Wylex nmfs intumescent

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NMFS Intumescents & Accessoriesfor use in Consumer Units forDomestic Household Premises

Amendment No. 3 BS 7671

Wylex_NMFS_6pp.qxp 12/11/2015 09:37 Page 3

New RegulationRegulation 421.1.201 in Amendment 3 (January 2015) requiresconsumer units (and similar equipment) to have enclosuresmade from non combustible materials (Steel) and the purposeof this new regulation is to (as far as reasonably practicable)contain any fire within the non combustible enclosure and tominimise flames from escaping.

Market ReactionThose involved in this market e.g. social landlords, electricalcontractors appreciate the fire containment capabilities of noncombustible enclosures but have expressed concerns overcable entries, because these unavoidably penetrate the noncombustible barrier that is formed by the steel enclosurethrough the removal of cable entry knockouts.

Installation practices may result in a reduction in the capabilityof the enclosure to contain any fire that may occur, with theconcern being that a fire path could exist along the cables andthrough the cable entries to other combustible materials in thesurrounding areas.

IET & BEAMA GuidanceThe IET and other industry organizations have partly addressed these concernswith advice for installers to ensure that the requirements of BS7671 &BSEN61439-3 are met i.e. that the installed consumer unit achieves IP4X on thetop elevation and IP2XC elsewhere.

Good workmanship and proper materials must be applied by the installer. Thecable installation entry method shall, as far as is reasonably practicable, maintainthe fire containment of the enclosure.

This can generally be achieved by the installer ensuring that the cable accessholes they make in the enclosure do not leave gaps greater than:

l 1.0mm for the horizontal top surface and

l 2.5mm for all other surfaces

The installer could for example, select as they deem appropriate; trunking,conduit, cable gland or cable entry accessories to minimise the opening aroundthe cables.

For rear cable access, the minimum number of rear knockout(s) shall be removedto accommodate the cable(s).

However, customer questions remain as to what further steps could be taken toensure that the necessary cable entries do not undermine the intention of thisnew and important fire safety requirement.

NMFS INTUMESCENTS, NON COMBUSTIBLEENCLOSURES & RETRO FIT UPGRADES


Intumescents & How It WorksIntumescent material when exposed to heat rapidlyexpands and fills the surrounding area effectivelysmothering fire and preventing spread by extinguishing flames.

The Wylex SolutionWorking with a leading UK manufacturer ofintumescents, Wylex have introduced the NMFS rangeof intumescent material strips which fit inside theconsumer unit (self adhesive). If this intumescent stripis exposed to heat the fire resistant “char” flowsaround the cables filling the enclosure smothering thefire by reducing the oxygen supply further, soextinguishing the fire at source.

Other ConsiderationsOnce expanded this highly insulating char alsorestricts the heat of any fire from reaching the steelenclosure of the unit and thus minimises the externaltemperature of the units.

This is an important added consideration. If the unitwere unprotected by intumescents and should a fireremain unchecked and undetected within a steelenclosure it is possible for the external surface toreach temperatures that can ignite surroundingmaterials that are in contact with those hot surfaces.

By incorporating the NMFS material a metal consumerunit does not reach such temperatures.

With NMSF

Without NMSF

Auto ignition cotton material

TIME (1000 seconds = 16 minutes)

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Background & Other ApplicationsThe potential fire risk with insulated consumerunits has clearly been demonstrated by thefindings of London Fire Brigade, however theuse of plastic consumer units is still permitted incommercial (non domestic household)applications.

As with the steel consumer units the fitting ofthe NMFS intumescent strip dramaticallyreduces the risk of these units from causing afire to propagate.

In testing carried out by BM Trada / ChilternInternational Fire Ltd, an unprotected plasticconsumer unit ignited after a few minutes.Whilst the same unit with the NMFS strip fittedran for 90 minutes with very limited damage tothe external unit or elevated temperatureswhich could lead to ignition occurring. TheNMFS intumescent char was seen to fullysmother and insulate the heat source from therest of the unit minimising the chance of firepropagation.

NMSF intumescent strips can address theconcerns of specifiers and installers alike andprovides an additional means of reducing theeffect of a fire.

We are not endorsing intumescents withinplastic consumer units as a solution for newinstallations. However local authorities andhousing associations with a large installed baseof insulated units and an extended conversionprogramme may see this as a low costenhancement of an existing consumer unit.

With NMSF

Without NMSF

Auto ignition cotton material

Without NMSF flame are visibleexternal to enclosure at 7mins

TIME (1000 seconds = 16 minutes)

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visiblemins

Insulated unit after 90 minutes testing withintumescent installed.


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l Wylex NMFS intumescent strips were designedand developed in association with Tenmat, aQueens Award winning fire protection company,for use with Wylex consumer units

l NMFS intumescent strips are fully tested under themost onerous conditions by UKAS approved firelaboratory BM Trada / Chiltern International Fire Ltd.

l NMFS intumescent strips will dramatically subdue orfully extinguish any fire which may occur in a steelconsumer unit and exceed the requirements andintentions of Amendment 3 Regulation 421.1.201

l NMFS intumescents have a 30 year lifespan

l NMFS can be fitted in seconds - self adhesivestrips with no special tools required

l Tests confirm the intumescent suppresses firepropagation and reduces the enclosure surfacetemperature

l Use with Wylex EIU mains tails gland & NMCEsemi blind cable entry fittings

l Include NMMB (non combustible blank in unusedways) for maximum non combustible performance

l Suitable for use with NH upgrade kits(replacement cover & lid assembly) for retrofitto existing NH metal cased units

INTUMESCENT STRIPS

CONSUMERCAT REF PRODUCT UNIT WIDTH

NMFS07 Intumescent fire barrier 7MOD 188mmNMFS10 Intumescent fire barrier 10MOD 241mmNMFS13 Intumescent fire barrier 13MOD 292mmNMFS16 Intumescent fire barrier 16MOD 343mmNMFS21 Intumescent fire barrier 21MOD 438mm

Application guidance covering the full consumer unit range is available from Wylex Technical Department

FIRE RETARDENT MEMBRANE CABLE ENTRIES

CAT REF PRODUCT

NMCE1 Membrane cable entries kit 1 3 x 32mm & 7 x 20mmNMCE2 Membrane cable entries kit 2 10 x 20mm

MAINS TAILS GLAND

CAT REF PRODUCT

EIU Moulded cable gland kit for metal consumer unit toprovide additional support and supplementaryinsulation similar to Class II construction for theincoming cables.

Suitable for 16mm2 or 25mm2 double insulated cable 32mm knockout

As recommended in the IET On Site Guide

NON COMBUSTIBLE BLANK

CAT REF PRODUCT MODULE

NMMB Metal blanking plate - Twist fit 1

Test criteria in metal consumer units included the use of Wylex membrane cable entries and mains tailsentry glands as recommended in the IET On-Site-Guide 2015, furthermore Wylex recommends use of noncombustible way blanks to ensure that as much of the enclosure as possible is manufactured from noncombustible materials.


ELECTRIUM SALES LIMITED A SIEMENS COMPANYCommercial Centre, Lakeside Plaza, Walkmill Lane, Bridgtown, Cannock WS11 0XE.

eMail: [email protected] Web: www.electrium.co.uk

UK SALESTelephone: 01543 455020 Facsimile: 01543 455021 eMail: [email protected]

TECHNICALTelephone: 01543 438320 Facsimile: 01543 438321 eMail: [email protected]

EXPORT SALESTelephone: +44 1543 455049 Facsimile: +44 1543 455048 eMail: [email protected]

Although every effort has been made to ensure accuracy in the compilation of the technical detail within this publication, specifications and performance data are constantly changing. Latest details can be obtained from Wylex.

Publication No. WY2255 11/15Printed in England.


Wylex nmfs intumescent

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