When applying containment methodology to original or older buildings the most important elements to be upgraded are the doors, floors and walls, penetrations (metal conduits) through floors and walls, and cavity barriers in the roof spaces. During a fire, smoke and heat are forced through any gaps or openings due to the air pressure in the compartment. Traditionally these gaps were filled with bricks and mortar or shutters, etc. but now, as discussed previously, intumescent materials are used. Cavity barriers Voids or cavities pose another problem in buildings. These allow smoke and flames to spread, generally unnoticed through a building. To prevent such fire spread the cavity needs to be compartmentalised. Fire-retardant material or blankets are used across the entire cavity space to create a fire barrier, which can restrict the fire spread to some degree. The below images show the compartmentation materials being used in a roof void in a terraced property. This typical cavity barrier installation in a roof space has been retrofitted to an existing property and is designed to give a specific integrity performance to reduce fire spread. To prevent radiated heat from igniting adjacent material, the barrier is set back from the roof truss, timbers passing through the barrier are protected for some distance on either side, and the roof space is kept clear of debris. The illustration that follows shows the installation of fire-retardant materials in a 'stud' , or internal partition wall.
©SHEilds – All rights reserved FC V 5 JUN 2021
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