Don’t get burnt by non-compliance: Fire-rated downlights

The rules around recessed lights are complex and the result is that not all products out there are truly compliant, leaving you and your customers exposed.

Could your product manufacturer provide the required verification? You might be surprised.  Despite claiming compliance, not all manufacturers test across all ratings and, when additional minutes can mean the difference between surviving a fire or not, testing, compliance and certification is crucial.

Don’t leave yourself and your customers unprotected.

 

Anthony Parkinson, Technical Manager at Ansell Lighting, guides you through the regulations and how to ensure you choose the correct fire rated downlight for the right ceiling type:  

 Electrical Safety First, the UK’s leading charity on fire safety, recommends fire rated downlights (FRDs) are installed in any ceilings where recessed lights are specified.

This is obviously sound health and safety advice - FRDs have in-built protection that prevents fire and smoke spreading in the event of a blaze.

However, the Building Regulations and National Housebuilding Council (NHBC) standards relating to recessed lights can be complex and misunderstood – with the NHBC recently clarifying its guidance to builders and developers in order to strengthen compliance with fire resistance standards.

So what do the ratings mean?

The three fire resistance ratings, of 30, 60 and 90 minutes, which indicate the length of time a complete floor-ceiling structure must be able to withstand fire to enable the evacuation of people and prevent the rapid spread of flames and smoke can also be complicated as they differ according to the building structure and number of floors. For example, the ceiling of a typical semi-detached house will require a lower fire rating than one at the top of a high rise tower block or offices, and if a structure has a 90 minute rating that does not mean it is automatically covered for a 30 or 60 minute rating.  It’s crucial that manufacturers test against all ratings, as in this case, minutes mean survival.

Additionally, there are distinct specifications of ceiling thickness and joist spacing according to each time category, and these vary according to the different types of joist in use. Therefore, understanding a building’s fire resistance ratings and the specific requirements relating to different types of ceiling joist is essential when specifying downlights.

There are three types of joist to consider – solid timber, I-Joist and metal web/open web (commonly called the Posi Joist).

 

Solid Timber Joist

The most traditional of all ceiling joists, the solid timber joist is typically only seen in domestic dwellings which were constructed more than 20 years ago, though you will also see them used within internal floor and separating constructions for both residential and commercial applications.

Specifications for each fire resistance rating category are:

30 minute construction

  • 600mm joist centres
  • 220mm x 63mm
  • 15mm Type A wallboard and plasterboard

60 minute construction

  • 600mm joist centres
  • 220mm x 63mm
  • 2 x 15mm Type F Fireline plasterboard

90 minute construction

  • 450mm joist centres
  • 220mm x 63mm
  • 2 x 15 mm Type F Fireline plasterboard

 

I-Joist