BRANZFIRE: Application to Realistic Burning Items in a Room Fire with Smoke Detectors and Sprinkler Activation Times

Abstract

Smoke detectors, heat detectors and sprinklers are devices associated with fire detection, with smoke detectors being the most widely used in homes. BRANZFIRE is an efficient zone type computer fire modeling software used to simulate fires in multiroom structures. This modeling software can calculate various important variables involved in a fire scenario like the upper layer and lower layer temperatures, optical smoke density, smoke detector, heat detector and sprinkler activation times. A single room, closed door, wall fire scenario is used to run various simulations. The fire is located halfway along the shorter wall and the exterior door is closed. Smoke and heat detectors are located on the ceiling every 0.5 meters away from directly above the fire. Activation times of smoke detectors and sprinklers are calculated for standard t 2 -fires with varying heat release rates: the ultra-fast, fast, medium and slow fires. The model is extended to calculate activation times of smoke detectors and sprinklers with real-world fires for six furniture fire. Three different smoke detector sensitivities are considered in all cases, to exemplify the effect of sensitivity on the activation times. Results obtained from BRANZFIRE simulation indicate that the constrained heat release rate falls below the specified heat release rate in most of the cases, because of lack of availability of oxygen as the smoke descends in the closed room. Smoke detector activation times were compared, for different fires, based on detector sensitivity. It was observed that smoke detector activation times are much lower than heat detector and sprinkler activation times. In the case of medium and slow fires, smoke detector sensitivity plays a more important role in detection times than with ultra-fast and fast fires. This is especially so when the detector is further away from the fire object. Results are also presented and discussed for six different typical items of furniture.