DESCRIPTION AND APPLICATION

The heat and smoke suppression systems (EFC) are made of chambers with natural ventilation operated either manually or automatically, sometimes coupled with antismoke curtains.

These systems are based on the principle of extracting heat and smoke from the areas where fire has started, contributing to limit its diffusion and to create below the smoke curtains a safe area where people can evacuate and first aid interventions are possible.

They also contribute to delay the flash over (total fire development) and to reduce the risk of a general breakdown of the structures caused by high temperatures.

Obviously their limit lies in a limited application, namely in ground floor buildings and/or top floors in higher buildings since their use in intermediate floors is not possible.

These systems consist of small domes made of metal frames to which the sealing material made of polycarbonate or fibreglass is fitted.



The small domes are fitted with a manual or automatic device for their opening and are connected, individually or collectively, to a fire detection system. Their opening must be guaranteed to happen within 60 seconds.
The thermal detection sensor has a fixed threshold or a thermal speedometer.

The most important factor for a good operation of these systems is the correct size of the evacuator; in fact this depends on the smoke layer which can be accumulated on the ceiling The smoke and heat evacuators must be evenly spread in the area to be protected. For the calculation of their number it is recommended to use a higher number of small dimensions instead of the contrary.

In particular, the following has to be taken into account:

One evacuator every 200 sq. metres of surface on premises
having roofs with an inclination of more than 12° or shed
roofs;
An evacuator every 400 sq. metres on premises with roofs
having inclination between 12° and 30°.


In case areas to be protected include walls, beams and other building structures, an evacuator on each single area should be installed.

In rooms where goods or materials producing strong smoke are present, additional evacuators must be fitted with independent and automatic opening device.

During the installation of the evacuators it is recommended to cover with insulating material the ceiling surfaces and the intrados where they are fitted.

In rooms where false ceilings exist and accumulation of heat can occur, it is necessary to create additional openings.