Ignoring the 17th edition wiring regulations can be fatal…
“999, what is your emergency?…” At around 3am on 2nd February 2005 a fire was reported in a fourteenth floor flat of Harrow Court tower block, in Stevenage. Two unextinguished tea-light candles left burning on top of the plastic casing of a television caused the TV to ignite, in turn engulfing the bedroom in a 900°C blaze.
Three dead – two brave firefighters in the line of duty and the trapped mother-of-two they were trying to save.
How could this happen?
Plastic trunking had melted causing cables to drop across the doorway of the flat creating an impenetrable web-like barrier, invisible amidst the frantic activity and thick black smoke.
Fire Brigade Union’s report devoted a section specifically to ‘Cable Support Failure’, concluding that the Social Housing provider may have contributed to deaths in that they may have failed to ensure their contractor complied with BS5839-1 2002; clause 26.2(f)…’. Harrow Court investigations make repeated reference to how the cabling of the alarm had become insecure as a result of it being secured by plastic-only and not metal clips, this being a factor attributable to the loss of life.
What was it like to be there?
Surviving support crew recalled the conditions ‘like a jet engine coming out of the flat’, their horrific testimony described finding their entrapped colleague ‘tangled and twisted up with cables… that were coming down from the ceiling… like he was stuck to the ground… with cables across his front, but mainly behind him…melted onto his breathing apparatus set and tunic’. Melted cable insulation had adhered to the inside palm of his glove.
The air supply in breathing apparatus depletes quickly in such desperate conditions, from a maximum of just 35 mins. Firefighters protective clothing doesn’t make them invincible; the protective qualities are measured only in terms of minutes, and in extreme fire situations such as backdrafts, the terms go down to seconds and becomes more about minimising injury.
This was a one-off… right?
Sadly no, in November 2007 four firefighters died in a vegetable packing warehouse in Warwickshire. Arson allegedly started the blaze, which reached 600°C in six minutes. Again plastic conduit had melted allowing cables to fall. Survivor’s testimony recalled ‘my hands starting to scald in wet gloves… conditions were so poor I couldn’t see where the cables were coming from’.
The helmet torch of one firefighter became entangled in cable, there are suspicions also that the hosereel may have caught on the cables – when seconds make all the difference lost time can cost life.
Again tragedy struck again in 6th April 2010 in the a ninth floor flat of Shirley Towers in Southampton. As the fire spread rapidly through its phases, plastic trunking all around the flat melted. One firefighter managed with assistance to escape cable entanglement with burns. Two were entangled inside the flat as ‘cables fell between their cylinder and breathing apparatus set making it extremely difficult to move without assistance’. Despite managing to cut the wires and drag colleagues out of the flat for emergency treatment, the fallen cables – which had severely hampered rescue efforts – proved fatal as both had been fatally exposed to the excessive heat of the inferno. HM Coroner recommended all social housing providers replace plastic only cable containment with support conforming to BS5839 part 1 : clause 26.2 (f) as a minimum.
What can be learnt from these deaths?
The Institution of Engineering and Technology (IET) published BS7671: 2008 Amendment 3. Section 521.11) stating ‘Wiring 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.’
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 precludes the use of plastic cable clips, ties or trunking ‘where these products are the sole means of cable support’.
Amendment 3 of BS7671 (which covers general wiring regulations) has effectively widened legislation to ensure ALL cables in escape routes are secured using non-combustible fixings.
How can I comply?
For several years D-Line have pioneered market-leading fire-rated solutions for holding cables in PVC trunkings or direct to substrates. Now Safe-D® Clips can secure bundles of cable in PVC trunking profiles up to 50mm wide.
Are Safe-D® Clips fully certified as fire-rated?
Yes! To provide assurance and peace-of-mind, all 3 sizes of Safe-D® Clip have been certified by Exova Warringtonfire confirming compliance to the highest standards of BS5839-1 section 26 (e) – 2 hour tested at 930°C (+40 – 0°C) while maintaining circuit integrity. Tests confirmed that all Safe-D Clips, when containing Enhanced Fire Performance 1.5mm 2c cables, and subjected to 930°C (+40 -0°C) for 2 hours at a voltage of 500V rms, kept the cables secure and maintained their circuit integrity. Safe-D Clips withstood required levels of shock, vibration and water spray.
Note the 2 hour test is significant, as it affords the maximum time usually required for the evacuation of buildings classified as ‘BD4: High density occupation, difficult conditions of evacuation’.
Maintaining circuit integrity means for example that supplies to mains-wired emergency lighting, detectors and alarms will not be compromised by cable failure. Safe-D Clip certifications ensure compliance to all other standards and regulations relevant to BS7671 Amendment 3.
As a life-safety issue, for peace-of-mind certified products should always be used… where actual recorded tests in fire conditions confirm that the assured material and the design will always be suitable and fully fit-for-purpose.
Are all metal clips suitable?
No! Stainless Steel for example can fail above 538°C, so unsuitable in typical fire conditions, clips with untreated edges will corrode if exposed to any condensation.
Are there any equivalent fire-rated solutions?
Safe-D Clips have no equivalent! From start-to-finish Safe-D Clips provide an exceptional consistency of performance and installer-experience – we’ve supplied millions over the past 10 years without a single reported failure.
- Safe-D Clips are manufactured in the UK using specific high-temperature pliable steel produced to BS EN standards with full traceability.
- Unlike punch-cut zintec versions with raw edges, Safe-D Clips have a passivated finish to protect against corrosive elements, and minimise the risk or rust-failure.
- Compared to narrower push-over tabs, Safe-D Clips all feature 20mm tabs-widths; while the specific pliable-gauge and smooth-rounded corners (as required by design code BS7671 522.8.11) protect both cables and installers; making Safe-D Clips the quickest and easiest to install.
What is an escape route?
An escape route is a route designated for escape to a place of safety in the event of emergency. These may include not only defined routes such as corridors, stairways and hallways, but also open areas through which escaping persons might reasonably be expected to need to pass on their way to a place of safety.
How does this affect me?
As in the case of Harrow Court, Authorities investigate the chain of responsibility to assign accountability for fatalities. Urged by the pleas of grieving families, duty Authorities inspect every decision made and who made them. Specifiers, designers, contractors and asset managers etc. all have a duty of care to adhere too.
We don’t have the time – How long does it take to install Safe-D Clips?
Just a second or two, they can be fixed in-tandem with trunking while fixing to the substrate. And it might save hours spent needing to retro-fit an installation, inspected as non-compliant – and save danger to reputation, of a job discovered not to be of British Standard.
When seconds make all the difference it is worth spending a few more – clip and comply to save lives!
For more information, go to www.d-line-it.co.uk