Many residential and commercial buildings feature atria as a design feature to create a light well or to incorporate lifts or stairs into the design in a visually aesthetic way. However, they also provide a passage whereby smoke and fumes resulting from a fire could easily spread up through the entire building and affect multiple floors. Therefore, having effective smoke control and suppression systems in place in buildings with atria is essential.
An atrium can pose many design challenges. The fact that it is likely to lack vertical compartmentation against smoke travel means that it is easy for smoke to spread laterally into higher levels and to other parts of the building, unless there are suitable measures to control the smoke.
A well-designed smoke control system should be able to maintain smoke free escape conditions on all occupied levels to allow evacuation with the minimum risk of smoke inhalation, injury or death.
There are a number of design approaches available. A single approach or a number of different approaches may be used in a building, depending upon the location of the fire. The most common approaches are summarised below:
Compartmentation: Smoke control is provided by making each space a separate, fully fire resisting compartment so that smoke does not escape into other areas. This option does not require smoke ventilation but requires expensive and restrictive construction.
Compartment extract: If smoke ventilation is to be provided, maximum protection is achieved if smoke is not allowed to escape from the fire room but is directly extracted outside. However this requires either multiple individual systems or complex ducted systems so is rarely used unless essential.
Balcony extract: The complexity of compartment extract may be reduced if smoke is allowed to flow into a balcony section from one of a number of rooms and extracted from under the balcony.
Atrium extract: The simplest and most common system, this allows smoke to spill into the atrium and be extracted from under the roof. There are practical limitations on the clear height that can be achieved.
Temperature control: For a fully glazed atrium, a temperature control smoke ventilation system in the atrium can limit smoke temperatures to avoid glass failure, thus protecting occupants of other rooms.
Smoke clearance: Used in some low-risk atria.
Colt has been developing smoke control solutions for atria for decades and will be able to advise you on the best approach for your building.
Conor Logan is Associate Technical Director of Colt UK, Smoke and Climate Control Division. Conor designs innovative smoke control and HVAC systems and was Chairman of the Smoke Control Association for over 9 years.