Downlighters in Dwellings

Building Control Technical Guidance Leaflet No. 9


This leaflet is one of a series produced by the Hertfordshire Building Control Technical Forum


The use of downlighters is becoming increasingly common in dwellings and domestic extensions. This has prompted debate on their compliance with associated areas of the Building Regulations.

The purpose of this guidance note is to consider the areas of concern and demonstrate how these luminaires can be specified in order to accord with the various requirements. Subjects covered include fire safety, sound insulation, conservation of fuel and power and compatibility with roofing underlay materials.

Fire Safety // Fire Resistance of Floors

Approved Document B of the Regulations includes requirements that floors in dwellings achieve a fire rating. This is normally 30 minutes for low-rise buildings where the floor is not a compartment floor. When installing downlighters in such a floor, the question arises as to whether or not they will adversely affect its fire resistant properties to the extent that it will not comply

Whilst there is not a great deal of research information available on this subject, tests sponsored by the DETR (now CLG) and carried out by The Timber Research and Development Association* provided useful guidance. The view of many construction professionals is that additional protection in the form of intumescent covers, boxing or fire resisting fittings is a necessary provision in all cases. It may be that these opinions have been influenced by commercially driven advice from companies dealing in such products. It is important that decisions are based on sound and independent scientific research, it being all too easy to request a higher standard knowing that it is unlikely to be challenged. Building Control Surveyors must be vigilant against being influenced by potentially biased information from the commercial sector. There are some excellent sources of independent advice that they can use to make balanced judgements when checking designs or work on site.

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