About smoke ventilation
Preservation of life in the event of a fire is greatly enhanced if a comprehensive smoke control and ventilation system is in place. In 2008/9 there were around 75,000 fires in the UK with over 300 deaths and 12,000 injuries. Most of the deaths and injuries were caused by heat and smoke – emphasising the necessity for controllable openings which will allow smoke to escape.
Effective and Safe
Smoke control using natural ventilation is a particularly effective means of protecting escaping occupants, those awaiting rescue and fire-fighters from the immediate dangers of fire and smoke. In principle, high-level outlet vents and low-level inlet vents open automatically in the event of a fire to allow cool air into the building with smoke and hot air to flow out. This improves the conditions for occupants to escape and fire-fighters to enter. In the absence of ventilation, smoke fills the room, being drawn back down from the ceiling by convection as temperatures rise, leading to potential—and particularly dangerous—‘flashover’.
The specific design of an effective and safe smoke ventilation system requires specialist involvement, perhaps by the mechanical and electrical consultant, and may well form part of a fire engineering solution.
Helping You Comply with Building Regulations
Guidance to building regulations includes specific use of smoke ventilation systems, as outlined overleaf. In England and Wales, Part B of the Building Regulations covers fire and the Approved Document (AD B) Volume 2 provides guidance applicable to flats and non-dwellings. The following national, regulatory guidelines have similar requirements: Section 2 of the Scottish Building Standards Agency Technical Handbooks 2007; Technical Booklet E of the Building Regulations (Northern Ireland); Technical Guidance Document B of the Government of Ireland Building Regulations 2006. AD B identifies a number of situations where AOVs provide natural ventilation are appropriate, including:
- Small single stair blocks of flats
- Common escape routes in larger blocks of flats
- Basement areas
- Enclosed car parks
- Vertical smoke shafts, as part of a smoke control design
