Smoke and heat exhaust ventilation systems create a smoke free layer above the floor by removing smoke and thus improve the conditions for the safe escape and/or rescue of people and animals and the protection of property and permit the fire to be fought while still in its early stages. They also exhaust hot gases released by a fire in the developing stage.The use of smoke and heat exhaust ventilation systems to create smoke free areas beneath a buoyant smoke layer has become widespread. Their value in assisting in the evacuation of people from construction works, reducing fire damage and financial loss by preventing smoke logging, facilitating fire fighting, reducing roof temperatures and retarding the lateral spread of fire is firmly established. For these benefits to be obtained it is essential that smoke and heat exhaust ventilators operate fully and reliably whenever called upon to do so during their installed life. A heat and smoke exhaust ventilation system is a scheme of safety equipment intended to perform a positive role in a fire emergency. Components for smoke and heat exhaust systems should be installed as part of a properly designed smoke and heat exhaust system.

Smoke and heat exhaust ventilation systems help to:

- Keep the escape and access routes free from smoke ;
- Facilitate fire fighting operations by creating a smoke free layer ;
- Delay and/or prevent flashover and thus full development of the fire ;
- Protect equipment and furnishings ;
- Reduce thermal effects on structural components during a fire ;
- Reduce damage caused by thermal decomposition products and hot gases.

Smoke ventilation consists in the evacuation of smoke and heat, these gases being replaced by fresh air.

Smoke ventilation may be achieved through natural or / and powered ventilators. Therefore, 4 types of systems are possible:
Type 1 : Natural ventilators for extraction / natural inlets for replacement fresh air
Type 2 : Natural ventilators for extraction / powered ventilators for replacement fresh air
Type 3 : Powered ventilators for extraction / natural inlets for replacement fresh air
Type 4 : Powered ventilators for extraction / powered ventilators for replacement fresh air
Important: For any smoke area, Natural and powered solution shall not be mixed for extraction or inlets