For fire incidents that occur within a building, we utilise a Fire Dynamic Simulation (FDS) to assist in determining the fire origin as well as having a better visualisation of the situation for our clients.
FDS is a computational fluid dynamics model of fire-driven fluid flow. It is a computer program that computes large eddy simulation, which is the mathematical model for turbulence in computational fluid dynamics, emphasising on smoke and heat transport from fire and describing the development of fire.
Figure 1
In this case, we present the case of a fire within a consumable store. The simulation suggested that the fire was initiated from the top middle timber wall partition of the consumable store (red arrow).
Figure 2
Figure 3
At 35.1 seconds, the fire started to spread towards the east and smoke started to fill the ceiling of Level 1 (Figure 2) and reached an elevated temperature of 1000°C at the surrounding area. At 454.5 seconds, the fire started to roll over, the smoke, filled up the ceiling layer creating a ceiling jet (Figure 3).
Figure 4
The fire continued to develop and resulted in the temperature of the ceiling jet at the entire Level 1 to exceed 600°C. At 498.3 seconds, the walls of RDWP, aluminium and door materials stores were ignited and as the fire consumed oxygen, insufficient oxygen at the middle caused the fire inside the consumable store to be extinguished. This decreased the temperature in the middle of the consumable store to around 300°C.
Figure 5
Eventually, at 1238.4 seconds, the entire Level 1 was filled with smoke, flame front concentrating at the north and south sides of the store, with temperatures reaching 1000°C, and most of the timber walls of the store were consumed by the fire.
Due to the location of store walls at the periphery, the fire was more intense here, depriving the centre from oxygen. Only after the fire had fully consumed the periphery walls, the fire started to travel back towards the centre, particularly along the timber partition of consumable store.
In this phenomenon, the timber partition of consumable store was exposed to prolonged heat for a period of time, causing severe damage to the ceiling which exposed the rebars.
Aside from the helps of FDS, we have also conducted the process of elimination, of which the team has taken several steps such as visiting the burnt site and photographing evidence, collecting samples, and acquiring witness statements to rule out the possible causes of fire to the consumable store. After detailed analysis of the case, ForSci has concluded that the root cause of the fire was electrical failure.
