Appraising the flammability hazards of hydrocarbon refrigerants using quantitative risk assessment model. Part II. Model evaluation and analysis

Hydrocarbons are being used as alternatives to conventional non-flammable refrigerants. However, flammable refrigerants pose fire and explosion hazards, so if used in refrigeration or air conditioning equipment, the impact on safety should be negligible. This paper details empirical data that can be used in a quantitative risk assessment model presented in the earlier part of this study. Data for leakage, hardware failure and sources of ignition are used to demonstrate the application of the model, and the sensitivity of key variables. In particular, it examines the effects that design, installation of equipment and external conditions have on the frequency of ignition and the associated consequences. Further, efficacy of risk-reducing measures, such as refrigerant mass, room size, installation height, and ventilation rates is also examined. Results for selected types of equipment are also presented, and these are discussed in relation to fire risk data for similar equipment.