EPA Protocol Gases move ahead at Pittcon
The National Institute of Standards and Technology (NIST) Gas Panel Meeting held in Atlanta on March 15 in conjunction with PITTCON saw further discussion on upcoming revisions of the 1997 Environmental Protection Agency (EPA) Traceability Protocol for Gaseous Calibration Standards
The National Institute of Standards and Technology (NIST) Gas Panel Meeting held in Atlanta on March 15 in conjunction with PITTCON saw further discussion on upcoming revisions of the 1997 Environmental Protection Agency (EPA) Traceability Protocol for Gaseous Calibration Standards.
Those with an interest have put forward numerous suggestions for revisions to the protocol. Among the issues up for discussion was the addition of new gas mixtures to the list of EPA Protocol Gases, which must be traceable to NIST standards. As a result of the meeting, NIST indicated that it would consider certifying standards containing hydrogen chloride and zero air in addition to its new Research Gas Materials (RGMs) for ammonia, nitrous oxide, and natural gas, according to Bob Wright from the EPA’s Air Pollution Prevention and Control Division. The other gases are still under consideration.
Another suggested amendment that will go forward is a change in the lower pressure limit from 150 psig to 100 psig. The limit has now been brought in line with NIST’s limit for Standard Reference Materials (SRMs). The revised protocol will also allow recertifications down to 100 psig from the current 500 psig limit.
Further work in progress focuses on extending the shelf life of EPA Protocol Gases. To date, the certification periods on gases have been based on ‘best estimates’ with a margin of error built in, rather than on hard scientific data. For example, the low NO and CO limits do not conform to reality. The EPA hopes to incorporate existing NIST data for some gases, but is also actively calling for data from members of the specialty gas community, particularly producers who have data on their gases’ longer-term stability. This data will be used confidentially. The aim is to develop a shelf life certification based on hard scientific data for everyone’s benefit, in some cases extending certification periods with the agreement of NIST.
The Protocol Gas Verification Program (PGVP) and Minimum Competency Requirements for Air Emission Testing final rule was published this March (also see Specialty Gas Report, Q1 2011, p10.) The EPA issued the final rule to establish these two ongoing programs to better ensure the accuracy of calibration gases and the competency of emission stack testers.
The PGVP is considered a verification program because its current level of evaluation does not allow for a large enough sample of EPA Protocol Gases from any one specialty gas producer to yield a statistically rigorous assessment of the accuracy of the producer’s gases. As such it will not provide end users with a scientifically defensible estimate of whether gases of acceptable quality can be purchased from a specific producer. Rather, the results provide information to end users that the specialty gas producer is participating in the program and the information in the verification report may be helpful when selecting a producer.
The EPA has also recently published its 2010 PGVP results. Both the source-level and ambient air PGVP components (run by two different organizations within EPA) name producer names and give verification results. The results of the ambient Air PGVP can be found in its annual report at:
http://www.epa.gov/ttn/amtic/aapgvp.html
And the source-level results can be found at: http://www.epa.gov/airmarkets/emissions/pgvp-detail.html
To contribute your company’s data on EPA Protocol Gas shelf lives to the program confidentially, please contact Bob Wright:
Phone: 919-541-4502
Fax: 919-541-1536
E-mail: wright.bob@epa.gov
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