SUPPLEMENT FEATURE CABLING & CABLE MANAGEMENT LSHF and LSF are not the same


Confusion still remains surrounding the difference between LSHF / LS0H (low smoke halogen-free / low smoke zero halogen) and LSF (low smoke and fume) cables. Here, FS Cables outlines the fundamental differences


C


orrectly specified, both products offer a solution but it’s crucial to know when


and where it’s appropriate to use them. LSHF cables are those that give off less


than 0.5% hydrogen chloride gas when burnt, compared with around 28% from traditional PVC cabling. Hydrogen chloride gas can be deadly and poses great risk to both people and equipment in buildings in the event of fire. LSF in data and signal and control


cables is usually a modified PVC compound which, while producing slightly less hydrogen chloride gas and smoke than standard PVC, is still a significant threat. Don’t be confused or take the risk - if


the job specifies LSHF, then LSF cables will not perform to the correct level in the event of fire. You could be putting lives at risk.


LSHF BUYERS GUIDE When specifying cable for installations in confined areas, computer rooms and other sensitive environments, low smoke halogen-free cables offer significant advantages over traditional PVC. Hospitals, airports and train stations are some examples of areas that can be


LSF (Low Smoke & Fume)


Ideal For: • Outdoor installations • Low risk residential buildings


• Areas which are easier to evacuate in the event of fire


Should Not Be Used:


• Not suitable for public or commercial buildings or areas that are difficult to evacuate in the event of fire


• Near sensitive electronic equipment


• Not to be used where LSHF, LSOH, LSZH or OHLS has been specified


Benefits: • Flexibility – LSF compound is based on PVC and is generally much more flexible than LSHF


• Cost – cheaper to produce and faster to manufacture than LSHF


• Availability – standard product available from many manufacturers


S6 JUNE 2014 | CABLING & CABLE MANAGEMENT Benefits:


• 0.5% hydrogen chloride gas emission for safer environments


• Increasingly a wide range of cables is becoming available in LSHF


• Choose a specialist manufacturer or distributor who can provide you with datasheets or test reports


FS Cables www.fscables.com T: 01727 840 841


difficult to evacuate in the event of fire. It is now recognised that smoke and poisonous fumes can pose a greater threat to life and property than the fire itself. Standard PVC cables are made up of


halogens which, when burnt, give off toxic gases such as hydrogen chloride. When exposed to water/moisture in the air or fire sprinkler systems for example, hydrogen chloride forms highly noxious and corrosive hydrochloric acid. The effects of burning PVC are two-


fold. Firstly, the dense smoke produced can reduce visibility and obscure exit routes. Secondly the harmful hydrogen chloride gas given off is dangerous to people and also has a corrosive effect on electronic equipment - potentially causing random, unpredictable failure over a period of time. Specifying low smoke halogen-free


(LSHF) cable goes a long way to reducing this risk. LSHF cables are those which emit negligible amounts of halogens when burnt and have reduced smoke emission properties. Compared with around 28% acid gas


emissions of standard PVC, LSHF cables give off less than 0.5% HCl (Gases Evolved During Combustion BS EN 50267, IEC 60754-2). Visibility through smoke emission is measured through a 3m³ smoke test (pictured below) to IEC 61034. Confusion still surrounds the


Above: the difference between LSF (top) and LSHF (above) LSHF (Low Smoke Halogen Free)


Ideal For:


• Public buildings – hospitals, schools, commercial buildings, airports, train stations


• Computer rooms, datacentres – anywhere close to critical electronic equipment


• Buildings where evacuation in the event of fire could be slowed


Should Not Be Used:


• Where impact resistance or high flexibility is required


• Where the cable is exposed to harsh weather conditions or high levels of UV


terminology used to describe LSHF cables and caution should be exercised when specifying. While LSHF, LS0H, LSZH and 0HLS are the same, it is important to note that LSF is not. LSF (Low Smoke and Fume) often refers to modified PVC compound which can still emit up to 22% HCl and should be regarded as only slightly better than PVC in the event of fire. Also beware standard PVC cables


which are over-sheathed with a LSHF compound. When the jacket burns through the PVC inner sheath or insulation will give off poisonous fumes in just the same way. The FSC range of LSHF cables are LSHF


throughout - insulation and sheath. If you are unsure of what you are


buying, ask for written confirmation that the cable is LSHF throughout.


Enter 239 / ELECTRICALENGINEERING


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