Second Performance Audit of Inspection and Maintenance Calibration Gases

摘要

The purpose of the audit was to determine the accuracy of calibration gases being used by state and local inspection and maintenance (I/M) programs. Forty-six calibration gas cylinders were borrowed from 16 representative I/M programs. Typically, they contained propane (or hexane), carbon monoxide, and carbon dioxide in nitrogen. Research Triangle Institute (RTI) analyzed these calibration gases using nondispersive infrared photometry and gas chromatography with flame ionization and thermal conductivity detectors.