Development of gas-blending systems for calibration: application to hydrogen fluoride, arsine and phosgene in air

Preparation of samples of known concentration of hydrogen fluoride, arsine and phosgene in air from 0.5 to 10 times the TLV is described. These are required to evaluate and calibrate analytical monitoring devices used for measuring these gases in work atmospheres. Dynamic gas-blending systems have been constructed and evaluated at the National Bureau of Standards for preparing these samples. Measurements to estimate the long term concentration stability of these gases are also included.