MODELLING FIRE SCENARIOS IN RESIDENTIALBUILDINGS WITH RESPECT TO THE BENEFIT OFSMOKE DETECTORS AND FLAME RETARDANTS INHIGH RISK ITEMS

摘要

Fire losses in Europe and especially in Germany are still high, in Germany approximately 500 deaths per year. About 80 % of them occur in residential buildings . Smoke detectors are often promoted to reduce these fire losses. Investigations by NIST and SP have shown that smoke detectors have a positive effect on fire safely. Nevertheless, they also revealed that escape times can be very short in residential fires, even down to around 4 minutes. The highly increased usage of flammable plastics and textiles in the domestic environment are probably the reason for this decrease in escape time from about 17 minutes in the 1970s to around 4 minutes nowadays. Recent British and German statistics of home fires revealed that living and bedroom fires are the most relevant fire scenarios because they primarily lead to fatalities.Computer modelling of several fire scenarios in residential buildings shows the benefit of improving the fire behaviour of high risk items like upholstery, mattresses or electrical devices by the use of flame retardants. The mentioned items are often involved in an early stage of the fire. The NIST investigation and two large scale tests performed with the Berlin fire service were used as a basis for the computer modelling using CFD (Computational Fluid Dynamics) techniques. The data were also used for validation of the models. One of the large scale tests was performed in a children's room, because often an accumulation of high risk items can be found in children's rooms. In addition, children tend to behave wrongly in a fire: they cannot judge the risk of a fire and tend to hide instead of escaping once it gets out of control. The results of our computer models show that there is a clear benefit in terms of fire parameters (e.g. Temperatures) and escape time, if flame retardants are applied to selected furniture or electrical appliances. Therefore, we recommend employing both technologies, smoke detectors for alerting people and flame retardants for limiting the actual fire risk.