Fire Exposures of Fire Fighter Self-Contained Breathing Apparatus Facepiece Lenses
Amy E. Mensch, George G. Cajaty Barbosa Braga, Nelson P. Bryner
National Institute of Standards and Technology (NIST), conducted experiments which demonstrated a range of realistic thermal exposures and environmental conditions that firefighters could be exposed to. Self-contained breathing apparatus (SCBA) facepieces were exposed to thermal environments from propane-fueled calibration experiments and furnished townhouse fire experiments. The rooms and the facepieces were instrumented to measure temperatures of the environment and the facepieces. The fire experiments lasted 5 minutes to 10 minutes and produced ceiling temperatures of approximately 500 °C (932 °F) to 750 °C (1382 °F) in the room adjacent to the fire. A heat flux gauge was also installed next to the facepieces and measured peak heat fluxes from approximately 2 kW/m2 to 55 kW/m2. Eight facepieces were tested in six different experiments, with three facepiece lenses showing evidence of thermal degradation from the exposure. Maximum exterior lens temperatures were as high as 300 °C (572 °F) in these cases. The environments that caused the failures were identified in an attempt to characterize the thermal performance of SCBA facepieces. Although much was learned about conditions associated with thermal degradation of SCBA facepiece lenses, more experiments are needed to be able to understand the thermal degradation and more definitively predict the conditions that are likely to cause a facepiece lens failure.