Simulation of critical evacuation conditions for a fire scenario involving cables and comparison of two different cables

Previous studies on the evaluation of irritant species from burning cables in a modified prEN 50399 fire test produced FEC/FED values based on ISO TS 13571. However, the ISO standard mentions in its scope that these indices can only be used within e.g. modelling. For this reason Europacable (ECBL) initiated a preliminary case-study to asses the possibility of using modern fire safety engineering techniques. The scope of the project was the evaluation of the evacuation conditions for a realistic fire scenario involving two types of cable fires that produce different levels of heat, smoke and gases. Both CFD (Computational Fluid Dynamics) modelling by means of the software package FDS (Fire dynamics simulator) and evacuation modelling by means of the software package Simulex were performed. The results were used to calculate FED (fractional effective doses) and FEC (fractional effective concentration). The results showed that the developed methodology allows evaluation of critical evacuation conditions based on not only temperature and visibility, but also on gas composition. One of the selected cables created critical conditions for some of the occupants during evacuation for the chosen design fire when the production of irritant gases (HCl, acreolein, Formaldehydes) is considered