Recommending a Ventilation Rate for Gas Compressor Buildings

Abstract

In cold climates, a building ventilation rate must be selected to control contaminants adequately but must not be excessive. Measurements of natural gas (total hydrocarbons), hydrogen sulfide, and carbon monoxide in 16 gas compressor buildings containing 42 compressors (up to 2000 HP each) showed total hydrocarbons to be the critical material requiring additional control by ventilation (primary control is by containment). Ventilation rates were estimated by tracer gas decay (Freon 12®, measured by infrared analyser), thus hydrocarbon leakage rates could be calculated. Of the compressors studied, 95% had leakage rates below 130 Ipm of natural gas. The principles of dilution ventilation allowed calculation of a recommended ventilation rate which would control natural gas hydrocarbons to less than 1000 ppm, the present health standard, in the majority of the Company's gas compressor buildings (130 mYmin per operating compressor). Results of the study include implementation of a leak detection and maintenance program, a recommendation to sealweld all threaded pipe fittings (a major source of leakage), and a review by safety advisors of procedures for entry into areas contaminated with gas. Future review of building ventilation requirements will have a documented base to work from, something which was lacking in the past. Drummond, I.: Recommending a ventilation rate for gas compressor buildings.