بررسی تجربی پارامترهای ریسک آتش‌سوزی برای تعدادی مصالح ساختمانی پلیمری و ارائه یک روش جدید طبقه‌بندی

Fire is a potential threat for all buildings. It can produce life and property losses and even ending to fail of the building. Therefore; fire safety is one of the most important requirements in design and construction of buildings. In other side, the use of polymeric building materials has been considerably developed in construction industry in recent years. Most of these materials are highly flammable and can seriously contribute to growth of probable fires in buildings. Hence; it is needed to evaluate the fire behavior of these materials and restrict their application in buildings, if they show a high contribution to fire growth. In this research, the fire behaviors of 10 polymeric building materials were studied with cone calorimeter at 50 kW/m2. The reaction to fire properties of the burned specimens were presented and discussed. The correlations between the acquired fire parameters were evaluated. This could assist in analysis of the fire growth risk of the specimens. The fire risk of the tested materials was evaluated with different methods, including methods proposed by Richardson, Östman and Nussbaum, Petrella and the software program conetools. The results were compared and it was revealed that there were some disagreements. The reasons of these disagreements were discussed. The most tested materials showed a dangerous behavior against the fire. They released considerable amount of heat and high peaks of heat release rate. Especially epoxy, MDF, HDF and polycarbonate samples showed high potentials for contribution in fire growth. The results showed that the time to ignition, heat release rate and total heat release are the least fire parameters that should be considered in any fire risk classification method. The time to ignition has an important influence on flame spread on the linings and on time to flashover in the room of origin of fire. Disregarding the time to ignition in any classification method, as it can be seen in that proposed by Richardson, could result in incorrect predictions of fire risk of materials. A new classification method for reaction to fir of materials is proposed in this paper. In this method, the combustibility of materials is evaluated when they are exposed to a radiant heat flux 50 kW/m2 for 15 minutes. The method is an improved version of the method given by Richardson. The peak of heat release rate, total heat release and propensity to flashover (i.e. the ratio of the peak rate of heat release to the time to ignition) are used for classification of fire risk of materials in this method. It is fairly simple and does not need fire tests in medium or large scales (like SBI or room corner tests). It is proposed for use in chapter three of building code of Iran, which is allocated to fire safety of buildings.