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Low Smoke Zero Halogen Cables from Prysmian Cables UK

Welcome

Low Smoke Zero Halogen Cables from Prysmian Cables UK

Welcome

Low Smoke Zero Halogen Cables from Prysmian Cables UK

Posted: 24th August 2011

Low smoke cable confusion

Prysmian’s FP Product Manager Simon Hopkins discusses the confusion surrounding low smoke cable terminology and how you may not be getting the performance you expect.... 

If it was the case that all products, to coin a certain phrase ‘did exactly what they said on the tin’ then buyers would always get what they expected. Put this into the context of the cable industry. Each cable tagged with the ‘low smoke’ label would meet the same defined and trusted standards and manufacturers would all use the same words and acronyms to describe their products. This is not always so true.

A lot has already been said and done on the issues of unsafe, non-approved and counterfeit cable entering the UK marketplace and of course this is good for everyone. However, it is also important that the details provided by manufacturers to describe their cables’ performance are also accurate and true. For an installer or contractor this is vitally important, as it allows the purchaser to ascertain which products comply with their exact requirements.

For some time within the industry there has been a general agreement on the two phrases ‘low smoke’ and ‘halogen free’. It is pretty obvious what ‘low smoke’ means but with ‘halogen free’ it can be less clear. It may imply that halogens are not present in the materials used to make a cable. However, it is more commonly used, in a combination with the phrase ‘low smoke’, to describe a cable that produces small amounts of halogen acid gas and smoke when burnt.

The worrying thing is, with regard to ‘low smoke halogen free’ cables, there is lack of agreed terminology. A situation exists where reliance on descriptive trade names has resulted in traditional PVC cables being misleadingly described. The result is that purchasers may on the face of it think that they are buying a cable that performs in a certain way based on its name even though a set of industry developed and agreed British Standards are well established. In fact, this can result in the purchase of products which do not have expected performance.

It is well documented that PVC cables, in the event of fire produce aggressive hydrogen chloride acid gas when burnt. If this gas is inhaled or comes into contact with skin or eyes it causes extreme irritation and choking. Not only this, but in a fire PVC cables give off hazardous and dense black smoke that can obscure emergency exit signs and routes, compromising the safe evacuation of buildings.

It is therefore paramount that buyers, installers and specifiers know what they use is up to task. With phrases like LSOH (Low Smoke Zero Halogen), LSHF (Low Smoke Halogen Free), OHLS (Zero Halogen Low Smoke), LSF (Low Smoke and Fume) so widespread and misused within the cable industry it’s easy to see how confusion can arise.

Correctly used, the phrases “halogen free” and “zero halogen” relate to clearly defined test methods and performance requirements. You may think, well great but what does this actually mean? Cables using these terms or acronyms must emit no more than 0.5% halogen acid when burnt. However, purchasers must watch out, as acronyms such as LSOH are increasingly used as generic descriptions despite actually being a trademark.

A problem arises because not all manufacturers use LSOH with the same meaning as the actual trade mark owner. This means buyers can be misled into believing they are purchasing a low smoke halogen free cable as defined by the appropriate tests, when actually they are getting a cable product that will not perform to the required level.

The acronym LSF also needs careful consideration as there are no specific standards for LSF cables. In fact, LSF was also a trade mark used by BICC Cables. It is true to say that this term LSF is sometimes used to describe PVC cable that has been modified. When tested, this type of cable can emit more than 20% hydrochloric acid –significantly more than what would be expected from an LSOH cable.

In summary, when used correctly, the terms “low smoke” and “halogen free” related to precisely defined test methods and results.

“Low smoke” describes a product tested in accordance with BS EN 61034-2. This smoke density test (known as the 3 metre cube test) measures how much light is transmitted through the smoke produced by a burning 1 metre length of cable, where 0% means the light is totally obscured and 100% is full light transmission. A minimum requirement of at least 60% residual light transmission must be achieved.

“Halogen free” describes a product tested in accordance with BS EN 50267-2-1. Under fire conditions these products must emit no more than 0.5 % halogen acid.

The next time you buy, install or specify a low smoke halogen free cable follow these simple pointers:

• Be sure to purchase product from a reputable manufacturer and brand
• Always be certain that the cable bought complies with the relevant British Standard and is approved by third party assessors like LPCB and BASEC
• If no BS product standard exists, look out for compliance with the low smoke and halogen free BS test standards and requirements described earlier, as a minimum.
• Never place an over reliance on acronyms alone as this opens up the possibility of buying a product without the performance you expect and one that could place lives in danger if installed.

Bio:Simon Hopkins graduated in Chemistry and Polymer Science from Loughborough and has spent over twenty years promoting Prysmian Cables (formerly Pirelli) in the Utility and Construction business.
 

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