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Building Products April 2017

SECURITY AND FIRE PROTECTION APRIL 2017 | BUILDING PRODUCTS 61 basement, ground floors and upper storeys that are no more than 5m from ground level. Any storeys that are between 5m and 18m will require a 60min. fire resistance, as will compartment walls for separating buildings. Storeys of 18m and above require 90min. to 120min. of fire resistance. Various solutions exist to meet the Building Regulation requirements however it is not possible to fully meet these requirements without adopting an approved system. A collaborative approach to building is required and it is important to ensure the construction interface details between walls, floors and the external envelope are designed to help with fire compartmentation. Despite the Buildings Standards suggesting that the wall and ceiling both require the same minimum fire resistance for residential dwellings, the actual specification of these elements often differs, and this is where a system cannot be beaten for fire resistance. While the first consideration in fire protection is always for the individuals at risk; the occupants, emergency workers or passers-by, the second objective in design is to try and minimise the structural damage sustained in the event of a fire. The principle means of achieving a fire resistant construction element is to maintain the element’s loadbearing capacity. The amount of resistance required is a common misconception. Fire resistance periods are stated in terms of minutes so as to ensure that if a fire does occur, the loadbearing capacity of a building will continue to function until all occupants have had enough time to escape. When determining resistance requirements the size, height and usage of the building are taken into account. For residential developments, fire resistance of at least 30min. is required for storeys that are no more than 5m from ground level. Any storeys that are between 5m and 18m require 60min. of resistance but this can be reduced by 30 minutes if a sprinkler system is installed. Requirements rise again from 18m when upward of 90min. and 120min. of fire resistance is necessary. A combination of materials is used to achieve fire resistance. This includes structural elements, insulation materials and plasterboard lining. Focusing on plasterboard, resistance can be achieved with the use of specially design fire panel, plasterboard capable of withstanding fire and maintaining the structural integrity of the building long enough for occupants to escape. The thickness and density of the plasterboard plays a significant part in this fire resistance. A single layer of 15mm plasterboard for example offers up to 60min. of fire resistance and this rises to 120min. when two layers of 12.5mm plasterboard are used. Mandeep Bansal is Technical Services Manager at Knauf


Building Products April 2017
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