How do downlights meet the new NHBC requirements? | Deta

How do downlights meet the new NHBC requirements? | Deta

Deta’s Technical Manager, Andrew Pegrum explains how the company has worked quickly to ensure its fire rated downlight fittings satisfy the new NHBC requirements for recessed light fittings.

The NHBC’s Technical Extra (Issue 25) publication states that in relation to downlighter penetrations within intermediate floors (used within two and three storey new-build homes) constructed with engineered floor joists:

“fire resistance downlighters and fire hoods are only deemed to be acceptable if test evidence supports their use in a similarly engineered joist floor build up.”

On this basis, Deta had firmly considered that its fire rated downlights had met this criteria, following successful testing of its fire rated downlights in an engineered floor construction with one of the major I-joist manufacturers. Consequently, Deta had considered that its fire rated downlights should be qualified for installation and approval within any similarly engineered I-joist floor construction.

The NHBC subsequently advised that since the specification of I-joists and floor constructions differ between manufacturer and by installation, they don’t necessarily consider all I-joists and floor constructions to be similar. This creates a wide range of variables which calls for either an assessment to be provided by a suitably qualified fire engineer or for each manufacturer’s I-joist to be tested with fire rated downlights.

Seeking assessments can be difficult as it is understood that different manufacturers’ I-joists may behave differently under fire conditions. This, at least for the present, has resulted in the need for fire rated downlights to be tested in each manufacturer’s I-joist specification in order that test evidence can be provided to match with the floor construction installed.

Successful testing

Deta’s immediate response was to implement an extensive testing programme to test fire rated downlights in floor constructions using engineered joists from other leading manufacturers. Having worked in co-operation with several leading engineered joist manufacturers, as well as house building developers, Deta has been able to demonstrate its fire rated downlights satisfy the new guidelines.

DownlightsSuccessful testing has been carried out with leading fire testing laboratories in the UK and across Europe. These test results have now been shared with the NHBC, which has approved the installation of Deta’s current (L1680/2 and L1690/2) and new (L1701) fire rated downlights within 30 minute intermediate floors using the following constructions:

  • James Jones I-Joist
  • Metsa Wood I-Joist
  • Staircraft I-Joist
  • Steico I-Joist
  • Solid Timber Joist

Deta’s fire rated downlights can be installed in these floors in line with the test floor specification, without the need for noggins or for fire hoods to be fitted. The company is continuing the programme further to test its downlight fittings in floor constructions using engineered joists from other manufactures and is working in close partnership with them to secure further approvals from the NHBC.

A comprehensive set of NHBC approvals

Ordinarily, the test programme to gain NHBC approval for fire rated downlights in multiple I-joist floor constructions would have taken many months to complete. Deta, however, has managed to deliver a successful outcome and provide results that the NHBC has been able to approve in a matter of weeks.

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