The publication of the 3rd amendment to the 17th Edition (BS7671:2015) Wiring Regulations states (in Chapter 52 â€“ Selection and Erection of Wiring Systems) under section 521.11 that â€śWiring systems in escape routes shall be supported in such a way that they will not be liable to premature collapse in the event of fire.â€ť This becomes mandatory for all non-domestic installations from 1st July 2015.
In Note 1, there is particular reference to failure of non-metallic trunking leading to cables hanging across access/egress routes hindering evacuation/fire-fighting activities.
In Note 2, it specifically states this precludes the use of non-metallic clips, cable ties or trunking as the sole means of support. For example, where a non-metallic cable trunking is used, a suitable fire-resistant means of support must be provided to prevent cables falling out in the event of fire.
Prior to this, it was already a legal requirement (BS5839 Part 1) that surface mounted Fire Performance cables must be secured using metallic fixings which withstand the same temperatures and vibration as the fire resistant cables, maintaining adequate support for the cables in a fire.
Designers and installers will now have to use non-combustible methods of cable containment and restraint for all cables in any and all areas of a building that can be considered an escape route. This might include general office/retail space as well as the usual corridors, stairwells, service corridors etc., which form part of an escape route.
TheÂ Safe-D Clips
The Safe-D Clips, manufactured by D-Line, haveÂ been tested by Warrington Fire, confirming compliance to BS5839 Part 1 Section 26.2dâ€“ resistance to fire with mechanical shock and resistance to fire with mechanical shock and water spray. The tests confirmed that Safe-D Clips, when containing two Fire Performance 1.5mm 2 core cables, and subjected to 930Â°C (+40 -0Â°C) for two hoursÂ at a voltage of 500V rms, enable the cables to maintain circuit integrity.
The clipsÂ are manufactured from high temperature steel with a gold passivated finish that can withstand mild corrosive elements â€“ in ceiling voids for example. Once fastened directly onto the building structure or fixed within plastic trunking, tabs on the Safe-D ClipsÂ can be easily folded to secure two cables. Fixing time is halved as one clip fits two fire performance 2c 1.5mm, compared to fixing one P-clip per cable.
The company has extendedÂ the range and size of these certified clips for use inside and outside of proprietary non-metallic trunking in readiness for the 1st July 2015.
The clips comply with BS 5266 for installation of emergency lighting â€“ especially in retrospective works that become necessary following reassessment of installations carried out to a previous version/standard.
Furthermore, the clips will assist in complying with BS8519 (designed to increase the protection of emergency and fire personnel as well as evacuees). Â BS8519 impacts on all the components in the cable systems such as fixings and containment methods so that they do not compromise the circuit integrity in the event of a fire. The publication of the 3rdÂ amendment to the 17thÂ Edition (BS7671:2015) states in (Chapter 52 - Selection and Erection of Wiring Systems) under section 521.11 that â€śWiring systems in escape routes shall be supported in such a way that they will not be liable to premature collapse in the event of fire.â€ť