### 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-C2 BP-C7 BPTS8-1 RC-C201 RC-C202 RC-C203 SRE1 SRE2 SRE3 SRE4 SRE5 SRE6 Engine IDppmvd CH2O @ 15% O2 Company B Company B Company C Company C Company A Company A Company A



### Figure 1. Comparison of EPA Method 323 CH2

### O 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 000
, 1 1 * * * Va

Vt * f d A c K m = 

### rather than Va Vt * F A c K m * * = 

### ; that is,

replace “F” with “df” and add conversion factor for μg to mg: g mg μ 000
, 1 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.

### 5 

## 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 * f d A c K m * * =


### 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 (CH2

### O @ 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 8.4619 μg/(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 8.4619 μg/(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 notequipped with post-combustion controls. The Test Company A emission measurements (CH2

### O @ 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 14.255Z 1.06

1,400 92% None 607 Test Company A 3/25/09 5.1 10.3 2.8 6.5799 μg/(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 14.255Z 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 (CH2

### O @ 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 6.5799 μg/(ml*A) 3.35 Jaques Compressor Station Waukesha

L594LT 1,400 90% SR-E6 Ox Cat 783 Test Company C 4/1/08 3.33 8.2 1.73 14.255 Z 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 (CH2

### O @ 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

10 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 14.255Z 0.75

92% SR-E3

Ox Cat 767 Test Company C 4/1/08 11.0 8.1 5.7 14.255Z 1.10

92% Ox Cat 777 Test Company A 5/28/09 1.71 7.3 0.74 6.4286 μg/(ml*A) 0.24

94% Ox Cat 787 Test Company C 11/19/08 10.2 7.7 5.1 14.255Z 0.76

92% SR-E4

Ox Cat 762 Test Company C 4/1/08 9.44 7.8 4.8 14.255Z 1.10

90% Ox Cat 780 Test Company A 5/28/09 2.95 7.8 1.3 6.4286 μg/(ml*A) 0.32

93% Ox Cat 780 Test Company C 11/19/08 7.37 8.1 3.8 14.255Z 1.23 JaquesCompressor Station Waukesha L594LT 1,400

90% SR-E5

Ox Cat 780 Test Company C 4/1/08 4.75 7.7 2.4 14.255Z 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 (CH2

### O @ 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 6.5665 μg/(ml*A) 5.12

78% 736 Test Company A 1/8/09 0.13 9.5 0.07 7.0199 μg/(ml*A) 2.51

85% 706 Test Company A 6/18/09 0.41 7.8 0.19 6.7151 μg/(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 6.5665 μg/(ml*A) 4.50

85% 596 Test Company A 6/18/09 0.21 8.0 0.1 6.7151 μg/(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 11.507 μg/(ml*A) 2.92

65% 601 Test Company A 2/6/09 0.1 9.9 0.05 6.7465 μg/(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.