

before analyzing any of the samples. 

Following calibration, an independent 

standard shall be analyzed. The measured 

value of the independently prepared 

standard must be within ±10 percent of the 

expected value. 

11.2 Sample Preparation. Carefully 

separate the sections of each sorbent trap. 

Combine for analysis all materials associated 

with each section; any supporting substrate 

that the sample gas passes through prior to 

entering a media section (e.g., glass wool 

separators, acid gas traps, etc.) must be 

analyzed with that segment. 

11.3 Field Sample Analyses. Analyze the 

sorbent trap samples following the same 

procedures that were used for conducting the 

Hg0 and HgCl2 analytical bias tests. The 

individual sections of the sorbent trap and 

their respective components must be 

analyzed separately (i.e., section 1 and its 

components, then section 2 and its 

components). All sorbent trap section 1 

sample analyses must be within the 

calibrated range of the analytical system. For 

wet analyses, the sample can simply be 

diluted to fall within the calibrated range. 

However, for the destructive thermal 

analyses, samples that are not within the 

calibrated range cannot be re-analyzed. As a 

result, the sample cannot be validated, and 

another sample must be collected. It is 

strongly suggested that the analytical system 

be calibrated over multiple ranges so that 

thermally analyzed samples do fall within 

the calibrated range. The total mass of Hg 

measured in each sorbent trap section 1 must 

also fall within the lower and upper mass 

limits established during the initial Hg0 and 

HgCl2 analytical bias test. If a sample is 

analyzed and found to fall outside of these 

limits, it is acceptable for an additional Hg0

and HgCl2 analytical bias test to be performed 

that now includes this level. However, some 

samples (e.g., the mass collected in trap 

section 2 or the mass collected in trap section 

1 when the stack gas concentration is <0.5 

μg/m3), may have Hg levels so low that it 

may not be possible to quantify them in the 

analytical system’s calibrated range. Because 

a reliable estimate of these low-level Hg 

measurements is necessary to fully validate 

the emissions data, the MDL (see section 

8.2.2.1 of this method) is used to establish 

the minimum amount that can be detected 

and reported. If the measured mass or 

concentration is below the lowest point in 

the calibration curve and above the MDL, the 

analyst must do the following: estimate the 

mass or concentration of the sample based on 

the analytical instrument response relative to 

an additional calibration standard at a 

concentration or mass between the MDL and 

the lowest point in the calibration curve. 

This is accomplished by establishing a 

response factor (e.g., area counts per Hg mass 

or concentration) and estimating the amount 

of Hg present in the sample based on the 

analytical response and this response factor. 

Example: The analysis of a particular 

sample results in a measured mass above the 

MDL, but below the lowest point in the 

calibration curve which is 10 ng. An MDL of 

1.3 ng Hg has been established by the MDL 

study. A calibration standard containing 5 ng 

of Hg is analyzed and gives an analytical 

response of 6,170 area counts, which equates 

to a response factor of 1,234 area counts/ng 

Hg. The analytical response for the sample is 

4,840 area counts. Dividing the analytical 

response for the sample (4,840 area counts) 

by the response factor gives 3.9 ng Hg, which 

is the estimated mass of Hg in the sample. 

11.4 Analysis of Continuing Calibration 

Verification Standard (CCVS). After no more 

than 10 samples and at the end of each set 

of analyses, a continuing calibration 

verification standard must be analyzed. The 

measured value of the continuing calibration 

standard must be within ±10 percent of the 

expected value. 

11.5 Blanks. The analysis of blanks is 

optional. The analysis of blanks is useful to 

verify the absence of, or an acceptable level 

of, Hg contamination. Blank levels should be 

considered when quantifying low Hg levels 

and their potential contribution to meeting 

the sorbent trap section 2 breakthrough 

requirements; however, correcting sorbent 

trap results for blank levels is prohibited. 

12.0 Calculations and Data Analysis 

You must follow the procedures for 

calculation and data analysis listed in this 

section. 

12.1 Nomenclature. The terms used in the 

equations are defined as follows: 

B = Breakthrough (%). 

Bws = Moisture content of sample gas as 

measured by Method 4, percent/100. 

Ca = Concentration of Hg for the sample 

collection period, for sorbent trap ‘‘a’’

(μg/dscm). 

Cb = Concentration of Hg for the sample 

collection period, for sorbent trap ‘‘b’’

(μg/dscm). 

Cd = Hg concentration, dry basis (μg/dscm). 

Crec = Concentration of spiked compound 

measured (μg/m3). 

Cw = Hg concentration, wet basis (μg/m3). 

m1 = Mass of Hg measured on sorbent trap 

section 1 (μg). 

m2 = Mass of Hg measured on sorbent trap 

section 2 (μg). 

mrecovered = Mass of spiked Hg recovered in 

Analytical Bias or Field Recovery Test 

(μg). 

ms = Total mass of Hg measured on spiked 

trap in Field Recovery Test (μg). 

mspiked = Mass of Hg spiked in Analytical Bias 

or Field Recovery Test (μg). 

mu = Total mass of Hg measured on unspiked 

trap in Field Recovery Test (μg). 

R = Percentage of spiked mass recovered (%). 

RD = Relative deviation between the Hg 

concentrations from traps ‘‘a’’ and ‘‘b’’

(%). 

vs = Volume of gas sampled, spiked trap in 

Field Recovery Test (dscm). 

Vt = Total volume of dry gas metered during 

the collection period (dscm); for the 

purposes of this method, standard 

temperature and pressure are defined as 

20 °C and 760 mm Hg, respectively. 

vu = Volume of gas sampled, unspiked trap 

in Field Recovery Test (dscm). 

12.2 Calculation of Spike Recovery 

(Analytical Bias Test). Calculate the percent 

recovery of Hg0 and HgCl2 using Equation 

30B–1. 

R

m

= × Eq recovered

mspiked

100 . 30B-1

12.3 Calculation of Breakthrough. Use 

Equation 30B–2 to calculate the percent 

breakthrough to the second section of the 

sorbent trap. 

B m

m

= × Eq 2

1

100 . 30B-2


jlentini on PROD1PC65 with RULES2ER07SE07.028</MATH> ER07SE07.029</MATH>
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51525 

12.4 Calculation of Hg Concentration. 

Calculate the Hg concentration measured 

with sorbent trap ‘‘a’’, using Equation 30B–

3. 

C m m

V Eq a

t

= ( ) + . 1 2 30B-3

For sorbent trap ‘‘b’’, replace ‘‘Ca ’’ with 

‘‘Cb ’’ in Equation 30B–3. Report the average 

concentration, i.e., 1⁄2 (Ca + Cb). 

12.5 Moisture Correction. Use Equation 

30B–4 if your measurements need to be 

corrected to a wet basis. 

C C B Eq w d ws = ×− () . 1 30B-4

12.6 Calculation of Paired Trap 

Agreement. Calculate the relative deviation 

(RD) between the Hg concentrations 

measured with the paired sorbent traps using 

Equation 30B–5. 

RD

C C

C C Eq a b

a b

= −

+

×100 . 30B-5

12.7 Calculation of Measured Spike Hg 

Concentration (Field Recovery Test). 

Calculate the measured spike concentration 

using Equation 30B–6. 

C m

v

m

v

Eq rec

s

s

u

u

= − . 30B-6

Then calculate the spiked Hg recovery, R, 

using Equation 30B–7. 

R C v

m

Eq rec s

spiked

= ××100 . 30B-7

13.0 Method Performance 

How do I validate my data? Measurement 

data are validated using initial, one-time 

laboratory tests coupled with test programspecific tests and procedures. The analytical 

matrix interference test and the Hg0 and 

HgCl2 analytical bias test described in 

Section 8.2 are used to verify the 

appropriateness of the selected analytical 

approach(es) as well as define the valid 

working ranges for sample analysis. The field 

recovery test serves to verify the performance 

of the combined sampling and analysis as 

applied for each test program. Field test 

samples are validated by meeting the above 

requirements as well as meeting specific 

sampling requirements (i.e., leak checks, 

paired train agreement, total sample volume 

agreement with field recovery test samples) 

and analytical requirements (i.e., valid 

calibration curve, continuing calibration 

performance, sample results within 

calibration curve and bounds of Hg0 and 

HgCl2 analytical bias test). Complete data 

validation requirements are summarized in 

Table 9–1. 

14.0 Pollution Prevention [Reserved] 

15.0 Waste Management [Reserved] 

16.0 References 

1. EPA Traceability Protocol for 

Qualification and Certification of Elemental 

Mercury Gas Generators, expected 

publication date December 2008, see 

www.epa.gov/ttn/emc. 

2. EPA Traceability Protocol for 

Qualification and Certification of Oxidized 

Mercury Gas Generators, expected 

publication date December 2008, see 

www.epa.gov/ttn/emc. 

3. EPA Traceability Protocol for Assay and 

Certification of Gaseous Calibration 

Standards, expected revision publication 

date December 2008, see www.epa.gov/ttn/ 

emc. 

17.0 Figures and Tables 

BILLING CODE 6560–50–C 


jlentini on PROD1PC65 with RULES2ER07SE07.030</MATH> ER07SE07.031</MATH> ER07SE07.032</MATH> ER07SE07.033</MATH> ER07SE07.034</MATH>
51526 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 


jlentini on PROD1PC65 with RULES2ER07SE07.026</GPH>
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51527 

Appendix B [Amended] 

■ 3. Amend Performance Specification 

12A in Appendix B to part 60 by 

revising sections 8.6.2, 8.6.4, 8.6.5, and 

8.6.6.1 to read as follows: 

Performance Specification 12A—

Specifications and Test Procedures for Total 

Vapor Phase Mercury Continuous Emission 

Monitoring Systems in Stationary Sources 

* * * * * 

8.6.2 RM. Unless otherwise specified in 

an applicable subpart of the regulations, use 

Method 29, Method 30A, or Method 30B in 

appendix A to this part or American Society 

of Testing and Materials (ASTM) Method 

D6784–02 (incorporated by reference, see 

§ 60.17) as the RM for Hg concentration. Do 

not include the filterable portion of the 

sample when making comparisons to the 

CEMS results. When Method 29, Method 

30B, or ASTM D6784–02 is used, conduct the 

RM test runs with paired or duplicate 

sampling systems. When Method 30A is 

used, paired sampling systems are not 

required. If the RM and CEMS measure on a 

different moisture basis, data derived with 

Method 4 in appendix A to this part shall 

also be obtained during the RA test. 

* * * * * 

8.6.4 Number and Length of RM and 

Tests. Conduct a minimum of nine RM test 

runs. When Method 29, Method 30B, or 

ASTM D6784–02 is used, only test runs for 

which the paired RM trains meet the relative 

deviation criteria (RD) of this PS shall be 

used in the RA calculations. In addition, for 

Method 29 and ASTM D6784–02, use a 

minimum sample time of 2 hours and for 

Method 30A use a minimum sample time of 

30 minutes. 

Note: More than nine sets of RM tests may 

be performed. If this option is chosen, paired 

RM test results may be excluded so long as 

the total number of paired RM test results 

used to determine the CEMS RA is greater 

than or equal to nine. However, all data must 

be reported including the excluded data. 

8.6.5 Correlation of RM and CEMS Data. 

Correlate the CEMS and the RM test data as 

to the time and duration by first determining 

from the CEMS final output (the one used for 

reporting) the integrated average pollutant 

concentration for each RM test period. 

Consider system response time, if important, 

and confirm that the results are on a 

consistent moisture basis with the RM test. 

Then, compare each integrated CEMS value 

against the corresponding RM value. When 

Method 29, Method 30A, Method 30B, or 

ASTM D6784–02 is used, compare each 

CEMS value against the corresponding 

average of the paired RM values. 

8.6.6 * * * 

8.6.6.1 When Method 29, Method 30B, or 

ASTM D6784–02 is used, outliers are 

identified through the determination of 

relative deviation (RD) of the paired RM tests. 

Data that do not meet the criteria should be 

flagged as a data quality problem. The 

primary reason for performing paired RM 

sampling is to ensure the quality of the RM 

data. The percent RD of paired data is the 

parameter used to quantify data quality. 

Determine RD for two paired data points as 

follows: 

RD

C C

C C Eq a b

a b

= −

+

×100 . 12A-1

where Ca and Cb are concentration values 

determined from each of the two samples, 

respectively. 

* * * * * 

PART 72—PERMITS REGULATION 

■ 4. The authority citation for part 72 

continues to read as follows: 

Authority: 42 U.S.C. 7601 and 7651, et seq. 

■ 5. Revise the definition of ‘‘sorbent 

trap monitoring system’’ in § 72.2 as 

follows: 

§ 72.2 Definitions. 

* * * * * 

Sorbent trap monitoring system 

means the equipment required by part 

75 of this chapter for the continuous 

monitoring of Hg emissions, using 

paired sorbent traps containing iodated 

charcoal (IC) or other suitable reagents. 

This excepted monitoring system 

consists of a probe, the paired sorbent 

traps, an umbilical line, moisture 

removal components, an air tight 

sample pump, a gas flow meter, and an 

automated data acquisition and 

handling system. The monitoring 

system samples the stack gas at a rate 

proportional to the stack gas volumetric 

flowrate. The sampling is a batch 

process. Using the sample volume 

measured by the gas flow meter and the 

results of the analyses of the sorbent 

traps, the average mercury 

concentration in the stack gas for the 

sampling period is determined, in units 

of micrograms per dry standard cubic 

meter (μg/dscm). Mercury mass 

emissions for each hour in the sampling 

period are calculated using the average 

Hg concentration for that period, in 

conjunction with contemporaneous 

hourly measurements of the stack gas 

flow rate, corrected for the stack 

moisture content. 

* * * * * 

PART 75—CONTINUOUS EMISSION 

MONITORING 

■ 6. The authority citation for part 75 

continues to read as follows: 

Authority: 42 U.S.C. 7601, 7651k, and 

7651k note. 

■ 7. Amend § 75.15 as follows: 

■ a. Revise paragraph (f); 

■ b. Revise paragraph (i); and 

■ c. Add new paragraph (k). 

The revisions and additions read as 

follows: 

§ 75.15 Special provisions for measuring 

Hg mass emissions using the excepted 

sorbent trap monitoring methodology. 

* * * * * 

(f) At the beginning and end of each 

sample collection period, and at least 

once in each unit operating hour during 

the collection period, the gas flow meter 

reading shall be recorded. 

* * * * * 

(i) All unit operating hours for which 

valid Hg concentration data are obtained 

with the primary sorbent trap 

monitoring system (as verified using the 

quality assurance procedures in 

appendix K to this part) shall be 

reported in the electronic quarterly 

report under § 75.84(f). For hours in 

which data from the primary monitoring 

system are invalid, the owner or 

operator may, in accordance with 

§ 75.20(d), report valid Hg concentration 

data from: A certified redundant backup 

CEMS or sorbent trap monitoring 

system; a certified non-redundant 

backup CEMS or sorbent trap 

monitoring system; or an applicable 

reference method under § 75.22. If no 

quality-assured Hg concentration are 

available for a particular hour, the 

owner or operator shall report the 

appropriate substitute data value in 

accordance with § 75.39. 

* * * * * 

(k) During each RATA of a sorbent 

trap monitoring system, the type of 

sorbent material used by the traps shall 

be the same as for daily operation of the 

monitoring system. A new pair of traps 

shall be used for each RATA run. 

However, the size of the traps used for 

the RATA may be smaller than the traps 

used for daily operation of the system. 

* * * * * 

■ 8. Amend § 75.20 by adding new 

paragraph (d)(2)(ix) to read as follows: 

§ 75.20 Initial certification and 

recertification procedures. 

* * * * * 

(d)* * * 

(2)* * * 

(ix) For non-redundant backup Hg 

CEMS and sorbent trap monitoring 

systems, and for like-kind replacement 

Hg analyzers, the following provisions 

apply in addition to, or, in some cases, 

in lieu of, the general requirements in 

paragraphs (d)(2)(i) through (d)(2)(viii) 

of this section: 

(A) When a certified sorbent trap 

monitoring system is brought into 

service as a regular non-redundant 

backup monitoring system, the system 

shall be operated according to the 

procedures in § 75.15 and appendix K of 

this part; 

(B) When a regular non-redundant 

backup Hg CEMS or a like-kind 


jlentini on PROD1PC65 with RULES2ER07SE07.035</MATH>
51528 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

replacement Hg analyzer is brought into 

service, a linearity check with elemental 

Hg standards, as described in paragraph 

(c)(1)(ii) of this section and section 6.2 

of appendix A of this part, and a singlepoint system integrity check, as 

described in section 2.6 of appendix B 

of this part, shall be performed. 

Alternatively, a 3-level system integrity 

check, as described in paragraph 

(c)(1)(vi) of this section and paragraph 

(g) of section 6.2 in appendix A of this 

part, may be performed in lieu of these 

two tests. 

(C) The weekly single-point system 

integrity checks described in section 2.6 

of appendix B of this part are required 

as long as a non-redundant backup Hg 

CEMS or like-kind replacement Hg 

analyzer remains in service, unless the 

daily calibrations of the Hg analyzer are 

done using a NIST-traceable source of 

oxidized Hg. 

* * * * * 

■ 9. Amend § 75.57 by revising 

paragraph (j)(7) to read as follows: 

§ 75.57 General recordkeeping provisions. 

* * * * * 

(j) * * * 

(7) Record the gas flow meter reading 

(in dscm, rounded to the nearest 

hundreth) at the beginning and end of 

the collection period and at least once 

in each unit operating hour during the 

collection period. 

* * * * * 

■ 10. Amend § 75.81 by revising 

paragraph (a)(1) to read as follows: 

§ 75.81 Monitoring of Hg mass emissions 

and heat input at the unit level. 

* * * * * 

(a) * * * 

(1) A Hg concentration monitoring 

system (as defined in § 72.2 of this 

chapter) or a sorbent trap monitoring 

system (as defined in § 72.2 of this 

chapter), to measure the mass 

concentration of total vapor phase Hg in 

the flue gas, including the elemental 

and oxidized forms of Hg, in 

micrograms per standard cubic meter 

(μg/scm); and 

* * * * * 

■ 11. Amend § 75.84 by revising 

paragraph (f)(1)(ii)(J) to read as follows: 

§ 75.84 Recordkeeping and Reporting. 

* * * * * 

(f) * * * 

(1) * * * 

(ii) * * * 

(J) For units using sorbent trap 

monitoring systems, the hourly gas flow 

meter readings taken between the initial 

and final meter readings for the data 

collection period; and 

* * * * * 

Appendix A to Part 75—[Amended] 

■ 12. Amend Appendix A to part 75 by 

removing the twentieth sentence in 

paragraph (a) of section 6.5.7 which 

currently reads ‘‘For the RATA of a 

sorbent trap monitoring system, use the 

same size trap that is used for daily 

operation of the monitoring system.’’

and adding in its place ‘‘For the RATA 

of a sorbent trap monitoring system, the 

type of sorbent material used by the 

traps shall be the same as for daily 

operation of the monitoring system; 

however, the size of the traps used for 

the RATA may be smaller than the traps 

used for daily operation of the system.’’. 

■ 13. Amend Appendix B to part 75 by 

revising section 1.5.2 to read as follows: 

Appendix B to Part 75—Quality 

Assurance and Quality Control 

Procedures 

* * * * * 

1.5.2 Monitoring System Integrity and Data 

Quality 

Explain the procedures used to perform the 

leak checks when sorbent traps are placed in 

service and removed from service. Also 

explain the other QA procedures used to 

ensure system integrity and data quality, 

including, but not limited to, gas flow meter 

calibrations, verification of moisture removal, 

and ensuring air-tight pump operation. In 

addition, the QA plan must include the data 

acceptance and quality control criteria in 

section 8 of appendix K to this part. All 

reference meters used to calibrate the gas 

flow meters (e.g., wet test meters) shall be 

periodically recalibrated. Annual, or more 

frequent, recalibration is recommended. If a 

NIST–traceable calibration device is used as 

a reference flow meter, the QA plan must 

include a protocol for ongoing maintenance 

and periodic recalibration to maintain the 

accuracy and NIST–traceability of the 

calibrator. 

* * * * * 

■ 14. Amend Appendix K to part 75 as 

follows: 

■ a. Amend section 5.1 by revising 

Figure K–1; 

■ b. Revise section 5.1.3; 

■ c. Revise section 5.1.5; 

■ d. Revise section 7.1.3; 

■ e. Revise section 7.2.3; 

■ f. Revise section 7.2.5; 

■ g. Amend section 8.0 by revising 

Table K–1; 

■ h. Revise section 9.2; 

■ i. Revise section 10.4; 

■ j. Remove and reserve section 11.5; 

■ k. Revise section 11.6; and 

■ l. Revise section 11.7. 

The revisions and additions read as 

follows: 

Appendix K to Part 75—Quality 

Assurance and Operating Procedures 

for Sorbent Trap Monitoring Systems 

* * * * * 

5.1 * * * 

BILLING CODE 6560–50–C 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51529 


jlentini on PROD1PC65 with RULES2ER07SE07.027</GPH>
51530 Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 

* * * * * 

5.1.3 Moisture Removal Device 

A robust moisture removal device or 

system, suitable for continuous duty (such as 

a Peltier cooler), shall be used to remove 

water vapor from the gas stream prior to 

entering the gas flow meter. 

* * * * * 

5.1.5 Gas Flow Meter 

A gas flow meter (such as a dry gas meter, 

thermal mass flow meter, or other suitable 

measurement device) shall be used to 

determine the total sample volume on a dry 

basis, in units of standard cubic meters. The 

meter must be sufficiently accurate to 

measure the total sample volume to within 2 

percent and must be calibrated at selected 

flow rates across the range of sample flow 

rates at which the sorbent trap monitoring 

system typically operates. The gas flow meter 

shall be equipped with any necessary 

auxiliary measurement devices (e.g., 

temperature sensors, pressure measurement 

devices) needed to correct the sample volume 

to standard conditions. 

* * * * * 

7.1.3 Pre-test Leak Check 

Perform a leak check with the sorbent traps 

in place. Draw a vacuum in each sample 

train. Adjust the vacuum in the sample train 

to ∼15′′ Hg. Using the gas flow meter, 

determine leak rate. The leakage rate must 

not exceed 4 percent of the target sampling 

rate. Once the leak check passes this 

criterion, carefully release the vacuum in the 

sample train then seal the sorbent trap inlet 

until the probe is ready for insertion into the 

stack or duct. 

* * * * * 

7.2.3 Flow Rate Control 

Set the initial sample flow rate at the target 

value from section 7.1.1 of this appendix. 

Record the initial gas flow meter reading, 

stack temperature (if needed to convert to 

standard conditions), meter temperatures (if 

needed), etc. Then, for every operating hour 

during the sampling period, record the date 

and time, the sample flow rate, the gas flow 

meter reading, the stack temperature (if 

needed), the flow meter temperatures (if 

needed), temperatures of heated equipment 

such as the vacuum lines and the probes (if 

heated), and the sampling system vacuum 

readings. Also, record the stack gas flow rate, 

as measured by the certified flow monitor, 

and the ratio of the stack gas flow rate to the 

sample flow rate. Adjust the sampling flow 

rate to maintain proportional sampling, i.e., 

keep the ratio of the stack gas flow rate to 

sample flow rate constant, to within ±25 

percent of the reference ratio from the first 

hour of the data collection period (see section 

11 of this appendix). 

* * * * * 

7.2.5 Essential Operating Data 

Obtain and record any essential operating 

data for the facility during the test period, 

e.g., the barometric pressure for correcting 

the sample volume measured by a dry gas 

meter to standard conditions. At the end of 

the data collection period, record the final 

gas flow meter reading and the final values 

of all other essential parameters. 

* * * * * 

8.0 * * * 

TABLE K–1.—QUALITY ASSURANCE/QUALITY CONTROL CRITERIA FOR SORBENT TRAP MONITORING SYSTEMS

QA/QC test or specification Acceptance criteria Frequency Consequences if not met 

Pre-test leak check ........................ ≤4% of target sampling rate ......... Prior to Sampling .......................... Sampling shall not commence 

until the leak check is passed. 

Post-test leak check ...................... ≤4% of average sampling rate ..... After sampling ............................... Sample check invalidated.** 

Ratio of stack gas flow rate to 

sample flow rate.

Maintain within ±25% of initial 

ratio from first hour of data collection period.

Every hour throughout data collection period.Case-by-case evaluation. 

Sorbent trap section 2 breakthrough.≤5% of Section 1 Hg mass .......... Every sample ................................ Sample invalidated.** 

Paired sorbent trap agreement ...... ≤10% Relative Deviation (RD) ..... Every sample ................................ Sample invalidated.** 

Spike recovery study ..................... Average recovery between 85% 

and 115% for each of the 3 

spike concentration levels.

Prior to analyzing field samples 

and prior to use of new sorbent 

media.

Field samples shall not be analyzed until the percent recovery 

criterion has been met. 

Multipoint analyzer calibration ....... Each analyzer reading within 

±10% of true value and r2 ≥0.99.

On the day of analysis, before 

analyzing any samples.

Recalibrate until successful. 

Analysis of independent calibration 

standard.

Within ±10% of true value ............ Following daily calibration, prior to 

analyzing field.

Recalibrate and repeat independent standard analysis samples until successful. 

Spike recovery from section 3 of 

sorbent trap.

75–125% of spike amount ............ Every sample ................................ Sample invalidated.** 

RATA ............................................. RA ≤20.0% or Mean difference 

≤1.0 μgm/dscm for low emitters.

For initial certification and annually thereafter.Data from the system are invalidated until a RATA is passed. 

Gas flow meter calibration (At 3 

settings initially, and 1 setting 

thereafter).

Calibration factor (Y) within ±5% 

of average value from the initial 

(3-point) calibration.

Prior to initial use and at least 

quarterly thereafter.

Recalibrate the meter at three 

settings to determine a new 

value of Y. 

Temperature sensor calibration ..... Absolute temperature measured 

by sensor within ±1.5% of a reference sensor.

Prior to initial use and at least 

quarterly thereafter.

Recalibrate. Sensor may not be 

used until specification is met. 

Barometer calibration ..................... Absolute pressure measured by 

instrument within ±10 mm Hg of 

reading with a mercury barometer.

Prior to initial use and at least 

quarterly thereafter.

Recalibrate. Instrument may not 

be used until specification is 

met. 

** And data from the pair of sorbent traps are also invalidated. 

* * * * * 

9.2 Gas Flow Meter Calibration 

9.2.1 Preliminaries. The manufacturer or 

supplier of the gas flow meter should 

perform all necessary set-up, testing, 

programming, etc., and should provide the 

end user with any necessary instructions, to 

ensure that the meter will give an accurate 

readout of dry gas volume in standard cubic 

meters for the particular field application. 

9.2.2 Initial Calibration. Prior to its initial 

use, a calibration of the flow meter shall be 

performed. The initial calibration may be 

done by the manufacturer, by the equipment 

supplier, or by the end user. If the flow meter 

is volumetric in nature (e.g., a dry gas meter), 

the manufacturer, equipment supplier, or end 

user may perform a direct volumetric 

calibration using any gas. For a mass flow 

meter, the manufacturer, equipment supplier, 

or end user may calibrate the meter using a 

bottled gas mixture containing 12 ± 0.5% 

CO2, 7 ± 0.5% O2, and balance N2, or these 


jlentini on PROD1PC65 with RULES2
Federal Register / Vol. 72, No. 173 / Friday, September 7, 2007 / Rules and Regulations 51531 

same gases in proportions more 

representative of the expected stack gas 

composition. Mass flow meters may also be 

initially calibrated on-site, using actual stack 

gas. 

9.2.2.1 Initial Calibration Procedures. 

Determine an average calibration factor (Y) 

for the gas flow meter, by calibrating it at 

three sample flow rate settings covering the 

range of sample flow rates at which the 

sorbent trap monitoring system typically 

operates. You may either follow the 

procedures in section 10.3.1 of Method 5 in 

appendix A–3 to part 60 of this chapter or 

the procedures in section 16 of Method 5 in 

appendix A–3 to part 60 of this chapter. If 

a dry gas meter is being calibrated, use at 

least five revolutions of the meter at each 

flow rate. 

9.2.2.2 Alternative Initial Calibration 

Procedures. Alternatively, you may perform 

the initial calibration of the gas flow meter 

using a reference gas flow meter (RGFM). The 

RGFM may either be: (1) A wet test meter 

calibrated according to section 10.3.1 of 

Method 5 in appendix A–3 to part 60; (2) a 

gas flow metering device calibrated at 

multiple flow rates using the procedures in 

section 16 of Method 5 in appendix A–3 to 

part 60; or (3) a NIST–traceable calibration 

device capable of measuring volumetric flow 

to an accuracy of 1 percent. To calibrate the 

gas flow meter using the RGFM, proceed as 

follows: While the sorbent trap monitoring 

system is sampling the actual stack gas or a 

compressed gas mixture that simulates the 

stack gas composition (as applicable), 

connect the RGFM to the discharge of the 

system. Care should be taken to minimize the 

dead volume between the sample flow meter 

being tested and the RGFM. Concurrently 

measure dry gas volume with the RGFM and 

the flow meter being calibrated the for a 

minimum of 10 minutes at each of three flow 

rates covering the typical range of operation 

of the sorbent trap monitoring system. For 

each 10-minute (or longer) data collection 

period, record the total sample volume, in 

units of dry standard cubic meters (dscm), 

measured by the RGFM and the gas flow 

meter being tested. 

9.2.2.3 Initial Calibration Factor. 

Calculate an individual calibration factor Yi

at each tested flow rate from section 9.2.2.1 

or 9.2.2.2 of this appendix (as applicable), by 

taking the ratio of the reference sample 

volume to the sample volume recorded by 

the gas flow meter. Average the three Yi

values, to determine Y, the calibration factor 

for the flow meter. Each of the three 

individual values of Yi must be within ±0.02 

of Y. Except as otherwise provided in 

sections 9.2.2.4 and 9.2.2.5 of this appendix, 

use the average Y value from the three level 

calibration to adjust all subsequent gas 

volume measurements made with the gas 

flow meter. 

9.2.2.4 Initial On-Site Calibration Check. 

For a mass flow meter that was initially 

calibrated using a compressed gas mixture, 

an on-site calibration check shall be 

performed before using the flow meter to 

provide data for this part. While sampling 

stack gas, check the calibration of the flow 

meter at one intermediate flow rate typical of 

normal operation of the monitoring system. 

Follow the basic procedures in section 

9.2.2.1 or 9.2.2.2 of this appendix. If the onsite calibration check shows that the value of 

Yi, the calibration factor at the tested flow 

rate, differs by more than 5 percent from the 

value of Y obtained in the initial calibration 

of the meter, repeat the full 3-level 

calibration of the meter using stack gas to 

determine a new value of Y, and apply the 

new Y value to all subsequent gas volume 

measurements made with the gas flow meter. 

9.2.2.5 Ongoing Quality Assurance. 

Recalibrate the gas flow meter quarterly at 

one intermediate flow rate setting 

representative of normal operation of the 

monitoring system. Follow the basic 

procedures in section 9.2.2.1 or 9.2.2.2 of this 

appendix. If a quarterly recalibration shows 

that the value of Yi, the calibration factor at 

the tested flow rate, differs from the current 

value of Y by more than 5 percent, repeat the 

full 3-level calibration of the meter to 

determine a new value of Y, and apply the 

new Y value to all subsequent gas volume 

measurements made with the gas flow meter. 

* * * * * 

10.4 Field Sample Analysis 

Analyze the sorbent trap samples following 

the same procedures that were used for 

conducting the spike recovery study. The 

three sections of each sorbent trap must be 

analyzed separately (i.e., section 1, then 

section 2, then section 3). Quantify the total 

mass of Hg for each section based on 

analytical system response and the 

calibration curve from section 10.1 of this 

appendix. Determine the spike recovery from 

sorbent trap section 3. The spike recovery 

must be no less than 75 percent and no 

greater than 125 percent. To report the final 

Hg mass for each trap, add together the Hg 

masses collected in trap sections 1 and 2. 

* * * * * 

11.5 [Reserved] 

11.6 Calculation of Hg Concentration 

Calculate the Hg concentration for each 

sorbent trap, using the following equation: 

C M

V Eq

t

=

*

( . K-5)

Where: 

C = Concentration of Hg for the collection 

period, (μgm/dscm) 

M* = Total mass of Hg recovered from 

sections 1 and 2 of the sorbent trap, (μg) 

Vt = Total volume of dry gas metered during 

the collection period, (dscm). For the 

purposes of this appendix, standard 

temperature and pressure are defined as 

20 °C and 760 mm Hg, respectively. 

11.7 Calculation of Paired Trap Agreeement 

Calculate the relative deviation (RD) 

between the Hg concentrations measured 

with the paired sorbent traps: 

RD

C C

C C Eq a b

a b

= −

+

×100 ( . K-6)

Where: 

RD = Relative deviation between the Hg 

concentrations from traps ‘‘a’’ and ‘‘b’’

(percent) 

Ca = Concentration of Hg for the collection 

period, for sorbent trap ‘‘a’’ (μgm/dscm) 

Cb = Concentration of Hg for the collection 

period, for sorbent trap ‘‘b’’ (μgm/dscm) 

* * * * * 

[FR Doc. 07–4147 Filed 9–6–07; 8:45 am] 

BILLING CODE 6560–50–P 


jlentini on PROD1PC65 with RULES2ER07SE07.036</MATH> ER07SE07.037</MATH>