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What is "SHEVS"?

"SHEVS" is also known as a smoke and heat exhaust ventilation systems. These are either natural or powered systems used to remove smoke, caused by a fire, from a building. These systems will enable a clear escape route on the lower bottom of the building as well as help to reduce the damage of the fire to the building.

In order for Curvent's ventilation experts to design the most effective smoke and heat ventilation solution, it is important to consider a wide range of factors that we have listed below:

Natural versus powered ventilation

The first factor to consider in the design of a effective smoke ventilation system is whether to use natural or mechanical ventilation.

Natural smoke ventilation utilises the characteristic lightness of the hot gases to drive the smoke up and through the ventilators. These systems regularly have a double capacity for both smoke ventilation and everyday ventilation.

In contrast powered smoke ventilation relies on mechanical extraction through, for instance, extractor fans.

Smoke containment

The second factor is to look at the rooftop space. Where the rooftop space is extensive, it's important to restrain the spread of smoke inside the roof space. This requires high level smoke barriers or hindrances to partition the rooftop space into discrete smoke reservoirs.These smoke barriers could be fixed or automatic smoke curtains or heat resistant boards or glazing.

Smoke barriers are regularly used in complex buildings and structures, for example, shopping malls and atrium buildings to control the flow of smoke into the mall or building.

Clear layer

A third factor to consider when you are planning a smoke / fire ventilation system is the height of the clear layer of air below the smoke.

It should be sufficiently high enough to protect the building and escape routes and to guarantee that the smoke barriers won't adversely influence the building usage while being kept as low as possible to limit the expenses of the smoke control system.

Replacement air

Lastly a supply of replacement air is essential. As smoke and gases are extracted, sufficient air needs to take their place, otherwise the building will become depressurized and the smoke ventilation system will become ineffective. The replacement air supply may be from natural ventilators in smoke reservoirs remote from the fire or from dedicated low level air inlet ventilators or from automatic doors.

Contact Curvent International for a more comprehensive understanding of your system’s design requirements.

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