Fighting Fire With Technology
17 September 1999
FIGHTING FIRE WITH TECHNOLOGY
The Building Research Association is fighting fires not with hoses, but with sophisticated computer technology.
BRANZ has developed its own computer program to see how buildings can be better protected from fire, in a fire science and engineering project which is an investment of the Public Good Science Fund.
"We have two main aims: to reduce deaths and injuries resulting from fires in buildings, and to reduce the cost of providing fire protection in buildings, while maintaining accepted standards of safety," says Colleen Wade, who is leading the project.New Zealanders have about $200 billion invested in buildings.
BRANZ's new computer program, BRANZFIRE, models overall fire development. The model predictions are being compared with similar experiments by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia and with Swedish experimental data.
A fully functional, developmental version of BRANZFIRE is presently being assessed by industry practitioners.Ms Wade says BRANZ aims to reduce deaths and injuries by ensuring that fire does not spread prematurely downward through fire-rated floor-ceiling systems.
"This research project entailed a real-scale fire experiment in a ‘firecell’ [specially constructed room] consisting of walls of timber frame with paper-faced gypsum plasterboard linings and a complete floor-ceiling system," she says.
Measurements during the experiment recorded the relative rates at which fire spread through the walls, floor and ceiling. Another project aims to reduce fire deaths and injuries from uncontrolled fire spread on exterior cladding materials.
"This entailed developing an improved method of predicting fire-spread and potential hazards associated with exterior cladding materials. To find the necessary data, full-scale ‘flame spread’ experiments were done using exterior cladding products and systems typically found in New Zealand," Ms Wade says.
"The results prompted recommendations for changes to New Zealand Building Code Acceptable Solutions. It is now proposed to develop a design procedure for fire engineers to be better able to select external wall cladding based on fire engineering principles, including the building geometry and fire size," she says.
A fourth project aims to reduce the cost of providing safe and effective lightweight fire barriers in buildings. "A user-friendly design method is also being developed for predicting the fire-resisting performance of lightweight timber-framed interior and exterior walls in real fires. The work entails developing a computer model for predicting the heat transfer and structural behaviour of timber-frame wall construction in a fire," she says.
Part of this project entails describing the thermal properties of framing and lining materials (such as gypsum plasterboard and particleboard), including the effects of charring and erosion of materials during the fire.
Colleen Wade, fire researcher, BRANZ. Ph: (04) 235-7600
Patricia Donovan, Ph 04-498 78 09 Mobile 025 226 4136