Quantified Risk Assessment of Fire Incidence inside Hyperbaric Chamber: A Case Study

An enclosed human occupancy chamber is commonly known as hyperbaric chamber system (HCS). The medical treatment to divers suffering from decompression sickness is administered inside a hyperbaric chamber. The hazards inherent inside the chamber include sudden loss of pressure, fire and rapid loss of life-supporting gases. Fire can be catastrophic inside the oxygenenriched confined space of a hyperbaric chamber. The fire protection system (FPS), a hazard barrier against fire is designed to respond to the true demand of the initiating event (fire incidence) which can happen at any time. The paper is devoted to the risk assessment of fire incidence inside a hyperbaric chamber and gives a methodology for risk assessment for incident of fire using fault tree and event tree analyses. The mean proportion of time the system is not functioning upon demand is a measure of safety for the fire protection system, which is estimated using the mean fractional dead time (FDT). The minimum mean time between hazards (MTBH) of a life-safety system, indicates the minimum performance level of hazard barriers designed to provide protection against hazards, can be considered as design matric for risk analysis. The MTBF of FPS is calculated and its usefulness is discussed.