Steel Buildings in Europe

Part 2: Concept Design 2 - 47 7.3 Standing seam sheeting Standing seam sheeting has concealed fixings and can be fixed in lengths of up to 30 m. The advantages are that there are no penetrations directly through the sheeting that could lead to water leakage and fixing of the roof sheeting is rapid. The fastenings are in the form of clips that hold the sheeting down but allow it to move longitudinally (see Figure 7.4). The disadvantage of this system is that less restraint is provided to the purlins than with a conventionally fixed system. Nevertheless, a correctly fixed liner tray should provide adequate restraint. 3 1 2 1 Outer sheet 2 Insulation 3 Standing seam clip Figure 7.4 Standing seam panels with liner trays 7.4 Composite or sandwich panels Composite or sandwich panels are formed by creating a foam insulation layer between the outer and inner layer of sheeting. Composite panels have good spanning capabilities due to composite action of the core with the steel sheets. Both standing seam (see Figure 7.4) and direct fixing systems are available. These will clearly provide widely differing levels of restraint to the purlins. The manufacturers should be consulted for more information. 7.5 Fire design of walls Where buildings are close to a site boundary, most national Building Regulations require that the wall is designed to prevent spread of fire to adjacent property. Fire tests have shown that a number of types of panel can perform adequately, provided that they remain fixed to the structure. Further guidance should be sought from the manufacturers.