Part 1: Architect’s Guide 1 - 44 Table 6.4 Additional and specific criteria Criteria Additional criteria S Air tightness to cold smoke: Prevents propagation of smoke in fire, even if relatively cold C Automatic shut down: Door, valve or shutter closes automatically M Resistance to impact: Vertical partition to resist lateral mechanical shock Criteria Specific criteria B0 Outlet ducts for smoke (30 min): Outlet duct removes hot gases during the first 30 minutes D Barriers (30 min): Confine hot gases and smoke during initial 30 minutes F Smoke vents (30 min): Remove hot gases and smoke during initial 30 minutes Tests or calculations are needed to demonstrate or justify the fire performance of a building element or product. Tests are defined by standards which define the methods and experiments to be undertaken for a specific type of behaviour. Calculations can be based on conventional approaches (constant increase in temperature over time), or on the new approach to fire safety engineering introduced by the Eurocodes, through advances in knowledge about the behaviour and development of fire. 6.2.4 Passive fire protection methods As with other materials, the strength and stiffness of steel decrease at elevated temperatures. Conventional fire resistance of an unprotected steel section rarely exceeds 30 minutes when subjected to normal levels of loading. Passive fire protection is therefore used to slow down the heating of steel structures in order to give the required fire resistance. A number of systems are available: these are listed below. They provide the steel structure with the appropriate levels of protection, regardless of building end-use. They are sometimes combined. Screen protection Screen protection isolates the structure from an advancing fire by the interposition of elements that form a continuous wall. In a vertical position they serve as wall panels; when horizontal, they are suspended ceilings. All products used must have been tested for fire resistance. The screen should be chosen for its fire resistance properties and can be used for acoustic and thermal insulation, as well as for aesthetic reasons.
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