| The escape of propane into an enclosed space poses an obvious safety risk to both nearby inhabitants and the surrounding structure. Infrequently, accidental release of propane into enclosed spaces such as basements or cellars has resulted in fire or explosion causing both property damage and human trauma.
In this paper, the use of carbon dioxide, CO2, as a surrogate to study the migration of propane gas within an enclosed environment is proposed. Concepts of tracer gas testing are described along with an explanation of the basic physics regarding the injection of gas into a ventilated enclosed volume.
Three experiments are described in which the injection of a gas mixture containing approxi mately 50% CO2 and 50% propane into a test chamber was undertaken at flowrates of 0.94 SLPM,* 5.19 SLPM, and 15.09 SLPM (2 CFH, 11 CFH and 32 CFH, respectively) through a water heater propane burner/flame spreader assembly.
These experimental data demonstrate that CO2 migrates in the same manner as propane (i.e., the measured concentration histories of propane and CO2 are essentially the same at a given spatial location as a function of time). Further, these data demonstrate that CO2 is an acceptable surrogate for the study of propane migration in the range of 0 to 9.5% propane concentrations within an enclosed environment.
Additional experimental data is provided to illustrate the detailed flow behavior associated with the ingress and migration of CO2 into a ventilated test chamber. Extensive concentra tion history data is presented on the migration of CO2 (and hence propane) in a test volume for a CO2 injection rate of 8.49 SLPM (18 CFH) and an air exchange rate of 0.55 air changes per hour (ACH). | 