Steel Buildings in Europe

Part 6: Fire Engineering 6 - 15 Figure 3.2 Sprinkler and its activation 3.2 Passive fire protection The high temperatures induced in a building by the outbreak of a fire affect all construction materials, such that their strength and stiffness is reduced as the temperature increases. It is often necessary to provide fire protection to structural members in multi-storey steel buildings in order to delay the loss of load bearing capacity. Structural members may be insulated by using fire protection materials, such as boards, sprays and intumescent coatings. The performance of these fire protection materials is tested and assessed in accordance with EN 13381 [5] . The thickness of protection required in a given building will depend on the fire protection material selected, the fire resistance period required by national building regulations, the section factor of the member to be protected, and the critical temperature of the member. 3.2.1 Fire protection methods and materials There are two types of passive protection materials, namely non-reactive and reactive. Non-reactive protection materials maintain their properties when they are exposed to a fire. Boards and sprays are the most common non-reactive materials. Reactive protection materials are characterised by a change in their properties when they are subject to fire. The most well known example of this type of protection is the intumescent coating. Boards A variety of proprietary boards, with thicknesses ranging from 15 to 50 mm, are widely used to protect steel members to achieve a 30 to 120 minute fire resistance. Boards are generally manufactured from either mineral fibres or naturally occurring plate-like materials such as vermiculite and mica, using cement and/or silicate binders. Boards may be fixed to steel members either mechanically, using screws, straps and/or galvanized angles, or glued and pinned.