Steel Buildings in Europe

Part 6: Fire Engineering 6 - 21 Table 3.5 Typical depths and spans of composite floors Trapezoidal steel decking Re-entrant steel decking Single span Double span Single span Double span Required fire Resistance (minutes) Depth (mm) Span (m) Depth (mm) Span (m) Depth (mm) Span (m) Depth (mm) Span (m) 60 140 3,8 140 4,2 101 3,0 101 3,4 90 150 3,1 150 3,3 105 2,9 105 3,3 120 160 3,1 160 3,4 115 2,4 115 2,9 3.3.2 Integrated beams Integrated beams are part of a floor construction system where the steel beams are contained within the depth of an in-situ or pre-cast concrete slab, instead of supporting the slab on the top flanges of the beams. Consequently, the overall depth of the floor construction is minimized. The whole steel section, except for its bottom flange or plate, is insulated from the fire by the surrounding concrete. Figure 3.8 ASB - Integrated beam (rolled asymmetric steel beam) Figure 3.9 IFB - Integrated beam (I-section with a plate welded to its bottom flange) d d