Steel framed glazed windows can be designed and installed to protect life and property in the event of fire. Combining the transparency of glass with fire safety is a challenge that demands high standards of construction, which is then independently tested and assessed by recognised competent authorities.
Some of the standard window ranges have been examined by Warrington Fire Research (reports available upon request) to meet such standards and are illustrated in this Data Sheet, which summarises key features of construction, indicates a variety of appropriate glass types, and gives pointers to their scope of application. They use hot rolled profiles from the SMW, W20 and W40 ranges to provide fire-resistant glazed fixed windows, which will maintain their integrity in a typical fire for 30 or 60 minutes.
Glazing systems are tested in accordance with BS476: Part 22: 1987 "Methods for determination of the fire resistance of non-load−bearing elements of construction" and assessed with respect to their ability to satisfy the performance criteria referred to in paragraph 7.6.1: integrity and insulation.
The integrity criterion is satisfied when, for the required duration, a test specimen neither collapses nor develops cracks or apertures through which can pass flame or hot gases.
When fixing windows, perimeter fixings must be no more than 150mm from corners and maximum 450mm (30 minutes integrity) / 250mm (60 minutes integrity) centre to centre. Fixings should be made through the frame and be affixed to good structural openings of either brick, block, concrete masonry or steelwork which should have both stability and integrity greater than the window frame. Should lugs be required to fix the windows - these should be at least 25mm wide x 2mm thick steel.
All fire-resisting glazing is to be set onto non-combustible setting blocks and is to be secured by cold-formed 0.6mm thick steel channel beads which are snapped over steel mushroom head studs and are finished at corners with corner cover clips. All studs placed at maximum 75mm from corners and maximum 300mm centres. Ceramic or mineral fibre tape to be placed either side of glass edge and is to be capped with intumescent silicone / acrylic sealant.