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Smoke Control systems and the function of SHEVs

Whitesales SHEV system


Smoke control is essential to help firefighters tackle blazes more safely and effectively, so they can save more lives and reduce structural and material damage to buildings. Smoke Heat Exhaust Vent systems (SHEVs) are designed to delay or prevent flashover – to slow or stop fire developing to catastrophic levels.

Statistics show that 53% of fire-related fatalities result from people being overcome by smoke or gas, rather than dying from the fire itself. Smoke control systems are life-saving devices – greatly increasing an occupants’ chances of survival in the event of fire by keeping escape routes smoke-free.

The primary objectives of the smoke ventilation system is to protect the staircase and common circulation areas. The performance criteria and the design of the system will therefore vary depending on the layout of the common corridors or lobby of the building. Often a building’s design will determine which ventilation system is most appropriate, with British Standard guidance varying depending on a building’s height and the distance from the furthest apartment entrance door to the nearest escape route. Where appropriate the system selected can be driven by design aspirations, space constraints or architectural restrictions.

Mechanical ventilation systems, in particular, provide exceptionally effective smoke control, as well as greater building design flexibility.

Mechanical smoke ventilation systems are comprised of an extract shaft serving common corridors and lobby areas of a building. When smoke is detected within an area covered by the system, the vent to the smoke shaft on the floor where the fire is located will open (all other vents must remain shut). At the same time, the head of stair vent will open to provide make-up air for the smoke extraction system. The fan at the top of the mechanical smoke shaft extracts the smoke and
prevents migration of smoke into the adjacent compartments. The alternative to mechanical ventilation is a natural smoke ventilation system, which opens air ways, and uses natural air-flow dynamics to remove smoke, when a fire occurs.

All SHEV products must pass stringent tests carried out by a fully independent test laboratory and bear the compulsory CE mark. They should also be designed and manufactured to ISO 9001 and meet the requirements of Building Regulations ADB and ADL. Full specification details should be outlined in supporting materials and declaration of performance documents.

We understand the complexities of design and specification of building smoke control. It can be difficult to keep up to date with ever changing products and constantly evolving standards and regulations. With this in mind, we have developed our CPD seminars to provide you with the thorough knowledge you need – book our smoke control CPD, ‘No Fire without Smoke’.

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