Steel Buildings in Europe

Part 2: Concept Design 2 - 47 h h l l l l 0 0 0 0 0 0.25 h h h 0 0 0.7 h h h h h 0.5 0 0.4 0 0.8 2.5 Figure 5.7 Limits of sizes and spacing of circular and rectangular web openings 5.3.3 Services integration Service ducts may pass through openings in the web of the beams. Ducts for air conditioning are approximately 400 mm deep, but vary between manufacturers. Larger service units, wh ich are typically 450 mm deep, but up to 750 mm for variable air volum e (VAV) units can be situated between beam s. The overal l depth of the floor zone will be typically: 1000 mm for 13,5 m span beam (with 300 mm deep web openings) 1200 mm for 15 m span beams (with 400 mm deep web openings) 5.3.4 Fire protection Fire protection may be in the form of board protection or intum escent coating (intumescent coatings can be applied o ff-site as a single coating up to 1,8 mm thick in order to achieve 90 minutes fire resistance), as illustrated in Figure 5.5. 5.4 Cellular composite beams with composite slab and steel decking 5.4.1 Description Cellular beams are beam s with circular openings with regular spacing along their length, as illustrated in Figure 5.8. The beam s are m ade by cutting and re-welding hot rolled steel sections. Openings, or ‘cells’, are normally circular, which are ideally suited to circular du cts, but can be elongated, rectangular or hexagonal. Cells may have to be filled in to create a solid web at positions of high shear, such as at supports or either side of point loads along the beam.