What is the Purpose of a Smoke Ventilation System?
Smoke ventilation (or smoke control) systems are designed to:
- Protect escape routes for occupants to evacuate safely and unimpeded by the effects of smoke
- Assist fire fighters entering the building to find and tackle the fire quickly
- Protect stock and machines and loss of production capacity
- Reduce the risk of explosions and roof collapse
How does a smoke ventilation system work?
Each building's smoke control system will be designed to its specific requirements, but the basic principle of how smoke ventilation in each building works will remain the same in each instance. Smoke vents (also known as AOVs or "automatic opening vents") will be installed throughout a building to protect escape stairs or any common areas, such as corridors. In the event of a fire, smoke or heat detectors will activate the vents to open, allowing smoke to rise up and out of the building. Effective smoke vent systems will remove smoke from an escape route, thereby reducing the toxins in the air and improving visibility. By doing this, smoke ventilation not only helps to ensure a safe exit for building occupants, but also aides firefighters when entering and locating and tackling the fire. Because of these reasons, smoke ventilation systems are considered "life safety systems" and play an extremely important role in fire safety.
Different Types of Smoke Ventilation Systems
Different building types and designs will require different smoke control approaches to ensure effective smoke extract is achieved. However, there are two main approaches - they are outlined below:
Natural smoke ventilation:
- Have fail safe operation
- Are self-compensating
- Operate silently
- Have no time or temperature limits
- Are lightweight
- Are sensitive to wind effects
Mechanical smoke ventilation:
- Are not wind-pressure sensitive
- Are suitable for ducting
- Have a fixed extract volume
- Require noise and weight considerations associated with them
- Have a dedicated air inlet
- Have a standby unit in case of fan failure
Natural ventilation has the benefit of not requiring any power or any other functionality to work, (apart from the vents being open) as the smoke just escapes under its own buoyancy. They also have the added benefit of being ‘self-compensating’, meaning the hotter the smoke gets, the more effective the ventilators work, due to the increase in smoke buoyancy caused by the heat. Mechanical systems extract at one rate only, so regardless of the amount of smoke, it will be extracted at a steady pace. Mechanical systems are also designed to extract smoke at a certain temperature for a set amount of time, eg. 300 degrees Celsius for 1 hour. With natural ventilation, these constraints do not apply.
Mechanical systems have the benefit of not being sensitive to wind effects, as natural ventilators are. Plus, mechanical ventilators can be ducted, which allows them to be used in multi-level buildings. It must be noted that because of the power-reliance that mechanical systems have, it is standard practice to provide fire-rated wiring for them, a standby power supply and a stand-by unit, in case of fan failure.
Colt Smoke Ventilation Systems
Colt's unrivalled smoke control expertise and team of highly experienced designers and consultants can help you design the right smoke control system for your building.
Learn more about our smoke control design approach here.
We have also developed a wide range of high quality smoke control products and components, including AOVs, natural flap ventilators, mechanical ventilators and more. View our full smoke control product range here.