Failure of firefighter escape rope under dynamic loading and elevated temperatures
Fire Service escape rope systems are a firefighter’s last resort for a controlled exit from elevated floors of a burning structure when conditions rapidly deteriorate. The escape rope is likely to be deployed from a room that is at least partially involved with fire and must support a fully loaded firefighter making a hasty exit, resulting in dynamic loading. These dynamic loads are accompanied by elevated temperatures, which will affect the strength and stiffness of the rope. Current standards only require that escape rope systems be tested at room temperature and under quasi-static loading in order to be certified as a personal escape rope. A pilot study will be presented that provides the first experimental quantification of the decline in rope strength and stiffness at elevated temperatures. These data are interpreted with a simple kinetics model for the dynamic loading of rope for various escape scenarios, suggesting that the “factor of safety” that is assumed in current escape rope standards is quickly eliminated by the dynamic forces during escape and temperature dependent strength deterioration. Suggestions and guidelines for an improved certification protocol are forwarded.
KeywordsBurning Fatigue Furnace Nylon Harness
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