Mechanical Smoke Ventilation: How It Protects People and Buildings

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In a building fire, smoke is usually what stops people reaching an exit and what stops firefighters reaching the fire. Mechanical smoke ventilation exists to deal with exactly that problem: it removes smoke and hot gases quickly, so escape routes stay usable and the building stays accessible.

This post explains how mechanical smoke ventilation works, where it is used, what its certification means, and why the air that replaces the smoke matters as much as the fans that remove it.

How mechanical smoke ventilation works

A mechanical smoke ventilation system uses powered fans to pull smoke and hot fumes out of a building during a fire. Its purpose is twofold: to provide a means of escape for occupants and to give the fire-fighting services access to the building.

The key advantage over natural smoke ventilation is predictability. Natural systems rely on smoke rising and escaping through openings. A mechanical system does not depend on that, and once it is activated the full volume flow is available regardless of the fire load. That consistency is why mechanical systems are the preferred choice in buildings where natural ventilation cannot be relied on.

Where it is used

Mechanical smoke ventilation suits buildings where smoke has nowhere natural to go, or where the consequences of smoke build-up are severe:

• Multi-storey buildings

• Basement areas

• High-risk industrial warehouses

• Atriums

The fans can be installed on the roof, in the walls, or within a fire-rated duct system. The right option depends on the layout of the building and the requirements of the project, which is why the system should be considered early in the design stage and not added at the end.

Certification and performance

Curvent's mechanical smoke ventilation is certified to EN 12101-3, the European standard for powered smoke and heat exhaust ventilators. The equipment is rated for 300°C with a minimum operating time of 120 minutes.

Those two figures matter in practice. A fan that stops when the temperature rises is of no use in the one situation it was installed for. A rating of 300°C for 120 minutes means the system is tested to keep extracting through the period when occupants are evacuating and firefighters are working.

Don't forget the supply air

A fan can only extract smoke if air can enter the building to replace it. Supply air openings are a prerequisite for satisfactory operation, which makes them a core part of the design and not an afterthought.

When the openings are too small, badly placed or blocked, the fans work against a vacuum and extraction falls well short of what the system is capable of. Checking that supply air paths exist, and stay clear, is one of the simplest ways for building owners and facilities managers to protect their investment.

Working with Curvent

Curvent International has manufactured ventilation and smoke ventilation equipment in South Africa since 1984. We supply and install mechanical smoke ventilation systems and work with consultants, contractors and building owners to match the system to the building.

If you are planning a project that needs smoke extraction, get in touch with Curvent International to discuss the right solution.