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2010 EPA Protocol Gas Audit Results


EPA PROTOCOL GAS AUDIT RESULTS FOR ORIGINAL TAG VALUES

Specialty Gas Company Name Production Site Name Vendor ID Gas Conc Level NO SO2 CO2 Totals
Pass
(%dif)
Fail
(%dif)
Pass
(%dif)
Fail
(%dif)
Pass
(%dif)
Fail
(%dif)
# of
Passes
# of
Fails

Air Liquide

Air Liquide
500 Weaver Park Road
Longmont, CO 80501

Very Low

Low -0.65

0.60

0.14

3

Mid -0.35

-0.47

0.26

3

High -0.31

-0.36

-0.10

3

Air Liquide
1290 Combermere Street
Troy, MI 48083

Very Low

Low

2.57 0.44

0.63

2 1
Mid -0.09

-0.15

-0.21

3

High 0.24

0.00

0.33

3

Air Liquide
11426 Fairmont Parkway
Laporte, TX 77571

Very Low

Low 0.21

-0.84

0.01

3

Mid 0.81

0.09

-0.08

3

High 0.36

-0.08

-0.26

3

Airgas

Airgas
12722 S. Wentworth Ave
Chicago, IL 60628

Very Low

Low -1.34

1.90

-0.82

3

Mid -0.34

-0.08

2.66 2 1
High 0.37

-0.16

0.54

3

Airgas
630 United Drive
Durham, NC 27713

Very Low

Low -0.23

-0.22

-0.37

3

Mid 1.16

-0.08

-0.47

3

High

2.22 -0.20

0.06

2 1

Airgas
600 Union Landing Road
Riverton, NJ 08077

Very Low

Low -1.51

1.64

-0.33

3

Mid -0.12

0.09

-0.76

3

High 1.99

0.22

-1.69

3

Linde

Linde
80 Industrial Drive
Alpha, NJ 08865

Very Low

Low -0.45

1.38

0.54

3

Mid 0.34

-0.08

0.21

3

High 0.13

-0.04

-0.04

3

Liquid Technology Corp

Liquid Technology Corp
2564 Pemberton Dr
Apopka, FL 32703

Very Low

Low

-2.26 -2.03

3.24

1

2
Mid

2.53

-2.50 0.97

1 2
High

2.55

-2.90 -0.49

1 2

Matheson Tri-Gas, Inc

Matheson Tri-Gas, Inc.
1650 Enterprise Parkway
Twinsburg, OH 44087

Very Low

Low 0.51

-5.05 -0.45

2 1
Mid 0.01

-0.78

-0.53

3

High

2.88

-3.56 -0.94

1 2

Praxair

Praxair
5700 South Almeda Street
Los Angeles, CA 90058

Very Low

Low

-5.17 -0.34

0.15

2 1
Mid -0.93

-0.49

0.31

3

High -0.60

-0.08

-1.05

3

Praxair
145 Shimersville Road
Bethlehem, PA 18015

Very Low

Low -0.62

-1.86

0.56

3

Mid -1.49

-0.30

0.55

3

High -2.13

-0.38

-1.19

3

Red Ball Technical Gas Services

Red Ball Technical Gas Services
555 Fontenac St.
Shreveport, LA 71107

Very Low

Low 1.32

-0.12

-0.52

3

Mid -0.09

0.33

0.44

3

High -1.11

0.30

-0.31

3

Scott-Marrin Inc.

Scott-Marrin, Inc.
6531 Box Springs Blvd.
Riverside, CA 92507

Very Low

Low -0.93

-0.21

-0.13

3

Mid -0.92

0.08

-0.27

3

High -1.61

-0.05

-0.56

3

Specialty Air Technologies

Specialty Air Technologies
6544 Cherry Avenue
Long Beach, CA 90805

Very Low

Low 0.85

-0.59

-0.19

3

Mid -0.22

-0.88

-0.61

3

High -1.01

-0.78

0.19

3

Specialty Gases of America

Specialty Gases of America
6055 Brent Drive
Toledo, OH 43611

Very Low

Low 0.85

-0.69

0.24

3

Mid -0.75

-0.45

-0.38

3

High -1.09

0.17

-0.92

3

% dif = 100 x (Tag Value - NIST Value) / NIST Value

Very Low = 0 - 10 ppm for NO and SO2; and 0 - 1.0% for CO2.

Low = 11 - 100 ppm for NO and SO2; and 1.1 - 8.0% for CO2.

Mid = 101 - 600 ppm for NO and SO2; and 8.1 - 15.0% for CO2.

High = Above 600 ppm for NO and SO2; and above 15.0% for CO2.

Without informing the production site that a blind sample of their cylinders was being audited, three cylinders per production site were purchased by a company that normally purchases these types of cylinders. The cylinders in the sample were analyzed by the National Institute of Standards and Technology (NIST). Within each parameter (NO, SO2, CO2), all low concentrations were essentially identical, all mid concentrations were essentially identical, and all high concentrations were essentially identical.

The above audit results are for the cylinder original concentration for each component and do not include any re-analyses that may have been performed by a production site. The rationale for including summary results for only original tag values is that gas cylinder purchasers will receive cylinders with tag values based on original analysis, not re-analysis, so it is important for a gas production site to produce an accurately labeled cylinder the first time. Please see the full audit report for more complete information and for any re-analyses and corrective actions performed by a production site.

A gaseous component is said to fail when the absolute value of the difference between the audit and vendor concentration values is greater than 2.20%. The 2.20% value is determined by using the "paired t test" at 95% confidence, with an uncertainty of plus or minus 2.0% (fixed by Part 75, Appendix A, section 5.1.4(b)) for the gas vendor and an expanded uncertainty (coverage factor k=2) of plus or minus 1.0% (maximum acceptable) for the audit. If on future audits, e.g., for very low concentration gases, the plus or minus 1.0% audit expanded uncertainty value changes, the 2.20% value may change. If the absolute value of the difference between the audit value and the vendor value is 2.20% or less, then (because of the uncertainties in the total measurement system) statistically there is no difference between the two values. Thus, a difference of 2.10% would be interpreted as being equal to one of, for example, 0.40%.

Nothing can be said regarding the performance of any EPA Protocol gas production site not included in the audit. Any accuracy assessment is an instantaneous snapshot of the process being measured. These results should not be regarded as a final statement on the accuracy of EPA Protocol gases. They can be used as a general indicator of the current status of the accuracy of EPA Protocol gases as a whole. However, individual results should not be taken as definitive indicators of the analytical capabilities of individual producers. EPA presents this information without assigning a rating to the gas vendors, for example, who is the best or who is approved or not approved and specifically does not endorse any particular vendor.

 


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