# TECHNICAL REPORT

Summary of Formaldehyde Emissions Measurement and D ata

Collection for Four-Stroke Rich Burn Spark Ignited

Reciprocating Internal Combustion Engines

National Emission Standard for Hazardous Air Pollut ants

40 CFR, Part 63, Subpart ZZZZ

PREPARED FOR:

1220 L Street NW

Washington DC 20005



## PREPARED BY:

Innovative Environmental Solutions, Inc.

P.O. Box 177

Cary, IL 60013-0177

April 9, 2010 Rev 1 16666 Northchase Drive

Houston, TX 77060 15508 Wright Brothers Drive

Addison, TX 75001 3809 South FM 1788

Midland, TX 79706Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### i TABLE OF CONTENTS

Executive Summary............................

................................................... .....................................ii

1. Project Objectives and Data Sources................

................................................... ........................ 1

1.1. Formaldehyde Emissions Measurement Program .........

................................................... .... 2

1.2. Collection of Existing Formaldehyde Emissions Data.

................................................... ..... 4

1.3. Summary of MACT Floor Database Engines and Tests ...

................................................... 4

1.4. Report Content.....................................

................................................... .............................. 4

2. MACT Floor Determination: Basis and Analysis Approa ch................................................. ...... 6

2.1. Identifying Best Performing Units ..................

................................................... .................. 7

2.2. MACT Floor Variability.............................

................................................... ....................... 9

3. Data Summary and Discussion: Four-Stroke Cycle Rich Burn Engines.....................................1 2

3.1. Selection of Best Performing Units.................

................................................... ..................12

3.2. MACT Floor Variability for 4SRB Engines ............

................................................... .........13

4. Sized Based Subcategories ..........................

................................................... .............................14

5. Conclusions and Recommendations....................

................................................... .....................16

6. Sources............................................

................................................... ..........................................17

Table 3-1: 4SRB “Best Performing” Engine Test Data Summary........................................... ........12

Table 3-2: Summary of MACT Floor Engines..........

................................................... ....................13

Appendix A: 4SRB Engine Test Data

Appendix B: Data Review Process and Short Term Tes t Validation

Appendix C: Formaldehyde Emissions Measurement Tes t ProtocolTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### ii Executive Summary

This report discusses and presents the data, analys is, and conclusions from a program to compile

formaldehyde emissions testing data for four-stroke rich burn (4SRB) gas-fired engines. To address

the need for additional formaldehyde emissions data and in response to a request by EPA to provide

additional test data, Exterran, J-W Power Company, and Compressor Systems, Inc. (collectively

referred to as "EJC") conducted an intensive field testing program directed at 4SRB engines less than

500 hp. The American Petroleum Institute (API) sup plemented and augmented the EJC field test data

with existing test data.

These data were developed to support comments previ ously submitted on the Reciprocating Internal

Combustion Engines (RICE) National Emission Standar ds for Hazardous Air Pollutants (NESHAP)

that EPA proposed on March 5, 2009. The data analy sis and conclusions in this report are based on the

Clean Air Act, relevant court findings, and a test plan specifically designed to inform the MACT floor

analysis.

The following two-step methodology was used to dete rmine the 4SRB MACT floor:

• The MACT floor 4SRB engines were first identified b y sorting the engines based on the lowest

(i.e., best performing) formaldehyde (CH 2 

### O) test for each engine, which compares the engines

on a common operating basis, and the best performin g 12% were selected as MACT floor

engines.

• The MACT floor 4SRB emission limit was then determi ned by considering emissions

variability from the population of the best perform ing 12% of all engines tested (i.e. the floor

engines). All floor engine tests were reviewed to determine emission levels at all operating

conditions that can be “reasonably expected to recu r” and the highest level (i.e., 13 ppmvd @

15% O 2 

### ) is the floor such that each MACT floor engine can “meet the standard every day and

under all operating conditions.”

Our method for identifying MACT floor engines, whic h is based on the lowest CH 2 

### O emissions

, provides the best assurance that tests completed at similar operating conditions are compared on an

equitable basis. Other methodologies contemplated by EPA have compar ed engines operating at

vastly different loads or operating conditions. Th is would not be an accurate or equitable comparison

for selecting the “best performing” engines. Moreo ver, the approach for evaluating emission

variability from the MACT floor engines is consiste nt with methodologies previously employed by

EPA in other MACT rules and complies with the relev ant D.C. Circuit Court rulings which provide

that the best performing MACT floor engines should be able to achieve the resulting MACT floor

emission standard at all times.

The EJC and API member companies’ data collection e ffort produced the following results:

• A total of 51 engines and 120 individual engine tes ts were analyzed for this technical report.

• Seven (7) engines, 12% of the total, comprise the b est performing MACT floor engines.

• A total of 38 floor engine tests at a variety of op erating conditions were used to assess

variability.

• The floor engine tests showed formaldehyde emission s ranging from 3.18 parts per million

volumetric dry (ppmvd) to 12.05 ppmvd (corrected to 15% oxygen).

EJC-API supports “work practice” standards for majo r sources, as an alternative to emission standards,

for engines with a rated capacity less than 300 hp. EJC-API supports “management practice” standardsTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### iii for area source engines less than 500 hp. However, if EPA were to proceed with establishing an

emission limit for 4SRB engines, EJC-API advocates establishing a MACT floor emission limit of no

lower than 13 ppmvd @ 15% O 2 

### that is supported by the test data and analyses. In reviewing this

MACT floor emission limit, it should also be noted that the test program that provided all of the floo r

engines focused on engines located in southwestern states, where fuel quality and ambient temperature

could have resulted in a low formaldehyde emission bias. For this reason, EJC-API requests that the

EPA take into account variability issues that are p ertinent to other regions of the United States (e.g

., colder climate areas) and consider that best-perfor ming engines in those areas may not be able to

achieve an emission limit based on engine testing t hat did not implicate all potentially relevant

emissions-affecting variables.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 1 1.0 Project Objectives and Data Sources

A rule to amend the Reciprocating Internal Combusti on Engines (RICE) National Emission

Standards for Hazardous Air Pollutants (NESHAP) was proposed on March 5, 2009. The

proposal addresses reciprocating internal combustio n (IC) engines that are located at area sources

of hazardous air pollutants (HAPs), engines with a site rating of less than or equal to 500

horsepower (hp) located at major sources of HAPs, a nd existing stationary compression ignition

engines greater than 500 hp located at major source s. The Proposed Rule represents the third

version of this NESHAP. In November 2009, EPA exte nded the Final Rule deadline for spark

ignited (SI) RICE to August 10, 2010.

As discussed during the comment period, stakeholder s in the natural gas industry that own or

operate natural gas-fired RICE are concerned about the paucity of test data that was relied on to

support the MACT floor in the proposed rule. To ad dress these concerns and in response to a

request by EPA to provide additional test data, Ex terran, J-W Power Company, and Compressor

Systems, Inc. (collectively referred to as "EJC") c onducted an intensive field testing program

directed at 4-stroke rich burn engines less than 50 0 hp. EJC own and operate fleets of rental

compressors that primarily service rural oil and ga s exploration and production operations.

These compressors are driven by natural gas-fired e ngines, and as proposed, this rule will

significantly impact nearly every engine owned by E JC.

The American Petroleum Institute (API) shared the s ame data concerns and has supplemented

and augmented the EJC field test data with existing test data. API is a national trade association

with more than 400 member companies involved in all aspects of the oil and gas industry.

Natural gas-fired RICE represents the largest popul ation of engines in the exploration and

production, and transmission sectors for API member company operations. As the interests of

both EJC and API are aligned in terms of the impact s associated with this rulemaking, EJC and

API are submitting this technical report together a nd are referred to in this document as EJCAPI.

The proposed rule impacts existing area source engi nes and establishes limits based on very

limited emissions data associated with small natura l gas fired reciprocating engines. In an effort

to supplement the emissions data available for the rulemaking, EJC-API requested emissions

data from its members. The objective of the data c ompilation was to:

• 

### Assess the availability of applicable emissions dat a for 4-stroke rich burn (4SRB) engines;

• 

### Collect available emissions data for 4SRB engines;

• 

### Compile and organize the data into a report for tra nsmittal to EPA; and,

• 

### Review and analyze the data to assess implications for the emission standard, including the

basis for the maximum achievable control technology (MACT) standard as required under

the Clean Air Act.

The Clean Air Act requires that the MACT standards for existing units at major sources be based

on the average emission limitation achieved by the best performing 12% of engines in a

subcategory (i.e., the “MACT floor”). In recent D. C. Circuit Court cases, discussed further in

Section 2.2, the MACT floor emission limit can cons ider emission variability and must be

achievable at all times and under the most adverse circumstances that are reasonably expected toTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 2 recur. This report discusses and presents the conc lusions from the test program and 4SRB data

analysis as it relates to the Clean Air Act, court findings, and test plan considerations.

1.1 Formaldehyde Emissions Measurement Program

The proposed rule includes formaldehyde (CH 2 

### O) emission standards for rich burn engines.

Since CH 2 

### O compliance testing is not required for many engin es, it was expected that existing

CH 2 

### O emissions data would be minimal. In anticipation of this lack of data, particularly as it

relates to variable operating conditions, EJC imple mented a robust testing program.

The overall purpose of this testing program was to obtain emissions data to support revisions to

the MACT floor limits in the upcoming Final Rule th at will amend the NESHAP for

reciprocating IC engines embodied in 40 CFR, Part 6 3, Subpart ZZZZ. Specifically, the MACT

floor emissions test project objectives were to:

1. Establish a test program to consistently obtain emi ssion data for developing MACT floor

emission limits that address the size, type, and op eration of affected engines. The focus of

the MACT floor testing program was directed toward smaller (less than 500 hp) natural gasfired engines.

2. Obtain emissions data over the range of engine oper ating conditions that are expected to be in

the MACT floor data set (i.e., engines in the best performing 12% of engines in the 4SRB

subcategory) to allow determination of emission limits that incl ude normal operational

variability. Engine parameters that could impact e missions variability include:

• Excess O 2 

### ;

• Percent load;

• Multiple engines of identical make / model;

• Fuel quality; and,

• Ambient affects including temperature, relative hum idity, & elevation.

These specific MACT floor data objectives were esta blished because EJC-API understands that,

based on recent Circuit Court case decisions, EPA h as the latitude to set the floor at a level that is

a reasonable estimate of the emissions from the bes t performing units under the worst reasonably

foreseeable circumstances. The importance of this concept is addressed in more detail in Section

2.2, which outlines the EJC-API approach to variabi lity.

A test plan was prepared that outlined the technica l approach for data collection and the plan was

provided to EPA in advance of field testing activit ies. In addition, test procedures and changes

to data collection methodologies were discussed wit h EPA during several teleconferences and

subsequent meetings. EPA provided concurrence on t he data collection approach during an

October 5, 2009 meeting with API.

Several oil and gas producing areas that had a vari ety of engine make and models and ages of

smaller (less than 500 hp) gas fired engines were i dentified for MACT floor testing activities.

The primary goal was to identify sets of engines in close proximity to minimize time to mobilize

to the next test location. For this reason, the te sting program may have conservatively biased theTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 3 results lower as the average ambient temperatures f rom this region are higher than temperatures

in northern tier States.

Emission measurements were conducted in accordance with EPA and ASTM test methods.

However, the data were not collected consistent wit h performance or compliance testing

requirements (e.g. three one-hour tests at 100 + 10% engine load); rather the testing approach

was to efficiently identify potential MACT floor en gines and then test these engines over a range

of operating conditions to assess emission variabil ity. This approach was employed to maximize

data collection in consideration of the time and te sting resource constraints. To identify potential

MACT floor units (i.e. best performing 12 %), the t esting effort focused on comparing all

engines on a common operating basis. In order to a ccomplish this goal, initial tests on engines

were conducted by adjusting carburetor settings and fuel pressure to “manually adjust” the

engine operation to an “expected” lower formaldehyd e emissions operating point corresponding

to an exhaust oxygen concentration of one half perc ent or less.

Units with the potential for becoming MACT floor en gines were then tested over a range of

loads and air-to-fuel ratios using single one hour and shorter period tests. The shorter, single test

approach was employed to optimize emissions variabi lity characterization (i.e. conduct as many

tests as practical on an engine, given testing on a n engine was typically limited to one day or

less). This approach was discussed with Gary McAli ster of EPA’s Emissions Measurement

Center during the August 5, 2009 meeting at RTP and was tentatively approved based on a

favorable comparison of the standard deviations amo ng the short-term FTIR measurements and

the 1-hour data sets. Additional detail regarding the testing procedures is provided in Section

2.1and Appendix B.

The project quality assurance/quality control (QA/Q C) activities associated with the collected

test data included review of emission measurement m ethod performance requirements, engine

operation monitoring equipment calibrations, and ma ss balance engineering calculations.

QA/QC requirements for the instrumental emission me asurement methods include interference

checks, calibration error checks, system bias tests , drift checks, and linearity requirements.

Emission test reports were reviewed for adherence t o reference test methods and QA/QC results

were compared to method performance requirements.

Engine operating parameters were monitored during t he testing to estimate engine operating load

and fuel consumption. These parameters included co mpressor suction and discharge gas

pressures and temperatures, and fuel gas flow rate. Compressor suction and discharge pressures

were typically measured by control panel pressure g auges. These panel gauges were then

calibrated against a reference pressure gauge and t est data adjusted accordingly. Compressor

temperatures were typically measured with a panel m eter and a second temperature by an IR

meter or thermocouple was conducted to verify the m easurement. Fuel gas flow rate was

measured using rotary gas meters. These meters mea sure actual gas volume and thus require gas

pressure and temperature measurements to determine fuel flow at standard pressure and

temperature. Post test calibrations of the rotary flow meters and pressure gauges were conducted

and measurement data adjusted accordingly.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 4 QA/QC activities also included calculation of engin e brake-specific fuel consumption (BSFC)

based on fuel use and engine load measurements. BS FC is calculated as Btu/hp-hr and is a

measure of engine efficiency. BSFC is impacted by numerous parameters - including engine

design, load, age, maintenance schedule, and fuel p roperties and ambient conditions - and can

range considerably, especially at lower loads for o lder engines. BSFC values calculated from

engine fuel use and load measurements were compared to the expected BSFC range to assess the

measurements. For engines with calculated BSFC ou tside the expected range, measurement

data were further examined and the data noted. Unc haracteristic BSFC values for some MACT

Floor engines were caused by a damaged fuel gas pre ssure gauge and the resulting erroneous fuel

consumption. Appendix B includes additional discus sion of QA/QC measures taken to ensure

data objectives are met.

1.2 Collection of Existing Formaldehyde Emissions D ata

Because formaldehyde emissions testing has typicall y not been required for smaller engines,

very little emissions data exist for engines less t han 500 hp, which are primarily located at rural

sources. API members compiled and provided a minim al amount of data summaries for review

and inclusion in the MACT floor analysis.

1.3 Summary of MACT Floor Database Engines and Tests

Fifty one (51) 4SRB engines with rated capacities o f between 100 hp and 500 hp were included

in the MACT Floor analysis. The majority of the 4SR B engines tested were Caterpillar (37) and

Waukesha (13), with one engine from Cummins (1). T hirty one (31) of the fifty one (51)

engines had multiple tests conducted. Within the p opulation of the best performing twelve

percent engines, thirty eight (38) individual tests were completed. These data are further

discussed in Sections 2 and 3.

1.4 Report Content

The data collection effort compiled a significant a mount of CH 2 

### O data for rich burn engines.

These data are useful for demonstrating engine oper ation, emissions variability, and informing

MACT floor emission limits that can be achieved at all times and under the most adverse

circumstances which can reasonably be expected to r ecur. This report presents and summarizes

the results of the 4SRB engines CH 2 

### O emissions data collection effort.

While this is primarily a “data report”, the docume nt includes analysis and discussion that

provides a technical summary of the CH 2 

### O emissions data. Section 2 provides a discussion of

“MACT floor” analysis based on the EJC-API understa nding of Clean Air Act requirements and

recent court cases, including assessment of the bes t performing 12% of engines and variability

within the MACT floor engine population. Section 3 presents summary data and tables for the

4SRB engine subcategory. Section 4 discusses the r esulting size based subcategories for the

4SRB engines. Section 5 summarizes the results and provides concluding remarks.

The detailed data and quality assurance / quality c ontrol (QA/QC) information are provided in

the appendices. Appendix A provides data tables fo r the 4SRB engines that include a unique

engine identifier, unique test identifier, engine i nformation (e.g., make, model, type), test

information (e.g., test date, test method, engine l oad), and emissions data. Appendix B discussesTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 5 QA/QC review of data and the standard methods used for testing. Appendix B also includes a

discussion of the representativeness of short-term (i.e., less than 1-hour) test runs conducted for

the purpose of assessing emissions variability. In addition to these appendices, an Air Hygiene

source test report for engines that populate the MA CT floor will be provided to EPA separately.

This third party test report contains a summary of the engine make, model, OEM horsepower,

test condition, altitude, ambient conditions, fuel analysis, sampling and analytical procedures,

test results and calculations, and QA/QC for the te st program.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 6 2.0 MACT Floor Determination: Basis and Analysis Approa ch

Section 112(d)(3)(A) of the Clean Air Act requires that the emission standards for existing

engines at Major Sources be based on “the average e mission limitation achieved by the best

performing 12% of the existing sources...”. This emi ssion level is typically referred to as the

“MACT floor”. The MACT floor determination is a tw o step process. The MACT floor engines

are first identified and then the entire emissions database for these MACT floor engines is then

considered to determine the level of the standard. The consideration of the entire emissions

database stems from recent decisions from the D.C. Circuit Court (Court) that supported the

consideration of variability in establishing emissi on standards.

For this analysis, EJC-API considered the Clean Air Act, Court decisions regarding the basis for

determining Section 112(d) emission standards, the EPA analysis for existing compression

ignition engines in the March 3, 2010 RICE NESHAP amendments, and recent EPA MACT

floor analyses from other NESHAP rules. In additio n, this analysis is supplemented by our

understanding of reciprocating engine emissions, th e inherent variability in emissions from

natural gas-fired reciprocating engines, and operat ing conditions such as load that can affect rich

burn engine CH 2 

### O emissions.

For rich burn gas-fired engines, the proposed rule establishes CH 2 

### O as the regulated HAP. Since

CH 2 

### O measurement is not common in compliance tests, av ailable tests results for affected

engines did not offer sufficient data to determine the MACT floor or to address variability.

Consequently, EJC implemented the testing program d escribed above in Section 1.1.

In advance of EPA’s MACT floor analysis, EJC-API is providing this document to illustrate our

MACT floor analysis and consideration of variabilit y. Our methodology is based on Clean Air

Act requirements and recent Court directives for es tablishing a MACT floor emission limit that

must be met every day under all operating condition s. Because there are many existing SI RICE

and it is not practical or feasible to expect stake holders to develop a detailed understanding of

emissions from all engines during this rulemaking, any available dataset will have inherent

limitations or deficiencies, and those limitations need to be carefully assessed in the analysis.

For example, although this report provides data fro m more than 50 engines, there are practical

limitations that could lead to an unreasonable conc lusion depending upon the technical analysis

of the data. For illustration, a best performing e ngine located at approximately sea level and

tested at warm ambient temperatures may result in l ower formaldehyde emissions; that same

engine located at higher altitudes and colder ambie nt temperatures would likely have higher

formaldehyde emissions. These and other factors th at may affect emission variation are

discussed in Section 2.2.

Sections 2.1 and 2.2 provide the EJC-API analysis a nd discussion on the technical perspective of

the data collected by EJC-API, including identifica tion of the “MACT floor” engines and

consideration of variability. These sections also discuss the field test program design

considerations as they relates to the MACT floor an alysis.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 7 2.1 Identifying Best Performing Units

This section addresses two issues related to identi fying the MACT floor units: averaging of

numerous test runs from a single engine operating o r test condition (i.e. emission test averages)

and engine-to-engine comparisons when emission meas urements were conducted at multiple

engine operating/test conditions. These issues are discussed with consideration of the EJC

testing program that collected the majority of the emission data.

As described in Section 1.1, a test plan was develo ped, adjusted, and communicated to EPA to

focus limited resources toward completing data coll ection and inform MACT floor decisions.

The overall goal of this test program was to maximi ze the number of MACT floor test engines

and complete testing over a range of expected opera ting conditions to inform emissions

variability from potential MACT floor engines. A d eliberate approach (i.e. reduce the number of

variables potentially impacting the emissions) desi gned to identify the best performing 12

percent of 4SRB engines was adopted following initi al field tests by conducting subsequent tests

on all units at a consistent, lower excess air/O 2 

### setting.

Consequently, all rich burn engines were tested at a common operating condition, the highest

available load and a common excess air/O 2 

### setting of 0.5% or lower. This approach was adopt ed

to maximize the opportunity for identifying MACT fl oor engines, and minimize resources

required to test the engine population within the l ower 88 percentile engine population. Once a

candidate MACT floor engine was identified, the eng ine would be tested at several excess air

settings/air-to-fuel ratios (up to 2% O 2 

### ) and/or loads (i.e. depending on ability to adjust or alter

work) to determine expected emission variability (i .e. variability based on operating envelope).

The MACT floor engines are based on the test data a t the common operating condition.

However, the MACT floor emission limit would be bas ed on the emissions over the range of

loads and/or air-to-fuel ratios (i.e., emission lim it considers variability) as discussed further in

Section 2.2.

EJC-API understands that for the March 2010 compres sion ignition NESHAP amendments,

when multiple “test runs” are available for a singl e “test” condition, such as three high load test

runs for a compliance test, EPA used the average of the three runs when comparing emissions

data between engines to identify the best performin g 12%. If only a single test run is available

for a particular engine operating condition (e.g., most EJC tests), then that test result is used for

the comparison between engines to identify the best performing 12%. EJC-API supports this

approach as is further discussed in Section 3.

The next step is to consider how to evaluate engine s and compare data between engines when

some engines have multiple tests. In the EJC-API d ata set, most engines were tested at multiple

operating conditions and only one engine has multip le test runs at the same operating condition.

As described below, EJC-API strongly recommends tha t for engines with multiple CH 2 

### O

emission tests, the lowest or best performing CH 2 

### O emissions from each engine should be used

for engine-to-engine comparisons to identify the be st performing 12%. This approach provides

the best assurance that tests completed at similar operating conditions are equitably compared

when defining the engines in the top 12%.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 8 EPA has previously considered potential approaches to determining the MACT floor that

included using either the highest CH 2 

### O test result or averages from multiple test points at

disparate operating or test conditions. EJC-API b elieves that it is inappropriate to select the

MACT floor engine using either of these approaches and that the selection methodology

described in this report is more technically defens ible, particularly when there are multiple

engines in the MACT floor. To further clarify the rationale for selecting the lowest or best

performing CH 2 

### O emissions units, consider the limitations introdu ced by selecting the highest

CH 2 

### O emissions to identify the MACT Floor unit. If the top 12% is selected based on comparing

the highest

CH 2 

### O from multi-test engines (i.e., the engines are so rted from lowest to highest

based on the highest emission test condition), it i s likely that an operating condition with higher

characteristic emissions (e.g., lower load and/or h igher AFR) from the multi-test engines would

be compared to a high load/low AFR test (lower char acteristic emissions) for the single-test

engines. This is an inequitable comparison :

• 

### which precludes the comparison of CH 2 

### O data at common operating conditions (e.g., high

load and nominal AFR) for the multi-test versus sin gle test engines;

• 

### would likely result in single test engines in the M ACT floor although they have higher

emissions than the multi-test engine at a common op erating condition;

• 

### prevents consideration of operating conditions that reflect “best performance” for multi-test

engines; and

• 

### could result in multi-test engines being precluded from or limited in the population of

engines in the best performing 12%.

This approach would also result in limited data for assessing variability and is in direct conflict

with the test plan that was developed with the expr ess purpose of gathering formaldehyde

emissions data over a range of achievable engine op erating conditions. Under this very plausible

scenario the single test engine could be in the MAC T floor although it may have higher

emissions than the multi-test engine at a common op erating point. Using the average of multiple

test conditions across divergent operating conditio ns is similarly inappropriate for assessing the

MACT Floor technologies (i.e., engine make and mode l).

EJC-API believes that the most logical and technica lly defensible approach is to compare

engine-to-engine data under similar operating condi tions where feasible, and that such a

comparison has a higher probability of identifying the better performing engines. For example,

comparing CH 2 

### O emissions from two engines at a common operating condition (e.g., highest

available load and a common excess air/O 2 

### setting of 0.5% or lower) provides an indication o f

the better performer. However, comparing high load /low excess air emissions (with lower

characteristic CH 2 

### O) from one engine with low load/high excess air em issions (with higher

characteristic CH 2 

### O) from another engine is not equitable. The floor engine selection process

must provide a reasonable basis for assessing which engine is the better performer and

significant discrepancies in key operating paramete rs (e.g., AFR, load) that are known to impact

CH 2 

### O emissions precludes a rational comparison.

Engine emission characteristics also support the co mmon operating condition comparison that is

best achieved by comparing lowest emissions from mu lti-test engines. For example, for rich

burn reciprocating engines, it is generally expecte d that CH 2 

### O emissions are more variableTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 9 across the range of typical engine conditions (e.g. , load and AFR) on an individual engine than

the variability that would be reflected by comparin g multiple similar engines at a common high

load operating condition. If all engines in the da taset were tested under a similar range of

operating conditions and had a similar number of te st points, this issue would be less compelling.

However, for the data provided in this report, wher e the number of tests per engine varies from

one or two tests on many engines to as many as seve n tests on other engines, this analytical

approach is important not only for defining best pe rformers, but also for providing the ability to

consider data from multiple tests to better underst and emissions variability.

While not detailed in this report, review of the EJ C-API dataset confirms the concerns expressed

here. When the data are sorted based on the best p erforming or lowest CH 2 

### O emissions for

multi-test engines, the result is many engines with multiple tests in the MACT floor (i.e., a total

of 38 individual tests from 7 MACT floor engines fu rther detailed in Section 3). In contrast,

sorting the engines based on maximum emissions resu lts in 16 tests to assess variability, with

five of the seven engines having either one or two test runs. The latter approach limits and

significantly hinders the ability to assess emissio ns variability for the best performing 12% of

engines.

Thus, it is imperative that the “best performing” e ngines within a subcategory be based on

selecting the lowest CH 2 

### O test from multi-test engines for comparison with other engines. EJCAPI believes that this approach is consistent with the Clean Air Act and has the most technical

merit for identifying best performing engines. In addition, this approach is consistent with the

EJC testing that is the source of the majority of t he test data; engines that were initially identifie d

as best performers were subsequently tested at lowe r loads and higher AFRs that resulted in

higher CH 2 

### O emissions. Conversely, engines that were not ini tially identified as best performers

were not subsequently tested at operating condition s expected to produce higher CH 2 

### O

emissions. Thus, the only equitable engine-to-engi ne comparison for EJC tested engines is at the

common, best performance operating condition. Fina lly, because this approach will limit the

likelihood that multi-test engines will be inapprop riately excluded from the “MACT floor”

engine population, this approach also facilitates c onsideration of the range of emissions for best

performing engines and CH 2 

### O emissions variability. Section 3 of this report uses this approach

for identifying the engines in the “MACT floor”.

2.2 MACT Floor Variability

EPA has indicated that review of emissions variabil ity should be limited to the “MACT floor”

units (i.e., the engine population in the best perf orming 12%). This report does not discuss

possible alternatives to this interpretation for th e variability assessment, but this approach does

introduce limitations when considering the vast arr ay of engine types and applications. The

limited resources and regulatory timeframe did not allow for an extensive test program to

provide a wide range of engine make/models, altitud es, ambient conditions, fuel quality, and

applications to be comprehensively evaluated. Es tablishing an emission limit based on limited

test data from a very large population of affected sources emphasizes the need to properly

characterize variability from the test data set. T herefore, it is imperative that EPA consider the

limited dataset over the entire population of MACT floor engines to assess variability.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 10 For example, it is commonly understood that fuel qu ality, ambient conditions (e.g., temperature,

humidity or precipitation), and elevation can impac t emissions. Both higher elevation and cooler

ambient temperature are likely to result in an incr ease in CH 2 

### O emissions. Additionally, reduced

fuel quality, not uncommon for field gas-fired engi nes, impacts combustion and could increase

products of incomplete combustion (i.e. formaldehyd e). If data from the MACT floor engine

population are limited to engines at lower elevatio n and/or from warmer weather tests, as is the

case for many of the EJC-API tests, then variabilit y associated with these factors will not be

captured. Furthermore, the field gas fuel for the EJC-API tests was generally of high quality (i.e.

high methane and low diluent content) and promoted stable combustion. It should be noted that

some engines with multiple tests over a broad range of operating conditions may provide

informative emissions variability data, but if the lowest CH 2 

### O emissions are not within the best

performing 12%, then that data set is not included in the analysis (e.g., key emissions

information related to variability is lost).

This report is an “emissions data report” with comp lementary technical discussion. Thus,

detailed citations and legal justification are not provided, but recent Court decisions provide

insight into assessing variability when establishin g the MACT floor for existing engines. The

2007 Brick MACT encapsulates many of these decision s by referring to the recent record from

similar challenges. Examples supporting EPA’s abil ity to incorporate variability in the MACT

floor include:

• 

### The Brick MACT decision reiterates a finding from t he 2001 Cement Kiln MACT (“Cement

Kiln”) decision and a related 1999 decision where t he D.C. Circuit Court explained, “EPA

would be justified in setting the floors at a level that is a reasonable estimate of the

performance of the ‘best controlled similar unit’ u nder the worst reasonably foreseeable

circumstances.”

• 

### “Cement Kiln” also acknowledges that it is accepta ble for EPA to consider the range of

emissions from the best performing sources and that results at more adverse conditions “are

more helpful than normal operating data would be in estimating performance under a variety

of conditions and thus in helping to assure that pr operly designed and operated sources can

achieve the standard.”

• 

### The Brick MACT decision also references the 2003 Mo ssville Environmental Action versus

EPA decision in which the D.C. Circuit Court “...held that floors may legitimately account

for variability because “each [source] must meet th e [specified] standard every day and under

all operating conditions.”

• 

### A similar premise is evident in a 1999 Sierra Club versus EPA decision noting that the

MACT floor standard must be achieved at all times a nd, “under the most adverse

circumstances which can reasonably be expected to r ecur.”

Thus, it is acceptable and expected for EPA to cons ider emission levels associated with normally

anticipated and recurring operating conditions, and Court decisions acknowledge that data from

more adverse operating conditions can inform the ba sis of the standard. For the context of the

rich burn engine emission standard considered in th is report, higher CH 2 

### O emissions associated

with reasonable operating conditions likely to recu r are of special interest. These operating

conditions and associated emissions are of interest due to the nature of the dataset, where low

elevation, warm ambient temperature tests are preva lent due to location and timing of the engineTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 11 testing. Thus, the data distribution is not indica tive of the entire population of engines operations

and more adverse conditions (for CH 2 

### O emissions) such as higher elevation operation, co ld

ambient temperatures, and poor fuel (field gas) qua lity are under-represented in the MACT floor

units.

In addition to the items listed above, Court cases buttress EPA’s position that the floor should

not be based on “worst performer” units with the MA CT floor technology (i.e., rich burn engines

without HAP control for this standard) that are not within the best performing 12%. For

example, the Brick MACT decision references a Cemen t Kiln MACT finding, “...that EPA may

not use emission levels of the worst performers to estimate variability of the best performers

without a demonstrated relationship between the two ...” While demonstrating a relationship

could provide an avenue to consider variability fro m units outside the top 12% (e.g., a unit not

within the floor that is the same make and model as a MACT floor unit, but located at a different

elevation), this is not pursued in the analysis dis cussed in Section 3.

Furthermore, case law supports establishing a MACT floor to reflect the impact that external

sources, such as ambient conditions and fuel, may h ave on the best performers' emissions. In

Mossville Environmental Action versus EPA

, the court supported EPA's decision to evaluate

emissions from all plants in a sector, and not the just the plants in the top 12%, because emission

variability was driven by "the type of resin being produced, not the technology or processes

applied to control emissions." As referenced above , the Brick MACT court recognized that the

MACT emission standard may account for variability because the standard must be "met all day

every day" and that the final emission standard in Mossville reasonably estimated that variability

for the best performing source.

In summary, in considering variability, EJC-API is recommending that EPA:

• 

### incorporate the range of emissions from best perfor ming engines into the standard setting

process;

• 

### consider that the operating conditions associated w ith higher CH 2 

### O test results points are

within the envelope of reasonable operations and li kely to recur;

• 

### consider that the CH 2 

### O emission data distribution here is not indicative of the entire

population of engines operations and more adverse c onditions (for CH 2 

### O emissions) such as

fuel quality, altitude effects, ambient temperature , and humidity effects are underrepresented.

• 

### consider that the resulting 4SRB MACT floor is cons idered conservative and would be

expected to increase if these adverse conditions di scussed above would have been included

within the test program;

• 

### consider that the units must meet the standard ever y day and under all operating conditions;

and

• 

### establish a standard that MACT floor units can meet if operating “under the most adverse

circumstances which can reasonably be expected to r ecur.”Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 12 In Section 3, data are summarized for the engines t hat comprise the best performing 12%. The

analysis and discussion follow the principles discu ssed above, and the following sections

illustrate these principles based on the CH 2 

### O emissions data collected by EJC-API.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 13 3.0 Data Summary and Discussion: Four-Stroke Cycle Ric h Burn Engines

To determine the number of 4SRB engines in the best -performing 12 percent, the number of

engines was multiplied by 12 percent and rounded up . For the data discussed in this section, 51

engines were tested and 12% equates to 6.12, which places 7 engines into the MACT floor. A

total of 120 engine tests are associated with the f ifty one 4SRB engines that have rated capacities

between 100 and 400 horsepower (hp). The majority of the 4SRB engines tested were

Caterpillar (37) and Waukesha (13), with one engine manufactured by Cummins. The majority

of the engine tests were supplied via the engine te sting program managed by EJC. As discussed

above, numerous parameters are expected to impact f ormaldehyde emissions from 4SRB engines

including load, fuel quality, excess air, engine ag e and maintenance practices/schedule,

elevation, and ambient conditions. While the proje ct attempted to test engines over their asfound operating envelop, the testing was not design ed to be a parametric investigation and a

quantified evaluation of the individual parameters impacting CH 2 

### O emissions was well beyond

the scope of this testing project; however, the dat a generally show CH 2 

### O emissions increasing

with lower load and higher excess air.

3.1 Selection of Best Performing Units

Table 3-1 summarizes the primary formaldehyde emiss ion test data set for the ten best

performing 4SRB engines with rated capacities of be tween 100 hp and 500 hp. The full set of

engine test data is provided in Appendix A. As dis cussed above, the 51-engine dataset results in

a MACT floor (top 12%) comprising the seven engines having the lowest formaldehyde

concentration in any single test.

Table 3-1. 4SRB “Best Performing” Engines Test Dat a Summary

Engine

No. Test

No. Make Model Test Date Test

Method Rated

HP CH2O 1



### 17 T36 Waukesha F1197GU 9/23/2009 RM 320 192 3.18

43 T105 Caterpillar 3306 TA 10/8/2009 RM 320 203 3.31

21 T47 Caterpillar 3406 TA 9/24/2009 RM 320 325 3.53

5 T9 Caterpillar G-342TA 9/11/2009 RM 320 265 4.71

14 T26 Waukesha F1197GU 10/1/2009 RM 320 192 4.72 MACT FLOO R ENGINES

34 T75 Waukesha F1197G 9/30/2009 RM 320 192 4.94 (Top 12%)

38 T88 Waukesha F1197G 10/2/2009 RM 320 192 4.96

41 T100 Caterpillar G3406TA 10/6/2009 RM 320 325 5.52

15 T30 Caterpillar 3306 NA 9/21/2009 RM 320 145 5.52 NON-FL OOR ENGINES

42 T102 Caterpillar 3406 TA 10/7/2009 RM 320 325 5.97 (Port ion of Bottom 88%)

NOTE1: ppmvd @ 15% O2 during best performing test f or the engine

RM: EPA Reference MethodTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 14 3.2 MACT Floor Variability for 4SRB Engines

To assess emissions variability for the best perfor ming 12% of 4SRB engines, emission levels

associated with the tested range of operating condi tions for the MACT floor engines were

considered. Table 3-2 summarizes the MACT floor en gines CH 2 

### O emission test data. A review

of the operating conditions for the 38 MACT floor e ngine tests determined that all tests were

conducted during routine operating conditions that will recur. In addition to presenting the range

of test data points, Table 3-2 also presents the nu mber of tests associated with each engine. The

number of tests provides an indication of the abili ty to assess variability from the MACT floor

engine population (i.e., emissions information from a single engine at multiple operating

scenarios). Without multiple test points at differ ent engine operating conditions, variability

cannot be assessed.

It should be noted that this data set is still rela tively limited and the tests were conducted at a

single point in the engine’s operation; thus, the a vailable emission data surely do not reflect

inherent variability that will occur over time (e.g . caused by different load, ambient conditions,

fuel quality, time lapse since maintenance/overhaul , etc.) nor capture more adverse conditions

that are likely to occur and could increase emissio ns of formaldehyde as well as other products of

incomplete combustion. Thus, it is reasonable to c onclude that the upper bound of these MACT

Floor engines test results reflects some, but not a ll, of the variability for best performing units. A

complete summary of the entire test data set is con tained in Appendix A. Note that one engine

(i.e., No. 51 listed in Appendix A within the lower 88 percentile) contains multiple test runs at

the same engine operating/test condition and theref ore an average of these four test runs were

used in the MACT floor engine selection for this so urce.

Table 3-2. Summary of MACT Floor Engines.

Engine

No. Make Model Rated

HP MIN

CH 2 

### O 1 

### MAX

CH 2 

### O 1 

### #

Tests

17 Waukesha F1197GU 192 3.18 7.59 3

43 Caterpillar 3306 TA 203 3.31 8.64 4

21 Caterpillar 3406 TA 325 3.53 10.94 5

5 Caterpillar G-342TA 265 4.71 12.05 6

14 Waukesha F1197GU 192 4.72 9.42 7

34 Waukesha F1197G 192 4.94 7.71 6

38 Waukesha F1197G 192 4.96 7.92 7

NOTE1: ppmvd @ 15% O2Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 15 4.0 Sized Based Subcategories

Section 112(c)(1) of the Clean Air Act (CAA) grants EPA broad discretion to establish

“categories and subcategories” of sources to be reg ulated under §112. Additionally, CAA

§112(d)(1) provides that the Administrator “may dis tinguish among classes, types and sizes of

sources within a category or subcategory” when esta blishing MACT standards.

In the final compression ignition rule (FR 9648 Vol . 75, No. 41) EPA promulgated work practice

standards instead of numerical emissions limits for engines less than 100 hp at major sources.

For SI engines, which have a very different emissio ns profile than CI engines, EJC-API believes

that work practice standards should apply to engine s less than 300 hp at major sources. EJC-API

believes that it is appropriate to establish a high er size threshold for gas fired engines based on

health effects issues surrounding diesel particulat e that do not pertain to gas fired engines.

Because of the difference in emissions between CI a nd SI engines, it is hard to justify the cost of

emissions testing for engines less than 300 hp even at major sources.

For major sources, CAA §112(h) indicates that “if i t is not feasible in the judgment of the

Administrator to prescribe or enforce an emission s tandard for control of a hazardous air

pollutant or pollutants, the Administrator may, in lieu thereof, promulgate a design, equipment,

work practice, or operational standard, or combinat ion thereof”. EJC-API strongly encourages

the use of work practice standards of CAA §112(h) f or major sources in lieu numerical standards

for 4SRB engines with rated capacities of less than 300 hp.

The Clean Air Act gives EPA even more discretion fo r engines located at area sources, rather

than major sources. For area sources, section 112(d )(5) allows “Generally Achievable Control

Technology” (GACT) to be less stringent than major source MACT and also allows management

practices in lieu of emission standards. EJC-API strongly encourages the use of management

practice standards of CAA §112(d)(5) for area sourc es in lieu numerical standards for 4SRB

engines with rated capacities less than 500 hp. Th e majority of the natural gas SI RICE

population is understood to be predominately rural area source engines whereas HAP emission

limits from stationary RICE are principally an urba n risk-driven requirement.

If EPA were to require a numerical emission limit f or 4SRB engines, EJC-API advocates

establishing a MACT floor of no lower than 13 ppmvd @ 15% O 2 

### (i.e., maximum emission

value for MACT Floor engines in Table 3-2, 12.05 pp mvd @ 15% O 2 

### , rounded to the next whole

number) for all regulated 4SRB engines based on the analysis and results presented in Sections 2

and 3. However, it should be further noted that th e emissions data from the test program that

supports this emission limit are conservatively bia sed low because limited test data was obtained

during better than average conditions (warm climate , low elevation and good fuel quality). EJCAPI believes that if additional testing would have been conducted to quantify these operating

(e.g., fuel quality, maintenance schedule) and ambi ent (e.g., temperature, altitude, humidity)

parameters expected to impact formaldehyde emission s, the resulting MACT floor emission limit

would have been higher.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 16 5.0 Conclusions and Recommendations

EJC-API understand that the Clean Air Act requires that the emission standard for existing units

located at major sources be based on the average em ission limitation achieved by the best

performing 12% of engines in a subcategory. The co urts have also emphasized, however, that

EPA must set floor limits that reflect emissions du ring operating conditions that can be

“reasonably expected to recur”. We have establishe d in previous comments to this rule and other

rules that emissions from engines are extremely sen sitive to operating conditions that can vary in

terms of ambient conditions (temperature, humidity, and altitude), fuel quality, load, air/fuel

ratio, and many other parameters. The concept of v ariability, which directly addresses this

sensitivity, must be reflected properly in the fina l rule. With this concept in mind, EJC-API

request that EPA implement the MACT floor analytica l methodology presented in this

document.

The technical merits of our approach can be summari zed as follows.

• In terms of MACT Floor engines selection, the EJC-A PI methodology identified the “best

performing” engines by comparing the emissions at c ommon operating conditions that were

found to be the best performing conditions for such engines. Other methodologies

contemplated by EPA have compared engines operating at vastly different loads or operating

conditions, which would not allow for a meaningful comparison when selecting the “best

performing” engines.

• In terms of variability assessment, the EJC-API met hodology allows for emissions at

operating conditions that can be “reasonably expect ed to recur”. Other methodologies used

by EPA in other MACT rules mirror the EJC-API analy sis, which reinforces the theoretical

basis of this method (i.e., a floor engine should b e able to meet the standard).

Finally, we are recommending the following specific elements be included in the final rule.

1. Management practice standards should be employed in lieu of an emission limit for area

source engines with rated capacities less than 500 hp.

2. Work practice standards should be employed in lieu of an emission limit for major source

engines with rated capacities less than 300 hp.

3. Based on the range of emission values presented in Table 3-2 and considering the

technically sound methodology presented in this doc ument, if a numerical MACT floor

emission limit for the 4SRB engines is established by EPA, the limit should be set no

lower than 13 ppmvd (at 15% O 2 

### ).Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### 17 6.0 Sources

The following sources of information were utilized in preparation of this report.

1. National Emission Standards for Hazardous Air Pollu tants for Reciprocating Internal

Combustion Engines: Proposed Rule – Federal Registe r Volume 74, pages 9698 through

9731 (dated March 5, 2009)

2. “Comments On The Proposed Revisions To The National Emission Standards For

Hazardous Air Pollutants For Reciprocating Internal Combustion Engines” – Docket

Document Nos. EPA-HQ-OAR-2008-0708-0242.1 & 0242.2 submitted by API (dated

June 3, 2009)

3. “Exterran Technical Comments on the Proposed Revisi ons To The National Emission

Standards For Hazardous Air Pollutants For Reciproc ating Internal Combustion Engines–

submitted dated June 3, 2009

4. Letter from Stephanie Meadows (API) to Melanie King (EPA) dated August 3, 2009

providing a list of issues and meeting agenda

5. August 5, 2009 meeting with EPA and API

6. Letter from Jeff Holmstead to Robert Wayland dated August 17, 2009 outlining project to

collect engine emissions data to support NESHAP dev elopment

7. On 8-18-09 EJC meeting with EPA on August 18, 2009 to discuss testing protocol and

other issues.

8. “40 CFR 63 Subpart ZZZZ - Natural Gas Fired Engine MACT Floor Test Plan &

Equipment / Operations Information Gathering” by IE S (dated October 2, 2009) – also

provided as Appendix C to this document

9. Test Method 320: Measurement Of Vapor Phase Organic And Inorganic Emissions By

Extractive Fourier Transform Infrared (FTIR) Spectr oscopy added to Appendix A of 40

CFR 63

10. National Emission Standards for Hazardous Air Pollu tants for Reciprocating Internal

Combustion Engines; Final Rule - Federal Register V olume 75, pages 9648 through 9690

(dated March 3, 2010)Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



## APPENDIX A

4SRB ENGINE TEST DATATechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-1Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O21T1Caterpillar3306 NAAs Found - 1 hr Test9/9/2009RM 32014573.4%21.412T2CaterpillarG3406 TAAs Found - 1 hr Test9/10/2009RM 32032557.6%8.072T3CaterpillarG3406 TAO2-1% Period Test9/10/2009RM 320325--10.232T4CaterpillarG3406 TAO2-1.9% Period Test9/10/2009RM 320325--12.703T5CaterpillarG3306 NAAs Found - 1 hr Test9/10/2009RM 32014566.0%13.573T6CaterpillarG3306 NAO2-1.9% Period Test9/10/2009RM 320145--18.613T7CaterpillarG3306 NAO2-1% Period Test9/10/2009RM 320145--15.374T8WaukeshaF11976As Found - 1 hr Test9/11/2009RM 32019270.1%16.655T9CaterpillarG-342TAAs Found - 1 hr Test9/11/2009RM 32026570.9%4.715T10CaterpillarG-342TAAs Found, Low O29/11/2009RM 32026563.4%6.12Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-2Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O25T11CaterpillarG-342TAHigh Load, Low O29/11/2009RM 32026573.6%5.215T12CaterpillarG-342TAHigh Load, High O29/11/2009RM 32026573.6%9.245T13CaterpillarG-342TALow Load, High O29/11/2009RM 32026537.7%12.055T14CaterpillarG-342TALow Load, Low O29/11/2009RM 32026537.7%9.526T15Caterpillar3306 NAAs Found - 1 hr Test9/14/2009RM 32014565.6%9.447T16WaukeshaF1197GUAs Found - 1 hr Test9/14/2009RM 32019264.2%6.558T17CaterpillarG3408TAAs Found - 1 hr Test9/15/2009RM 32040059.5%8.599T18Caterpillar3306 NAAs Found - 1 hr Test9/15/2009RM 32012957.7%16.5210T19CaterpillarG3306 NAAs Found - 1 hr Test9/15/2009RM 32014532.3%9.1611T20CaterpillarG3406 NAAs Found - 1 hr Test9/16/2009RM 32019237.4%10.1812T21Caterpillar3306 NAAs Found - 1 hr Test9/17/2009RM 32014580.6%17.5913T22Caterpillar3306As Found - 1 hr Test9/19/2009RM 32014535.8%15.0814T23WaukeshaF1197GUAs Found - 1 hr Test9/19/2009RM 32019239.6%5.3214T24WaukeshaF1197GUAs Found - Retest10/1/2009RM 32019255.7%7.73Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-3Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O214T25WaukeshaF1197GUAs Found, Low O210/1/2009RM 32019255.7%5.0214T26WaukeshaF1197GUHigh Load, Low O210/1/2009RM 32019263.5%4.7214T27WaukeshaF1197GUHigh Load, High O210/1/2009RM 32019263.5%9.4214T28WaukeshaF1197GULow Load, High O210/1/2009RM 32019241.7%8.2914T29WaukeshaF1197GULow Load, Low O210/1/2009RM 32019241.7%5.4915T30Caterpillar3306 NAAs Found - 1 hr Test9/21/2009RM 32014569.7%5.5215T31Caterpillar3306 NAAs Found - Retest10/2/2009RM 32014585.5%13.2415T32Caterpillar3306 NAAs Found, Low O210/2/2009RM 32014585.5%9.36Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-4Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O215T33Caterpillar3306 NAMid O210/2/2009RM 32014585.5%13.6916T34CaterpillarG342TAWAs Found - 1 hr Test9/23/2009RM 32026533.2%6.0516T35CaterpillarG342TAWAs Found, High O29/23/2009RM 32026533.2%6.2017T36WaukeshaF1197GUAs Found - 1 hr Test9/23/2009RM 32019235.9%3.3117T37WaukeshaF1197GUAs Found, High O29/23/2009RM 32019235.9%7.5917T38WaukeshaF1197GUMid Load9/23/2009RM 32019253.6%3.1818T39CaterpillarG3306NALow O2- 1 hr Test9/23/2009RM 32014559.5%7.3218T40CaterpillarG3306NAAs Found9/23/2009RM 320145--13.7819T41Caterpillar3306NALow O2- 1 hr Test9/23/2009RM 32014557.5%9.8419T42Caterpillar3306NAAs Found9/23/2009RM 320145--17.97Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-5Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O220T43CaterpillarG3306NALow O2- 1 hr Test9/23/2009RM 32014570.4%10.9220T44CaterpillarG3306NAAs Found9/23/2009RM 320145--14.3221T45Caterpillar3406 TALow Load, Low O2, 1hr9/24/2009RM 32032552.6%3.7421T46Caterpillar3406 TAAs Found9/24/2009RM 32032552.6%10.9421T47Caterpillar3406 TAMid Load, Low O29/24/2009RM 32032568.3%3.5321T48Caterpillar3406 TAMid load, High O29/24/2009RM 32032568.3%8.4321T49Caterpillar3406 TALow Load, High O29/24/2009RM 32032552.6%9.6522T50CaterpillarG3406TAAs Found - 1 hr Test9/24/2009RM 32032568.6%7.30Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-6Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O223T51CaterpillarG3406NALow Load, Low O29/25/2009RM 32021540.5%7.4523T52CaterpillarG3406NALow Load, High O29/25/2009RM 32021540.5%17.1923T53CaterpillarG3406NAHigh Load, High O29/25/2009RM 32021566.5%15.5923T54CaterpillarG3406NAHigh Load, Low O29/25/2009RM 32021566.5%7.4923T55CaterpillarG3406NAMid Load, Low O29/25/2009RM 32021560.5%6.4023T56CaterpillarG3406NAMid Load, High O29/25/2009RM 32021560.5%15.76Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-7Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O224T57Caterpillar3406 NALow O2- 1 hr Test9/25/2009RM 32021596.8%13.8325T58Waukesha1197As Found - 1 hr Test9/26/2009RM 32019254.7%9.1625T59Waukesha1197High Load, Low O29/26/2009RM 320192--9.1826T60CaterpillarG3306NALow O2- 1 hr Test9/26/2009RM 32014545.2%8.0626T61CaterpillarG3306NAAs Found9/26/2009RM 320145--11.8727T62CaterpillarG3406TALow O2- 1 hr Test9/28/2009RM 32032595.2%10.6128T63WaukeshaF1197Low O2- 1 hr Test9/28/2009RM 32014098.4%9.6429T64CaterpillarG3306NAAs Found - 1 hr Test9/28/2009RM 32014552.8%13.6130T65WaukeshaF1197GAs Found - 1 hr Test9/28/2009RM 32019264.1%7.55Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-8Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O231T66CaterpillarG 3406TAAs Found, Low O2- 1hr Test9/29/2009RM 32032556.3%6.0731T67CaterpillarG 3406TAHigh Load, Low O29/29/2009RM 32032556.9%6.0831T68CaterpillarG 3406TAHigh Load, High O29/29/2009RM 32032556.9%14.2431T69CaterpillarG 3406TALow Load, High O29/29/2009RM 32032541.5%16.5431T70CaterpillarG 3406TALow Load, Low O29/29/2009RM 32032541.5%9.5732T71Caterpillar3406TAAs Found9/29/2009RM 320325--23.1532T72Caterpillar3406TAAs Found, High O2-1hr Test9/29/2009RM 32032553.3%12.73Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-9Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O233T73CaterpillarG3306NALow O2- 1 hr Test9/29/2009RM 32014561.3%9.1033T74CaterpillarG3306NAAs Found9/29/2009RM 320145--15.3434T75WaukeshaF1197GAs Found - 1 hr Test9/30/2009RM 32019267.2%4.9434T76WaukeshaF1197GAs Found, High O29/30/2009RM 32019265.1%7.5734T77WaukeshaF1197GMid Load, Low O29/30/2009RM 32019254.7%6.8434T78WaukeshaF1197GMid Load, High O29/30/2009RM 32019254.2%7.6034T79WaukeshaF1197GLow Load, Low O29/30/2009RM 32019247.9%5.3134T80WaukeshaF1197GLow Load, High O29/30/2009RM 32019247.4%7.7135T81Caterpillar3306 NAAs Found9/30/2009RM 320145--8.28Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-10Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O235T82Caterpillar3306 NALow O2- 1 hr Test9/30/2009RM 32014586.3%10.8336T83CaterpillarG3406NALow O2, 1 hr Test9/30/2009RM 32021566.3%18.3836T84CaterpillarG3406NAAs Found9/30/2009RM 320215--33.6937T85WaukeshaF1197GAs Found10/1/2009RM 320186--15.1637T86WaukeshaF1197GLow O2, 1 hr Test10/1/2009RM 32018682.1%7.9438T87WaukeshaF1197GAs Found10/1/2009RM 32019254.2%6.6838T88WaukeshaF1197GAs Found - Mid Load,Low O210/2/2009RM 32019262.0%4.9638T89WaukeshaF1197GMid Load, High O210/2/2009RM 32019258.9%6.29Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-11Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O238T90WaukeshaF1197GHigh Load, High O210/2/2009RM 32019247.9%7.9238T91WaukeshaF1197GHigh Load, Low O210/2/2009RM 32019250.0%5.3638T92WaukeshaF1197GLow Load, Low O210/2/2009RM 32019242.7%5.1538T93WaukeshaF1197GLow Load, High O210/2/2009RM 32019244.8%7.2439T94CaterpillarG3406 NAAs Found10/5/2009RM 32021594.2%13.9239T95CaterpillarG3406 NALow O210/5/2009RM 32021594.2%14.0040T96CaterpillarG3306TAAs Found10/5/2009RM 32020357.9%12.7240T97CaterpillarG3306TALow O210/5/2009RM 32020357.9%7.25Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-12Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O241T98CaterpillarG3406TALow Load, High O210/6/2009RM 32032581.2%13.7841T99CaterpillarG3406TALow Load, Low O210/6/2009RM 32032581.2%8.1141T100CaterpillarG3406TAAs Found, Low O210/6/2009RM 32032593.5%5.5241T101CaterpillarG3406TAAs Found, High O210/6/2009RM 32032582.2%12.4242T102Caterpillar3406 TAAs Found10/7/2009RM 32032561.5%5.9743T103Caterpillar3306 TAAs Found, High O210/8/2009RM 32020350.7%8.6443T104Caterpillar3306 TAAs Found, Low O210/8/2009RM 32020351.7%3.53Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-13Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O243T105Caterpillar3306 TAMid Load, Low O210/8/2009RM 32020345.8%3.3143T106Caterpillar3306 TAMid Load, High O210/8/2009RM 32020345.8%7.3744T107WaukeshaF1197GUAs Found10/9/2009RM 32019268.8%10.6944T108WaukeshaF1197GUAs Found, High O210/9/2009RM 32019268.8%8.3845T109WaukeshaF-1197 GAs Found10/9/2009RM 32019251.8%10.4745T110WaukeshaF-1197 GAs Found, Low O210/9/2009RM 32019251.8%6.5746T111WaukeshaF-817GAs Found10/9/2009RM 32013224.6%24.3647T112Caterpillar3306 NAAs Found10/10/2009RM 32014591.1%12.7447T113Caterpillar3306 NAAs Found, Low O210/10/2009RM 32014591.1%14.4748T114CaterpillarG3406 NA10-Minute Pre-Run10/7/2009RM 320215100.0%10.0648T115CaterpillarG3406 NAOne-Hour Pre-Catalyst10/7/2009RM 320215100.0%12.1749T116Caterpillar330610-Minute Pre-Run10/8/2009RM 320195100.0%10.43Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010A-14Appendix AEngine No.TestNo.MakeModelTest ConditionTest DateTestMethodRatedHPLOAD1CH2O249T117Caterpillar3306One-Hour Pre-Catalyst10/8/2009RM 320195100.0%10.6250T118CumminsKTA 19GC10-Minute Pre-Run10/8/2009RM 320380100.0%19.0450T119CumminsKTA 19GCOne-Hour Pre-Catalyst10/8/2009RM 320380100.0%9.02513T120CaterpillarG342-TAPre-catalyst, 60 minMarch-April 2009RM 32325068%9.2NOTE1: Compressor suction discharge and suction pressures were not available for some engine tests (i.e., load couldnot be calculated)NOTE2: ppmvd @ 15% O2 during best performing test for the engineNOTE3: Value in "CH2O" column is an average of 4 runs (i.e., 10 ppmvd, 8.5, 8.9, and 9.5)RM: EPA Reference MethodShaded cells indicate load data is based on post-test calibration of pressure gauges and fuel flow metersTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### APPENDIX B

QA/QC PROCESS AND DATA REVIEWTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### B-1 Appendix B Appendix B: Data Review Process and Short Term Tes t Validation

This appendix outlines the procedures used to ensur e that reliable and accurate data were used in

the MACT floor analysis. A test protocol (see Appe ndix C) was established prior to the

emission measurement campaign to facilitate the col lection of quality engine emissions data. In

accordance with the test protocol, engine emission data collected for this project included

formaldehyde, oxygen, and moisture. Engine design and operating data were also collected to

document the engine operating conditions. All of t his information was used to help determine

the quality of information associated with engine t ests and inform the decision to include the

engine in the MACT floor analysis.

Because emission data were provided by a variety of sources including EJC and numerous API

member companies, a standard process to screen and access data quality was developed. This

process included:

• 

### Preliminary screening – all test data were initially screened to determi ne if the tests complied

with the basic project objectives. Section B.1 des cribes the engine test data screening

process;

• 

### Emission test method QA checks – emission tests that passed the initial screening were then

reviewed for compliance and consistency with the st andard measurement methods. Sections

B.2 and B.3 list the quality assurance activities a nd requirements for the measurement

methods and summarize results for the MACT floor en gines;

• 

### Engine operating data review - Section B.4 discusses the engine operating data collection,

calibration of equipment for key process measuremen ts, and calculation of engine efficiency

parameters to evaluate engine load determinations.

• 

### Short test run data evaluation – to accommodate tests at additional operating con ditions,

some emission measurements were conducted for a per iod less than the standard one-hour

performance test. Section B.5 discusses the validi ty of these shorter duration tests and

statistically compares them to the standard (60-min ute) tests.

Engines with emission test data measured in complia nce with the standard test methods and that

had reliable engine operating data (i.e., engine lo ad) were included in the MACT floor analysis.

Conversely, engine data that was not determined of suitable quality, test duration, or under a

reasonable engine operating condition were eliminat ed from the analysis and are not included in

this report.

B.1 Preliminary Engine Test Data Screening

All test data were initially screened to determine if the tests complied with the primary project

objectives. More specifically, the objective of th e preliminary engine tests screening (i.e. prior to

more detailed data review and MACT floor analysis) was to eliminate engines and tests that did

not meet the project data quality objectives and in clude only emission tests with sufficient data

for QA checks and a representative measurement. Th e following discusses the parameters used

to screen engine tests.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### B-2 Appendix B • Insufficient QA Data and Test Documentation : Engines tests were not included in the MACT

floor analyses because the quality assurance data a ssociated with the tests was incomplete.

• Insufficient Data Collection (non-representative me asurement) : Engine tests were rejected

when they reported emissions after less than three (3) minutes of engine operation, an

insufficient time to conduct a representative emiss ion measurement.

• Stable Engine Operation : Engine test data were collected or were invalida ted during

transient or unstable engine operations. As an exam ple, an engine test would be eliminated if

oxygen was above 2%.

The data remaining after this screening process was considered appropriate for further evaluation

and analysis. Test reports have been provided for all MACT floor engines and following a

screening assessment were reviewed against the deta iled Reference Method test requirements

discussed below.

B.2 CH 2 

### O Emissions by FTIR (EPA Method 320)

EPA Method 320 quality assurance/quality control (Q A/QC) requirements include pre- and post

test Calibration Transfer Standard (CTS) calibratio ns and QA Spike Recoveries. The CTS

calibrations are direct injection of the CTS calibr ation gas to the FTIR cell. The peak absorbance

for the pre- and post-test CTS gas analyses must be within ±5 percent of the mean value. For

these tests, the ASTM D 6348 requirement that the C TS gas analyses be within 5% of the

certified value was also followed. The QA Spike Re covery requires that the calibration gas be

spiked into the sample gas flow. Three independent spikes are conducted and the average

recovery of the spiked gas should be within 0.7 to 1.3 times the expected concentration. Table

B-1 summarizes the reported Method 320 QA/QC data f or the MACT floor engines.

Table B-1. EPA Method 320 Method Performance for M ACT Floor Engines

MACT Floor

Engine ID Engine

Make/Model Pre-Test

CTS Post-Test

CTS QA Spike

Recovery Test

Status

Acceptance Criteria = +/- 5% of CTS Cal Gas 70 – 130%

17 Waukesha F1197GU 1.8% 1.3% 103% Pass

43 Caterpillar 3306 TA 1.2% 2.2% 84% Pass

21 Caterpillar 3406 TA - 0.1 1.7% 112% Pass

5 Caterpillar G-342TA 1.4% -1.2% 93% Pass

14 Waukesha F1197GU 0.5% 1.7% 123% Pass

34 Waukesha F1197G 2.9% 4.9% 98% Pass

38 Waukesha F1197G 1.6% 3.3% 95% Pass



### B.3 Oxygen Emissions by EPA Method 3A and ASTM Meth od 6522

Oxygen emissions were measured using EPA Method 3A and ASTM Method 6522 for portable

analyzers. The daily QA/QC activities and method pe rformance requirements for Method 3A

include:

• 

### Pre-Test Measurement System Performance TestsTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### B-3 Appendix B - 

### Calibration Error Test . The low-, mid-, and high-level calibration gases are sequentially

introduced directly to the analyzer. The analyzer calibration error is calculated for the

three levels as the difference between the analyzer reading and the calibrated gas value

divided by the calibration span. Method Performanc e specification is + 2% of calibration

span. An alternative specification, difference bet ween the analyzer reading and the

calibrated gas value < 0.5 %, can be used for low concentration measureme nts.

- 

### System Bias Check. An upscale gas (mid- or high-level) and then a l ow/zero gas are

introduced at the probe upstream of all sample cond itioning components. The system

bias is calculated as the difference between the an alyzer reading during the direct

calibration and during the system bias divided by t he calibration span. Method

Performance specification is + 5% of calibration span. An alternative specificat ion,

difference between the analyzer reading during the direct calibration and during the

system bias < 0.5 %, can be used for low concentration measureme nts.

• 

### Interference Check . Potentially interfering gases (e.g. CO 2 

### ) are introduced to the

analyzer. The total interference response must not be greater than 2.50 percent of the

calibration span for the analyzer tested.

• 

### Post-Run System Bias Check & Drift Assessment,

- 

### System Bias Check . As discussed above.

- 

### Drift Check . Low-level and upscale drift is calculated as the difference between the pretest and post-test System Bias Check values. Meth od Performance specification is + 3%.

An alternative specification, difference between th e pre-test and post-test System Bias

Check values < 0.5 %, can be used for low concentration measureme nts.

The QA/QC activities and method performance require ments for ASTM 6522 include:

• 

### Equipment Preparation Measurement System Performanc e Tests

- 

### Linearity Check . A linearity check is performed for each electroch emical cell by injecting

the zero and mid- and high-level calibration gases to the analyzer. Method Performance

specification is < 2.5% of calibration gas concentration. These chec ks are repeated

whenever a cell is replaced.

- 

### Interference Check. An interference check is required for the CO elec trochemical cell.

Method Performance specification is that interferen ce responses must be < 5% of the

average stack gas concentration for each test run.

- 

### Stability Check. The stability check is performed for each electro chemical cell by

injecting calibration gas for a 30 minute period. Method Performance specification is

that the difference between the lowest and highest one-minute averages must be < 2.0%

of the calibration gas concentration. These checks are repeated whenever a cell is

replaced or exposed to greater than 125% of the hig hest calibration gas concentration.

• 

### Pre-test Measurement System Performance Tests

- 

### Calibration Error Check . The zero and span calibration gases are sequentia lly introduced

to the analyzer at the probe tip. The Method Perfo rmance specification for the zero gas is

< 3% of the calibration gas concentration for CO and < 0.3% O 2 

### for the O 2 

### cell. TheTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### B-4 Appendix B Method Performance specification for the span gas i s < 5% of the calibration gas

concentration for CO and < 0.5% O 2 

### for the O 2 

### cell.

• 

### Post-test Measurement System Performance Tests

- 

### Calibration Error Check . The zero and span calibration gases are sequentia lly introduced

to the analyzer at the probe tip. The Method Perfo rmance specification for the zero gas is

< 3% of the calibration gas concentration for CO and < 0.3% O 2 

### for the O 2 

### cell. The

Method Performance specification for the span gas i s < 5% of the calibration gas

concentration for CO and < 0.5% O 2 

### for the O 2 

### cell.

- 

### Interference Verification. Calculate the CO interference response based on the post-test

calibration data and average emission concentration for the test. Method Performance

specification is that interference responses must b e < 5% of the average stack gas

concentration for each test run.

For all the MACT floor engines, method performance requirements were achieved for the

emission measurements.

B.4 Engine Design and Operating Data

For the EJC testing, engine design information were provided by the operators prior to test

mobilization and then verified on-site. These data included engine make and model, site-rated

horsepower, and compressor make, model, number of s tages, and stage characteristics. Engine

operating parameters were monitored during the test ing to estimate engine operating load. These

parameters included compressor suction and discharg e gas pressures and temperatures, fuel gas

flow rate, and engine speed. Compressor manufactur er software was used to estimate the

compressor load and parasitic power requirements (e .g., pumps, alternator, and fans) were

estimated from the engine speed and engine manufact urer specifications.

Process monitoring equipment was calibrated. Compre ssor suction and discharge pressures were

typically measured by engine control panel pressure gauges. These panel gauges were then

calibrated against a reference pressure gauge and t est data were adjusted accordingly.

Compressor temperatures were typically measured wit h a panel meter and a second temperature

measurement by an IR meter or thermocouple was cond ucted to verify the measurement. Fuel

gas flow rate was measured using rotary gas meters. These meters measure actual gas volume

and thus require gas pressure and temperature measu rements to determine fuel flow at standard

pressure and temperature. Post test calibrations o f the rotary flow meters and pressure gauges

were conducted and measurement data adjusted accord ingly.

QA/QC activities also included calculation of engin e brake-specific fuel consumption (BSFC)

based on measurements of fuel use and engine load. BSFC is calculated as British thermal units

per horsepower hour (Btu/hp-hr) and is a measure of engine efficiency. BSFC is impacted by

numerous parameters - including engine design, load , age, maintenance practices and schedule,

fuel properties and ambient conditions - and can ra nge considerably, especially at lower loads for

older engines. For 4SRB engines less than 500 hp, BSFC typically ranges from 7,500 to greater

than 12,000 Btu/hp-hr. Table B-2 summarizes key op erational data for the MACT Floor engines

including BSFC. With the exception of two engines, BSFC values were generally within theTechnical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### B-5 Appendix B expected range and provided confidence in the engin e load determinations. For engines with

calculated BSFC values outside the typical range, t he fuel flow and engine load measurement

data were further examined. Two 4SRB MACT Floor en gines, engine nos. 34 and 38, had

BSFCs below the expected range for numerous operati ng conditions. These were both

Waukesha F1197G engines. Post-test calibration of the fuel gas pressure gauge used during the

testing of these two engines determined that the ga uge was damaged, and the fuel pressure and

fuel flow measurements were likely erroneous. A co mparison of the fuel pressures measured

during these MACT Floor engine tests with fuel pres sures measured for other Waukesha F1197G

engines in the area indicated that the MACT Floor e ngines fuel pressures and fuel flows were

likely biased low. In addition, recalculation of t he MACT Floor engines BSFC using fuel

pressures measured on other Waukesha F1197G engines produced BSFC values in the expected

range; thus, it was concluded the measured fuel flo ws were biased low and the engine load

measurements were reliable. As discussed in the bod y of the report, numerous parameters are

expected to impact formaldehyde emissions from 4SRB engines including load, fuel quality,

excess air, engine age and maintenance practices/sc hedule, elevation, and ambient

conditions. While the project attempted to test en gines over their as-found operating envelope,

the testing was not designed to be a parametric inv estigation and a quantified evaluation of the

individual parameters impacting CH 2 

### O emissions was well beyond the scope of this testi ng

project; thus, it would not be appropriate to attem pt to quantitatively correlate the CH 2 

### O

emissions data to the operating data in Table B-2. However, an inspection of the data generally

shows CH 2 

### O emissions increasing with lower load and higher e xcess air.Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010B-6Appendix BTable B-2. MACT Floor Engines Operating Data.Unit IDNumberEngineManufacturerEngineModelOperating ConditionFuel LHV(Btu/SCF)BSFC(Btu/hp*hr)OEM MaxHorsepower(hp)EngineSpeed(RPM)BrakeHorsepower(hp)Load (%)Caterpillar 3306 TA As Found, High O2 926 7,534 2031,646 103 51%Caterpillar 3306 TA As Found, Low O2 926 8,188 2031,649 105 52%Caterpillar 3306 TA Mid Load, High O2 926 9,636 2031,632 93 46%43Caterpillar 3306 TA Mid Load, Low O2 926 8,933 2031,126 93 46%Waukesha F1197GU As Found - 1 hr Test 927 12,851 192 1,156 76 40%Waukesha F1197GU As Found - Retest 927 8,520 192 1,215 107 56%Waukesha F1197GU As Found, Low O2 927 11,019 192 1,215 107 56%Waukesha F1197GU High Load, High O2 927 9,452 192 1,245 122 64%Waukesha F1197GU High Load, Low O2 927 9,682 192 1,245 122 64%Waukesha F1197GU Low Load, High O2 927 9,069 192 1,200 80 42%14Waukesha F1197GU Low Load, Low O2 927 9,529 192 1,200 80 42%Waukesha F1197G As Found 1,006 6,597 192 1,310 10454%Waukesha F1197GAs Found - Mid Load,Low O21,006 6,385 192 1,311 119 62%Waukesha F1197G High Load, High O2 1,006 5,700 1921,017 92 48%Waukesha F1197G High Load, Low O2 1,006 6,488 192 1,075 96 50%Waukesha F1197G Low Load, High O2 1,006 5,816 192 1,097 86 45%Waukesha F1197G Low Load, Low O2 1,006 7,458 192 1,046 82 43%38Waukesha F1197G Mid Load, High O2 1,006 5,644 192 1,294 113 59%Waukesha F1197GU As Found - 1 hr Test 1,023 12,851192 975 69 36%Waukesha F1197GU As Found, High O2 1,023 10,899 192-- 69 36%17Waukesha F1197GU Mid Load 1,023 11,918 192 1,125 103 54%Technical Report: 4SRB Natural Gas-Fired Engine Emissions Data for MACT FloorApril 2010B-7Appendix BTable B-2 MACT Floor Engines Operating Data (Cont).Unit IDNumberEngineManufacturerEngineModelOperating ConditionFuel LHV(Btu/SCF)BSFC(Btu/hp*hr)OEM MaxHorsepower(hp)EngineSpeed(RPM)BrakeHorsepower(hp)Load(%)Waukesha F1197G As Found - 1 hr Test 967 4,229 1921,320 129 67%Waukesha F1197G As Found, High O2 967 4,775 192 1,313 125 65%Waukesha F1197G Low Load, High O2 967 4,722 192 1,355 91 47%Waukesha F1197G Low Load, Low O2 967 4,931 192 1,372 92 48%Waukesha F1197G Mid Load, High O2 967 4,744 192 1,340 104 54%34Waukesha F1197G Mid Load, Low O2 967 4,640 192 1,352 105 55%Caterpillar G-342TA As Found - 1 hr Test 1,084 7,473 265 1,000 188 71%Caterpillar G-342TA As Found, Low O2 1,084 8,377 265 1,100 168 63%Caterpillar G-342TA High Load, High O2 1,084 8,192265 1,100 195 74%Caterpillar G-342TA High Load, Low O2 1,084 8,834 265 1,100 195 74%Caterpillar G-342TA Low Load, High O2 1,084 8,935 265 1,025 100 38%5Caterpillar G-342TA Low Load, Low O2 1,084 10,867 265 1,025 100 38%Caterpillar 3406 TA As Found 1,004 9,460 325 -- 17153%Caterpillar 3406 TA Low Load, High O2 1,004 8,003 325 -- 171 53%Caterpillar 3406 TA Low Load, Low O2, 1 hr 1,004 9,217 325 1,788 171 53%Caterpillar 3406 TA Mid load, High O2 1,004 6,644 325 1,775 222 68%21Caterpillar 3406 TA Mid Load, Low O2 1,004 7,422 325 1,775 222 68%Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

March 2010



### B-8 Appendix B B.5 Validity of Shorter Test Runs Data

Sixty minute test runs are typically conducted for compliance test measurements. This time

period is partially a remnant of compliance tests c onducted using integrated grab samples with

subsequent, off-site analysis; for these tests, six ty minute (or longer) testing is required to ensure

source operating and emission variability was captu red and a representative sample was

collected. Emission variability can be caused by n ormal process cycling (e.g. caused by the

process control system or inherent to a continuous batch process such as an incinerator where

waste is periodically charged) or instability (e.g. caused by changing process inputs or inherent

equipment operating characteristics). FTIR provide s real-time measurements; thus, it is possible

to observe if the source emissions are varying or i f the source is operating at a stable, steady-state

condition. If emissions are stable, then a represe ntative measurement can be conducted in a

relatively short time; that is, a sixty minute samp le period is not needed for a representative

measurement. Conversely, if emissions are observed to vary, then a longer measurement would

be required to encompass the emission variability a nd provide a representative average

measurement.

The engines tested for this program generally opera ted at steady state conditions during the

emission testing. Engine operators were present du ring the testing to minimize testing delays

and the engine settings and the process (i.e., gas well production) were monitored for stable

operation. The minute-to-minute FTIR formaldehyde measurements confirmed the stable engine

operation. Because engine operations and emissions were essentially invariant, it was possible to

conduct shorter test runs for some engine operating conditions. The shorter test runs were used

because project time and resources were constrained . An emphasis was placed on quickly

identifying candidate MACT floor engines and collec ting variability test data over a range of

expected operating conditions as opposed to spendin g limited resources gathering data from the

lower 88 percentile units. FTIR testing on each en gine was typically limited to one day or less;

thus, shorter test runs optimized the project resou rces (FTIR test day) and produced a larger and

more variable (i.e., more representative) data set for MACT floor analysis.

Based on the observed FTIR minute-to-minute formald ehyde measurements, a ten-minute test

period was selected for some operating conditions. As noted above, the CH 2 

### O emissions were

essentially invariant over the ten-minute period an d FTIR data logger observations indicated a

representative sample was measured. FTIR spectromet er interferograms consisting of 28 coadded scans were recorded continuously during the t est periods, and provided approximately 30-

second average concentrations. These values are th en averaged in 2 blocks and reported once

per minute to the data logger; thus, for a 10-minut e test, a total of 20 samples were effectively

collected.

As discussed above, collecting a representative sam ple requires that any emissions cycling or

variability be encompassed by the sample period. In addition to the ten-minute tests, at least

two sixty-minute tests were conducted on each MACT Floor engine. Table B-3 compares the

relative standard deviations for the 10- and 60-min ute tests for the MACT floor engines. Test run

standard deviations were calculated using each one- minute average as a single data point within

a test (i.e., 10 data points within a 10-minute tes t). The relative standard deviation (RSD) is

expressed as percentage:Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### B-9 Appendix B RSD = 100 x Standard Deviation of Sample Points / M ean of Sample Points

Smaller RSDs indicate that the data are closer to t he mean (i.e., data have lower variance) than

larger RSDs. If the 10-minute sample period was no t sufficient to encompass engine emission

variability or cycling, then the RSDs would be expe cted to be much larger for the 10-minute tests

than the 60-minute tests. Inspection of the RSD da ta in Table B-3 shows that this did not occur.

Ten-minute test RSDs are generally comparable or lo wer than the sixty-minute test RSDs When

viewed as an overall group of tests, the average RS D for the 10-minute tests is 5.9% and is lower

than the RSD for the 60-minute tests (6.9%). In ad dition, no 10-minute test had an RSD value

greater than 10%, while four (4) separate 60-minute tests had RSDs greater than 10%, and the

range of RSDs for 10-minute tests is smaller (1.2% to 9.9%) than the range for 60-minute tests

(2.8% to 14.4%).

In summary, the observed steady emissions (i.e., no cycling or upward or downward trends)

during the ten-minute tests and the comparable RSDs for the 10- and 60-minute tests CH 2 

### O

measurements indicate that the 10-minute measuremen ts were representative of the engine

operating condition during the test. Therefore, th e short-term test data have been retained for the

purpose of assessing emissions variability from the MACT floor engines.Technical Report: 4SRB Natural Gas-Fired Engine Em issions Data for MACT Floor

April 2010



### B-10 Appendix B Table B-3. Comparison of Standard Deviations for S hort-Term and Long-Term Tests.

Test

No. CH 2 

### O 1 

### Standard

Deviation RSD RSD Standard

Deviation CH 2 

### O 1 

### Test

No. Engine

ID

60-Minute Tests 10-Minute Tests

43 T15 3.53 0.51 14.4% 5.6% 0.48 8.64 T13

43 T16 7.37 0.57 7.7% 5.4% 0.18 3.31 T14

14 T23 5.32 0.52 9.8% 3.5% 0.27 7.73 T24

14 T25 5.02 0.53 10.6% 2.8% 0.13 4.72 T26

14 T27 9.42 0.41 4.4% 4.6% 0.25 5.49 T29

14 T28 8.29 0.42 5.1%

38 T88 4.96 0.43 8.7% 5.2% 0.35 6.68 T87

38 T90 7.92 0.34 4.3% 3.7% 0.23 6.29 T89

38 T93 7.24 0.37 5.1% 9.9% 0.53 5.36 T91

38 9.5% 0.49 5.15 T92

17 T36 3.31 0.27 8.2% 8.7% 0.66 7.59 T37

17 T38 3.18 0.37 11.6%

34 T75 4.94 0.54 10.9% 1.2% 0.09 7.57 T76

34 T77 6.84 0.29 4.2% 2.3% 0.12 5.31 T79

34 T78 7.6 0.21 2.8%

34 T80 7.71 0.22 2.9%

5 T9 4.71 0.17 3.6% 4.2% 0.22 5.21 T11

5 T10 6.12 0.43 7.0% 9.7% 0.92 9.52 T14

5 T12 9.24 0.37 4.0%

5 T13 12.1 0.74 6.1%

21 T45 3.74 0.30 8.0% 5.6% 0.61 10.94 T46

21 T47 3.53 0.16 4.5% 9.8% 0.83 8.43 T48

21 9.4% 0.91 9.65 T49

NOTE1: ppmvd @ 15%O2Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

March 2010



### APPENDIX C

FORMALDEHYDE EMISSIONS MEASUREMENT

TEST PROTOCOL

# 40 CFR 63 Subpart ZZZZ

Natural Gas Fired Engine MACT Floor Test Plan

&

Equipment / Operations Information Gathering

PREPARED FOR:

Stephanie Meadows

Upstream Senior Policy Analyst

American Petroleum Institute

1220 L Street, NW

Washington, D.C. 20005



## PREPARED BY:

innovative environmental solutions, inc.

P.O. Box 177

Cary, IL 60013-0177

September 30, 2009 Version 1

### October 2, 2009

Final Draft Test Plan

1 

## MACT Floor Test Program Background and Objectives

The March 2009 proposed revisions to the Federal Na tional Emission Standards for Hazardous Air

Pollutants (NESHAP) for reciprocating internal comb ustion (IC) engines (74 FR 9698) include

emission standards based on insufficient and techni cally flawed emissions data. The resulting paucity

of data are not sufficient to complete a MACT floor analysis or representative of the affected engine

populations. Flaws in the existing data include em ission test methods with known negative biases and

inappropriate engine operation during the testing. Based on industry comments, EPA has

acknowledged that additional emissions data and ana lysis is needed to define emission limits for the

Final Rule. To address the data deficiency and inf orm the MACT floor analysis, API and a consortium

of engine rental companies are coordinating an emis sion test project on existing reciprocating interna l

combustion engines at oil and gas (O&G) facilities. This document identifies the Test Plan for that

project to ensure accepted and consistent methods a re used for the testing. The test results will be

integrated into a single emissions test report at t he completion of the test program.

For major source engines and most area source engin es, the Proposed Rule includes emission limits.

The emission limits are based on the “MACT floor”, and the technology basis is an “uncontrolled”

engine. In some cases, the emission limit is the M ACT floor emission level, while in other cases EPA

assumed that “above the floor” catalytic control is warranted and based the emission limit on the floo r

level less a 90% reduction from catalytic control. These emission limits will not be achievable by th e

vast majority of uncontrolled existing engines; tha t is, for an uncontrolled unit to meet the emission

level associated with the “best performing” MACT fl oor limit, catalytic control will be required for

nearly all units. Refer to API Comments 5.1 and 6.2 for additional d etail.

This test program is designed to obtain uncontrolle d “as found” emission data to support revisions to

the MACT floor limits in the upcoming Final Rule th at will amend the NESHAP for reciprocating IC

engines 40 CFR, Part 63, Subpart ZZZZ. Data collec ted as part of this intensive effort are needed to

develop technically defensible emission standards.

The MACT floor emissions test project objectives in clude:

3. Establish a test program to consistently obtain emi ssion data for developing MACT floor

emission limits that address the size, type, and op eration of affected engines. The focus of the

MACT floor testing program is primarily directed to ward smaller natural gas fired engines

(< 500hp).

4. Obtain operational variability data from engines th at are expected to be in the MACT floor data

set (i.e. engines in the best performing 12 percent of engines in each category/subcategory) to

allow determination of emission limits that include normal operational variability. Variability

parameters may include:

• Excess O 2 

### from 4SRB;

• Percent load;

• Multiple engines of identical make / model;

• Fuel quality; and,

• Ambient affects including temperature, relative hum idity, & elevation.

### October 2, 2009

Final Draft Test Plan

2 Variability is an important consideration because i t allows consideration of operating factors

when establishing the MACT floor emission limit. T hus, these data are a key component of the

test program. For example, when establishing the s tandard, our understanding is that EPA is

not required to use an average of the best performi ng twelve percent of units as the MACT

floor emission limit. Rather, EPA has the latitude to select the limits at the worst reasonable

condition for the best controlled similar unit . [“EPA would be justified in setting the floors at

a level that is a reasonable estimate of the perfor mance of the ‘best controlled similar unit’

under the worst reasonably foreseeable circumstance s.” Sierra Club v. EPA , 167 F.3d 658

(D.C. Cir. 1999)].

In addition, in Mossville Environmental Action Now v. EPA , 370 F.3d 1232 (D.C. Cir. 2004),

the Court held that floors may legitimately account for variability because “each [source] must

meet the [specified] standard every day and under a ll operating conditions.” Thus, emission

variability can be considered in setting emission l imits, and MACT floor emission limit can be

based on the highest emissions for MACT floor engin es considering operational variation.

Table 1 presents a draft test matrix template for the primary engine categories. The engine category

priorities discussed in this plan are based upon th e RICE fleet used by natural gas production and

gathering facilities and test data reviewed in the RICE NESHAP proposal. As testing commitments,

locations, schedules, and engine types are finalize d, Table 1 will be completed as a stand alone

supplementary document that identifies engine makes /models and counts. At present, industry and

trade associations anticipate on the order of 100 t ests will be completed over a range of engine types

, sizes, and operating conditions.

Additional subcategories or further refinement of t he horsepower ranges can be completed based on

participant direction and engine types available fo r testing. Since the MACT floor is based on an

uncontrolled engine, NSCR and oxidation catalyst eq uipped engines are not preferred for the purpose

of establishing the MACT floor. Should controlled engines be included in the measurement program,

pre-catalyst testing is recommended. In addition, proper consideration of air fuel ratio (AFR) syste m

test impacts should be made. Potential test consid erations includes disconnecting the AFR and

reverting to manual adjustments or AFR system bypas s (see 4SRB O 2 

### considerations below).

Similar to the proposed draft test matrix, Table 2 presents a table to summarize emissions data that i s

compiled from previously completed tests (i.e., ava ilable test results from O&G companies). These

data may be used to establish or confirm MACT floor emission limits or further the understanding of

emissions variability. These data are expected to be very limited for smaller burn engines (i.e., whe re

formaldehyde is needed) and primarily encompass lar ger lean burn units.October 2, 2009Final Draft Test Plan3Table 1. Test Matrix and Test Engine Count (MACT floor basis is 12% of the engines tested)Size Category(HP)Number of4SRBEnginesNumber of2SLBEnginesNumber of4SLBEnginesSubcategory-Specific(e.g. cranes, aircompressors, etc.)50-100 hpMACT FloorEngine CountXXXX100-250 hpMACT FloorEngine CountXXXX250-500 hpe.g. ...5 (Ajax DPC 280)MACT FloorEngine CountXXXX>500 hpTotalX Y Z AAOctober 2, 2009Final Draft Test Plan4Table 2. Existing Test Data to Support MACT Floor DeterminationSize Category(HP)Number of4SRBEnginesNumber of2SLBEnginesNumber of4SLBEnginesSubcategory-Specific(e.g. cranes, aircompressors, etc.)50-100 hpMACT FloorEngine CountXXXX100-250 hpMACT FloorEngine CountXXXX250-500 hpMACT FloorEngine CountXXXX>500 hpe.g. ...1 - (Clark TLA-6)TotalX Y Z AA

### October 2, 2009

Final Draft Test Plan

5 

## Reference Test Methods and Procedures

Testing should be conducted in accordance with EPA/ ASTM reference test methods and

procedures; however, due to time constraints and li mited resources, data will typically not be

specifically conform to performance or compliance t est criteria (e.g., three one-hour tests are not

recommended for the purpose of gathering MACT floor engine performance data on multiple units

when continuous test method (e.g., FTIR) is used). Because these data will be submitted to EPA for

regulatory development, adherence to the test metho ds is necessary. Any exceptions or deviations

to the reference method procedures must be document ed to assess the appropriateness, quality,

adequacy, and representativeness of the emission da ta.

The testing will include a single one hour test on an “as-found” engine (i.e. no adjustment to the

engine will be made – excluding 4SRB O 2 

### exhaust levels as discussed below). For units ide ntified

as MACT Floor engines, subsequent tests at varied l oad conditions, possible varied ambient

condition (e.g. early morning vs. mid-day operation ), and, for 4SRB units, varied exhaust O 2 

### levels

should be conducted to gather data that characteriz es emissions variability.

Preferred Test Methods and Notes

• Although Fourier Transform Infrared spectroscopy (F TIR) – [EPA Method 320 or ASTM

D6348] is more costly and resource intensive than t he alternative Method 323 acetylacetone

method, it provides near real time measurements and flexibility for assessing formaldehyde

emissions from rich burn MACT floor candidate units . Alternatives to FTIR are discussed

below. FTIR species include:

- CO

- CO 2



### - NO and NO 2



### - Formaldehyde

- C1 – C6 speciated hydrocarbons (e.g., to determine VOCs)

- Ammonia

- Moisture

FTIR provides near real time instrument response an d the ability to judge test results (e.g.,

whether the unit is a MACT floor engine). One-minut e average data should be logged and

archived for all FTIR measured compounds. If Metho d 323 formaldehyde data are obtained,

care must be taken to ensure that sample flow rates are within the prescribed range (0.2 to 0.4

liters per minute) and three one hour test runs are required. A potential list of FTIR testing

companies is provided as Attachment 2.

• O 2 

### and CO 2 

### by instrumentation – [EPA Method 3A] - Determination of Oxygen and Carbon

Dioxide Concentrations in Emissions from Stationary Sources (Instrumental Analyzer

Procedure)] or portable analyzer [ASTM D6522-00];

• Moisture by FTIR or impingers [EPA Method 4];

### October 2, 2009

Final Draft Test Plan

6 • Exhaust gas flowrate by F-factor [EPA Method 19];

• Sample Ports and Location [EPA Method 1 or 1A]. Tw o sample ports should be located at 90

degrees apart and at least two, and ideally eight, stack or duct diameters downstream from and

at least one half, and ideally two, diameters upstr eam of any process change or exhaust to

atmosphere. One port will be used for a thermocoup le measurement and the second for the

heated FTIR sample probe.

• For 2SLB and 4SLB engines, the NESHAP emission limi ts are based on the surrogate

compound CO and a simplified gas measurement approa ch can be used. CO, NOx and O 2 

### can

be measured using [ASTM D6522] - Determination of Nitrogen Oxides, Carbon Monoxide, and

Oxygen Concentrations in Emissions from Natural Gas -Fired Reciprocating Engines,

Combustion Turbines, Boilers, and Process Heaters U sing Portable Analyzers

Quality Assurance / Quality Control

All testing should be conducted in adherence with t he reference test methods. Method deviations

should be documented and explained (e.g. sample por t location). Because formaldehyde is highly

water soluble, sample line temperature maintenance is required to avoid moisture condensation.

Recommended additional procedures to ensure data qu ality include:

• 

### Low concentration O 2 

### calibration gases for measuring oxygen in rich bur n engines exhaust.

From EPA Method 7E/3A “to the extent possible, the measured emissions should be between 20

to 100 percent of the selected calibration span.” T hus, to measure 0.5% O 2 

### , the calibrated range

should be about 0 – 2%.

• 

### Similarly, a range of CO 2 

### calibration gases will be required to measure CO 2 

### from both rich burn

and lean burn engines.

• 

### QA Spikes for the FTIR systems are recommended for each engine using formaldehyde and the

spiking compound. Stack gas formaldehyde concentr ations should be measured immediately

before and after the QA spike.

• 

### CO 2 

### measurements by both continuous analyzer (EPA Meth od 3A) and by FTIR can be used to

gauge the uncertainty in the FTIR emission measurem ents.

• 

### The operator must identify the test load and report the basis for determining the operating load

for the test.

Reporting

Emissions should be reported in units of ppmvd, ppm vd @ 15% O 2 

### , lb/hr, and g/hp-hr. Test reports

should be provided to IES to facilitate review and validation of MACT floor units. Multiple test

reports are not required for test campaigns on mult iple engines. A single summary report is

preferred.

### October 2, 2009

Final Draft Test Plan

7 Additional Test Considerations

Engines should be tested “as found”, and engine ope ration should not be altered or adjusted prior to

initial testing other than to adjust the “baseline O 2 

### ” for 4SRB engines as discussed below.

Operating conditions should be logged (see Attachme nt 1). Engine exhaust temperature should be

monitored for the duration of all tests. For 4SRB engines, emissions are dependent on the amount

of excess oxygen (i.e., related to the air-to-fuel ratio). Thus,

Four-stroke rich burn engine considerations:

• 

### If the “as-found” excess O 2 

### is higher than 0.5%, then a short term test will b e completed

before adjusting to a “baseline O 2 

### level”. In this case, test the 4SRB for approxima tely 10

minutes at the "as found" oxygen measured value and record the data. Stable operation of

the engine over this timeframe can be documented ba sed on 1-minute test data.

• 

### Baseline O 2 

### level : If the as found excess O2 is greater than 0.5%, after the step above is

completed adjust the fuel regulator or carburetor s etting to obtain an exhaust O 2 

### concentration of approximately 0.5% or lower (basel ine test condition for 4SRB engines).

The manual adjustment is necessary because these en gines are unsophisticated and do not

include active control of excess air. Complete a o ne hour test at this condition. This test

point is likely to be the “best performing level” f or that particular test condition (i.e., load,

ambient conditions, etc.). If exhaust oxygen is at 0.5% or lower "as found", the one hour

test will be completed at the as found condition. As found units greater than 0.5% O 2 

### are

unlikely to be MACT floor engines – thus the excess air adjust will provide more valuable

data for the analysis and the range of “as found” O 2 

### levels is also pertinent information.

• 

### Subsequent fuel pressure adjustments or carburetor settings (e.g. for variability testing)

should result in exhaust O 2 

### concentrations less than 2 percent for consistency with the EPA

definition of a rich burn engine. The “as found” c onditions should be documented as

indicated above.

Two- and four-stroke lean burn engine consideration s:

• CO as surrogate for lean burn engines;

• O 2 

### calibrations should be within the expected range o f operation (e.g. approximately 10 to

18 % O 2 

### ).

Variability Testing

If a particular engine appears to be a candidate “M ACT floor” engine (i.e., within the best

performing 12% based on the number of engines in th e test program), then additional testing will be

completed on that engine. These tests will vary th e excess O 2 

### level (via carburetor or fuel pressure

adjustment) over multiple test points and also vary load, as feasible. If the “as found” test was at

reduced load, load adjustment to a higher load will be attempted. Lower load tests will also be

attempted. Multiple excess O 2 

### levels will be tested at each load. The number of data points to

conduct this testing introduces test timing issues, because there is not time or resources available t o

spend multiple days testing a single engines. Thus , abbreviated run times will be used for most test

### October 2, 2009

Final Draft Test Plan

8 conditions – i.e., ten minutes of FTIR data with st able operation and emissions stability ensured for

that period.

1. Excess O 2 

### from 4SRB – Measure emissions for MACT floor units to establish emission

range. Simplest matrix could be lowest excess O 2 

### (nominally 0.5% or lower) and ~2%

excess O 2 

### . Additional excess air and load conditions could be tested as time permits.

2. Percent Load – Engine load can be changed by adjust ing the suction, restricting the

discharge, and/or changing the bypass valves. Targ et test loads are 50%, 75%, and 100% of

maximum achievable load. These load levels are per tinent because the “maximum

achievable” load in practice for production engines will often be less than the rated load.

When load is changed to a different test condition, obtain a ten minute test run for most

excess O 2 

### tests, with the 0.5% excess O 2 

### test and interim excess O 2 

### test runs lasting 10

minutes. For each load, the higher excess O 2 

### test run at 2% O 2 

### will acquire one hour of data.

The higher O 2 

### test condition may bound the upper end of the emis sions variability range, so

a one hour test run is proposed for these tests. T hese data should provide insight on

formaldehyde variability for “MACT floor” 4SRB engi nes. Test data should be continuously

recorded during load transitions.

3. Identical Make / Model – Document information on id entical or “similar” MACT floor

units. “Location-based” issues that may affect emi ssions such as altitude and ambient

temperature may need to consider data from an engin e that is the same make and model as

MACT floor engines. (For example, MACT floor data in Texas; altitude and temperature

data may be available for an identical engine in Ne w Mexico or Colorado.)

4. Fuel Variability – Obtain and document fuel analyse s for evaluating effect on emissions.

5. Ambient parameters temperature, barometric pressure , relative humidity, and altitude –

should be documented during testing for evaluating the effect on emissions

6. Other

The dataset will be reviewed to evaluate whether am bient effects can be discerned. Depending

upon that review, it may be necessary to consider d ata from engines that are not MACT floor units,

but identical make and model to MACT floor units, t o assess variability from external

environmental factors. Fuel analysis records will b e collected and the data analyzed to assess

potential impacts of varied fuel quality on emissio ns.



## Schedule

Pending a potential extension request, EPA has requ ested all supporting MACT floor data by the

end of October. Industry responses on test engines completing Table 1 and available test reports for

Table 2 should be accompanied with tentative schedu le(s) for completing the test or providing the

data.

### October 2, 2009

Final Draft Test Plan

9 

# Attachment 1

Supplemental Engine Data

In addition to the source test report, the following information will assist in the determ ination of

whether an engine is a “best performing 12 percent MACT floor engine” [Clean Air Act mandated

target from §112(d)(2)]. All emissions data should be reported as ppmvd @ 15 % O 2



### .

### October 2, 2009

Final Draft Test Plan

10



## Required Supplemental Information

Company

Contact Name __________ email address __________ Ph one number __________

Engine and Driven Equipment

Engine Make __________ Engine Model ___________ Ins tallation Date __________

Engine serial number or unique identifier _________

_________________________________

Engine Age ________________________

Nameplate hp _________________ Site Rated hp ______

____

Circle One 4SRB 2SLB 4SLB

Location _________________________________ Elevatio n __________(feet above sea level)

Pollution Controls Y / N Description (including ma ke and model): _____________

___________________________________________________ ___________________________

Ignition system _______________ (e.g. Altronic)

Engine condition upon arrival: ____________________

______________________________

Date and description of last preventative maintenan ce: _______________________________

Maintenance interval and description: _____________

________________________________

Engine life cycle (overhaul interval (yr) remaining life of overhaul (yr)) _________________

Aftermarket AFR __________ As Found Setting _______

___

Driven Equipment

Make __________ Model ___________

Compressor Cylinder Bore __________ Stroke ________

__

Generator Rating __________

Test Conditions & Murphy Panel Data

Percent Load __________ including parasitic hp ____

______

Description of how load was determined: ___________

_________________________________

___________________________________________________ _____________________________

___________________________________________________ _____________________________

RPM __________ Suction Pressure __________ Suction Temperature __________

### October 2, 2009

Final Draft Test Plan

11 Discharge Pressure __________ Discharge Temperature

__________

Manifold Temperature __________ Pressure __________

Water Jacket Temperature __________ Compressor VVC P position: _____________

Fuel Gas Analysis: include representative fuel gas analysis

Fuel Meter: make __________ model # __________ accu racy __________ ± %

Fuel Line: pressure _____________ (psig) tempera ture ____________ ° F

EPA Test Method deviations

Describe all deviations:

___________________________________________________ _____________________________

___________________________________________________ _____________________________

___________________________________________________ _____________________________

___________________________________________________ _____________________________

Test Company ___________ email address _________ _____ Phone number __________

Contact

Ambient Test Conditions

Temperature __________ Atmospheric Pressure _______ ___ Relative Humidity _________



## Optional Information

Exhaust Temperature __________

Measured Fuel __________

Sample Port Location Description __________________

________________________________

___________________________________________________ _____________________________

___________________________________________________ _____________________________

### October 2, 2009

Final Draft Test Plan

12 

# Attachment 2

Selected FTIR Test Companies: Note that this list is for informational purposes o nly and does

not represent an endorsement of any source test fir m

ACCT a Division of CECO

5440 Alder, Houston, TX 77081-1798

(800) 836-7333

Fax (713) 664-6444

actt@ceconet.com Spectral Insights LLC

214 Argonne Drive

Durham, NC 27704

(919) 620-6549

www.spectralinsights.com

Air Compliance Testing, Inc.

5525 Canal Road

Cleveland, Ohio 44125

216-525-0900

www.aircomp.com TRC Environmental Corporation

Ross A. Thompson

Lead Project Manager - Operations Manager -

Lubbock Air Measurements

7902 Oakridge Avenue Suite One

Lubbock, Texas 79424

806/ 744-8422 Office

806/ 744-8423 Fax

806/ 773-8851 Cell

rthompson@trcsolutions.com

Air Hygiene, Inc.

Paul Little

Director of Customer Service

5634 South 122 nd 

### East Avenue, Suite F

Tulsa OK 74146

(918) 289-6378

www.airhygiene.com

Clean Air Engineering, Inc.

500 W. Wood Street

Palatine, IL 60067, USA

800-627-0033

www.cleanair.com

Enthalpy Analytical, Inc.

Bryan Tyler

2202 Ellis Road

Durham, NC 27703

919.850.4392

bryan.tyler@enthalpy.com

Pace Analytical

1700 Elm Street SE

Minneapolis, MN 55414

(612) 607-6398

www.pacelabs.com

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