Cable Management ●From previous page

asphyxiants present in smoke. When PVC burns it releases hydrogen chloride (HCl) gas, which is classed as a toxic irritant. Experiments have shown that, unlike for example CO, it is impossible to continue sleeping when HCI is present, even in harmless concentrations. Understanding LS0H (low smoke zero halogen) specs or requests is

also really important to ensure the correct product is selected. Zero halogen solutions generally refer to cable sheathing, are intended to produce less toxic/dense smoke and are most often installed in sensitive environments such as underground rail systems etc. LS0H (or LSZH) does not, however, mean the product shares the same desirable fire hazard properties as PVC-U. If there are good reasons why a zero halogen solution is required, the installer/client should make sure that a suitable balance is achieved with fire performance properties. Marshall-Tufflex offers more than 40 PVC-U, aluminium, GRP and steel

systems, ensuring that specifiers and clients are able to find the perfect trunking solution for their projects. It also offers a class-leading range of fire specific products:

Firefly Fire Safety Clips Proposed revisions to BS 7671 of the UK Wiring Regulations (section 521.10.202) due for issue in July, expand the need to avoid the risk of entanglement from just escape routes to all areas. The regulation states: “Wiring systems shall be supported such that they will not be liable to premature collapse in the event of fire”. The regulation must be read in context with Notes 1-4 within 521.10.202 to fully understand its requirements, not least the definition of a wiring system and locations to be protected.

Marshall-Tufflex offers a class-leading range of fire specific products.

Callmaster Accessory boxes designed for emergency applications including call points, smoke and heat detectors, panic alarms, warning lights, sounders and emergency stops. Supported by mini trunking and conduit in red.

BS 7671 requires wiring systems to be supported by fire-resistant fixings and fastenings to prevent cables collapsing in extreme heat.

However, electrical

contractors will be required to

use metallic clips (such as Firefly), ties or saddles to support qualifying wiring systems. This applies throughout an installation, not just the escape route. Firefly clips prevent cables falling in the event of a fire, ensuring escape routes are free from hazards. Designed for use within mini trunking, maxi trunking and conduit, they

are spring-loaded for easy installation/removal of cables and designed to offer quick installation and to maximise internal trunking space. They are fire resistant above 1,000°C for up to 120 minutes, far exceeding the requirements of 45 minutes at 930°C.

Fire barrier pads Dry lining boxes available with Envirograf intumescent (fire barrier)

pads. With fire barrier pads fitted, boxes comply with the requirements of BS7671IEE Wiring Regulations and Document B of the UK Building Regulations. BS 7671 requires wiring

systems to be supported by fire- resistant fixings and fastenings to

prevent cables collapsing in extreme heat. More recently the focus has shiſted to the performance of PVC-U cable management in the event of a fire, with specific questions asked about the use of surface mounted plastic wiring systems in older residential buildings.

24 | electrical wholesalerJune 2018

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