SPOTLIGHT: DRAKA
Cable integrity: In focus If the fire safety of a building is to performto the architect’s and engineer’s expectations - cable integrity is essential.
When it comes to fire- rated cables, three issues are continuing toworry architects, fire engineers, building control officers and installers. Sub- standard counterfeit cables are still being installed rendering some buildings as fire risk ‘time bombs’; insufficient attention is being paid to ensuring that cables have the appropriatemarkings; and there are instances where cables are being installed that do not complywith the relevant British Standard.
legislation and is fit-for-purpose “E
nsuring that the cable installed complies with the appropriate
is everyone’s concern,” Draka’s Mark Froggatt explains. Counterfeit cables can be found where the diameter of the copper wire has been reduced, lowering the current rating and increasing the resistivity of the cable. This could result in overheating, which could lead to fire or reduce the level of safety against electrical shock. There have also been numerous instances where materials other than pure copper, such as steel wire, copper-coated aluminium or badly recycled copper have been used. Instances where the insulation or sheathing is sub-standard are also commonplace. In many cases it’s not easy to
detect a rogue cable simply by looking at it, so corroborate what you are being told or shown, and that the markings on the cable
itself are not misleading, incorrect, or simply downright dishonest. Do not rely on the supplier’s assertions that it is manufactured to a specific standard; ask for copies of test certificates. Better still, use only cable that is supported by independent test certification by organisations such as BASEC or LPCB because, if the cable is from a producer that does not have this third-party accreditation, there is no guarantee that it is manufactured to the standard being claimed for it. This issue is closely linked to
the requirement for cable to carry the correct marking, without which there is no means of establishing its authenticity. In the absence of such marking it is probable that the quality and
performance of the cable is suspect and is from a disreputable supplier. Among themarkings that
should be visible on every cable are themanufacturer’s name and the British Standard number to which the cable claims to conform. Providing the cable has been tested by one, the name of the third-party approval organisation should also be included. However,merely stamping a BS number on a cable is not evidence that it actually complies. Even if a third-party approval organisation’s name is marked on the cable, if there are any doubts whatsoever – particularly if the cable is imported – themarking’s validity should be verified with the approval organisation. The third issue, that cable is
in some instances being installed that does not complywith the relevant British Standard – in this case BS 8519:2010 – is a result of confusion appearing to have arisen fromamisinterpretation of the different testmethods required for power and control cables. The Standard covers the
selection and installation of fire- resistant power and control cable systems for certain life safety and fire-fighting applications. It makes clear reference to three categories of circuit that are required to maintain their integrity under defined fire conditions for fire survival times of 30, 60 and 120 minutes. Appropriate cable tests are identified for each category. However, cables are being promoted as complying with the new Standard and suitable for power applications that have been not ratified in accordance with the relevant Standard, BS 8491:2008. These cables have been tested in accordance with BS EN 50200:2006 and are
suitable only as control cables.
Tel: 01332 345431 Email:
cableuk@draka.com Web:
www.drakauk.com
Draka UK Ltd, PO Box 6500 Alfreton Road, Derby, DE21 4ZH
42 | Architects Choice |
ArchitectNews.co.uk
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