Steel Buildings in Europe

Part 7: Fire Engineering 7 - 61 First, the equivalent fire duration is determined using this method. With the equivalent fire duration, a relationship between the incendiary effect of a natural fire and the “Einheitstemperaturzeitkurve” (ETK standard temperature time curve) is generated. The equivalence refers to the maximum temperature of structural components under a natural fire. Once the equivalent fire duration has been determined, two different methods are available. The first method is to determine the maximum floor surfaces using Table A.2. No requirements for fire resistance of structural components are needed when using this table. The second method requires somewhat more effort. First, the maximum floor surface is calculated using a formula. In this procedure, the fire resistance rating of the structural components has to be proven. This is done with the necessary fire resistance. Table A.2 Maximum floor area (m 2 ) according to safety category and equivalent fire duration Equivalent fire duration Safety category 15 30 60 90 K1 Without requirements 9000* 5500* 2700* 1800* K2 Fire detection 13500* 800* 4000* 2700* K3 Rescue service 1600-22500* 10000-13500* 5000-6800* 3200-4500* K4 Fire suppression (Sprinkler system) 30000 20000 10000 10000 Minimum heat extraction area 1 1 3 4 Maximum building width 80 60 50 40 In Table A.2, the maximum admissible floor surface can be defined with reference to its safety category and the equivalent fire duration. In addition, the corresponding heat extraction surface can be identified, indicated as a % of the floor surface and the corresponding maximum width of the building. Using the second method for the entire verification procedure, the maximum floor area (m²) is calculated using the base value for the surface area of 3000 m² and factors F1 to F5. A = 3000  F1  F2  F3  F4  F5 where: F1 the equivalent fire duration F2 the safety category F3 : the height of the lowest floors