1

innovative environmental solutions, inc.

Technical Memorandum

To: Lisa Beal, INGAA and Stephanie Meadows, API

From: Tom McGrath, Innovative Environmental Solutions, Inc

c: Gary McAlister/EPA, Bob Wayland/EPA, Melanie King/EPA, Hans Buenning/EPA

Region 8, Jeff Panek/IES, Jim McCarthy/IES

Date: October 22, 2009

Subject: EPA Method 323 Emission Test Data and Methodology Errors from EPA Region 8

Introduction

Recent formaldehyde emission test results from numerous gas-fired (IC) internal combustion

engines in EPA Region 8 were significantly lower (i.e. factor of 5 – 10) than historical test

results for these engines. These anomalous test results raised questions regarding the reliability

of EPA Method 323 “Measurement of Formaldehyde Emissions from Natural Gas-Fired

Stationary Sources—Acetyl Acetone Derivitization Method.” As a result, Method 323 was not

included in the proposed revisions to the RICE NESHAP (40 CFR 63 Subpart ZZZZ) as an

option for formaldehyde emission measurements.

In the docket for the recently proposed Subpart ZZZZ rule revisions, document EPA-HQ-OAR2008-0708-0020 discusses questionable test results from the Conoco Philips Sunnyside and

Argenta compressor stations. Review of tests referenced in the rulemaking docket indicated

testing errors rather than methodology as the cause of anomalous results. In addition,

conversations with EPA indicated that there were other questionable test results reported in

Region 8.

Since Subpart ZZZZ requires formaldehyde testing for rich burn engines and extractive FTIR is

the only other viable method, stakeholders are interested in retaining Method 323 if it is

technically acceptable and can meet test method performance objectives. Thus, Innovative

Environmental Solutions Inc. (IES) was tasked to review the basis for EPA’s decision to exclude

Method 323 from Subpart ZZZZ, review potential technical issues, and identify whether technical

evidence supports retaining the method to afford additional compliance testing flexibility for

Subpart ZZZZ. This memo discusses the result of that review and identifies systematic testing

errors, rather than method inadequacies, as the apparent cause for the questionable data reported in

Region 8. This review determined that questionable emission data were collected by a single

testing company which: frequently used a sample rate an order of magnitude or more above the

method maximum; appears to be improperly calculating the analytical calibration curve; and, could

have other introduced other measurement errors that are not evident in the test report (e.g., sample

recovery and sample line configuration, faulty analytical standards).

This memo includes background on the issue and a summary of test report review. In addition,

minor recommendations are provided for clarifying Method 323. An Attachment includes more

detailed discussion on the test report review, data comparisons, and testing deviations.
EPA Region 8 Method 323 Emission Data Review October 22, 2009

2

Method 323 and Comments on the Proposed Rule

Method 323 withdraws a sample from the stack and “bubbles” that sample through a chilled

impinger train (i.e., specialized glassware) containing water. Formaldehyde is absorbed in the

water, which is chemically treated and analyzed. Method 323 is an example of a “wet test

method” and important sampling and analysis parameters for wet methods include the total

sample volume, sample time, sample rate (volume divided by time), and amount (i.e., weight or

mass) of the species collected. When reviewing test reports for wet methods, there are many test

parameters, analytical results, and related calculations that warrant review. Sample rate, sample

volume, and recovered mass of the subject species (i.e., formaldehyde for Method 323) are key

starting points for the test report review. The procedures for Method 323 are standard

approaches for emissions testing. When compared to other “wet test methods”, Method 323 is

relatively simplistic in terms of sampling, sample recovery, and sample analysis.

Revisions to Subpart ZZZZ proposed in March 2009 concluded that Method 323 should be

excluded from the RICE NESHAP because it was not a final test method and performance

questions had been identified. In preparing comments for submittal by the June 2009 deadline,

IES reviewed related background material to identify whether technical comment was warranted.

IES reviewed the emission test reports from the Conoco Philips Sunnyside and Argenta

compressor stations and determined that the sample rate during the tests was approximately an

order of magnitude higher than the maximum sampling rate allowed by the test method (i.e.,

method maximum rate of 0.4 liters per minute (lpm) versus test rate of approximately 4 lpm).

Because the sample rate was well above the method specification, it is speculated that sample

breakthrough occurred (i.e., formaldehyde was not completely absorbed in the impinger solution

due to excessive sample rate) and the measurements were biased low. The emission tests that

appeared to include low bias were all conducted by a single company – referred to as Test

Company A. IES had follow-up conversations with Test Company A test personnel to discuss

whether data transcriptions could have occurred in the report – i.e., the sample volume and rate

were different than reported. Those conversations confirmed the higher sample rate. This

information was provided to EPA when comments were submitted on the Proposed Rule.

Summary of Test Report Review

In addition to the reports in the docket, it was indicated that additional Region 8 test reports

indicated questionable results. Based on discussion with Hans Buenning of EPA Region 8 and

review of numerous test reports, including both the recent “questionable” test data and historical

test data, it appears that all the questionable emission data are from a single emission testing

company – referred to as Test Company A in this memo. Historical test data from other testing

firms are labeled Test Company B and Test Company C. Figure 1 compares EPA Method 323

formaldehyde measurements conducted by Test Company A with Method 323 measurements by

the other companies on thirteen different engines.

The test reports reviewed typically addressed performance tests on engines with catalytic control

(e.g., engines subject to the RICE MACT). In Figure 1, eleven of the thirteen engines included a

catalyst. The two engines with higher emissions, identification numbers SR-E1 and SR-E2, did

not include catalytic control. Figure 1 clearly shows that Test Company A consistently

measured emission levels lower than the other two companies that completed tests on the same
EPA Region 8 Method 323 Emission Data Review October 22, 2009

3

engines. The Attachment provides additional discussion of systematic problems associated with

deviation from Method 323 procedures that contribute to the anomalous results.

0

5

10

15

20

25

BP-C2BP-C7BPTS8-1RC-C201RC-C202RC-C203SRE1SRE2SRE3SRE4SRE5SRE6

Engine ID

ppmvd CH2O @ 15% O2

Company B

Company B

Company C

Company C

Company A

Company A

Company A

Figure 1. Comparison of EPA Method 323 CH2O Emission Measurements Conducted by

Test Company A and Other Testing Companies for Numerous Engines.

These data include emissions from engines with post-combustion controls (i.e. oxidation

catalysts) and engines with no controls. For all the engines, every Test Company A

formaldehyde test result is lower than every formaldehyde measurement conducted by other

companies. Test Company A measurements are consistently lower regardless of parameters that

could impact formaldehyde emissions including engine load and pre-catalyst gas temperature.

Review of the emission test reports indicates that Test Company A frequently used a sample rate

an order of magnitude or more above the maximum specified in Method 323 and that Test

Company A may be incorrectly calculating the analytical calibration curve (i.e. low bias due to

calculation error). These two method deviations were specifically identified for Test Company

A and other procedural deviations could also have occurred. The calibration curve issue is

discussed in the Attachment and related recommendations for test method clarification are

provided below. In addition to method errors identified for Test Company A, minor deviations

were also observed for the other two companies – i.e., sample rate marginally above the method

specification.

Additional review and discussion of the test errors are provided in the Attachment. In summary,

this data review determined that the questionable data are very likely the result of systematic

errors by a single testing firm rather than fundamental flaws with the method. EPA Method 323

has been successfully employed for years for HAP characterizations (e.g., for major HAP facility

determinations), 40 CFR 63 Subpart ZZZZ compliance testing, and state required testing. In

addition, EPA Method 301 validation testing of the acetyl acetone colorimetric method

conducted by Radian Corporation that formed the basis for Method 323 met all the EPA Method

301 validation criteria. Thus, it appears that EPA Method 323 promulgation as an approved test

method and inclusion in the Subpart ZZZZ Final Rule planned for release in 2010 are warranted.

Method 323 procedures are straightforward and consistent with common procedures for wet
EPA Region 8 Method 323 Emission Data Review October 22, 2009

4

chemistry emission measurement test methods. This review indicates that testing errors were

relatively common in the test reports reviewed. Thus, testing companies should be attentive to

method requirements and agency test report review should ensure that method requirements are

followed.

Recommended Modifications to the Test Method

• Equation 323-5 should be

1,000

1

* * *

Va

Vt

m = Kc A df * rather than

Va

Vt

m = Kc * A* F * ; that is,

replace “F” with “df” and add conversion factor for μg to mg:

g

mg

1,000 μ

1

This revision is needed to correct the nomenclature and parameters referenced in the equation.

• In Section 12.1 Nomenclature, Kc should have units of “mg/2 ml aliquot”

This will add clarity to minimize the potential for confusion when developing the calibration

curve constant.

In addition, based on field experience, IES suggests the following method operating practice:

Orient the sample line and the impingers such that condensation in the sample line flows down into

the first impinger; that is, avoid a parallel, upward sloped, or looped sample line that may

contribute to sample line losses due to condensation (with formaldehyde retained in the

condensate) that collects in the line or backflows into the probe. During sample line recovery,

ensure that this sample line configuration is retained to avoid potential sample losses.
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Attachment:

Detailed Discussion of Testing Anomalies Identified from

Review of EPA Region 8 Method 323 Test Reports

Method 323 Summary

Method 323 withdraws a sample from the stack and “bubbles” that sample through a chilled

impinger train (i.e., specialized glassware) containing water. Formaldehyde is absorbed in the

water, which is chemically treated and analyzed. Method 323 is an example of a “wet test

method” and important sampling and analysis parameters for wet methods include the total

sample volume, sample time, sample rate (volume divided by time), and amount (i.e., weight or

mass) of the species collected. When reviewing test reports for wet methods, there are many test

parameters, analytical results, and related calculations that warrant review. Sample rate, sample

volume, and recovered mass of the subject species (i.e., formaldehyde for Method 323) are key

starting points for the test report review. The procedures for Method 323 are standard

approaches for emissions testing. When compared to other “wet test methods”, Method 323 is

relatively simplistic in terms of sampling, sample recovery, and sample analysis.

Test Report Review and Measurement Anomalies

The tables below compare Region 8 emission measurements by Test Company A to Method 323

emission data measured by other testing companies on the same engine. For each engine, the

data include emission controls, engine load, pre-catalyst or stack temperature, measured

emissions (3-run average), analytical calibration curve slope, and the average EPA Method 323

sample rate. It should be noted that there was not sufficient time to review all Region 8 test

reports, the test reports include varying levels of detail, and the primary focus was on test reports

questioned by Region 8 personnel; thus, there may be additional reports at Region 8 pertinent to

this analysis. It should also be noted that a detailed quality assurance (QA) review of these test

reports (either Test Company A reports or reports from other testing companies) has not been

completed and that the Method 323 sample rate and the analytical calibration curve slope were

the only test method parameters reviewed for every report. These testing issues were the focus

of the review because they were identified as problem areas where test procedures used in

practice deviated from Method 323 requirements. However, as discussed below, this cursory QA

review identified anomalies in the majority of the tests including incorrect sample rates, full-size

rather than midget impingers, and calculation errors.

The potential impact of a very high sampling rate on the formaldehyde emission measurements

was discussed above for the Test Company A emission test reports from the Conoco Philips

Sunnyside and Argenta compressor stations. In addition, additional review of some emission test

reports determined that Test Company A could be incorrectly calculating the analytical

calibration curve slope and, consequently, the formaldehyde emissions. This calibration issue is

explained here based on our understanding of the information provided in the test reports.
EPA Region 8 Method 323 Emission Data Review October 22, 2009

6

Method 323 equation 323-5, presented below, is used to calculate the mass of formaldehyde in

each sample based on sample absorbance during the colorimetery analysis.

Va

Vt

m = Kc * A* df *

Where: m = mass of formaldehyde in liquid sample (μg);

Kc = spectrophotometer calibration factor, slope of the least squares linear

regression line (μg/2 ml aliquot);

 A = measured absorbance of 2 ml aliquot;

df = dilution factor, 1 unless dilution is required to reduce the absorbance into the

calibration range;

 Vt = total volume of the impinger catch/rinsate (ml); and

 Va = volume of the analyzed sample aliquot (2 ml).

Note that Va is included in the calculation to properly account for sample aliquot size. However,

the report indicates that Test Company A calculates Kc in units of “μg/ml” rather than “μg/2 ml

aliquot”. If the reported units are correct, Test Company A calculations of formaldehyde mass

per sample are a factor of 2 low – i.e., Va should be removed from the equation for Test

Company A calculations. A comparison of the Test Company A least squares linear regression

line slope (Kc) with Kc’s reported by other companies and analytical labs determined that the Kc

for Test Company A is about half of all other values, supporting the supposition that Test

Company A calculations of formaldehyde mass per sample are a factor of 2 low.

Table 1 compares test data collected by Test Company A and another firm, Test Company B, at

the Red Cedar Spring Creek Compressor Station. The data are for three Caterpillar G3516

TALE engines identified as Units C-201, C-202, and C-203. The test reports indicate that these

engines are equipped with post-combustion emission controls (i.e., oxidation catalysts). For the

three engines, the Test Company A emission measurements (CH2O @ 15% O2) are about a

factor of five or more lower than the Test Company B measurements. The Test Company A

Method 323 sample rate is about a factor of 6 or 7 higher than the Test Company B sample rate

and the slope of the Test Company A analytical calibration curve is about half the Test Company

B analytical calibration curves slopes. Operating parameters expected to impact emissions, such

as Engine Load and Pre-Catalyst Temperature, varied little between the tests suggesting that

engine operation did not introduce a significant difference and the difference in the results is due

to a low bias to the Test Company A measurements caused by testing anomalies from excess

sample rate and calibration computational errors. Information on other equipment and

operational parameters and activities that could impact emissions, such as catalyst replacement

and/or maintenance/cleaning, was not provided in the test reports. It should be noted that the

Test Company B sample rate also exceeded the method maximum rate of 0.4 lpm; albeit only by

a relatively small margin of about 0.1 lpm.
EPA Region 8 Method 323 Emission Data Review October 22, 2009

7

Table 1. Emission Data for Red Cedar Spring Creek Compressor Station Engines C-201, C-202, and C-203.

Facility

Engine

Make/

Model

Rating

(hp)

Engine

Load

Engine

ID

Emission

Controls

Pre-Cat/

Stack

Temp (°F)

Testing

Company

Test

Date

CH2O

(ppmvd)

O2%

(dry)

CH2O

(@ 15%

O2)

Kc (μg/

(2 ml*A)

M323

Sample

Rate (lpm)

95% OxCat 770 Test

Company A 9/24/08 0.58 8.8 0.28 8.4619

μg/(ml*A) 3.5

100% OxCat 796 Test

Company B 10/12/07 6.7 7.6 3.0 2.312*A2

 +

13.698*A 0.51

100%

RC-C201

Ox Cat 798 Test

Company B 4/1/08 22.4 7.7 10 15.782 0.51

98% OxCat 820 Test

Company A 9/24/08 0.77 7.2 0.33 8.4619μg/(ml*A) 3.1

100% OxCat 792 Test

Company B 10/11/07 15.8 10.6 9.2 2.312*A2

 +

13.698*A 0.52

100%

RC-C202

Ox Cat 795 Test

Company B 4/1/08 3.2 7.8 1.4 15.782 0.49

95% OxCat 807 Test

Company A 9/24/08 0.53 8.0 0.24 8.4619μg/(ml*A) 3.7

100% OxCat 815 Test

Company B 10/10/07 6.8 10.0 3.7 2.312*A2

 +

13.698*A 0.51

Spring

Creek

Compressor

Station

CAT

G3516

TALE

1,340

100%

RC-C203

Ox Cat 815 Test

Company B 4/1/08 8.7 7.8 3.9 15.782 0.49

Table 2 compares test data collected by Test Company A and third firm, Test Company C, at the Samson Resources Jaques

Compressor Station – South Ignacio Central Delivery Point. The data are for two Waukesha L594LT engines identified as Units E1

and E2. The test reports indicate that these engines are not equipped with post-combustion controls. The Test Company A emission

measurements (CH2O @ 15% O2) for the two engines are five to more than ten times lower than the Test Company C measurements.

For both engines, the Test Company A Method 323 sample rate is about a factor of 4 higher than the Test Company C sample rate and

the slope of the Test Company A analytical calibration curve is about half the Test Company C analytical calibration curve slope.

Engine load, which is expected to impact emissions, varied little between the tests and the stack gas temperature was lower for the

Test Company A tests; thus, if formaldehyde emission differences occurred due to operating conditions, the Test Company A

measurements would be expected to be higher because lower combustion temperature typically increases formaldehyde. However, the

opposite results suggest a low bias to the Test Company A measurements. It should be noted that the Test Company C sample rate

also exceeded the method maximum rate of 0.4 lpm, but by a smaller margin than Test Company A tests.
EPA Region 8 Method 323 Emission Data Review October 22, 2009

8

Table 2. Emission Data for Samson Resources Jaques Compressor Station Engines E1 and E2.

Facility

Engine

Make/

Model

Rating

(hp)

Engine

Load

Engine

ID

Emission

Controls

Stack

Temp (°F)

Testing

Company

Test

Date

CH2O

(ppmvd)

O2%

(dry)

CH2O (@

15% O2)

Kc (μg/

(2 ml*A)

M323

Sample

Rate (lpm)

1,400 92% None 626 Test

Company A 3/25/09 3.8 8.0 1.8 6.5799

μg/(ml*A) 3.89

1,400

SR-E1

None 765 Test

Company C 4/1/08 44.0 7.9 22.3 14.255 Z 1.06

1,400 92% None 607 Test

Company A 3/25/09 5.1 10.3 2.8 6.5799μg/(ml*A) 3.34

Jaques

Compressor

Station

Waukesha

L5794LT

1,400 90%

SR-E2

None 771 Test

Company C 4/2/08 29.4 8.5 14.0 14.255 Z 0.96

Z. Calibration curve was not included in the test report. Calibration data provided by lab on 9/29/09 as typical for this analysis.

Table 3 compares test data collected by Test Company A and Test Company C at the Samson Resources Jaques Compressor Station –

South Ignacio Central Delivery Point. The data are for a Waukesha L594LT engine identified as Unit E6. The test reports indicate

that this engine is equipped with post-combustion controls, an oxidation catalyst. The Test Company A emission measurement (CH2O

@ 15% O2) is about a factor of four lower than the Test Company C formaldehyde measurement. The Test Company A Method 323

sample rate is about a factor of 3.5 higher than the Test Company C sample rate and the slope of the Test Company A analytical

calibration curve is about half the Test Company C analytical calibration curve slope. Operating parameters expected to impact

emissions, such as Engine Load and Pre-Catalyst Temperature, varied little between the tests suggesting a low bias to the Test

Company A measurements. Information on other equipment and operational parameters and activities that could impact emissions,

such as catalyst replacement and/or maintenance/cleaning, was not provided in the test reports. It should be noted that the Test

Company C sample rate also exceeded the method maximum rate of 0.4 lpm, but by a smaller margin.
EPA Region 8 Method 323 Emission Data Review October 22, 2009

9

Table 3. Emission Data for Samson Resources Jaques Compressor Station Engine E6.

Facility

Engine

Make/

Model

Rating

(hp)

Engine

Load

Engine

ID

Emission

Controls

Pre-Cat/

Stack

Temp (°F)

Testing

Company

Test

Date

CH2O

(ppmvd)

O2%

(dry)

CH2O

(@ 15%

O2)

Kc (μg/

(2 ml*A)

M323

Sample Rate

(lpm)

92% Ox Cat 777 Test

Company A 3/25/09 0.78 9.1 0.39 6.5799μg/(ml*A) Jaques 3.35

Compressor

Station

Waukesha

L594LT 1,400

90%

SR-E6

Ox Cat 783 Test

Company C 4/1/08 3.33 8.2 1.73 14.255Z

0.97

Z. Calibration curve was not included in the test report. Calibration data provided by lab on 9/29/09 as typical for this analysis.

Table 4 compares test data collected by Test Company A and Test Company C at the Samson Resources Jaques Compressor Station –

South Ignacio Central Delivery Point. The data are for three Waukesha L594LT engines identified as Units E3, E4, and E5. The test

reports indicate that these engines are equipped with post-combustion controls. For these three engines, the Test Company A Method

323 sample rate conforms with the test method while the Test Company C sample rate exceeded the method maximum rate of 0.4 lpm;

however, the Test Company A emission measurements (CH2O @ 15% O2) are lower than the Test Company C measurements by

factors ranging from about two to six. The slope of the Test Company A analytical calibration curve is about half the Test Company

C analytical calibration curve slope. These tests were conducted after the Argenta and Sunnyside Compressor Stations’ test data were

discussed with Test Company A personnel and Test Company A apparently corrected the sampling rate. Five of the six Test

Company A emission measurements are lower than the Test Company C data by more than a factor of two (the estimated error in the

analytical calibration curve slope / error in the calculated mass of formaldehyde in the samples); thus, these data suggest some

operating or measurement parameter could be impacting the Test Company A measurements. Operating parameters expected to

impact emissions, such as Engine Load and Pre-Catalyst Temperature, varied little between the tests suggesting a low bias to the Test

Company A measurements. Information on other equipment and operational parameters and activities that could impact emissions,

such as catalyst replacement and/or maintenance/cleaning, was not provided in the test reports. A specific finding that clearly explains

the differences was not identified. However, evidence of method deviations raises questions about other deviations that could have

occurred but are not evident in the tests reports.
EPA Region 8 Method 323 Emission Data Review October 22, 2009

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Table 4. Emission Data for Samson Resources Jaques Compressor Station Engines E3, E4, and E5.

Facility

Engine

Make/

Model

Rating

(hp)

Engine

Load

Engine

ID

Emission

Controls

Pre-Cat/

Stack

Temp (°F)

Testing

Company

Test

Date

CH2O

(ppmvd)

O2%

(dry)

CH2O

(@ 15%

O2)

Kc (μg/

(2 ml*A)

M323

Sample

Rate (lpm)

92% Ox Cat 763 Test

Company A 5/28/09 1.97 7.6 0.87 6.4286

μg/(ml*A) 0.26

95% Ox Cat 756 Test

Company C 11/19/08 9.18 7.8 4.6 14.255 Z 0.75

92%

SR-E3

Ox Cat 767 Test

Company C 4/1/08 11.0 8.1 5.7 14.255 Z 1.10

92% Ox Cat 777 Test

Company A 5/28/09 1.71 7.3 0.74 6.4286μg/(ml*A) 0.24

94% Ox Cat 787 Test

Company C 11/19/08 10.2 7.7 5.1 14.255 Z 0.76

92%

SR-E4

Ox Cat 762 Test

Company C 4/1/08 9.44 7.8 4.8 14.255 Z 1.10

90% Ox Cat 780 Test

Company A 5/28/09 2.95 7.8 1.3 6.4286μg/(ml*A) 0.32

93% Ox Cat 780 Test

Company C 11/19/08 7.37 8.1 3.8 14.255 Z 1.23

Jaques

Compressor

Station

Waukesha

L594LT 1,400

90%

SR-E5

Ox Cat 780 Test

Company C 4/1/08 4.75 7.7 2.4 14.255 Z 0.96

Z. Calibration curve was not included in the test report. Calibration data provided by lab on 9/29/09 as typical for this analysis.

Table 5 compares test data collected by Test Company A and Test Company B at two BP America Production Company facilities.

The data are for two 1,334 hp Waukesha L7042GL engines identified as Units C-2 and C-7 at the Salvador Compressor Station and a

1,090 hp Waukesha 5790 GL engine at the Treating Site #8 Compressor Station. The test reports indicate that these engines are

equipped with post-combustion emission controls (i.e. oxidation catalysts). For five of the seven Test Company A tests on the three

engines, the Method 323 sample rate is about a factor of 5 higher than the Test Company B sample rate. For four of these five tests,

the Test Company A emission measurements (CH2O @ 15% O2) are a factor of ten or more lower. For the fifth test, on Salvador

Compressor Station Unit C-7, the Test Company A measurements were about half the Test Company B measured emissions. Two of

the Test Company A tests were conducted after the Argenta and Sunnyside Compressor Stations’ test data were discussed with Test

Company A personnel (6/18/09 tests) and Test Company A apparently reduced the sampling rate; however, the Test Company A

emissions are still an order of magnitude or more lower than the Test Company B measurements. The slope of the Test Company A

analytical calibration curve is about half the Test Company B analytical calibration curve slope with the exception of the 6/10/08 test on
EPA Region 8 Method 323 Emission Data Review October 22, 2009

11

the Treating Station #8 engine. These data suggest, consistent with the above discussion, that something other than sample rate and the

incorrect analytical calibration curve could be impacting the Test Company A measurements. Review of expected operating

parameter impacts do not explain the difference. However, Test Company A systematic deviations from method procedures raise

serious questions their results. It should be noted that the Test Company B sample rate also exceeded the method maximum rate of

0.4 lpm; albeit only by about 0.1 lpm.

Table 5. Emission Data for BP America Production Company Engines.

Facility

Engine

Make/

Model

Engine

ID

Rating

(hp)

Engine

Load

Emission

Controls

Pre-Cat/

Stack

Temp (°F)

Testing

Comp.

Test

Date

CH2O

(ppmvd)

O2

(%dry)

CH2O

(ppmvd

@ 15%

O2)

Kc (μg/

(2 ml*A)

M323

Sample

Rate

(lpm)

75% 704 Test

Company A 7/30/08 0.74 10.0 0.4 6.5665μg/(ml*A) 5.12

78% 736 Test

Company A 1/8/09 0.13 9.5 0.07 7.0199μg/(ml*A) 2.51

85% 706 Test

Company A 6/18/09 0.41 7.8 0.19 6.7151μg/(ml*A) 0.55

BP-C-2 1,334

54%

Ox Cat

569 Test

Company B 5/30/07 4.1 10.4 2.3 0.5462*A2

 +

15.161*A 0.54

60% 654 Test

Company A 7/30/08 3.68 10.3 2.1 6.5665μg/(ml*A) 4.50

85% 596 Test

Company A 6/18/09 0.21 8.0 0.1 6.7151μg/(ml*A) 0.68

Salvador

Compressor

Station

Waukesha

L7042GL

BP-C-7 1,334

75%

OxCat

577 Test

Company B 5/31/07 7.9 9.4 4.0 0.5462*A2

 +

15.161*A 0.53

60% 706 Test

Company A 6/10/08 1.03 11.4 0.64 11.507μg/(ml*A) 2.92

65% 601 Test

Company A 2/6/09 0.1 9.9 0.05 6.7465μg/(ml*A) 3.98

Treating Site

#8

Compressor

Station

Waukesha

5790 GL

BPTS8-1 1,090

75%

Ox Cat

787 Test

Company B 8/1/07 15.3 9.6 8.0 3.2384*A2

 +

12.549*A 0.50
 EPA Region 8 Method 323 Emission Data Review October 22, 2009

12

Summary and General Observations on Test Method

Over a wide variety of engines and wide range of operating loads and pre-catalyst and stack gas

temperatures, Test Company A formaldehyde measurements were consistently lower than

Method 323 measurements performed by other testing firms. Very high sampling rates and

potential calculation errors likely contributed to the low bias for many of the tests. However,

after Test Company A made some corrections to their sampling approach, their results continued

to exhibit an apparent low bias. This could be due to other method deviations that are not

apparent from the test report.

Test Company A is not the only testing company that is conducting Method 323 with notable

method deviations. In addition to the EPA Region 8 data, IES reviewed numerous EPA 323 test

reports submitted to State of Colorado DPH&E and State of Wyoming DEQ. A general

observation was that the majority of the M323 emission tests were not performed in accordance

with the method. The most common method deviation, observed for a majority of the test

reports reviewed, was that the sampling rate exceeded the test method maximum of 0.4 liters per

minute. Typical sample rates (for companies other than Test Company A) ranged from 0.5 to 1.0

lpm. Another common method deviation was the use of sample trains configured with full size

EPA Method 5 impingers. In addition, many test reports were incomplete such that the emission

data could not be verified; for example, field data sheets and/or equipment calibrations were not

included in the report. As noted above, the procedures for Method 323 are “ordinary”, yet

method deviations were common. This indicates that testing companies and agency reviewers of

test plans and test reports need to be more attentive to ensure proper methods are followed.

In addition, IES review identified issues with Method 323 that require clarification.

Recommended corrections and clarifications are discussed in the memo.