Fire Rated Downlights: What Every Electrician Needs to Know

Downlights are on nearly every domestic and commercial job, and fire-rated versions are the correct specification in the vast majority of cases. Yet there's still a lot of confusion about what fire rating actually means, when you need IP65, and how insulation guards fit into the picture. This guide covers the essentials.

What Does "Fire Rated" Actually Mean?

A fire-rated downlight is designed to maintain the integrity of a ceiling as a fire barrier for a set period — typically 30, 60 or 90 minutes. Without a fire-rated fitting, cutting a hole in a plasterboard ceiling creates a gap that allows fire and smoke to spread between floors much faster.

The intumescent material inside a fire-rated downlight expands when exposed to heat, sealing the aperture and restoring the fire resistance of the ceiling. The rating (30 or 60 minutes) tells you how long the barrier remains effective under fire conditions.

For most domestic work — ground floor ceilings with habitable space above, or ceilings between any floors in a multi-storey dwelling — fire-rated downlights are the correct and often legally required specification under Approved Document B (fire safety) of the Building Regulations.

When Do You Need a Fire Rated Downlight?

The rule of thumb: if there is a habitable space directly above the ceiling you are fitting downlights into, use fire-rated fittings. This includes:

• Ground floor ceilings beneath first floor bedrooms or living rooms
• Any intermediate floor in a two or three-storey house
• Garage ceilings beneath habitable rooms above
• Flat roofs — check with building control

Non-fire-rated downlights are acceptable only where there is no habitable space above — a single-storey extension with roof space only, for example. In practice, specifying fire-rated fittings throughout is the safest default and avoids any ambiguity on sign-off.

IP Ratings: 20, 44 or 65?

The IP rating you need depends on where the downlight is installed:

• IP20 — dry indoor spaces only. Living rooms, bedrooms, hallways. Do not use in bathrooms.
• IP44 — splash resistant. Zone 2 in bathrooms (600mm either side of a bath or shower). Acceptable in most bathroom positions outside direct spray zones.
• IP65 — dust-tight and protected against low-pressure jets. Zone 1 in bathrooms (directly above a bath or shower enclosure to 2.25m). Also the correct spec for kitchens directly above cookers or sinks, and in shower rooms.

Most fire-rated downlights sold for domestic use are IP65 as standard — this means they're suitable across all bathroom zones and general domestic use. There is no downside to using IP65 in a dry room; the waterproofing simply doesn't come into play.

Cutout Sizes

This is where mistakes happen. Downlights come in various cutout diameters — the hole size required in the ceiling. The most common for domestic work is 70mm, but you also see 45mm (mini fittings), 83mm, and 145mm for larger panel-style fittings.

Measure before you cut — always. Ordering the wrong size means either cutting a larger hole (which is fine, within limits) or replacing the entire batch if the fitting is too big. Check the manufacturer datasheet for the minimum and maximum cutout before drilling.

The Integral Evofire range uses a 70mm nominal cutout but accepts 70–100mm adjustable versions, which gives useful flexibility on installations where the hole is slightly oversized.

Insulation Guards: Essential, Not Optional

A standard fire-rated downlight still requires ventilation space above it — the heat from the lamp needs somewhere to go. If the fitting is covered by loft insulation, it will overheat, reducing lamp life and creating a fire risk from a different direction.

Two solutions:

• Insulation guard — a cover placed over the downlight in the loft that keeps insulation away while maintaining the ceiling's thermal performance. Required with any downlight not rated for direct insulation contact.
• Insulation-compatible downlight — fittings like the Integral Evofire range with built-in insulation guard can be covered directly by insulation with no additional cover needed. These are more convenient on new builds and retrofits where access is limited.

If you're fitting downlights into a ceiling with loft insulation above and you're not using an insulation-compatible fitting, fit an insulation guard. This is not optional — it's a fire safety and warranty requirement.

GU10 vs Integrated LED

Most fire-rated downlights use a GU10 lamp holder, allowing the LED lamp to be replaced independently. This is the practical choice for most installs:

• Easy to source replacement lamps (available everywhere)
• Lamp colour temperature can be changed without replacing the fitting
• Lower fitting cost — pair the downlight with a separate GU10 LED

Integrated LED fittings (where the LED module is built in) offer longer rated life and sometimes higher efficacy, but when the LED fails, the entire fitting must be replaced. Generally better suited to commercial installs where lamp replacement during business hours is disruptive.

Products We Stock

• Integral LED Evofire Fire Rated Downlight 70mm IP65 White + GU10 Holder — the standard domestic spec, 70mm cutout, IP65, white bezel
• Integral LED Evofire 70-100mm IP65 + Insulation Guard — adjustable cutout version with built-in insulation guard, ideal for loft conversions and retrofits
• Integral LED Evofire Square IP65 70mm + Insulation Guard — square bezel variant for a modern finish, same fire performance
• Evofire 85 Fire Rated Downlight 70mm IP65 White — 4-Pack — multi-pack for larger rooms, 70mm cutout, IP65

Browse the full Fire Rated Downlights collection or the wider Downlights range. Same-day collection from our trade counter — 24 Western Avenue, Acton W3 7TZ. Call 020 8702 8080 to check availability on quantities.

Installation Checklist

• Confirm fire rating required — is there habitable space above?
• Check IP rating for zone — IP65 for bathrooms and above cooktops
• Measure cutout size before drilling
• Check for insulation in loft — use insulation-compatible fitting or add insulation guards
• Maintain 50mm clearance between fittings and joists
• Do not exceed the maximum lamp wattage stated on the fitting
• Test fire damper intumescent by checking it is present and undamaged before closing ceiling