Background

Research by the industrial members of the Consortium had shown that there was a need for computer modelling techniques to aid in the design of fire detection and non-halon suppression-extinguishment systems. Fixed halon systems are the most common form of fire suppressant, and are used exclusively in aircraft. With the introduction of the production ban on Chlorofluorocarbons (CFCs), aircraft manufacturers and operators require alternative suppression systems. Industry is therefore investigating alternative fire suppression and fire extinguishment systems using water mist, alternative gases and powders. These are significantly different in their operation and behaviour from halon based systems. Marconi Avionics (MAv), as a potential supplier of water mist based systems, has a strong need for tools to reduce the number of fire tests required during the development and certification of these systems. For example, a primary consideration for a water mist system for an aircraft application is the weight of water as this will have a direct effect on the running costs for the airline. The ability to be able to optimise the system for minimum water weight, without the need to conduct fire tests, will both reduce the development costs of the system and reduce airline's operating costs. In addition, data from the fire tests and the computer models would assist in the formation of a European requirement for water mist based fire suppression-extinguishment systems.

Current state of the art fire detection systems have one major drawback: false warnings. Approximately 95% of all reported smoke warnings within aircraft cargo areas are caused by false alarms. New fire detection technology is required to improve reliability and activate the new technology fire suppression systems. Cerberus Guinard (CG), as manufacturers of fire detection systems, requires tools to assist in the design of the new technology fire detection systems to determine the optimum type and location of the sensors for maximum selection effectiveness and reliability.

Discussions between the industrial and academic members of the Consortium concluded that the use of fire field models, based upon Computational Fluid Dynamics (CFD), could provide the basis for the development of these new sophisticated modelling techniques, techniques which could then be used by industry to optimise fire detection and suppression-extinguishment systems.