Fire Experiment Inside a Very Large and Open-Plan Compartment: x-ONE

The traditional design fires commonly considered in structural fire engineering, like the standard fire and Eurocode parametric fires, were developed several decades ago based on experimental compartments smaller than 100 m2 in floor area. These experiments led to the inherent assumption of flashover in design fires and that the temperatures and burning conditions are uniform in the whole of the compartment, regardless of its size. However, modern office buildings often have much larger open-plan floor areas (e.g. the Shard in London has a floor area of 1600 m2) where non-uniform fire conditions are likely to occur. This paper presents observations from a large-scale fire experiment x-ONE conducted inside a concrete farm building in Poland. The objective of x-ONE was to capture experimentally a natural fire inside a large and open plan compartment. With an open-plan floor area of 380 m2, x-ONE is the largest compartment fire experiment carried out to date. The fire was ignited at one end of the compartment and allowed to spread across a continuous wood crib (fuel load ~ 370 MJ/m2). A travelling fire with clear leading and trailing edges was observed spreading along 29 m of the compartment length. The flame spread rate was not constant but accelerated with time from 3 mm/s to 167 mm/s resulting in a gradually changing fire size. The fire travelled across the compartment and burned out at the far end 25 min after ignition. Flashover was not observed. The thermocouples and cameras installed along the fire path show clear near-field and far-field regions, indicating highly non-uniform spatial temperatures and burning within the compartment. The fire dynamics observed during this experiment are completely different to the fire dynamics reported in small scale compartments in previous literature and to the assumptions made in traditional design fires for structural design. This highlights the need for further research and experiments in large compartments to understand the fire dynamics and continue improving the safe design of modern buildings.

Experimental Study on Fire Sources for Full-Scale Fire Testing of Simple Sprinkler Systems Installed in Multiplexes

Fires are accidents that can cause numerous human casualties in multiplexes. The simple sprinkler systems applied in South Korea employ sprinklers to protect people against residential fires, as specified by the National Fire Protection Association (NFPA) standard 13D. Therefore, it is necessary to evaluate the fire control performance of multiplexes, which are at a greater risk than residential facilities. This study aims to verify the fire control performance of simple sprinklers in multiplexes and to develop a fire source that can be used as a protocol for testing fire suppression methods. The fire source was evaluated by using a 3 MW large-scale calorimeter (ISO 13784). The proposed fire source for multiplexes was applied in various forms according to the application methods, with ignition sources including cotton wick, wood crib, and heptane, and then the fire tests were conducted.

Numerical simulation on temperature in wood crib fires

Temperature from burning wood cribs will be simulated in this paper by sub-grid scale model in FDS. A baseline gas phase uncertainty is determined for simulating wood crib fire spread scenarios. This uncertainty is based on a sensitivity analysis of key input parameters and their subsequent effect on key output variables that are important for fire spread. Effects of different grid systems, computing domains and moisture contents on the predictions were studied first and then used to study the gaseous phase sensitivity. The gaseous phase input variables considered are: Smagorinsky constant, Prandtl number, and Schmidt number. The results show that the predictions for temperature have good agreement with experiment with the values of 0.25, 0.7, 0.4 and 5 for Smagorinsky constant, turbulent Schmidt number and turbulent Prandtl number respectively.

Experimental and Numerical Study of Water Mist Fire Suppression System Effectiveness on Shielded Fire

This study aims to investigate the effectiveness of water mist on suppressing a shielded fire. Full-scale experiments are carried out in a partition room of (lxwxh) 2x2x2.5 m size. Five water mist nozzle which consist of two type nozzle was used, high flow (fogjet) nozzle installed at top center of the room and fine spray nozzle installed at each side of room at high 1.5 m from ground. The pressure of water mist system was maintained at 20 bar which correspond to 2.6 lpm of water flow rate. Wood crib of 6.5 x 6.5 x 6 cm size was used as the fuel source. The obstruction used as a fuel shield has table like form with 40 x 40 cm cover area and 0.5 m height. The location of fuel source and fuel shield was varied (1) fuel source and shield at centre of room, (2) fuel source at one side of shield and the shield at centre of room, (3) fuel source and shield at corner of room, and (4)) fuel source at one side of shield and the shield at corner of room. Numerical simulation using FDS 6.5.3 was also performed to validate the use of FDS and get better understanding of the phenomena. The results showed that water mist was able to extinguish the fire around 20 s, 16 s, 30 s, and 24 s for scenario 1, 2, 3 and 4 respectively. It is also observe that the mist distribution around the shield and cover area of the shield play a role on the capacity and time needed of water mist to extinguish the fire.