WIXLIB

1.4Mineral fibre (MF) cores are used in avariety of panels for walls, ceilings and internalcompartment wallsPolystyrene (PS) has been used as a corematerial for over 30 years mainly for panelsused internally and for Cold Store panelsPhenolic (PF) cores have been used onselective projects for internal walls and ceilings.Other features ofinsulated panelsInternal panelFixing and securementTwo other features of insulated panels have aninfluence on fire performance and fire riskassessment. These are: External envelope panels, compartment wall andsome lining panels are securely fixed through thefacings to the structural framework of the building.This means that in the developing stages of a firethere is no collapse exposing a combustible coredue to the delamination of the facings as a resultof exposure to high temperatures. (Section 3)the manner in which panels are joined toadjacent panels andthe way panels are secured to the buildingframework or supported in other ways.Panels used internally are generally designed to befreestanding and often interlocking without fixingsto a supporting structure. Ceiling panels are oftensupported on the wall panels and may have theadditional support of hangar systems connected tothe external face of the panel or to a gridframework into which the panel is placed. As thefire develops and the temperature rises, theunrestrained facings buckle with the result that thecore can become increasingly exposed. (See 4.3Fire risk assessment)Panel-to-panel jointsComplex joints such as those used for theexternal envelope are fully engineered joints thatare designed to be weathertight and to preventair leakage. Their robust interlocking naturecombined with secure fixing to the buildingframework simultaneously gives better protectionof the core from direct flame attack.For internal panels, which do not have towithstand wind forces and driven rain, a moresimple tongue and grove arrangement is used thatalso aids the demountability and relocation of thepanels. These internal panel systems are mainlyused in a freestanding form to create anenvironmentally controlled internal space.External: Typicalengineered jointInternal: Simplertypical T&G JointPIR (LPCB certificated systems) from 2004 andsome IACSC system designs (4) from 1999 arerequired to have an approved structural support torestrict early collapse and exposure of the corematerial.1.5Alternative namesInsulated Panel is now the generally acceptedterminology for the panels covered in this Guide.Other terms used to describe insulated panels are‘Composite’ and ‘Sandwich’. ‘Composite’ is usedthroughout construction to refer to anycombination of materials that may be classed as a‘panel’ or might also be assembled on site andtherefore not a true panel. The other commonlyused term was ‘Sandwich’ panel, especially in thefood processing industry. It is still a terminologyused in the rest of Europe but has been replacedin the UK by ‘Insulated Panel’ in recent years.5

2Insulated Panels in buildingsExternalInsulated panels can be divided into twomain groups: Panels designed for the external roofs andwalls of buildingsPanels designed for use internally (see 2.3)The 2005 Regulatory Reform (Fire Safety) Orderstates that insulated panels used in buildingsshould be assessed as a possible ‘source of fuel’when undertaking a fire risk assessment.2.1IndustrialExternal roofs and wallsInsulated panels have over the past 15 yearsbecome the preferred choice for the externalmetal cladding of a wide range of buildingsacross virtually every construction sector.10 million m2 per year are installed and manybuildings in each sector will have insulatedpanels for the roof and/or walls.Since their introduction in the 1970s, insulatedpanels have been predominantly used in: EducationFactories and industrial premisesWarehouses and distributionWorkshops and transport depotsRetail: out-of-town stores; and distributionFrom the 1990s insulated panels have beenincreasingly used in the following areas: Offices, particularly low/medium storey heightLeisure including stadia, sports halls, cinemasEducation – schools, colleges and universitiesOfficeHotels, apartments and studentaccommodationHealth – smaller hospitals; hospitalextensions; clinicsTransport buildings – airports, bus stations,motorway servicesRetail6

2.2Which panels are used on the external envelope?Table 1 provides a useful summary of the types of panels and the core insulants that can be found in thevarious external applications.There are few hard and fast rules as many of panels can be specified for a variety of applications. Guidelinesand hints on how to identify the different types of panels, or even whether it is a panel, are given in Section 5.Table 1 External building envelopeSummary table – Use of the various types of Insulated Panels [IPs] by Construction Sector.SectorRoofFactories andwarehouses andretail distributionExternal wallPIR (LPCBPUR coreCan bePIR (LPCBPUR corecertified systems) pre 2004 confused with: certified systems) pre 2004MFcorePScoreRare in IPsAll IPsAll IPsSite assembledsystems(see 5.2)Most IPsMost IPs 10%of IPsOfficesAll IPsAll IPsSite assembledsystems(see 5.2)Majorityof IPsMajorityof IPsin20% Occasionallypanel unitsof IPs infill(see below)Retail –especially largeout-of-townAll IPsAll IPsSite assembledsystems(see 5.2)Most IPsMost IPs 10%of IPsLeisure –stadia, sportshalls and cinemaAll IPsAll IPsSite assembledsystems(see 5.2)Education,Health, Hotels,ApartmentsAll IPsAll IPsSite assembledsystems(see 5.2)Most IPsMost IPsOccasionally in 10% infillpanel unitsof IPs(see below)Transport –depots, hangarsworkshops, etcAll IPsAll IPsSite assembledsystems(see 5.2)Most IPsMost IPs 10%of IPsTransport –transit buildingsAll IPsAll IPsSite assembledsystems(see 5.2)All 3 core materials usedAll 3 core materials usedGuidance notes to accompany Table 1Roofs. This is probably the most straightforwardarea as all the roof panels used in the UK have aPIR or PUR core. The main consideration is toconfirm that it is an Insulated Panel and not a siteassembled or ‘built-up-system’ roof. Guidance onthis is given in Section 5.Walls. Again the first step is to confirm that thewall is an Insulated Panel and not a site-assembledsystem (Section 5). The majority of panels in mostsectors will have a PIR (LPCB certificatedsystems) or PUR core. MF cored panels have beenused to a much lesser extent in all sectors. PSRare in IPsCan beconfused with:Site assembledsystems(see 5.2)Site assembledsystems(see 5.2)Occasionally in Site assembledinfill panel unitssystems(see below)(see 5.2)Rare in IPsSite assembledsystems(see 5.2)Rare in IPsSite assembledsystems(see 5.2)cored panels occur rarely in external wall claddingsand also as infill panels.Infill panels. Curtain walling systems generally usean assembly for the opaque elements comprisingthe external facing, insulation (slab) and an internallining. However Curtain Walling ‘stick’ systems usefactory produced infill panel units of the samewidth as the window module and often with thetwo metal skins glued to the insulating corematerial. Historically the three main insulants – PS,PUR and MF were used. From 2002, PIR and MFhave been the predominant choice.7

22.3Insulated Panels in buildingsInternalInternal walls and ceilingsInsulated panels used internally account for lessthan 5% of the total panel usage. There are threeprincipal applications: As the walls and ceilings of internalcompartments to control temperature andhygiene.As lining panels, generally within existingbuildingsAs separating, usually fire resisting wallsbetween different sections of a building.Panels designed for internal use are similar indesign to those for external applications with theexception of the joint (Section 1.4). This isgenerally a simple construction designed for easeof construction and demountability to enablechanges in configuration and layout to be maderetrospectively.Internal walls2.4Which panels are usedinternally?Table 2 provides a useful summary of the types ofpanels and core insulations that can be found inthe various internal applications. The mostfrequent use of panels has been in foodprocessing; controlled assembly areas; and somefactories, warehouses and retail distribution.There are few hard and fast rules as all theinsulation types have been specified for most ofthese applications.Guidance notes to accompany Table 2Internal compartments – box within boxThese compartments are common within thefood processing industry and also in someindustries where a ‘clean’ environment is required.Wall panels are generally freestanding andinterlocking and are not connected to asupporting framework. Ceiling panels are generallysupported by the wall panels with the addition ofsupporting hangers where larger spans are used.Panels incorporating a polystyrene (PS) coredominated this type of application until the mid1990s, when substitution by PIR and MF panelsstarted due to concerns about fire performance.A number of fires where PS cored panels wereused extensively for the box-within-box type ofconstruction have highlighted the particular dangersthat may be associated with this form of insulationand construction, particularly where the core canbe exposed and contribute to the fire hazards.Lining panelsPanels used for lining are similar in terms of corematerials and joint design to the compartmentpanels described above. The performance in fire willin general be similar to the compartment panels.Internal – environmental room8NOTE: Aluminium foil faced lining boards shouldnot be confused with metal-faced insulated panels.Foil facings offer little protection and any fire riskassessment should be carefully considered if theselining materials are used.

Separating wallsInsulated panels are sometimes used as an alternative to the more general masonry compartmentwall constructions. These panels have varying degrees of fire resistance and are fully supported on astructural frame. Core materials are predominantly MF with some PIR (LPCB certified systems).Performance in fire is similar to that of the MF and PIR (LPCB certified systems) panels used for theexternal envelope (see Section 3).Table 2 – Internal building applicationsSummary table – Use of the various types of Insulated Panels [IPs] by Construction SectorSectorFactories andwarehouses andretail distributionFactories –food preparation,packaging,handling etcOfficesRetail –especially largeout-of-townLeisure – stadia,sports halls andcinemasInternal wall and ceilingPIR (LPCBcertified systems)MFcoreOccasional useOccasional useTransport –transit buildings;motorwayservices etc.SeeFoodFactoriesbelowMF panelsPS panelsPIR LPCBhave replaced PSusedin manycertified panelspanels in areasfood factorieshave graduallyaround hotpre 1995replaced PSprocesses andreducing inpanels from 1995 elsewhere fromrecent years1995PIRcoreMFcoreSomePIR panelsused forComp. wallMajority ofpanels forComp. wall areMF panelsAs aboveAs aboveFew IPs used internally in this sectorInternal wall liningPIR (LPCBMFPScertified systems) core coreOccasional useOccasional use———Few IPs used internally in this sectorAs aboveAs above———Few IPs used internally in this sectorAs aboveAs above——————Education,Health, HotelsTransport –depots, hangarsworkshops, etcPScoreCompartment wallFew IPs used internally in this sectorFew IPs used internally in this sectorSomeLPC PIRMF Panelsmost likelyto be used—As aboveAs above————MF Panelsmost likelyto be used———Note. Phenolic (PF) cored panels have also been used in small volumes as internal walls and ceilings in some food factory and cold store applications.9

33.1Performance in fire of Insulated PanelsThis section summarises the latest research andinformation on the fire performance of InsulatedPanels for both external cladding and internalapplications.The following have to be taken into consideration:Fire Safety Assessment under the RegulatoryReform (Fire Safety) Order is primarily concernedwith life safety and the prevention of fire. This isdifferent from assessing a building from theviewpoint of property protection or that of theFire Services where the fire is likely to be fullydeveloped rather than a developing fire. For lifesafety the prime focus is on the evacuation ofoccupants and on the safety of the fire rescueservice, which is mostly related to the earlierphases of the fire. Therefore, full account has to be taken of the factthat the major source of heat, smoke and toxichazard at the critical personnel evacuation phase ofa fire, in buildings clad in PUR, PIR and mineral fibrepanels, is created by the other materials involved inthe initial fire. It is these hazards that are mostlikely to be critical in terms of life safety and whichshould be the principal element of the Fire SafetyAssessment.Factors affecting performancein fire of insulated panelsInsulated Panels consist of an insulating corebonded to two metal facings as described in section1.1. The core can be made of various insulatingmaterials, ranging from limited-combustibility tocombustible and highly combustible. InsulatedPanels are considered by the Regulatory ReformFire Safety Order to be one of the potentialsources of fuel and therefore have to be assessedas part of the Fire Safety Assessment.10 IntroductionSecondly, in a fire safety assessment, theperformance of the panel should be viewed inrelation to the performance of the specific buildingarea, and should take into account the scale and fireload of the building contents and all other sourcesof fuel.3.2 In order to complete a Fire Safety Assessment it isessential to understand the way Insulated panelsmay perform in fire in its particular application. 3.3The type of panel and its core insulating materialWhether the panel is securely fixed orfree-standingFactors that have a direct influence on thescale of the fire i.e. type and magnitude of thefire load of the contents of the buildingOther factors such as open edges or cut holesthat expose the core and could influence thecontribution of any combustible core materialto the fire and which might affect the FireSafety Assessment.Influence of the type ofpanel systemThe metal facings of insulated panels effectivelyprotect the insulating core. The primary influencein the fire behaviour is temperature, the severityof the effect increasing with rising temperature,especially where the flames impinge directly onthe panels. Differing fire hazards are associatedwith each of the common types of insulation(PIR; PUR; MF; PF and PS see 1.3) used inInsulated Panels.External claddings with MF and PIR (LPCBcertificated systems) that are LPCB approved toLPS 1181 are regarded by the Association ofBritish Insurers as satisfying the original grade 2construction rules or be classed as a noncombustible building. (Note: This does not implythat the material is non-combustible)In a fire the following may occur, Production of smoke, less with MF, PIR (LPCBcertificated systems) and PFBuckling and delamination of the facings butnot necessarily collapse where the facings arefixed to the frameworkCharring and burning of non-meltingcombustible materials – PIR (LPCB certificatedsystems) and PUR – but not in amounts thatmay significantly contribute to the fire growth

Burning, shrinking away from the steel andmelting of combustible materials such aspolystyrene (PS) at an earlier stage withquantities of smoke and some potentialcontribution to fire growth particularly wherethe fire impinges on the panel.In a developing fire, the fire will generally belocalised and the temperatures lower. At this stagethe core of the Insulated Panels is protected bythe metal facings unless the temperature causesthe facing or panel to collapse, e.g. with somefreestanding PS cored panels where the core isseriously affected at temperatures below 180 C.For this reason it is important to distinguishbetween panels used for the external envelopethat are securely fixed to the building frameworkand remain in place to protect the core andinternal panels that are often freestanding orsupported on other panels. In the case of internalpanels the potential for collapse has to beconsidered in the Fire Safety Assessment.With regard to fire prevention, the mainconsideration should be to keep any combustiblecore materials protected and the panels securelyfixed to prevent collapse. Guidance on this pointcan be found in Section 5 on Fire RiskAssessments and within the DCLG Guides onRR(FS)O.Fire performance ofexternal panels3.4“Observation & recording – The tests generate anaverage heat output of 510KW and a max outputof 1MW sufficient to represent a fire in the laterstages of development”“Buckling of the internal lining occurs in all panelsbut joints stay essentially intact”assessment and life safety.The results indicate that: Information from Fire TestsExtensive large-scale fire tests on a range ofinsulated panels have been carried out by EPICin conjunction with the major test laboratories.The information is available on the EPIC web sitewww.epic.uk.com/fire tests and research.jsp##TheEpicFireTestsThe tests give a clear understanding of the wayinsulated panels and insulated cladding systemsperform during the developing stage of a fire atthe most critical time associated with fire risk Insulated Panels fixed to the building structure,in particular the roofs and external walls ofbuildings, remain secure without collapse evenwhen the fire changes from a developing todeveloped stageContribution of a combustible core to the firei.e. as a source of fuel, is limited and gradual inthe developing stage of a fireThe contribution in terms of smoke and gasesis minimal for MF, PIR and PF but slightlygreater for PURThe contribution from PS cores is greater atan earlier stage due to the low melting point(120 C) and can result in the generation ofblack smoke. The bond of the facing is alsocompromised at an earlier stage increasing thepossibility of collapse.11

33.5Fire performance of insulated panelsExternalInformation from firecase historiesExample – LeisureEPIC and its professional fire consultants haveanalysed a number of fires, both internal andexternal, in which Insulated Panels have beenaffected by fire. The studies have concentrated onPUR cored panels and LPCB certified PIR panelsystems, which are the most common panel types,and relate to panels that have been subject to adeveloped fire as distinct from the developing fire,which is more relevant to fire risk assessment.The case histories clearly illustrate how panelsperform in actual fires when they are used as theroofs and walls of buildings and are securely fixedto the building framework.The findings from a variety of the case studies aresummarised below. These have been taken fromthe fire services or fire consultants reports. Thecase histories are available for view and downloadon the EPIC web site:www.epic.uk.com/fire case studies.jspExample – Industrial manufacturer 12Severe fully developed fire due to large amountof plastic componentsNo fire spread through the PUR insulatedpanels to the adjacent manufacturing unitsPUR panel partition wall prevented fire spreadMinimal smoke damage to adjacent units withminimal loss of production Internal fire reached a fully developed stageThe PUR panels did not contribute to firegrowth or fire spreadThe insulated panels did not collapse andremained attached to the buildingFire fighters entered the building andextinguished the fire safelyExample – Hospital Severe fire sufficient to damage intumescentcoatings and distort the steel beamsPIR (LPCB Certified) panels did not collapseor ignitePIR (LPCB Certified) panels did not contributeto the fire spread

Example – School It is a requirement of PIR (LPCB certificatedsystems) and some IACSC system designs (4) thatthey are securely fixed to a supporting frameworkto prevent early collapse in fireIntense heat in the vicinity of the fire sufficientto damage the purlinsPanel facings remained in place despite severebuckling and delamination and exposure of thecore materialThe LPCB approved PIR panels helped toprevent fire spread across the top of thecompartment wallInsulated panels used as the external roofs andwalls of buildings.In all case studies the expert’s view was that thePUR insulated panels or PIR (LPCB certificatedsystems) did not contribute significantly to the firedevelopment and the fire load3.6Up to 1995 the majority of applications usedpolystyrene insulated panels, often in associationwith a hot process e.g. cookers, fryers, ovens etc.Following a number of large-scale serious fires theuse of panel systems with a highly combustiblepolystyrene core was reviewed. From the mid1990’s the use of polystyrene panels rapidlydeclined in favour of PUR, PIR (LPCB certificatedsystems) and MF, with MF panels replacing PS inareas round hot processes.Internal applicationsSmall quantities of phenolic (

4.1 Introduction to Fire Risk Assessment for Insulated Panels 14 4.2 Insulated Panels used as the external envelope 14 4.3 Insulated Panels used for internal applications 16 4.4 Insulated Panels used as internal linings 17 4.5 Insulated Panels used as internal compartment walls 17 Section 5 Identifying Insulated Panels and other cladding systems 18