In response to the call for the development of risk informed, performance-based building fire regulations, a literature review was conducted to link the traditional safety factor approach in fire safety engineering to failure probability. It can be demonstrated that a safety factor alone is an insufficient measure, or is only a first-order measure of risk or failure probability. To achieve a higher order estimate of failure probability, an -percentile method is proposed. As part of this methodology, it is also proposed that the fire engineering briefing process involve nominations of percentile values for design fire scenarios as well as other parameters that define the scenarios.

A series of full-scale fire suppression tests was conducted at the San Pedro de Anes test tunnel facility near Gíjon, Asturias, Spain in February 2006. The fuel was wooden pallets or a mixed load of wood and high density polyethylene pallets. Fire protection was provided by water mist systems in different configurations. Because of facility restrictions, some scenarios of great interest, such as a free burn fire, could not be investigated. However, in order to complement the experimental results, a number of computational fluid dynamics simulations were conducted on a 140 m section of the tunnel facility. The Fire Dynamics Simulator, version 4, was used for the numerical investigation. An algorithm was developed to allow the fire to spread along the top of a series of pallet loads in such a way that the measured heat release rate was reproduced. Verification and validation studies confirmed that the model predicted the measured ventilation speeds and peak temperatures. The agreement between the simulations and the field measurements was very good prior to activation of the water mist. Back-layering was modeled well. After activation of the mist, the simulations predicted a large drop in gas temperatures, and retreat of the back-layer, but under-predicted the thermal cooling by the water mist downstream of the fire. With the suppression system, high temperatures and heat fluxes were limited to the immediate vicinity of the burning pallets. The model was then used to simulate a free burn fire in the tunnel. The simulation demonstrated the catastrophic conditions created by an unsuppressed fire in a tunnel when compared against the thermally managed conditions under suppressed conditions.

The influence of multiple parameters on smoke exhaust efficiency in an atrium is the subject of this article. Detailed information is obtained through a series of four numerical simulations, all but one case involving a mechanical exhaust system. Quantitative smoke exhaust efficiencies in various cases are evaluated and compared. The investigated parameters include the activation time of the smoke exhaust system, the mechanical fan capacity, the elevation of make-up air inlets and the horizontal location or distributed arrangement of the inlet distribution. It is revealed that all these parameters have impacts on smoke exhaust efficiency to different degrees and hence on the performance of the smoke exhaust system. Improper design and operation may lead to a significant reduction in efficiency. The mechanism that causes the reduction of efficiency is discussed. Velocity and temperature fields are analyzed to reveal the interactions between the fire plume and the inlet jet flows.