||Performance Audit of Inspection and Maintenance Calibration Gases.
Wright, R. S. ;
Decker, C. E. ;
Barnard, W. F. ;
||Research Triangle Inst., Research Triangle Park, NC.;Environmental Monitoring Systems Lab., Research Triangle Park, NC.
||RTI/3180/18-01; EPA-68-02-4125; EPA/600/D-86/101;
Air pollution ;
Exhaust emission gases ;
Performance evaluation ;
Carbon monoxide ;
Motor vehicles ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
The purpose of the audit was to determine the accuracy of inspection and maintenance calibration gases for motor vehicle emission analyzers. Cylinders containing approximately 1.6 percent carbon monoxide and 640 parts per million propane in nitrogen were purchased from 13 specialty gas producers in 1984. Only three producers were able to provide cylinders that had been named according to the EPA Recommended Practice. RTI analyzed these gases in triplicate, using a gas chromatograph with flame ionization or thermal conductivity detectors. NBS Standard Reference Materials were used as reference standards for the analyses. Twelve of the 13 certified carbon monoxide concentrations were accurate to within plus or minus two percent relative. Nine of the 13 certified propane concentrations were accurate to within plus or minus two percent relative. Eleven of the 13 propane purities were greater than 99.0 percent. Confirmatory analyses at two EPA laboratories showed good agreement with RTI's analyses.