Novel full-scale atrium fire experiments and numerical validation under steady and transient venting conditions

A new set of 27 full-scale fire tests carried out in the "Fire Atrium" are presented and described. The facility was completely instrumented with 59 thermocouples to study and analyze the smoke behaviour, by varying the heat release rate (HRR), the fire location, the exhaust flow rates, the openings distribution, and the make-up air velocities. Different time dependent exhaust flow rates were also tested by acting on the four fans with two extraction velocities. Additionally, some asymmetric inlet vent configurations allowed to measure relevant fire swirls. The fuel mass loss rate measurementes, with load cells located under the pool fires, were crucial for the numerical characterization of these formations.
A selection of four fire tests ranging from 2.4 MW to 5.2 MW, under different steady and transient exhaust condititons, and make-up air configurations are numerically compared with FDS. The temperatures in the fire plume and in the far field, close to a wall of the atrium are assessed. A good agreement has been found, especially in the far field. The dynamic smoke layer interface behaviour is also evaluated by means of the least-square and the n-percent methods, being also numerically well predicted.