Understanding
Fire Rated Downlights
Fire resistance periods
In the UK, Building Regulations (Part B) mandate that ceilings in residential dwellings* must have 30, 60, or 90-minute fire resistance periods, depending on the height of the top floor above ground level or the depth of the basement.
Product selection
Fire Rating is a classification of complete ceiling construction, not individual elements.
Ceilings with a 30-minute fire rating are the most common, and are found in single dwellings of three stories or less or multi-occupancy and multi-use buildings below 5m total height. If a downlight that has only been tested in 60 or 90-minute constructions is installed in a 30-minute ceiling, it will compromise the fire resistance and invalidate all fire ratings.
Fire Rating is also invalidated if a product has not been tested and certified in combination with other key elements of the proposed ceiling construction, such as joist type or luminaire spacing.
Key considerations
Tested ceiling constructions
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30 minutes- 600mm joist centres, single layer 15mm Type A or Type F gypsum wallboard
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60 minutes- 600mm joist centres, double layer 12.5mm Type F gypsum Fireline
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90 minutes- 600mm joist centres, triple layer 12.5mm Type F gypsum Fireline
Joist Types
New joist options introduced in recent years have advanced distance spanning, weight saving, and practicality. However, updated test certificates are necessary to ensure product compatibility.
Product spacing
Each ceiling opening made for a recessed luminaire can weaken the overall fire barrier. The spacing of luminaires, as well as minimum distances from other ceiling features, is defined in the products test conditions and is important for their fire safety rating. Please review the details of each product certification carefully as it is the responsibility of the installer to ensure compliance with all relevant regulations.
Testing
The fire rating test conditions require suspending a complete ceiling structure above a 4 x 3-meter furnace and subjecting it to a predetermined time/temperature fire curve for 30, 60 or 90 minutes. The ceiling's fire rating is established after the full test period has elapsed, and the declared integrity of the structure is confirmed to remain intact.
Please refer to the table below for an overview of ceiling constructions covered by Astro's fire rating testing.
