| Popis: |
Dilution ventilation is often used to control potential airborne health hazards, fire, or explosive conditions by mixing contaminated air with uncontaminated (e.g., outdoor) air. Dilution ventilation of confined spaces is used to displace oxygen-deficient, explosive, or toxic atmospheres prior to worker entry. Application of dilution ventilation requires the selection of an empirical mixing factor. This study sought an objective means of measuring mixing effectiveness for application to selected petrochemical industry vessels. The tracer gas sulfur hexafluoride (SF6) was metered into the air entering the vessel of interest, and the SF6 concentration was monitored at the vessel exhaust with an infrared analyzer modified to sample at 90 L/min for rapid response. The rate of SF6 concentration rise and decay was recorded using a datalogger. The mixing factor was calculated on the basis of measured ventilation rates, vessel dimensions, and SF6 rise and decay curves. Air in the vessels analyzed did not exhibit ... |
