Product Reviews

Value Proposition: Integral Lighting – Evofire downlight

For most of us, the more the world shifts, the more we wish that things could stay the same. But when it comes to technology that yearning for what we’ve always known can sometimes get in the way of innovation when a real game-changing opportunity comes along. Let’s take a look at the fire-rated downlight and consider how we’ve always dealt with that thorny problem.

The fundamental requirement for a fire-rated downlight is to stop the spread of fire through the fixture into the ceiling void. But this has always been at odds with a luminaire designed to accept a tungsten halogen filament lamp, which relies on the passage of air through the fixture to stop early lamp failure through lamp over-heating.

That obvious contradiction in the fixture design brief has been resolved by some fine engineering design that has seen the tungsten halogen fire-rated downlight become a standard feature of emergency lighting design. But it’s not the end of the story.

(Left)The open-back solution of the EvoFire fire-rated downlight where the fire barrier exists between the bezel and the ceiling surface. (Right) A cutaway image of a conventional ‘can’fire-rated downlight.

But what happens if we remove one of the traditional design parameters? If there’s no need for thermal management of a very hot light source, then what does that do to the engineering of the fire-rated downlight? The answer to that is to be found in a new range of fire-rated downlights produced by Integral LED.

The Evofire downlight is built specifically around an LED source, thus removing any need for high temperature cooling within the body of the luminaire. Although the high thermal levels of heat

from conventional lamps is absent, the Evofire’s open design means that the LED lamps run cooler, and that brings with it the additional benefit of extended operational life of the LED lamp. The interchangeable MR16 and GU10 lamp options run up to 10°C cooler than a typical enclosed LED lamp inside a can. To ilustrate the point, a variation of the standard Evofire is also available with a built-in guard that keeps insulation material away from the back of the fixture.

That leaves only one issue to resolve; how to maintain a satisfactory fire barrier within the fabric of the ceiling plane. The best place to locate that fire barrier is at the ceiling surface and Integral LED has achieved that by introducing a glass and steel barrier that meets the requirements of BS476 (Fire Tests) and is capable of 30/60/90 minutes of fire protection.

Once installed, the Evofire downlight has an IP65 rating within the space  and  an IP20 rating from within the ceiling void .

The downlight has an open back and is designed to accept either a GU10 or MR16 LED lamp. An extra feature for the designer is the clear glass screen that means a variety of beam widths can be employed, according to project need. And the open back construction also results in the LED sources running up to 10°C cooler, which is a definite bonus when operating LED lamps.

The radical way in which the fire-rating is produced also brings other benefits. Once installed, the Evofire downlight has an IP65 rating within the space (IP20 from within the ceiling void)

While the downlight is robust enough to withstand the heat of a fire as required by British Standards, it is also a simple construction. That means a substantial saving in the cost of an emergency lighting installation using the Evofire.

And we might say that this is just another step along the revolutionary road that the LED is leading us along. We must expect far more re-workings of ‘conventional’ form factors as LED luminaire designers come to terms with reduced operating temperatures, yet more miniaturisation, longevity of light sources and still-increasing efficiencies in performance.