smoke ventilation windows
Aluminum smoke ventilation windows applied in modern public buildings play a very important role in protecting the life and health of the people found inside these buildings. The efficient and safe evacuation of people from the entire building or from the part where the fire is contained depends on proper selection of smoke ventilation windows and their reliable operation. Conditions for conducting rescue and firefighting operations are also ensured in the smoke-free space. Aluminum window joinery is distinguished by exceptional durability, corrosion and temperature resistance, and the capability of operating in chemically aggressive environments. Thanks to such properties, natural smoke and heat extraction systems based on windows made of aluminum profiles seem best.
Aluminum smoke ventilation windows
are often hidden components of construction joinery, however they perform important functions when it comes to the fire safety of buildings. The greatest threat to human life and health in the part of a building where a fire has broken out is the smoke and volatile toxic substances emitted during burning of the interior furniture and finishings of the building and of its structural materials. Most victims of fires are people who have been poisoned by carbon monoxide or asphyxiated by poisonous gases resulting from burning of plastics. The smoke generated during a fire has a high temperature, reaching up to several hundred degrees Celsius and is a lethal threat for anyone found in the area where it is present. The absence of oxygen and visibility enabling evacuation, high temperature, and the presence of highly toxic gases are the main threats to life and health in the case of a fire. Corridors, stairwells and other traffic routes being evacuation routes in a building should be a zone protected against smoke, poisonous gases and high temperature during a fire. The most common method of securing such places in a building is a gravity smoke and heat extraction system in the form of smoke flaps and smoke ventilation windows.
Aluminum smoke ventilation windows
are a component of a gravity smoke extraction system, which works based on basic laws of physics associated with differences in gas temperatures and densities in the case of fire. A gravity system utilizes the natural movement of smoke and air caused by a thermal draught, the so-called chimney effect, in contrast to a mechanical system, which utilizes forced flow of air and smoke. A gravity smoke and heat extraction system consists of several components; the primary ones are smoke ventilation windows, a control unit, optical smoke detectors and manual fire alarms. Additional components are ventilation buttons, optical and sound signalers, precipitation detectors, wind intensity and direction sensors, and a weather control unit. The set of both the primary and additional components of a gravity smoke and heat extraction window system is selected from the perspective of their functionalities and proper inter-operation in the event of a fire. The system is activated automatically or manually; in the first case, the system is activated automatically by an impulse from the optical smoke detector, and in the second case, manually by pressing the fire alarm button. The heart of the system is the smoke extraction control unit, which, on one hand, receives fire threat signals from smoke detectors, manual fire alarms or the master fire alarm system, and on the other, transmits voltage signals for control of all executive elements of the system, including smoke ventilation windows. The primary task of a gravity smoke and heat extraction system is to create a layer free of smoke in the building’s evacuation routes, thus ensuring conditions for safe evacuation of the people in the fire hazard zone. An equally important task is facilitating the operations of rescue and firefighting services. By utilizing the phenomenon of rising and expansion of the smoke and gases generated by a fire, the gravity smoke extraction system removes hot fire gases through the aluminum windows. In this way, it also limits the action of these gases’ high temperature on the building’s structure, protecting it against destruction. An indispensable condition for the performance of such tasks by a smoke extraction window system is to ensure the required active smoke extraction surface.
The operation of smoke ventilation windows
is based on maximum opening of their casements in the event of a fire and extraction of smoke and fire gases outside of the building. Electric actuators are the mechanisms opening the casements of smoke ventilation windows. Depending on their design and method of operation, aluminum smoke ventilation windows can be equipped with chain, spindle or arm actuators. The selection of electric actuators accounts for the method by which smoke ventilation windows are opened, the casement opening angle, the dimensions and weight of the window and its glazing.
Technical requirements for aluminum smoke ventilation windows
are given in standard PN-EN 12101-2:2003 (Smoke and heat control systems - Part 2: Specification for natural smoke and heat exhaust ventilators). This standard defines, among other things, requirements concerning smoke ventilation windows being a component of gravity smoke and heat extraction systems. In the light of this standard, which has been in force since 2004, an aluminum window intended for smoke extraction from a building is not an independent construction joinery structure but an integral part - along with electric actuators - of the component of the gravity smoke extraction system, bearing the CE mark. Standard PN-EN 12101-2:2003 covers both testing and classification, making it possible to determine the reliability of smoke extraction windows, their capacity to operate at low temperatures, their resistance to wind and snow load, and resistance to the action of high temperature. Calculation of the active smoke extraction surface of aluminum windows also takes place according to standard PN-EN 12101-2, based on the window’s geometric surface and aerodynamic air flow factor, with consideration of the method by which the window casement is opened and the actuator’s maximum extension. Calculations require precise specification of the smoke ventilation window, encompassing the system of profiles, frame and casement cross-section, casement dimensions and the type of glazing applied, the type of actuator and the method of its fitting in the window.
Regardless of the calculated active smoke extraction surface of windows, the effectiveness of a gravity smoke extraction window system depends on many external and internal factors, such as the course of the fire, the temperature of fire gases and their thermal stratification, as well as wind force and direction.
The design of aluminum smoke ventilation windows
is based on traditional solutions of window systems. A window smoke ventilation system utilizes aluminum window designs in a broad range of overall dimensions and with various opening methods. Practically every type of window – besides sliding windows – can be manufactured as a smoke ventilation window. Windows with a vertical opening axis, opening both to the interior and to the exterior, are the most commonly encountered technical solution. An equally popular type of smoke extraction window is a window with a horizontal hinging axis; tilting windows or outward tilting windows. Yet another variant are horizontal and vertical revolving windows in single- or multi-plane versions. Roof windows, which, in fact, serve as smoke flaps, are also manufactured as smoke ventilation windows. The appropriate fitting consoles for installation of electric actuators are selected for every system of aluminum profiles and window opening method, so that the window and actuator constitute a cohesive component of the smoke extraction system according to standard PN-EN 12101-2.
The advantages of aluminum smoke extraction windows
are undoubtedly their aesthetically pleasing appearance as well as their reliability and resistance to external conditions. They are also distinguished by exceptional functionality, since, besides their primary function of extracting smoke from a building during a fire, they also serve for daily ventilation and aeration of buildings without the need for manual opening and closing of windows. With the appropriate signals from the control unit, aluminum windows make up an automatically operating system enabling effective air change in the building, at a specific time and accounting for current weather conditions.
Aluminum smoke ventilation windows can function as individual structures mounted in the wall or roof of a building but also as components fastened to the aluminum post-and-beam structures of facades or roof skylights. Aluminum smoke ventilation windows do not differ in appearance from other aluminum-glass structures installed in the same building, and only the electric actuators visible on the windows indicate the function they serve in the event of fire. An additional advantage for investors seeking aesthetically pleasing solutions is the possibility of painting the profiles of aluminum windows with the full RAL palette, including in structural variants, as well as the availability of the DECORAL multi-color imitation wood palette.
