In terms of Fire Safety Engineering, knowledge of the actual anticipated ﬁre behaviour of the materials in the shell of the building is essential to ensure that ﬁre growth and smoke production are not underestimated.
During a ﬁre, the thermal radiation level is determined using the sum of the permanent and variable ﬁre load. Burning ﬂue gasses are not only vertically discharged, the discharge direction changes under the inﬂuence of wind speed, to almost horizontal. The level of thermal radi- ation on adjoining roofs and exterior walls is therefore subject to the weather and can signiﬁcantly exceed the threshold value of 15 kW/m2. This means that exterior wall and roof surfaces of adjoining ﬁre compartments and adjoining buildings can become ignited. Such a ﬁre scenario is described in, for instance, European standard EN1187, part 3.