Steel Buildings in Europe

Part 7: Fire Engineering 7 - 34 where: p c is an empirical coefficient (depending on the slope of the roof and the type of steel structure )          Frames Lattice for Frames Portal for 1,45 slope 1,10 for 10% slope 1,16 for 5% slope 1,19 for 0% p c n eff is a coefficient related to the total number of heated bays n in the fire compartment (see Table 5.4) q is the linear load on roof [N/m] (equal to the load density multiplied by the spacing between frames) applied on the beam and calculated in fire situation ( q = G +  1  S n ), where G is the permanent load including self-weight of the steel frame and service overloads, S n is the snow load and  1 is the load factor according to load combination coefficients defined in EN 1990 and corresponding national annexes.  is the span of on heated bay connected to the column [m] Table 5.4 Values of coefficient n eff Portal frame Lattice Frame Setting of compartment in fire Setting of compartment in fire Number of bay in fire end middle end middle n = 1 n eff =0,5 n eff =1,0 n eff =0,6 n eff =1,0 n  2 n eff =1,0 n eff =2,0 n eff =1,0 n eff =1,0 Where columns of the steel frame support a boundary fire wall, columns should be designed (providing adequate robust base to columns) to resist a horizontal force calculated according to equation (29) but using n eff = 1,0. 5.5.2 Lateral displacements at the fire compartment ends In the event of fire, movements of steel single-storey buildings can be of the order of several tens of centimetres and therefore could lead to the failure of façade or the partition element if it is not sufficiently ductile or not accurately fixed. So it is important to check that façade elements and fire walls in contact with the steel structure are compatible with the lateral displacements developed at the ends of fire compartments and that they keep their integrity to avoid the collapse towards outside and the progressive collapse between different fire compartments