بررسي تجربي خطرپذيري آتش‌سوزي و همبستگي پارامترهاي خطر آتش‌سوزي براي برخي مصالح ساختماني پليمري

An Experimental Assessment of Fire Hazard and Correlations of Fire Parameters for Some Polymeric Building Materials

رفتار ده ماده ساختماني پليمري در برابر آتش با گرماسنج مخروطي در تابش kW/m2 50 آزمايش شد. خطرپذيري اين مواد در آتش‌سوزي شامل حرارت و دود آزاد شده، با روش هاي گوناگون بررسي و بحث شد. بيش‌تر مواد بررسي‌شده، رفتار خطرناكي براي آتش داشتند. از ديد حرارتي، نمونه هاي MDF، موكت و اپوكسي و از ديدگاه دود و سميت، نمونه هاي پلي‌كربنات و اپوكسي بسيار خطرناك نشان دادند. بنابراين براي به كار بردن اين مواد در ساختمان بايد مقررات مناسب، تدوين و محدوديت‌هاي كاربرد آن‌ها مشخص شود. پارامترهاي حرارتي ناشي از سوختن مواد، با هدف ارزيابي خطر آن‌ها در گسترش آتش‌سوزي بررسي شد. نتايج نشان داد كه پارامترهاي زمان افروزش، شدت رهايش گرما و كل رهايش گرما، مهم‌ترين ويژگي‌ها براي تعيين خطر گسترش آتش‌سوزي است. زمان افروزش بر زمان وقوع گُر گرفتگي در اتاق و سرعت پيشروي سطحي شعله بر نازك‌كاري‌ها تاثير مهمي دارد و ناديده گرفتن آن مي‌تواند به پيش‌بيني اشتباه خطر گسترش آتش‌سوزي منجر شود. از ديدگاه سميت، منحني منوكسيد كربن كنار پارامتر سميت مي تواند براي ارزيابي خطر سميت به كار رود.

The use of polymeric and flammable building materials has been considerably increased in construction industry of Iran in recent years. Most of these materials are highly flammable and can seriously contribute in growth of a probable fire in buildings. In this research, the fire behavior of some polymeric building materials used as finishes was evaluated with cone calorimeter method at 50 kW/m2. The thermal fire parameters and smoke toxicity produced from the burning specimens were assessed; including time to ignition, flaming duration, peak of heat release rate, total heat release, smoke production rate, average specific extinction area, carbon dioxide and carbon monoxide production. The correlation between the thermal parameters was discussed and it was concluded the total heat release had direct dependence on combustible nature of the material and the surface density and reverse dependence on time to ignition. Meanwhile, the fire toxicity hazard parameters including carbon monoxide production rates and smoke toxicity were evaluated. The smoke toxicity was expressed in terms of the two parameters: fractional effective dose (FED) and toxicity index (LC50). The obtained results showed that the most tested materials had a dangerous behavior in case of fire and can cause flashover in the room. They released considerable amount of heat with high peaks of heat release rate. Especially epoxy, MDF and polycarbonate samples showed a high potential for contribution in fire growth. In addition, the epoxy, PVC and polycarbonate produced the highest amounts of smoke and carbon monoxide. It should be noted that the production amount of carbon monoxide was measured in an open system in which air is circulated with a certain velocity. So in a real fire, these values can be accumulated and increased in the room of fire. Among the tested samples, polycarbonate (PC) and PVC flooring (PVC-F) showed the highest value of FED, however it seems that the assessment of carbon monoxide versus time could provide more important information for assessment of smoke toxicity. The results showed that it is needed to regulate the fire behavior of building finishes and restrict their application in buildings. For this purpose, a fire risk classification was needed, which will be studied in further steps of the research.