Partially exposed steelwork
Standard fire tests have shown that structural members which are not fully exposed to fire can exhibit substantial levels of fire resistance without applied protection. Methods have been developed using this effect to achieve 30 and 60 minutes fire resistance. Where higher periods of fire resistance are called for, reduced fire protection thicknesses can be applied to the exposed steelwork since the heated perimeter is less than that for the fully exposed case.
There are four common ways in which this principle can be used:
Block infilled columns
30 minutes fire resistance can be achieved by the use of autoclaved, aerated concrete blocks cemented between the flanges and tied to the web of rolled sections
Shelf angle floor beams
Shelf angle floor beams are beams with angles welded or bolted to the web to support the floor slab.
Slim floor beams
In the UK there are two main slim floor options, these being SLIMFLOR® and SLIMDEK®
Web infilled columns
60 minutes fire resistance can be obtained when normal weight, poured concrete is fixed between column flanges by shear connectors attached to the web.
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