E Providing Environmental Technical Support Since 1989 C

/R Incorporated

1 

MEMORANDUM 

TO: Melanie King, EPA OAQPS/SPPD/ESG 

FROM: Bradley Nelson, EC/R, Inc. 

DATE: January 21, 2010 

SUBJECT: Summary of the October 14, 2009 Teleconference with the American Petroleum 

Institute and the U.S. Environmental Protection Agency to discuss the Proposed 

Test Plan for Existing Stationary Spark Ignition Reciprocating Internal 

Combustion Engines 

1.0 INTRODUCTION 

The American Petroleum Institute (API) requested this teleconference with EPA to 

discuss the proposed national emission standards for hazardous air pollutants (NESHAP) for 

existing stationary reciprocating internal combustion engines (RICE), and to propose a plan to 

gather additional test data for spark ignition (SI) RICE. This meeting summary will be available 

in the docket for this rulemaking (Docket ID No. EPA-HQ-OAR-2008-0708). The proposed 

NESHAP for existing stationary RICE was published in the Federal Register on March 5, 2009 

(74 FR 9698). 

2.0 ATTENDEES 

U.S. Environmental Protection Agency

Melanie King, OAQPS/SPPD/ESG 

Michael Horowitz, OGC 

Gary McAlister, OAQPS/AQAD/MTG 

American Petroleum Institute

Jeff Panek, IES 

Roger Zygmunt, Shell 

Jenny Yang, Marathon 

Tom McGrath, IES 

Paul Little, Air Hygiene 

Jeff Adams, BP 

Tom Monahan, ExxonMobil 

Jim McCarthy, IES 

Lynn Reed, ONEOK 
2 

Janet Bounds, Chevron 

Tim Helbig, ONEOK 

Matt Todd, API 

EC/R Incorporated

Bradley Nelson 

3.0 SUMMARY OF MEETING 

API started the teleconference by asking what the status was on the extension for the SI 

engine portion of the final NESHAP. EPA responded that it is currently in discussions and 

expects a response on the extension in the near future. 

API stated that it was in the process of developing “white papers” on the following 

topics: above the floor cost analysis, work practices for area sources, and maintenance intervals 

for work practices. The papers will be submitted to EPA when they are complete. API stated 

that the test data collection process for SI engines is ongoing and that it is currently looking for 

test contractors to perform the testing. API stated that testing would not begin until November 

2009 and API plans to look at emission variability during the testing campaign. EPA asked how 

many tests would be provided from the testing, in which API responded approximately 100 tests. 

The test plan for the proposed testing for SI engines is presented as Attachment A at the end of 

this meeting summary. 

API asked EPA if there had been any additional discussions on the urban/rural issue for 

existing stationary SI engines at area sources. API proposed only work practice standards for 

rural SI engines located at area sources in comments on the proposed rule. EPA indicated that no 

final decisions have been made on this issue. API also brought up the issue of variability of 

emissions test data. EPA stated that it would prefer to have variability data for all engines in the 

data set. API responded that it does not have the resources to test for variability for so many 

engines and stated that it could perhaps provide test data for the top 20 percent. API stated it is 

finalizing a technical paper on test data using Method 323 and will forward to EPA when the 

paper is completed. 

API asked EPA if it had received additional CI engine test data. API stated that the 

MACT floor for CI engines was based on test data from a single engine tested at various loads, 

which was inappropriate in API’s opinion. EPA responded that no CI engine test reports were 

received during the comment period, but emissions data was referenced in a few of the 

comments. EPA intends to follow up with the commenters to see if the referenced emissions 

data is available as a test report and will include in the MACT floor determinations. API also 

asked EPA if any decisions were made regarding the emission standards for cyclical engines, and 

whether the urban/rural classification would be extended to diesel engines. EPA responded that 

the options are being looked at and no final decisions have been made. 
3 

API stated that next steps were to wait for the decision on the final rule extension for SI 

engines, and to send EPA the technical papers for the Method 323 testing and the variability of 

emissions from SI engines.
4 

Attachment A 

40 CFR 63 Subpart ZZZZ 

Natural Gas Fired Engine MACT Floor Test Plan 

& 

Equipment / Operations Information Gathering
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 National Emission Standards for Hazardous Air 

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

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

of data makes it impractical to complete a MACT floor analysis representative of the affected engine 

populations. Flaws in the existing data include emission 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 analysis is needed to define emission limits for the 

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

of engine rental companies are coordinating an emission test project on existing reciprocating internal 

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

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

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

For major source engines and most area source engines, 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 MACT floor emission level, while in other cases EPA 

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

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

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

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

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

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

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

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

develop technically defensible emission standards. 

The MACT floor emissions test project objectives include: 

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

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

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

(< 500hp). 

2. Obtain operational variability data from engines that 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 O2 from 4SRB; 

 Percent load; 

 Multiple engines of identical make / model; 

 Fuel quality; and 

 Ambient affects including temperature, relative humidity, & elevation. 
October 2, 2009 

Final Draft Test Plan 

2 

 

Variability is an important consideration because it allows consideration of operating factors 

when establishing the MACT floor emission limit. Thus, these data are a key component of the 

test program. For example, when establishing the standard, our understanding is that EPA is 

not required to use an average of the best performing 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 performance of the ‘best controlled similar unit’ 

under the worst reasonably foreseeable circumstances.” 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 all operating conditions.” Thus, emission 

variability can be considered in setting emission limits, and MACT floor emission limit can be 

based on the highest emissions for MACT floor engines 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 the 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 finalized, 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 tests will be completed over a range of engine types, 

sizes, and operating conditions. 

Additional subcategories or further refinement of the horsepower ranges can be completed based on 

participant direction and engine types available for testing. Since the MACT floor is based on an 

uncontrolled engine, NSCR and oxidation catalyst equipped 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) system 

test impacts should be made. Potential test considerations includes disconnecting the AFR and 

reverting to manual adjustments or AFR system bypass (see 4SRB O2 considerations below). 

Similar to the proposed draft test matrix, Table 2 presents a table to summarize emissions data that is 

compiled from previously completed tests (i.e., available 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., where 

formaldehyde is needed) and primarily encompass larger lean burn units. 
October 2, 2009 

Final Draft Test Plan 

3 

Table 1. Test Matrix and Test Engine Count (MACT floor basis is 12% of the engines test

Size Category 

 (HP) 

Number of 

4SRB 

Engines 

Number of 

2SLB 

Engines 

Number of 

4SLB 

Engines 

50-100 hp 

MACT Floor Engine Count X X X 

100-250 hp 

MACT Floor Engine Count X X X 

250-500 hp e.g. ...5 (Ajax DPC 280) 

MACT Floor Engine Count X X X 

>500 hp 

Total X Y Z 
October 2, 2009 

Final Draft Test Plan 

4 

Table 2. Existing Test Data to Support MACT Floor Determination 

Size Category 

 (HP) 

Number of 

4SRB 

Engines 

Number of 

2SLB 

Engines 

Number of 

4SLB 

Engines 

50-100 hp 

MACT Floor Engine Count X X X 

100-250 hp 

MACT Floor Engine Count X X X 

250-500 hp 

MACT Floor Engine Count X X X 

>500 hp e.g. ...1 - (Clark TLA-6) 

Total X Y Z 
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 limited resources, data will typically not be 

specifically conform to performance or compliance test 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 methods is necessary. Any exceptions or deviations 

to the reference method procedures must be documented to assess the appropriateness, quality, 

adequacy, and representativeness of the emission data. 

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 O2 exhaust levels as discussed below). For units identified 

as MACT Floor engines, subsequent tests at varied load conditions, possible varied ambient 

condition (e.g. early morning vs. mid-day operation), and, for 4SRB units, varied exhaust O2 levels 

should be conducted to gather data that characterizes emissions variability. 

Preferred Test Methods and Notes

 Although Fourier Transform Infrared spectroscopy (FTIR) – [EPA Method 320 or ASTM 

D6348] is more costly and resource intensive than the 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 

- CO2

- NO and NO2 

- Formaldehyde 

- C1 – C6 speciated hydrocarbons (e.g., to determine VOCs) 

- Ammonia 

- Moisture 

FTIR provides near real time instrument response and the ability to judge test results (e.g., 

whether the unit is a MACT floor engine). One-minute average data should be logged and 

archived for all FTIR measured compounds. If Method 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. 

 O2 and CO2 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]. Two 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 upstream of any process change or exhaust to 

atmosphere. One port will be used for a thermocouple measurement and the second for the 

heated FTIR sample probe. 

 For 2SLB and 4SLB engines, the NESHAP emission limits are based on the surrogate 

compound CO and a simplified gas measurement approach can be used. CO, NOx and O2 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 Using Portable Analyzers.

Quality Assurance / Quality Control

All testing should be conducted in adherence with the reference test methods. Method deviations 

should be documented and explained (e.g. sample port location). Because formaldehyde is highly 

water soluble, sample line temperature maintenance is required to avoid moisture condensation. 

Recommended additional procedures to ensure data quality include: 

 Low concentration O2 calibration gases for measuring oxygen in rich burn 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.” Thus, to measure 0.5% O2, the calibrated range 

should be about 0 – 2%. 

 Similarly, a range of CO2 calibration gases will be required to measure CO2 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 concentrations should be measured immediately 

before and after the QA spike. 

 CO2 measurements by both continuous analyzer (EPA Method 3A) and by FTIR can be used to 

gauge the uncertainty in the FTIR emission measurements. 

 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, ppmvd @ 15% O2, 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 multiple 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 operation should not be altered or adjusted prior to 

initial testing other than to adjust the “baseline O2” for 4SRB engines as discussed below. 

Operating conditions should be logged (see Attachment 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 O2 is higher than 0.5%, then a short term test will be completed 

before adjusting to a “baseline O2 level”. In this case, test the 4SRB for approximately 10 

minutes at the "as found" oxygen measured value and record the data. Stable operation of 

the engine over this timeframe can be documented based on 1-minute test data. 

 Baseline O2 level: If the as found excess O2 is greater than 0.5%, after the step above is 

completed adjust the fuel regulator or carburetor setting to obtain an exhaust O2

concentration of approximately 0.5% or lower (baseline test condition for 4SRB engines). 

The manual adjustment is necessary because these engines are unsophisticated and do not 

include active control of excess air. Complete a one hour test at this condition. This test 

point is likely to be the “best performing level” for 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% O2 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” O2 levels is also pertinent information. 

 Subsequent fuel pressure adjustments or carburetor settings (e.g. for variability testing) 

should result in exhaust O2 concentrations less than 2 percent for consistency with the EPA 

definition of a rich burn engine. The “as found” conditions should be documented as 

indicated above. 

 

Two- and four-stroke lean burn engine considerations: 

 CO as surrogate for lean burn engines; 

 O2 calibrations should be within the expected range of operation (e.g. approximately 10 to 

18 % O2). 

Variability Testing

If a particular engine appears to be a candidate “MACT floor” engine (i.e., within the best 

performing 12% based on the number of engines in the test program), then additional testing will be 

completed on that engine. These tests will vary the excess O2 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 O2 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 to 

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 stable operation and emissions stability ensured for 

that period. 

1. Excess O2 from 4SRB – Measure emissions for MACT floor units to establish emission 

range. Simplest matrix could be lowest excess O2 (nominally 0.5% or lower) and ~2% 

excess O2. Additional excess air and load conditions could be tested as time permits. 

2. Percent Load – Engine load can be changed by adjusting the suction, restricting the 

discharge, and/or changing the bypass valves. Target test loads are 50%, 75%, and 100% of 

maximum achievable load. These load levels are pertinent 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 O2 tests, with the 0.5% excess O2 test and interim excess O2 test runs lasting 10 

minutes. For each load, the higher excess O2 test run at 2% O2 will acquire one hour of data. 

The higher O2 test condition may bound the upper end of the emissions variability range, so 

a one hour test run is proposed for these tests. These data should provide insight on 

formaldehyde variability for “MACT floor” 4SRB engines. Test data should be continuously 

recorded during load transitions. 

3. Identical Make / Model – Document information on identical or “similar” MACT floor 

units. “Location-based” issues that may affect emissions such as altitude and ambient 

temperature may need to consider data from an engine 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 New Mexico or Colorado.) 

4. Fuel Variability – Obtain and document fuel analyses 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 ambient effects can be discerned. Depending 

upon that review, it may be necessary to consider data from engines that are not MACT floor units, 

but identical make and model to MACT floor units, to assess variability from external 

environmental factors. Fuel analysis records will be collected and the data analyzed to assess 

potential impacts of varied fuel quality on emissions. 

Schedule 

Pending a potential extension request, EPA has requested 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 schedule(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 determination 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% O2. 
October 2, 2009 

Final Draft Test Plan 

10 

Required Supplemental Information 

Company

Contact Name __________ email address __________ Phone number __________ 

Engine and Driven Equipment

Engine Make __________ Engine Model ___________ Installation Date __________ 

Engine serial number or unique identifier __________________________________________ 

Engine Age ________________________ 

Nameplate hp _________________ Site Rated hp __________ 

Circle One 4SRB 2SLB 4SLB 

Location _________________________________ Elevation __________(feet above sea level) 

Pollution Controls Y / N Description (including make and model): _____________ 

______________________________________________________________________________ 

Ignition system _______________ (e.g. Altronic) 

Engine condition upon arrival: __________________________________________________ 

Date and description of last preventative maintenance: _______________________________ 

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 __________ 

Discharge Pressure __________ Discharge Temperature __________ 
October 2, 2009 

Final Draft Test Plan 

11 

Manifold Temperature __________ Pressure __________ 

Water Jacket Temperature __________ Compressor VVCP position: _____________ 

Fuel Gas Analysis: include representative fuel gas analysis 

Fuel Meter: make __________ model # __________ accuracy __________  % 

Fuel Line: pressure _____________ (psig) temperature ____________ °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 only and does 

not represent an endorsement of any source test firm 

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 122nd 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