In order to deliver a personalised, responsive service and to improve the site, we use cookies to remember and store information about how you use it. By using the website and agreeing to this policy, you consent to our use of cookies in accordance with the terms of this policy.

Accept Cookies Read more about Cookies

 

Brands » Alux » Natural Smoke and Heat Exhaust

Natural Smoke and Heat Exhaust


Skylights equipped with a natural smoke and heat exhaust system (NSHE) are one of the essential elements for providing safety in case of fires.

Which dangers does the NSHE system reduce substantially or prevent in the event of a fire?

  • Danger of Smoke during Fires
    • smoke prevents visibility in rooms that are on fire, as well as orientation for escaping or evacuation,
    • the composition of smoke is toxic, because there is a shortage of oxygen, which is replaced by toxic gases that quickly cause people to become intoxicated, faint or even suffocate,
    • makes the intervention from firemen and rescue units difficult.

Solution: Efficient natural smoke exhaust reduces the concentration of toxins and improves visibility in the room for easier evacuation and rescue.

  • Danger of Heat Development
    • in closed rooms, heat accumulates aggressively above the fire and fills up the room, 
    • the temperatures of accumulated gases reach very high values. In a short time the temperature can exceed the spontaneous combustion point of materials. Objects, linings and walls can ignite without even coming into contact with the flame. Due to high temperatures the load-bearing parts of structures can give in or ignite.

Solution: A natural heat exhaust provides the extraction of hot air through openings and the entry of outdoor air into the room. 

  • "Flashover" - Explosive Near-Simultaneous Ignition
    • the lack of oxygen, which is used up during combustion in closed rooms, has a potential highly dangerous effect. When materials overheat, a thick, overheated, almost liquid smoke develops, which becomes highly explosive. The result of this is a powerful explosion, which is often fatal for firemen and rescuers and destructive to equipment, rooms and buildings.

Legislation for Natural Smoke and Heat Exhaust 

On 1st September 2006, Slovenia adopted the European legislation that regulates fire protection requirements for devices for natural smoke and heat exhaust.
The SIST EN 12101-1:2005 standard defines the requirements which must be met by devices for natural smoke and heat exhaust with natural ventilation, which include dome skylights and skylight bands. The essential requirements of the new standard mostly refer to the areas presented below:


Akripol Skylights, Domes and Bands

  • Opening of Skylights

    Dome skylights that are intended for smoke and heat exhaust must have a minimum opening angle of 140°, whereas skylight bands that are intended for smoke and heat exhaust must have a minimum opening angle of 165°.

  • Aerodynamic/Effective Surface Area

    The aerodynamic/effective surface area of the opening mechanism is determined based on the geometric surface area of the skylight and using a flow coefficient, determined with experiments. Whenever the latter is not determined with experiments, the factor of 0.4 applies. The aerodynamic surface area of the apertures is the total aerodynamic surface area of all the apertures of the skylight for NSHE in one smoke sector. 

  • Possible Ways of Activating Devices for Natural Smoke and Heat Exhaust

    The SIST EN 12101-2 standard allows the use of pneumatic opening mechanisms that use CO2 gas as propellant and electrical opening mechanisms. Devices can be activated with a temperature vial, a manual switch or a signal sent from the fire central.

  • Opening under Load

    The SIST EN 12101-2 standard defines the obligatory testing for determining the snow load (SL) for which the device for natural smoke and heat exhaust is suitable. After being tested by being opened at a wind speed of 10m/s, the class of operation under snow load is determined (SL 0, SL 125, SL 250, SL 500, SL 1000 and SLA).

  • Operational Reliability

    The device for natural smoke and heat exhaust must open the skylight in less than 60 seconds. If the skylight is intended only for natural smoke and heat exhaust, it must withstand the test of being opened for a minimum of 50 times; if the skylight is intended for ventilation and natural smoke and heat exhaust, it must withstand the test of being opened for a minimum of 1000 times.

  • Performance at Low Temperature

    After testing is conducted, the system is assigned the minimum temperature at which the system is still operational; the standard defines the classes of T-25, T-15, T-05, T-00 and T A. The number next to the designation T stands for the chosen operational temperature – i.e. the temperature at which the system is still operational and not the outside temperature.

  • Temperature Stability

    The standard defines the classes of B 300, B 600 and BA under which the device for natural smoke and heat exhaust is still operational. A condition for being categorised into a specific class is that when the device is being tested, which lasts for 30 minutes at a specific temperature (the number next to the class B designation), the daylight area is not reduced by more than 10%.

  • Wind Load

    The standard defines the classes of WL 1500, WL 3000 and WL A; the numbers next to the WL designation stand for the wind suction load in Pa which must not cause damage to or open the devices for natural smoke and heat exhaust.

  • Reaction of Materials to Fire

    Based on the SIST EN 13501 standard, the class of the material of which the device for natural smoke and heat exhaust is made is determined.

In order to deliver a personalised, responsive service and to improve the site, we use cookies to remember and store information about how you use it. By using the website and agreeing to this policy, you consent to our use of cookies in accordance with the terms of this policy.

Accept Cookies Read more about Cookies