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Physical experiments and computer simulations are commonly employed to characterize and understand fire behaviour under different conditions. Many medium- to large-scale physical experiments utilize standardized wood cribs as the fire load, while corresponding computer simulations require physical and combustion properties of such fire loads. The design of physical experiments and accuracy of computational models depend heavily on the underlying combustion models. The current study proposes an improved two-step combustion model for soft and hard wood based on physical characterization of different wood samples. Two different types of wood, i.e. softwood and hardwood were characterized using cone calorimeter. Total of six cone tests were performed under irradiation levels of 30, 50 and 75 kW m−2 for each wood sample. Thermogravimetry analysis (TGA) of wood samples was carried out to estimate the combustion kinetic parameters (through different estimation methods) like activation energy, pre-exponential factor, and reaction order for numerical simulation of cone calorimeter tests. The kinetic parameters estimated through the Kissinger–Akahira–Sunose integral method were utilized to perform computer simulation of TGA and cone calorimeter in fire dynamic simulator (FDS) using one-step and two-step combustion models. Thermal degradation temperatures of both the types of wood were observed to be between of 200 and 500 ℃. During whole pyrolysis process, softwood was observed to possess larger activation energy than that of hardwood. The reaction models for softwood and hardwood were found to be diffusion type with reaction order of 2–3. TGA simulation results obtained by the two-step simulation approach were found to be better than that of one-step simulation approach. In case of cone calorimeter simulations, the two-step simulation approach yielded better prediction of heat release rate and time to ignition as compared to that of the one-step simulation approach. It is expected that the present study would be helpful in large-scale FDS fire simulation involving softwood and hardwood. [ABSTRACT FROM AUTHOR]

This paper investigates aluminium composite panels (ACPs) to understand the fire behaviour of combustible cladding systems under different fire scenarios. A fire dynamics simulator (FDS) is used to develop the numerical model of full-scale fire tests of combustible cladding systems using the procedures of the British BS 8414.1 standards. The results obtained from the FDS models are verified with test data. Seven test scenarios are investigated with four distinct parameters, i.e., cavity barrier, air-cavity gap, panel mounting (with and without joining gaps between the panels), and material combustibility qualities. A critical air-cavity gap (50–100 mm) is established at which maximum fire spread is noticed. Furthermore, variations in the cavity barrier, panel mounting, and material combustibility significantly impact the rapid fire spread of ACP cladding systems and the internal failure criterion. The results from the present study can serve as a basis for future research on the full-scale fire-test development of combustible ACPs. [ABSTRACT FROM AUTHOR]

Summary: This paper develops a Fire Dynamics Simulator (FDS) model to analyse fire spread for informal settlements, based upon full‐scale experiments. Informal settlements are frequently ravaged by fires, leaving thousands of people homeless, and with more than 1 billion people residing in informal settlements, there is a significant need to understand and improve the fire safety in such areas. Due to high levels of uncertainty inherent with input parameters regarding informal settlements, this work also investigates the sensitivity of fire behaviour to the input parameters used in numerical simulations. It is shown that spread times between two dwellings can vary from 1 minute after flashover to no spread at all, depending on the simulation input parameters selected. This paper highlights the importance of such input parameters when trying to model fire spread between dwellings. The simulations indicate that a simplified fire spread model for informal settlements is possible, especially for steel clad dwellings, however it showed that significant work is required for timber clad dwellings, that is, because the rate at which additional ventilation forms in the simulation for the timber clad dwellings is significantly slower than reality, which is as a result of the simplifications made. The simplification of using heating, ventilation, and air conditioning (HVAC) systems to model leakages, resulting from the corrugated flutes, showed good enclosure fire dynamics behaviour compared to the experiments, but created new challenges with regards to the spread mechanism, since HVAC systems do not allow electromagnetic waves to penetrate in the same manner as an opening. [ABSTRACT FROM AUTHOR]

Summary: The impact of sustainable building features on fire safety can be positive, neutral, or negative. An expert group ranked double skin facades (DSF) as being high risk due to a lack of knowledge of strategies to prevent fire and smoke spread through a DSF. Computational fluid dynamics modelling of prototype buildings with a 0.5 and 1.0‐m‐wide DSF has been carried out. External and internal vents to the DSF have varied in size and location, as well as the fire location, whether the building is fitted with sprinklers and other variables. The sensitivity of the model to grid resolution was checked using the 2 extremes of ventilation. Provided the vents to the DSF close in a fire, and flashover does not occur in rooms adjoining the DSF, or sprinklers are installed, smoke spread to higher floors via the DSF is limited. If a building is designed so the vents to the exterior from the DSF are greater in effective area than those from the interior to the DSF smoke flow will be predominantly to the outside of the building, and fire engineering design is likely to show that occupants will have time to escape. [ABSTRACT FROM AUTHOR]