When you are faced with the task of choosing a 2 legs downlight or 3 legs downlight for your home or business, one of the first factors you may want to consider is:
Do i need a fire rated downlight ?
A potential fire hazard is created when a hole is made in the ceiling to mount a recessed downlight. Plasterboard ceilings have the natural ability to act as a fire barrier. In any building where people may live or dwell above, the ceiling below must be fire resistant. Fire rated downlights are used to restore the fire integrity of the ceiling.
In the event of a fire, the tradiional downlight hole acts as a channel, allowing the fire to spread unhindered. Once the fire begins to spread through the hole, it can penetrate directly into the adjacent structure, which is usually made of wooden ceiling joists. Fire-rated downlights close the hole and slow the spread of fire. Modern fire rated downlights are equipped with expansion pads which expand when a certain temperature is reached and prevent the fire from spreading. Then the fire must find another way: to slow down its progress.
This delay allows occupants to escape the building, or ideally to allow additional time to put out the fire. You will notice that some fire rated downlights last 30, 60 or 90 minutes. This rating depends on the structure of the building and, more importantly, on the number of floors it has. For example, the top floor of an apartment building needs a fire rating of 90 or maybe 120 minutes, while the ceiling on the ground floor of the house needs 30 or 60 minutes.
If you cut the ceiling, you must restore it to its original state and not interfere with its natural ability to act as a fire barrier. LED fire rated downlights do not require fire classification, only recessed downlights have this requirement. Fire rated downlights are not necessarily required if you are installing recessed downlights in commercial grade ceilings with concrete structures and false ceilings.