Electrical Contracting News (ECN) July 2017 - Page 42

SPECIAL FEATURE FIRE DETECTION & SAFETY CLIP ON TO SAFETY Ever since 2005 when two firefighters lost their lives tackling a fire in a block of flats in Stevenage after one became entangled in electrical cabling, the industry has been moving towards metal cable clips as an alternative to plastic. This event also led to the amendment of BS7671 of the Electrical Regulations, a body of legislation which states that wiring systems should be supported in such a way that they will not collapse in the event of a fire. This is particularly relevant for escape routes. However, while the industry has been forced to adopt metal fixings for public buildings in line with this legislation, these rules do not cover commercial buildings, where plastic cable clips are still being used in earnest. Jasmina Prill, associate product manager fastenings and fixings at HellermannTyton, looks at why metal cable clips should become best practice for industry. U nder BS7671 of the Electrical Regulations, cabling in public buildings must be supported by fire resistant fastenings and fixings, which are not liable to premature collapse when exposed to extreme heat. This means that plastic cable clips, non-metallic cable ties and plastic trunking to support wiring systems are no longer compliant with electrical standards. Instead, these new rules address the greater need for safety when it comes to cable management and support in or near escape routes. It is now the responsibility of the electrical contractor to ensure that all cables and associate trunking, conduits, and cable trays, are securely attached to suitable fire resistant parts of the building fabric, using non-combustible fixings. Whilst this is now mandatory for public buildings, electricians should be making this best practice for all projects, particularly for commercial projects. Installers are advised to seek products which meet high standards of fire resistance, particularly for escape routes and areas that may be at risk of fire. 42 | July 2017 Plastic vs metal: A heated debate One of the strongest arguments for the use of metal nail clips is the improved safety that these provide when compared with plastic clips. Products such as HellermannTyton’s new metal nail clip for example, can withstand temperatures of well over 1,000°C, whilst the melting point of plastic is typically 170°C. This means