EuroWire May 2016

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May 2016 14
With the terms LSF and LSHF often interchanged due to the
misconception that they are acronyms for the same thing, the
Approved Cables Initiative (ACI) is warning contractors and
installers to be cautious of cable labelled or described as LSF as
this does not mean “halogen-free”.
The ACI believes that the two terms – LSF and LSHF – are
routinely and sometimes deliberately misused, and contractors
wanting to purchase halogen-free cable should look for LSHF (or
manufacturers’ equivalents) to ensure compliance.
LSF (Low Smoke and Fume) was developed nearly 40 years ago
in response to a demand for a cable product that, if burned,
offered lower hazard levels than existing PVC. Such materials
were a first attempt to answer the call for cables which would
give off lower amounts of acidic and corrosive gases in a fire, but
these cables were not and are still not halogen free.
LSHF (Low Smoke Halogen-Free) materials have excellent flame
resistance but, when affected by fire, have low emission of
smoke and low emission of corrosive gases or have halogen-free
materials. Such materials are not based on PVC.
In the UK, LSHF cables for fixed wiring applications are most
commonly available to the following standards:
• BS EN 50525-3-41 – Single core wiring cables (although
the standard does not include chemical tests for halogens
specifically)
• BS 7211 – Flat wiring cables (only tested for pH and
conductivity of smoke and not specifically for halogens)
• BS 6724 – Armoured 1kV cables (only tested for pH and
conductivity of smoke and not specifically for halogens)
• BS 8573 – Non-armoured 1kV cables (only tested for pH and
conductivity of smoke and not specifically for halogens
The most relevant standards that cables might need to conform
to in order to achieve LSHF rating are:
• BS EN 61034-2 (smoke emission)
• BS EN 60754-2 (pH and conductivity)
• BS EN 50525-1/BS EN 60754-1 (halogens)
BS 7671 (The Wiring Regulations) gives in Table 4A3 of the
edition amended in 2015, a complete list of the specified
standards with suitable cables for fixed wiring. All of these
are either LSHF or PVC types. There are none that relate to the
original concept of LSF.
To be sure of the correct cable choice where Low Smoke
Halogen-Free is specified, the ACI is advising contractors and
installers to:
• Check that your LSHF is genuinely halogen-free and is
manufactured to the appropriate standard
• Avoid anything described as “Low Smoke and Fume” or just
LSF
• Look for independent third party approval via bodies such as
BASEC.
Approved Cables Initiative – UK
Website:
ACI’s warning on LSF cables