Smoke Vents with Multiple Functions
Roof smoke vents are outlets for smoke and hot gases in case of fire and must meet fire safety standards, both local (P 118/1-2025) and European (EN 12101-2)
Fire safety standards requirements:
- temperature resistance (300 degrees Celsius, for 30 minutes);
- ability to withstand wind loads (WL 1500);
- ability to withstand snow loads (SL 300, SL900);
- operating capacity at low temperatures (-15° C);
- reliability (tested for at least 1000 open-close cycles: Re 1000).
Smoke Vents with Ventilation Function
For the daily natural ventilation of the building, it would be useful to use the smoke vent. Pneumatic smoke vents can have an additional daily ventilation function – an extra frame, operated by a chain motor, which can be opened for natural ventilation. Usually, that chain motor has a stroke of 300 mm and ensures a limited ventilation area.
Electric smoke vents can also be used for natural ventilation, but they must meet a very important requirement of the EN 12101-2 standard: reliability of at least 10,000 cycles!
It is not allowed for a smoke vent tested for smoke extraction at 1000 cycles (Re 1000) to be used for the automated natural ventilation function.
Smoke Vents with Roof Access Function
Being located on the building’s roof (terrace), it would be a substantial advantage for the smoke vent to also be used as a roof access vent. A roof access vent requires a free space of at least 800 x 800 mm. In standard-sized smoke vents (approximately 1 x 1 m), the dome opening mechanism is placed in the middle, so there is not enough space for a person to exit onto the roof.
However, a vent with a special opening system, even if it is 1 x 1 m in size, can provide enough space for a person to pass through.
Smoke Vents – Natural Lighting
Usually, the dome of smoke vents is made of acrylic glass or polycarbonate (cellular or compact), most often matte or semi-transparent. Although it allows some natural light to pass through, such a dome is not the ideal solution if we want to maximize natural light input. Therefore, for a smoke vent, it would be an advantage to be equipped with a glass dome.
Summarizing, a smoke vent certified for smoke extraction, 100% electric, operated by motors tested for 10,000 open-close cycles, with an opening mechanism designed to maximize the free passage space through the vent and equipped with a glass dome, would be a complex product with 4 distinct functions:
- smoke extraction;
- daily natural ventilation;
- roof access;
- maximum natural lighting.
You can find such a multifunctional roof vent in KADRA’s offer, and it is the ideal solution for stairwells of any type of building. This multi-functional smoke vent can be customized according to project requirements (double-curved dome made of multi-layer compact polycarbonate, multi-layer PMMA acrylic, a combination of acrylic and polycarbonate, or a flat dome made of insulating glass, multi-chamber PVC base or sheet metal – with thermal insulation, etc.).
Smoke Vents – Dimensions
The surface (area) of the smoke vent is a defining parameter of its performance. In addition to the geometric area, a smoke vent is defined by the Aerodynamic area – Aa (also called effective smoke extraction area or net smoke extraction area), which defines the actual smoke extraction capacity of the vent. Aa is calculated by multiplying the geometric area (Av) of the vent by a coefficient Cv, which is less than one and is determined by actual testing of the vent in an authorized laboratory (notified body), according to the European standard EN 12101-2:
Aa = Av x Cv
For example, a rectangular vent, with sides (width and length) of 1 m and a Cv coefficient of 0.7, will have an aerodynamic area Aa = 1 sqm x 0.7 = 0.7 sqm.
Regarding the dimensions of smoke vents, there are two distinct situations that lead to the choice of the appropriate smoke vent:
- The opening for installing the vent is already made in the roof. The vent will be ordered according to the dimensions of the opening in the roof.
- There is a specific requirement (for example, in the Fire Safety Scenario of the respective building) for a certain aerodynamic smoke extraction area Aa. In this case, the necessary geometric area (Av = Aa / Cv) is calculated, the dimensions of the vent are chosen, and, depending on them, the necessary opening is made in the roof.
At KADRA, you will find complete solutions for organized natural draft smoke extraction, stairwell smoke extraction solutions, electric or pneumatic smoke vents, automation for smoke extraction windows, and our over 30 years of experience is a guarantee that we can advise you on choosing the optimal solution.
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