Recessed ceiling fans and ventilation ducts are widely used in both domestic and commercial buildings and the use of forced / controlled ventilation is increasing because it can be more energy efficient than traditional ventilation methods.
Centralised ventilation units and heat recovery units result in a building having both horizontal and vertical penetration holes through the structure; thus creating pathways for the passage of fire and smoke. Once a hole is made in the ceiling for a polymeric fan or vent, the integrity of the construction and its ability to perform in a fire, is reduced significantly.
Ceilings subject to fire regulations must be fire protected in accordance with Approved Document B of the Building Regulations. Any vent opening must be fire stopped to reinstate the original fire rating of the ceiling. Unlike down lights, which are generally all fire protected, fans and vents are often left unprotected. A 100mm diameter fan or vent has several times the open area of a down light and lacks a metal “can” to slow the spread of fire. This, coupled with the ability of the fire to move all around the building via the ventilation system, makes it ever more important to fire protect ceiling mounted fans and vents.