When it comes to opening and closing windows, GEZE offers solutions for a variety of different applications. The complete solutions by GEZE combine different requirements on windows. The large product range comprises drive systems for daily ventilation, complete fresh air and exhaust air solutions for a safe and quick natural smoke exhaust in the event of a fire – also as SHEVs – and intelligent AOV control central units. In addition, GEZE offers a complete range of door systems as AOV fresh air openings.
GEZE attaches great importance to a comprehensive support from project planning to support for the technical implementation and to service and maintenance.
The manual window opening systems are used for comfortable daily ventilation.
The wide range of fanlight opening systems ensures an easy and reliable opening. The cranked turn and tilt hardware is the perfect solution for large scale windows.
Their area of application includes vertically installed bottom or top hung windows opening inwards and vertically installed top hung windows opening outwards. Solutions for special shapes are also offered, e.g. vertically installed angular, triangular, semi-circular and segmental arch windows
Smoke and heat extraction systems (AOV).
Why is a smoke and heat extraction system so important?
The smoke and heat extraction system (AOV) is classed under “preventive fire protection” and will save life in the event of a fire.
During a fire considerable quantities of combustion products such as smoke and fire gases and heat energy are produced. The most important task of an AOV is to discharge the products of combustion from the building efficiently and quickly. Rooms and buildings without AOV fill up with toxic smoke gases within a very short time. The risk for people trying to escape and the rescue services is strongly increased in buildings without AOV since the lack of smoke and heat extraction leads to an uncontrolled blazing fire, and the thick smoke makes active and passive rescue impossible.
Fire victims caused by direct contact with fire only occur very rarely. Almost 90% of all fatal fire accidents are due to suffocation caused by smoke gases. “Fire victims are smoke victims” – there are two reasons for this:
- Lethal constituents in smoky gas.
- Corrosive components which burn the lung and airways when breathed in.
Large amounts of smoke gas rise on account of thermal buoyancy and fill the room or the building with smoke. The high ambient temperature can lead to the building collapsing in worst cases.
Conservation of the property structure is thus a major task for the AOV. This way people can escape from the building through their own efforts, and the rescue services can carry out active rescue – evacuation of the building – for longer.
In summary, the following objectives are achieved by the use of smoke and heat extraction systems in buildings:
- Personal protection: keeping rescue routes smoke-free
- Active rescue
- Passive rescue
- Localisation of the fire
- Environmental protection: reducing damage to the environment
- Minimising damage caused by fire extinguishing activities
- Minimum use of extinguishing agents
- Property protection: conserving the building structure
- Support for fire-fighting
- Ventilation of the fire
- Minimisation of the thermal load
How natural smoke and heat extraction works
In the event of a fire, the AOV openings in the upper part of the building are opened. The hot ascending smoke gases can escape through these openings even during the initial phase. The necessary fresh air openings in the lower part of the building assist this process by balancing out the required mass flow.
Planning and design of AOV
The planning and design of AOV are subject to numerous European, national and regional regulations. For this reason, AOV systems should always be planned in agreement with local fire protection authorities. Major requirements which buildings have to meet are defined in the fire protection concept.
Components of an AOV
A GEZE AOV system is used for the daily ventilation of rooms and also for smoke extraction in the event of a fire. Windows, smoke flaps or skylight domes are equipped with electromechanical drives which open and close the fresh and exhaust air areas. The control unit has two independent power supplies (mains and battery) which guarantee operation in any situation. The functional safety of the cables and trigger mechanisms is monitored. In the event of a fire, the system is triggered quickly through automatic detectors (smoke or heat detectors), actuation via an external fire alarm system or manual actuation (AOV button). Natural smoke extraction ventilators (SHEVs) can be triggered depending on wind direction, so that in the event of a fire the building side away from the wind can be used for smoke dissipation. If the system is to be used for ventilation as well, further components will be required, such as vent switches, rain and wind controls. For automatic ventilation control, contacts from temperature or CO2 sensors can be connected. There are several standard plus ventilation functions available.
Special rules apply for planning, design and manufacturing if the building regulations, the fire protection concept or the building authorities require a natural smoke and heat exhaust ventilator (SHEV).
SHEV It is used to extract smoke and hot gases from a building in the event of fire. In accordance with EN 12101 Part 2 this controlled building product comprises a window with the respective components (profiles, seals, fittings), the infill (glass, panels etc.) and the drive system with the respective components (drive, consoles, fittings). GEZE offers drives which are tested and certified in accordance with EN 12101 Part 2 in SHEV. Customers have thus the possibility to manufacture SHEVs as system user and provide them with the necessary CE marking. See the SHEV system documents for further information.