The NTRM program is a collaboration between NIST and a specialty gas company to certify a production lot of gas standards. A specialty gas company produces a lot of NTRM candidate gas standards according to NIST technical specifications. The vendor then analyzes all of the cylinders comprising that lot against a NIST gas standard and sends the data to NIST. NIST analyzes the data and if the data passes our initial screening, selects 10 % of the cylinders for NIST audit. NIST certifies the lot based upon the vendor data and the NIST data. The vendor is then responsible for the NTRM cylinders, and can use them internally to produce protocol gases, or they may sell them to customers. Recently the NTRM program was expanded to include the NTRM Prime (NTRM*), where NIST analyzes every sample to address the needs of certain customers.
These two programs cannot provide all of the needed standards required by EPA so the Protocol Gas program was initiated. An EPA Protocol Gas standard is a standard prepared according to a procedure published by EPA. It defines a method to gain NIST traceability for gas standards, and it requires an SRM or NTRM for that traceability. To provide quality assurance for the Protocol Gases, NIST worked with EPA to set up a program for blind sampling of mixtures that are analyzed at NIST and the results are compared to information provided in the producer’s certificate. Certification measurements for all three programs are accomplished according to government and industry quality programs.
Start Date:October 1, 1972
Lead Organizational Unit:mml
U.S. Environmental Protection Agency
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