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Fire Rated Down Lights Guide

 Down lights and fire safety

This guide provides a quick reference for installers on

the appropriate selection and installation of fire rated down lights

in domestic premises, and on how to prevent them

from becoming a fire hazard.

 

1. Introduction to fire rated down lights

Poorly installed down lighters (recessed luminaires) is the cause of a significant number of fires in

homes every year. This guide provides a quick reference for installers on the appropriate selection and

installation of down lighters in domestic premises, and on how to prevent them from becoming a fire

hazard.

2. Why is down lighters a fire risk?

Under normal operating conditions, the surface temperature of tungsten halogen lamps can

exceed 200 ºC, which is above the ignition temperature of many combustible materials.

Without adequate ventilation to permit safe heat dissipation, down lighters not designed to be

covered by thermal insulation, or installed too close to combustible materials (such as roof

timbers) can cause fires or harmful thermal

effects to their surroundings.

Even when insulation is not present, there is a

risk that dust, debris and other potentially

combustible materials could ignite if they come

into contact with the hot lamp.

Overheating can occur where thermal insulation

is laid over existing down lighters and any

associated transformers that are not designed to

operate safely under these conditions.

The bases of the most common types of push-fit

extra-low voltage lamps (with aluminum or

diachronic reflectors) are identical (see section 4 for diagrams). However, most types of

down lighter are not designed to operate safely with both types of lamp. Consequently, lamps

can be fitted inadvertently that exceed the maximum rating of the luminaries or which reflect

heat in the wrong direction.

3. Fire rated down lights explained

Operating voltage

Down lighters operate at mains voltage (230 Volts), or are powered via a transformer at extra-low voltage

(12 Volts). Extra-low voltage (ELV) down lighters are often incorrectly described as “low voltage” on

Product packaging.

Fire performance

Down lighters may also be described as ‘Fire rated’. This means they have in-built fire protection that

Completely seals the down lighter in the event of fire in the room below, to prevent the spread of fire and

Smoke into other areas.

It is important that the fire performances of ceiling structures that have fire containment function or are

Required to carry load for a prescribed period of time are not compromised by the installation of

down lighters.

For ALL down lighters installed in ceilings, the Electrical Safety Council recommends the use of ‘fire rated’

Down lighters fitted with ‘aluminum’ reflector lamps to help ensure that any fire in the space below is

Kept out of cavities and that the heat build-up above and within the fitting is minimized.

Typical fully closed back ‘fire rated’ down lighter typical standard open back down lighter

In situations where a selected design or style of down lighter is not available with integral fire protection,

additional protection may be fitted at the time of installation in the form of

A purpose made ‘fire hood’, an insulated fire protection box, or similar.

Detailed guidance on the selection of suitable types of down lighter for

Particular applications is given in the Electrical Safety Council’s Best

Practice Guide 5 – Electrical installations and their impact on the fire

Performance of buildings.

Mounting on normally flammable surfaces

Down lighters are classified according to whether or not they are

Suitable for direct mounting on normally flammable surfaces.

‘Normally flammable’ materials are those which have an ignition

temperature of at least 200 °C and which will not deform or weaken

at this temperature. Examples are wood and wood-based materials

of more than 2 mm thickness.

Where a down lighter is suitable for direct mounting on

non-combustible surfaces only, either of these warning symbols

should be marked on the fitting.

Covering with thermal insulating materials

To avoid the risk of fire (as well as reduced lamp and service life) caused

by overheating, down lighters and any associated transformers must not

be covered by thermal insulation and need to be protected against

potential or future covering, unless they are specifically designed to

operate safely in this condition. Particular care must be taken where

loose-filled insulation is present, as this can be moved easily by drafts,

vermin, etc, and may then come into contact with the down lighter.

Down lighters marked with

Are suitable for covering with thermal insulation

Must not be covered with thermal insulation

Building Regulations do not prohibit the leaving of a small area around down lighters free from thermal

insulation where this is necessary to permit the dissipation of heat they generate. However, due

allowance for this should be made in the overall thermal and acoustic performance of the premises.

Alternatively, where access to the space above the down lighter can be achieved.

 

typical insulation support box Loft cover

Manufacturer’s instructions

In all cases, the manufacturer’s instructions supplied with the down lighter must be followed. The

manufacturer should specify, amongst other things, the amount of space to be left around the back of

the down lighter, its fire rating, whether the fitting can be covered with thermal insulation, and the

type/wattage of lamps that can be fitted.

ingress protection (iP) rating

Down lighters should be selected with the correct IP rating for the location in which they are to be

installed. For example, those located in bathrooms should have an IP rating based on the zone they are

installed in. In all cases, account must be taken of the requirements given in the current version of

BS 7671 (Requirements for Electrical Installations, IEE Wiring Regulations 17th Edition), the national standard

for the safety of electrical installations.

4. Down lighter lamps explained

The most widely available types of tungsten halogen lamp are manufactured with either a dichroiccoated

(cool beam) reflector or an aluminum reflector. The reflector type determines the way in which

most of the heat generated by the lamp is reflected.

reflector types

Diachronic (cool beam) lamps reflect visible light forwards while allowing most of

the radiated heat to pass out of the back of the lamp – Warning: these lamps

must only be used in down lighters specifically designed for their use, otherwise

overheating can occur.

Aluminum lamps reflect the visible light and most of the heat forwards out of the

front of the lamp. However, consideration must be given to the positioning and

intended use of down lighters fitted with aluminum reflector lamps to prevent

excessive heating of lighted objects.

Lamp bases

The most common tungsten halogen lamps for use in down lighters are push fit (GU4 or GU5.3) for ELV,

or twist and lock (GU10 or GZ10) for mains voltage types.

ELV lamp bases Mains voltage lamp bases

Although lamp bases are different in design to prevent ELV lamps being used in mains voltage fittings,

GU4, GU5.3 and GZ10 lamp holders will accept both aluminum and diachronic reflector lamps. the use of

diachronic reflector lamps in down lighters designed for use with aluminum reflector lamps only

could create excessive heat within the luminaire leading to an unsafe situation and risk of fire.

Down lighters marked with this warning symbol Must not be fitted with

diachronic reflector lamps.

GU4

4 mm 5.3 mm

GU5.3

GU10 GZ10

10 mm 10 mm

COOL

BEAM

Protective shield

Tungsten halogen lamps must be fitted with a protective shield (a

glass plate in front of the halogen filament) to ensure that particles

from a shattered lamp cannot cause harm. Down lighter fittings not

supplied with a glass protective shield must be fitted with a ‘self shielded’

lamp.

5. Safety symbols, information and markings

The relevant product standards relating to luminaries and associated control equipment specify safety

information that manufacturers must mark on down lighters, lamps and associated transformers, or

their packaging.

A recent revision of the product standard relating to luminaries (BS EN 60958-1) has resulted in some

symbols and markings having been changed to align with current international (IEC) standards. All the

provisions of the revised ‘2008 edition’ of BS EN 60958-1 are required to be implemented by April 2012.

As a result of the transitional arrangements, down lighters may be sold and marked with both old

and/or new symbols and information.

 

 

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