1 Aim

1.1 The aim of this Guide is to promote best practice by providing practical advice and guidance for designers, installers, verifiers and inspectors of domestic electrical installationswhere, as is often the case, the electrical work requires,or has required, the penetration of linings forming ceilingsand walls.

1.2 The guidance, which is intended to apply to electrical installations designed after July 2008, may also be of benefit to specifiers, builders,

building control bodies and other interested parties.

1.3 By following the guidance, it is considered that electrical installation work will not compromise the fire performanceprovisions that are mandatorily required to be incorporated intodomestic premises under the relevant building regulations.

2 Introduction

2.1 This Guide has been producedby the ElectricalSafety Council in association with the bodies indicated on page 2.

2.2 It addresses the impact that electrical installationsin domestic premiseshave on the fire performance

of loadbearing and non-loadbearing walls and floors (and sometimes ceiling membranes) that have a fire containmentfunction, or are requiredto carry a load for a prescribedperiod.

2.3 Fire safety in buildings generally requires that in the event of a fire:

• certain walls, floors and ceilings provide fire separation for the purposes of constructing fire compartments and/or protected escape routes, and

• the structure resists collapse.

2.4 The advice given in this Guide is aimed largely at preserving the structural stability of the premisesas much asthefire separation between areas. For example, in most domestic premises, it is the loadbearingcapacity of the floors that is threatened by early failure of ceiling linings, not the fire separating function.

2.5 Many modern forms of engineered construction have an inherentlylower level of fire resistance when compared to more traditional forms of construction, and are heavily reliant on the plasterboard or similar liningsfor achieving the requisite level of fire separation.

Result of an eight minute fire on lightweight joists

(Courtesy of Manchester City Council - Building Control)

2.6 Much of the guidanceis related to the effect that the installation of electrical equipment will have on the performance of the protective linings that are used to provide fire protection to lightweight joisted or studded constructions. In the case of the associated wiring, the need to preventfire from passing through holes in all elements,whether solid or lightweight, is also addressed.

2.7 Amongst these forms of construction are narrow section solid, stress graded timber joists,plywood/Orientated Strand Board (OSB) webbed I joists ('timberI beams'), tooth or nail-plated trussesand joists, composite timber studs and lightweight metal studs. Illustrations of these

vulnerable forms of construction are to be found in

Annex A.

2.8 The fire resistance of these elements can easily be compromised by inadequate fire sealing and

'making good'after any penetration to accommodate electricalequipment and associatedwiring.

2.9 Electrical equipmentthat has been identified as having a direct and significant influence on the fire performance of buildings includes:

• flush-mounted consumer units

• concealed and recessed luminaires, includingdownlighters

• flush-mounted electrical socket-outlets, flex outlet plates and data points

• flush-mounted switches, detection and control devices

• recessed wall luminaires

• concealed speakers.

2.10 The above items all require the removal of a part of the ceiling or wall lining, and replacement with glass,thin metal or plastic that does not provide the same level of fire protection to the structural members, causing a reduction in the fire performanceof the element. These are known as partial

penetrations.

2.11 In additionto the influence that these partial penetrations have on the fire performance,some installations can penetrate both linings, such as:

• associated wiring and conduits

• ventilation fans and related ductwork.

2.12 These installationshave a potential to compromise the fire containment capability, and guidance is included for these situations. These are known as full penetrations.

2.13 In additionto the above items that all have a direct influence on the fire performance of floors or walls,the following items can also have an indirectinfluence if the lining providessome or all of their support:

• heavy ceiling-hung luminaires, lighting tracks and overhead projectors

• wall-mounted brackets for televisions, heavy speakersandflat screen installations.

If the room is involved in fire, the weight of such items may lead to the premature failure of the lining material.

2.14 In additionto the risk of the electrical installation reducing the fire separation capabilities of those elements that need to resist fire spread or to remain structurally sound in a fire, a poorly constructed installation can potentially be the cause of a fire, for exampledue to heat generated by loose connections.

2.15 This Guide addresses all of these issues.

2.16 The fire separating capability of an element of construction is generally measuredby the duration for which the elementwill satisfy the criteria of a fire resistance test. Historically, these criteria have been determined by exposure to the BS 476:Part 20:

1987 heatingand pressure conditions, but more recently by the new Europeantesting regime as embodied in BS EN 1363-1. More information on the relevant test methods and criteria can be found in Annex B.

3 Scope

3.1 This Guide gives practical advice and guidancefor the installation,and the making good following theinstallation, of electrical equipmentand wiring in self-contained domestic premises (includingbungalows, multi-storey houses, individual flats and maisonettes) that are designed to accommodate a single family unit. The advice and guidanceapplies to both new and existing premises.

3.2 The Guide does not apply directly to Houses in Multiple Occupation, hostels, caravans or boats, or to the communal parts of blocks of flats or the

communal parts of maisonettes, nor does it apply to any premisesused for purposes other than a

dwelling (such assmall shops, factoriesor similar premises used solely asplaces of work). Guidance for these building types may be found in other Parts of this Best Practice Guide (in preparation).

3.3 The Guide gives advice on what needs to be done to maintain the fire resistance of walls and ceilingsin domestic premisesthat have been penetrated or partially penetrated in the process of installing electrical equipmentand wiring.

3.4 It does not consider in detail the impact that the installationof electrical equipmentand wiring may also have on the structural, acoustic or energy targets prescribedin building regulations.

3.5 The Guide gives recommendations astowhat is considered to be best practice, taking into account that electrical installers may not have adequate knowledge of the construction of the elements that are potentiallybeing compromised by their work.

3.6 Where an installer wishes to differentiate between new and traditional forms of construction, the guidance given in Annex Cmay assist. Some investigations may require the services of another professional,such as a surveyor or fire specialist.

Note: This Guide does not necessarily apply toallinnovative or unusual forms of construction or electrical equipment. If in doubt, specialist advice should be sought.

4 General electrical installationrequirements

4.1 This Guide takes into accountthe publication of BS 7671: 2008 (Requirements for Electrical Installations,IEE Wiring Regulations 17th Edition), whichis the latest version of the national standard for the safety of electrical installations, first published in 1882.

4.2 BS 7671 requires, in Section 421 (Protection against fire caused by electrical equipment), that equipment must not present a fire hazard to adjacent

materials, and that manufacturers' instructions must be complied with. Section 421 also requiresthat fixed equipment causing a concentration and focusing of heat (such asspotlamps) shall be at a sufficient distance from any fixed object or building element so that the object or element is not subjected to a dangerous temperature in normal conditions.

4.3 Also, in Section 527 (Selection and erection of wiring systems tominimise the spread of fire) of that standard, it is requiredthat wiring systems are selected and erected to minimisethe spread of fire, including:

• Within a fire-segregated compartment, the risk of the spread of fire must be minimisedby the selection of appropriate materials, and by the appropriate construction of the installation (Regulation527.1.1), and

• A wiring system must be installed so that the general building structural performanceand fire safety performanceare not reduced (Regulation

527.1.2), and

• Where a wiring system passes through elements of building construction such asfloors, walls, roofs, ceilings,partitions or cavity barriers, the openings remainingafter the passage of the wiring system must be sealed accordingto the degree of fire resistance (if any) prescribed for the respective elementof building construction before

penetration (Regulation 527.2.1).

4.4 Regulation 510.2 requires manufacturers' instructions to be taken intoaccount. It is important to do this in order, for example, to prevent

luminaires becoming a source of ignition. (Any installationinstructions that are considered to be inappropriate should be queried with the manufacturer concerned,and amended installation instructions requested.)

4.5 All terminations and joints, whether for low voltage (LV) or extra-low voltage (ELV) circuits, should be enclosed in accordance with Regulation 526.5 to preventfire spread should a loose connectionoccur.

4.6. As part of the initial verification process,the electrical installer has a duty to ensure that all the necessary fire precautions have been taken, irrespective of which party was responsible for that element of the electrical work (Regulation

611.3(vii)).

5 Legal

5.1 Building regulations for each part of the UK define fire performance objectives for the various elements that make up domestic premises, and give recommended performance levels in guidance supporting those regulations. The objectives are taken intoaccount in this Guide. For further information, see Annex D.

5.2 It is vital that the fire performanceof critical walls andfloors is maintained to at least the level recommended in the guidance supporting the regulations,after the installation of electricalequipment and associated wiring.

5.3 For properties in England and Wales, attention is drawn to the Party Wall Act. Under this Act, any work undertaken on the party wall between properties which could affect its performance(or indirectly affect the structureofan attached neighbouring property) is a notifiable activity. In Scotland, a building warrant is required for any work that adversely affects a separating wall or a separating floor.

5.4 The fitting of electrical equipmentin a masonry party wall has never been consideredas being notifiable, but cutting holes in the linings and installing 'plastic' accessories may be deemed to be covered by statutory requirements. The ElectricalSafety Council therefore recommendsthat the neighbour be advised of the intended work in order to give them the opportunity to object to, comment upon, or prevent the work taking place.

5.5 Electrical installationwork will often be undertaken on behalf of owners or tenants after the occupation of the premises and, assuch, it is not subjecttoany form of third party audit or final approval.The electrical installer is therefore subject to a duty of care to ensure that the fire performanceof the premises is not compromised. In Scotland, certain works requirebuilding warrant approval depending on the work proposedand the building type.

Note: In England & Wales, Part P of the Building Regulationsand, in Scotland, Building Standard 4.5, make this a requirement, putting the responsibility on the installer if self- certifyingthe work as compliantwith buildingregulations. Currently, electrical safety in Northern Ireland is not controlled under building regulations.

RECOMMENDATIONS

6 Flush-mounted consumerunits

Photos courtesy of Hager

6.1 Flush-mounted consumer units should not be installed in a fire separating wall. In exceptional circumstances, where this cannot be avoided, and subject to the agreement of the Local Authority, the enclosure of the consumer unit or a separate builder's work enclosure around the consumer unit must provide a proven level of fire resistance commensurate with the fire separating element.

Photo courtesy of MK

7 Downlighters

(recessedluminaires)

7.1 When exposed to a fire from below, downlighters may provide far less protection to a cavity and the structural elements within it than the plasterboard they are replacing, unless suitable precautions are taken.

7.2 The Electrical Safety Council recommends that, wherever possible, downlighters having integral fire protection are selected for use in all ceilings where thelining that is to be penetrated is the sole means of keeping fire and heat out of the cavity.

7.5 Not all designs and styles of downlighter may be available with integral fire protection, especially where higher lighting levels and/or larger coverage is required. In these situations, additional fire protection may be fitted at the time of installation

in the form of a 'fire hood', an insulatedfire-protective box, or similar.

Typical fire hood for a downlighter

Result of a downlighter fire

(Courtesy of Manchester City Council - Building Control)

7.3 There are a number of types of downlighter available,and it is important that the type selectedfor a particular application has test evidence tosupport its fire performancewhen incorporated in

a ceiling of the type into which it is to be installed.

Typical downlighters with integral fire protection

(Photos courtesy of Safe and Sound Lighting Ltd)

7.4 Generally, the tests should have been carried out in accordance with BS 476:Part 21: 1987 or

BS EN 1365-2. The nature of the test evidence can be critical, and is discussed in detail in Annex B.

7.6 Such separate forms of protection must be fit for purpose and not be easily dislodged or compromised after installationby subsequent work. Any suchprotection must conform to the guidance given in Annex E.

7.7 The Electrical Safety Council recommendsthat downlighters installed in a ceiling beneatha roof space have integral fire protection, or are providedwith some other suitable form of fire protection, in orderto safeguard escape from the premises, restrict the spread of fire, and reduce the risk of premature failure of the roof structure.

7.8. In order to avoid the risk of fire (aswell asreduced lamp and service life) caused by overheating, downlighters and any associated transformers must not be covered by thermal insulation. BuildingRegulations do not prohibit the leaving of a small areaaround downlighters free from thermal insulation where this is necessary to permit the dissipation of the heat they generate. However, due allowance for this should be made in the overall thermal performance of the premises.

7.9 In all cases, manufacturers' installation instructionsmust be followed to avoid downlighters becoming a source of fire.

7.10 Guidanceon the selectionof suitable types of downlighter for particular applications is given in Table 1, opposite.

©The Electrical Safety Council

Table 1: Recommendations for recessed luminaires/downlighters in floors and ceilings

Building

Location

Construction

Fire Resistance Required

Recommended

Bungalow

Roof ceiling

All

N/A

A

Two-storey house

Roof ceiling

All

N/A

A (assuming adequate compartmentation between adjacent dwellings)

First Floor

Robust

Modified 30 mins**

B, C, but A can be justified if traditional construction

confirmed (Annex C)

Lightweight

Modified 30 mins**

B, C

Below room over garage

All

30 mins

B , C

Over basement

All

30 mins

B, C

Three-storey house

Roof ceiling

All

N/A

A (assuming adequate compartmentation between adjacent dwellings)

First and Second Floor

All

30mins

B, C

Ceiling of garage under room

All

30 mins

B , C

Over basement

All

30 mins

B, C

Loft conversion

(2-storeys to 3)

First floor (when loft converted)

Robust

Modified 30 mins**

B, C, but A can be justified if traditional construction confirmed (Annex C)

Lightweight

Modified 30 mins**

B, C

Four-storey (or more)

house

Roof ceiling

All

N/A

A (Assuming adequate compartmentation between adjacent dwellings)

All Floors, including garage and

basement ceilings/ floors

All

60 mins

B, C

Flats

Top floor <5m

Compartment floor

All

30 min

D, B , C

Top floor <18m

Compartment floor

All

60 min

D, B , C

Top floor <30m

Compartment floor

All

90 min

D, B , C

Top floor >30m

Compartment floor

All

120 min

D, B , C

Duplex flats

Intermediate floor

All

30 min

B, C

KEY:

A = Unprotected downlighter permitted, but

page 9

suitable fire protection recommended for safety reasons

B = Downlighter with integralprotection

C = Downlighter with hood complyingwith Annex E D = Downlighter inserted in false (secondary) ceiling

= Ensurethat thermal insulation will not prejudice luminaire

= Should only be installedif it can be verifedthat the penetration will not have an adverse impact on accoustic performance

= Robustconstruction is definedin Annex C

= Lightweight engineered construction is defined in Annex A

** = See Annex F

NOTE: In Scotland, the guidance clause 5.1.10 (Domestic Handbook) recommends that downlighters installed in the ceiling of a combustible separating floor are fitted within the depth of a secondaryceiling.

8 Flush-mounted accessories (including switches, sockets, flex outletplates, data and telephone points etc)

8.1 Numerous flush-mountedaccessories are common in modern homes. These generally comprisetwo components:

• a recessed housing, or back box

• a face plate with integral socket, switch mechanism, flex outlet etc, and associated wiring terminals.

8.2 Back boxes may be eithermoulded plastic or steel construction, but all designs incorporate large knock- out sections,many times greater in diameter than the cables passing through them, which make them

very permeable in a fire after the face plate has been destroyed by the heat. This permeability will allow

hot gases into the cavity of the wall much more rapidly than the plasterboard.For fire separating applications, and for applications relied upon to resist collapse, this should be guarded against by providingadditional localised fire protection.

8.3 The risks associated with fire penetrating through flush-mounted accessories are significant when they penetrate a 30 minute fire-resisting loadbearing

stud wall, 'back-to-back' with other accessories in the same cavity (or interlinked cavities).

Photo courtesy of Greater Manchester Fire & Rescue Service

8.4 Therefore, where flush-mounted accessoriespenetrate each face of a 30 minute fire separating or loadbearing plasterboard lined wall within the same cavity space (that is, the gap between two studs), each accessory should be fitted with a back box that incorporatesintegral fire protection, or be fitted with a proprietary fire protection pad, unless evidenceof the fire resistance performanceof the accessories is available.

Plan view

Example of accessories being back-to back in the same cavity

space (can be at different heights)

The effect of fire on a socket-outlet

(Photo courtesy of Greater Manchester Fire & Rescue Service)

Example of accessories not being back-to-back in the same cavity

Plan view

8.5 Such back boxes or protective pads must have evidenceof performance to demonstrate that they have the ability to maintain the fire separation capability of a wall for 30 minutes, were they to be tested to BS 476: Part 21: 1987 (loadbearing) or

BS 476: Part 22 (non-loadbearing), or the EN

equivalent asappropriate (see Annex B), with plastic accessories fitted in both linings.

Plan view

The boxdepth must be selected so that with the pad in place, the required clearance is maintained between the pad and the accessory, and the wiring is not unduly distorted.

Plan view

Fire protection pad fitted externally

Intumescent pad being installed in a dry lining box

(Photo courtesy of Knauf Drywall)

Fire and acoustic rated cover fitted behind a dry lining box

(Photo courtesy of Tenmat Ltd)

Intumescent insert being installed in a dry lining box

(Photo courtesy of Tenmat Ltd)

8.6 Recommendations for the protection of flush-mounted accessories in timber or metal stud walls inparticular situationsare given in Table 2 (on the following page).

page 12

Table 2: Recommendations for flush-mounted accessories in timberand metal stud walls

Building

Location

Installation

Fire Resistance Required

Recommended

All DwellingTypes

Internal walls within a dwelling that do not have a fire separating function

One lining only or back-to-back

N/A

A

Bungalow

Internal walls

One lining only or back-to-back

N/A

A

Two-storey house

(detached)

Stairway enclosure

One lining only or back-to-back

N/A

A

Wall separating garage from other rooms

One lining only

30 min

A

Back-to-back

30 min

B

Two-storey house

(attached)

Stairway enclosure

One lining only or back-to-back

N/A

A

Wall separating garage from other rooms

One lining only

30 min

A

Back-to-back

30 min

B

Separating wall between dwellings #

Fitting in one or both linings #

60 min

B

Three-storey house

Stairway enclosure

One lining only

30 min

A

Back-to-back

30 min

B

Wall separating garage from other rooms

One lining only

30 min

A

Back to back

30 min

B

Three-storey house

(attached)

Stairway enclosure

One lining only

30 min

A

Back-to-back

30 min

B

Wall separating garage from other rooms

One lining only

30 min

A

Back-to-back

30 min

B

Separating wall between dwellings #

Fiting in one or both linings #

60 min

B

Four-storey (or more)

house

Stairway enclosure

One lining only or back-to-back

60 min

B

Wall separating garage from other rooms

One lining only

30 min

A

Back-to-back

30 min

B

Four-storey plus house (attached)

Stairway enclosure

One lining only or back-to-back

60 min

B

Wall separating garage from other rooms

One lining only

30 min

A

Back-to-back

30 min

B

Separating wall between dwellings #

Fitting in one or both linings #

60 min

B

Flats

Top floor <5m

Walls between occupancies #

Fitting in one or both linings

30 min

B

Top floor <18m

Walls between occupancies #

Fitting in one or both linings

60 min

B

Top floor <30m

Walls between occupancies #

Fitting in one or both linings

90 min

B

Top floor >30m

Walls between occupancies #

Fitting in one or both linings

120 min

B

Duplex flats

Internal stairway enclosure

One lining only

30 min

A

Back-to-back

30 min

B

KEY:

= Ensure that protection system will not prejudicewiringto accessory

= Should only be installedif it can be verifedthat the penetration

A = Unprotected accessory will not have an adverseimpact on accousticperformance

B = Accessory installed withapplied or integral protection # = Flush-mounted accessories should not be fitted in these walls unless unavoidable (Not permittedin Scotland)

©The Electrical Safety Council

NOTE: In Scotland, the guidance clause 2.2.7 (Domestic Handbook) recommends that combustible separating walls donotcontain pipes, wires or other services. In buildings with a storey height over 18 m, separating walls and floors must be constructed of non-combustible materials.

9 Flush-mounted wall luminaires and concealed speakers in walls or ceilings

9.1 This type of equipment varies significantly in size, design and construction. It is therefore not possibleto give specific advice in this Guide in respect of the best method of maintaining the fire performance of the lining(s) penetrated by such equipment.

9.2 In principle, however, speakers concealed in ceilinglinings should be treated by analogy with downlighters, and both luminaires and speakers flush-mountedinwalls should conform to the guidance given for flush-mounted accessories.

9.3 Where a luminaire or speaker has integral fire protection, then this must be to the appropriate test standard (see Annex B).

Photo courtesy of CEDIA/Smartcomm

9.4 If the equipment does not have integral fire protection then, when it is being installed in a ceilingor wall that is required to provide fire separation, the equipment has to be provided with an ad hoc form of fire protection and, where appropriate, acoustic insulation. It may be difficult for the installer to establishwhat form of protection is likely to

maintain the required fire resistance, and therefore any proposed method of providing protection should be tested, or more reasonablyassessed in

lieu of test evidence, by those authorities recognised in guidancein support of regulations*.

9.5 Proprietary protection is likely to become available in due course, and should be used when it does.

* Approved Document B for the Building Regulationsfor England

& Wales (A1 of Annex A), or the ScottishBuilding Standards

Technical Handbook, as appropriate

10 Cables, conduit and trunking penetrating internal fire separating walls and floors

10.1 This section provides guidance astowhat should be done to preserve the fire resistance of elementsthat are required to provide fire resistance,when cables have to pass through them. The guidance is applicable to situations where insulatedand sheathed cables, or cables in plastic conduitor

plastic trunking, pass through floors and walls.

10.2 The fire risk associated with non-fire performance cables and plastic conduitsandtrunking passing through building elementsis twofold. Initially there is a risk of a loss of integrity due to the heat and/or flames passing through any unsealed holes that have been made to allow the cable to pass through, resultingin flaming on the unexposedside. Secondly, the hole in a plasterboard lining will allowfire to get into the ceiling or wall void prematurely, cause ignition of the structurewhich can lead to a loss of loadbearing capacity.

10.3 With respect to the first of these, it is important that fire is not allowed to exploit either the initial penetration of the first lining (which could permit

fire to get into the cavity), or subsequently to penetrate the second lining (which would allow the fire to effectively bypass the protective barrier).

Fire seals aroundcables and trunking

10.4 Sealing the cable ingress point has to take into account that the insulation of non-fire performance cables will probably meltorchar away, leaving an unfilled gap between the conductorsand the lining. Depending upon the nature of the cable insulation,this may even have the potential to carry the flames on its surface into the void. On a single cable this is unlikely to be a serious risk, but the ability to make an adequate fire seal becomes increasingly difficult as the number of cables increase.

10.5 It is common and accepted practice to make good any hole around a cable by using inert filler such as plaster or grout, but this does not compensate for melting/flaming insulation, and will also be ineffective in voids between cables.

10.6 It is recommended, therefore, that the sealant used to make good holes through which cablespass has intumescent properties: that is, it has the ability to expand and fill any voids that are developing due to movement and/or meltingof cables, in order to maintain the fire resistance of the element.

10.7 The risk of fire gaining prematureaccess to any void is increasedif the cables are run through a plasticconduit or trunkingsystem, or are bunched. Any cosmeticsealing of the gap between the lining and the plastic conduitor trunking will certainly not be able to seal any voids between the cablesand the outer plastic casing following the melting of the conduit or trunking.

10.8 In elementsthat require high levels of fire resistance, especially where there is a sleeping risk (such as60 minute compartment walls and floors),

it is recommended that a proprietary cable transit or a fire resisting conduit be installed in the

construction element being penetrated, if serviceshave to pass through one or both linings that form the wall.

NOTE: In Scotland, the guidance clause 2.2.7 (DomesticHandbook) recommendsthat combustible separating walls do not contain pipes, wires or other services.In buildingswith a storey height over 18 m, separating walls and floors must be constructed of non-combustible materials.

11 Ventilation fans and related ductwork

11.1 Ventilation fans are normally fitted on an external wall rather than on an internal wall and, as a consequence, there is generally not a fire safety issue regarding the influence on the integrity and insulation rating of the wall due to such systems

when installed in a cavity blockwork or masonry wall.

11.2 However, if fire were to enter the cavity of a stud wall or the cavity between the inner wall and any outer 'sheathing', the building can suffer both undue structural damage if modern engineered construction is used, and/or disproportionate fire

spread in the cavity in more conventional properties.This cavity spread can result in an indirectloss of fire integrity between adjacentinternal enclosures, and therefore fire should be prevented from gaining access to any of the cavities.

11.3 When installing aventilation fan directly into a loadbearing external stud construction wall, the hole cutintothe inner and outer lining should be lined

out across the thickness of the wall with a continuousnon-combustible material, preferably with some insulatingproperties, through which the extract duct passes**. This liner should be fixed in placeso that it does not fall away over time.

11.4 When the vent from for example,a shower cubicle, is connected to an extended duct which runs within the floor void to an outsidewall possiblyvia an in-line fan, then this length of low meltingpoint ductwork (plastic or aluminium) will have no measurable fire resistance and fire entering into this duct, via the vent, will soon haveaccess to the joists. Indeed, should the fan be in extract mode at the time of the fire, fire will be drawn into this void quite quickly

Fire spread intobathroom via plasticduct

(Photo courtesy of Greater Manchester Fire & Rescue Service)

** This liner may, for example, consist of plasterboard tightly fitted at the corners and held in place by silicone sealant or the duct may be wrapped in a suitable intumescent-based liner.

11.5 Any voidbetween two joists that contain such a duct which is runningparallel with the joists should be lined on the face of both joists with fire protection board that duplicates the fire protection providedby the ceiling lining. The void beyond the duct should

be separated by a transversebarrier of the same rating. Similarly, the flooring above may need to be underdrawn with fire protection board if it is butt- jointed. The method of fire sealingthe wall/duct interface will vary depending upon whether it is a studded construction or a conventionalmasonry cavity wall (see Figures 11a and 11b).

11.6 Where the duct runs transverse to the joists, the amount of joist to be cut away is likely to be structurally significant and expert guidanceshould be sought, in respect of both the effect on the structureandthe fire separation measures.

Figure 11a: Joist/wall protection when installing vent into conventional masonry wall construction

Figure 11b: Joist/wall protection when installing vent into timberframe wall construction

12 Wall or ceiling-mounted electrical equipment

12.1 It has become increasingly common to mount heavy equipment such as TVs, speakers, flat screen installations etc on wall brackets, and to hang heavy luminaires, lightingtrack and projectors etc from the ceiling.

12.2 Plasterboard linings are not designed to carry such weights under fire conditionsand, unless these

items are fixed back only to the structural members in the wall or floor, they will pull down the linings once the board is weakened by the fire.

12.3 Weakening of normal and 'sound' grade plasterboard will occur rapidly after fire has consumed the room face paper lining and, whilst fibreglass-reinforced board will not fail quite as quickly or asdramatically, fixings will pull through it at a fairly early stage in the fire attack.

12.4 Obviously, early failure of these protective linings will allow fire attack on the studs and joists which again, if of engineered construction (see Annex A) will lead to prematurestructural failure.

Photo courtesy of CEDIA/Smartcomm

12.7 Additional structural members should then be fitted between joists and studs at the required fixing locations and the new plasterboard should be scribed, cuttosize/shape and fixed in accordance with plasterboard manufacturers' instructions,before fitting the suspended equipment. Joints between existingand new plasterboard linings should be filled and skimmed with plaster.

12.5 All heavy equipmentmounted on the face of walls or hung from the ceiling must be supported completely independently from the fire protective plasterboard linings. Whilst it may be permitted to fix directly to the joists, false ceiling members or studs,none of the fixings should rely solely on plasterboard.

12.6 If any additionalfixings are needed beyond those that the structure is able to provide, then a section of the lining should be completely removed and the edges of the 'hole' fitted with supports to which

'both' edges of the plaster board can be fixed.

ANNEX A

Examples of forms of modern engineered construction covered by this Guide.

Floor Joists

Space joists; consistingof timber top and bottom chords spaced apart by pressed steel 'boomerangs'

Narrow stress graded softwood joints (less than 38mm)

Studs

Timber 'I' beams; consistingof Orientated Strand Board (OSB) or plywood webs with solid timber or laminated timber top and bottom chords.

Steel webbed, timber 'I' beams; consisting of corrugated steel webs with timber top and bottom chords

Punched metal plate connected 'truss' joists

Glue laminated 'timber'studs

Steel 'C' studs

Narrow stress graded softwood studs (less than 38 mm)

ANNEX B

Under regulatory guidance there are a number of fire tests called up against which the elements, together with installed components as they will be in practice, have to be verified. The ability of the element to satisfy the structural fire requirements and fire separating objectives is adjudged bya series of establishedBritish and European test procedures.

The relevant standards are:

• Non-loadbearing walls and ceiling membranes:

BS 476: Part 22: 1987, or BS EN 1364: Parts 1 and 2.

• Loadbearing walls and floors; BS 476: Part 21: 1987, or BS EN 1365: Parts 1 and 2.

• Wires, cablesand conduit penetrating elements; BS EN 1366-3.

• Suspended ceilings that are providedonly for the protection of steel beams*; BS 476: Part 23: 1987. Note there is no directly comparable BS EN test for this purpose.

In respect of these tests, the criteria of failure are loadbearing capacity(BS 476 Part 21 and BS EN 1365 only), integrity and insulation, which are defined as follows:

Loadbearing capacity is the ability to carry the design loads for the specified period withoutcollapse or exceeding pre-determined deflection limits.

Integrity is the ability to resist the passage of flames, or the passage of critically hot gases (measured by means of an oven dry cotton pad).

Insulation is the ability to restrict temperature rise on the unexposed face to a mean temperature rise of 140 oC

and a maximum temperature rise of 180 oC.

Floor above in danger of collapse (Photo courtesy of Greater

Manchester Fire & Rescue Service)

*The use of a suspended ceiling provided for the purpose of protecting steel beams in lieu of cladding, or spraying them, is a very restricted application and will rarely be found in the domesticsector. Unfortunately, a number of proprietary products available for protecting downlighters will have erroneouslybeen tested to this standard, but these will not be suitable for 'making good' fixed ceilingsor suspended ceilings used toprovide protection to 'timber'joisted floors or other

'domestic' forms of construction.

ANNEX C

Guidance on what constitutes robust construction whichidentifies where unprotected downlighters may be fitted

When the installer wishes to fit unprotected** downlighters, it is necessary to establish the construction in detail and ensure that the floor is of one of the following constructions;

a) First floor of two-storey house:

• the joists are solid timber not less than 43 mm thickand at no more than 450 mmcentres, and

• the floorboards above are either tongue and grooved softwood greater than 18 mmthick or are tight fitting butt jointed softwood boards free from dead knots, or is 'timber'based jointedflooring not less than 18 mmthick, and

• the ceiling consistsof 12.5 mmplasterboard or

'sound' lath and plaster with the 'hooks' in good condition.

If downlighters are installed in a compartment floor (or separating floor in Scotland – see Annex F), they must be protected** regardless of the construction.

b) All other floors in a single family unit:

• As for the first floor above, except butt jointed floorboards are not permitted without an overlay of medium densityfibreboard (MDF), hardboardor plywood not less than 4 mm thick.

c) One hour fire resisting floors between flats:

• the joists are solid timber not less than 43 mm thickand at no more than 450 mmcentres, and

• the floorboards above are either tongue and grooved softwoodboards greater than 18 mmthick and free from dead knots, or is 'timber'based jointedflooring of a similar minimum thickness

• the ceiling consistsof two layers of plasterboard, not less than 30 mm1 thick for non-fire rated board or not less than 25 mm thick of fire rated 1 & 2 board.

**Protected means downlighters that incorporate integral fire protection or which are fitted with fire hoods that comply with the guidance given in Annex E of this Guide.

1 Excluding any textured surface which should be removed locally prior to fitting the luminaire

2 Type 5 to BS 1230 or Type F to BS EN 520

ANNEX D

Summary of the recommendations given in national regulatory fire safety guidance:

The requirements given in Table 1 and 2 of this Guide are the 'recommendations' made in the Guidance Document publishedin support of the relevant regional regulations.These Guidance Documentsoffer a prescriptive solution

to the 'functionally' expressed regulations in the relevant region of the UK. At the time of publication, the relevant regional regulations that deal with the fire safety issues are:

England & Wales

The Building Regulations 2000

• Approved Document B

- Fire Safety (Volume1)

- Dwellinghouses (2006 Edition)

Scotland

The Building (Scotland)Regulations 2004

• The ScottishBuilding Standards Technical Handbook

Domestic (2007)

Northern Ireland

The Building Regulations (Northern Ireland) 2000, as amended

• Technical Booklet E, 2005

The above regulations apply only to new build, or to major refurbishments (material alterations) that are notified after the dates given. Buildings already constructed and/or occupied will havecomplied with the regulations and associated guidance in force at the time of application.

These Guidance Documents would haveexpressed the recommended fire performanceof the structureinterms of the test standardsdescribed in Annex B

ANNEX E

Test procedure to evaluate the robustness of downlighter fire hoods

1. INTRODUCTION

This Annex provides requirements1 that need to be satisfied by a downlighter fire hood that is considered to be 'robust' in both its construction andfitting, and thereby meets the recommendations given in this Guide.

During installation, in order not to compromise the performanceof the downlighter, it is essential that the area immediately above the downlighter and the fire hood remains free from thermal insulation (see 7.9). Subsequent to its installation, however, the fire hood needs to demonstrate its ability to remain in place and resist crushing, that is to be

'robust' in the event of any application of thermal insulationor other material by others.

2. SCOPE

The purpose of this test procedureis to assess the ability of a downlighter fire hood which has satisfied the fire test requirements of BS 476:Part 21: 1987 to retain its mechanical stability over its working life whilst providing the requisite level of fire protection to the structureofthe buiding from a downlighter located beneath.

3. TEST PROTOCOL

The test protocolis a two part test.The first part deals with the ability of the specimen fire hood to resist compression after the application of the insulation within the test frame. The second part deals with the ability of the fire hood to resist dislodgement subsequent to installation.

4. TEST EQUIPMENT

The test assembly is designed to simulate a domestic ceiling. It consists of two softwood floor joists 225 mmx 47 mmx 1500 mmlongheld

450 mm apart, being screwed to similar sectioned timbers at either end.

The base of the test construction consists of a single sheet of 12.5 mmtypeplasterboard nailed to the underside of the timber framework. Two further sheets of 12.5 mmplasterboard 1500 mm x

300 mm are screwed to the inner face of the two major timber sections in a vertical position.

Midway down the length of the frame, a hole is cut in the centre of the plasterboard on the underside of the test frame. The size of the hole so cut shouldbe equal to that formed in the ceiling to accommodate the downlighter that the fire hood is designed to protect.

A 1400 mmlength of 400 mmwidemineral wool (24 kg/m3) is cut sufficient to provide an overall insulation depth of 270 mmwithin the test frame. The test assembly is held in position 2 mabove ground level by the use of appropriate scaffolding.

5. TEST PROCEDURE

5.1 Compressiontest

The specimen fire hood is located above the hole in the manner prescribed by the manufacturer. Unlessthe device is identified as being suitable only for installationfrom above, this will be positionedfrom below.

Once the specimenhas been located in position, the distance between the top innermostpart of the fire hood and the lower surface of the plasterboard of the main structure shall be measured in at least 3 places,averaged and noted (a).

1These test requirements have been developed by IFSA, the Intumescent Fire Seals Association. IFSA is a recognizedtrade associationfor manufacturers of intumescent materials and intumescent-based systems, membership of which requires all product claims tobesubstantiated.

Once this has been ascertained, the insulationdescribed above is laid down the length of the test rig so as to be resting on the upper surface of the plasterboard and specimen.

At this point, the distance referred to above will be measured again (b). The insulation shall remain in place for 25 days. After this period, the distance referred to above will be measured once more (c).

Once the above distances have been ascertained, the insulation should be removed and the

'dislodgement test' should be undertaken on the same test specimen

5.2. Dislodgement test

One end of the test assembly will remain supported via a 'hinge',whilst the opposingendis progressively raised or lowered at a rate of

100 mm/sec until either:-

a) the specimenfire hood becomes dislodged,in excess of the permitted amount or

b) the test assembly reaches an angle of

45 degrees.

6. PERFORMANCE CRITERIA

6.1. Compressiontest

In the case of the second measurement (b), a reductionin the average distance of less than 5%, or 5 mm (whichever is the smaller)is acceptable. For any reductionin excess of this figure, thespecimen is deemed to have failed. In the case of the third measurement (c), there should be no further reductionin distance measured.

6.2. Dislodgement test.

If the specimen moves laterally by more than

10 mm or a gap of 3 mm appears between the specimen and the top surface of the plasterboard prior to, or on completion of, the movement test, then the specimenwill be deemed to have failed.

ANNEX F

Glossary of terms

Luminaire – equipmentwhich distributes, filters or transforms the light transmitted by one or more lamps, andwhich includes all the parts necessary for supporting, fixing and protecting the lamps, but not the lamps themselves and, where necessary,circuit auxiliariestogether with the means for connecting them to the supply.

Critical application – An application where the consequencesof a failure to provide the fire resistance requirements for an elementwill have a direct impact on the life safety of the occupants,e.g. between adjacent dwellings.

Compartment wall/floor – known in Scotlandas separating wall/floor.

'Modified' fire resistance – In domesticapplications the fire resistance of the first floor has a loadbearing capacity of 30 minutes, but the integrity and insulation criteria are reduced (modified) to only 15 minutes.

House in MultipleOccupation - For England and Wales, thelegal definition of a House in Multiple Occupation is

to be found in Sections254-260 and Schedule 14 of the Housing Act 2004 or, in the case of Scotland, the Civic Government (Scotland) Act 1982 (Licensing of Houses in Multiple Occupation) Order 2000 asamended.

'Separating floor and wall' means in Scotland a floor or wall constructed to prevent the spread of fire between buildings or parts of buildings of separate habitation, such asflats and maisonettes.

Three-storey house: A house in single occupation with two floors above ground floor levels, often referred to asa townhouse.

House of four storeys, or more: A house that has three or more floors above ground floor where the height of the uppermost floor does not exceed 18 m.