Window Actuators
A component of process automation in modern buildings must be window automation, whether they are natural ventilation windows or smoke extraction windows through organized natural draft.
Window actuators (motors) can be operated from a local button or can be integrated into organized natural ventilation systems, can be integrated into BMS, control units can be equipped with wind, rain, temperature, CO2 sensors (for indoor air quality) etc.
Certain types of window actuators can also be used in building smoke extraction systems in case of fire, through organized natural draft, both for smoke and hot gas evacuation windows and for fresh air intake windows.
Window actuators ensure the safe opening and closing of windows, automatically or at the command of the local user, can ensure automatic opening in case of fire, prevent misuse (thus degradation) of windows and are a modern solution, increasingly widespread in modern buildings.
In terms of operation, the motor receives (from a control unit, from a locally placed button, or from the building’s BMS) a command to open or close the window. Modern actuators, with built-in control module, can communicate bidirectionally with the control system and can be monitored in real-time by it, being directly integrable actuators into BMS.
Window Actuators – Common Types
Below, you will find the most common types of motors for automatic window actuation.
Window actuators:
- Chain actuators
- Rack actuators
- Articulated arm actuators
- Rod actuators
- Slot and screw gear actuators
Chain actuators – for windows are the most economical and most commonly used option, especially for standard-sized ventilation windows, when large strokes (wide opening angles) are not required. They can be installed on both inward-opening and outward-opening windows, with hinges placed at the bottom, top (with some limitations), or side (with limitations). Generally, they have strokes of 200–700 mm (can reach 700–1200 mm) and pulling forces of 200–300 N (can reach 400–600 N). With some manufacturers, the pushing force is lower than the pulling force, and can even be insignificant for large strokes (1000–1200 mm).
Rack actuators for windows, thanks to the pinion-rack gear mechanism, allow large opening strokes and higher pulling/pushing forces, of up to 1000 N. The pulling force equals the pushing force, but rack actuators have the disadvantage of only being usable on outward-opening windows. They are also successfully used on roof hatches and can be paired up to 4 motors in a “syncro” system (synchronized operation).
They are recommended when dealing with large, heavy windows, even horizontal ones (roof hatches), that require strokes (larger opening angles).
Rod actuators generally have smaller strokes (200–500 mm) and forces of up to 650 N. There are versions with a higher IP protection rating that can be used outdoors, even for operating exterior shading systems (external blinds). The motion transmission system doesn’t allow for high opening speeds, which is why they aren’t used for smoke extraction windows. Like rack actuators, rod actuators are used on outward-opening windows.
Articulated arm actuators are window motors with very good performance, ensuring very large opening angles (up to 90 degrees), forces of up to 750 N (1500 N with two synchronized motors), and can be successfully used even on very large or very small windows, where no other type of actuator fits.
They are used on windows opening inward or outward, with hinges at the top, bottom, or side, and can be mounted both on the closing edge of the window and on the side edges.
For more details, see the KADRA article about actuators for special windows.
Slot and screw actuators are capable of strokes of 300–700 mm and forces of 500–750 N. They are a less common solution, but have the advantage of good performance, and it’s worth noting that they don’t change their dimensions during operation. In addition, they have a compact size and an attractive design, making them suitable for more demanding projects as well.
Smoke Extraction Window Motor
At first glance, ventilation window motors and smoke extraction window motors look similar and can sometimes be confused. There are even projects where, instead of smoke extraction motors, organized natural ventilation motors are installed. Quite often, during the IGSU inspection for the building’s fire safety approval, the replacement of non-compliant motors is required.
Generally, ventilation window motors are powered at 230V AC, but there are also versions powered at 24V DC. Most ventilation motors have a plastic housing, but some with a metal housing can also be found. The accompanying documents are what make the difference. A smoke extraction window motor will be tested, according to the European standard EN 12101-2, for several characteristics essential for smoke extraction:
- The ability to reach maximum stroke in the “open” position within 60 seconds maximum;
- The ability to maintain mechanical stability for 30 minutes at a temperature of 300 degrees Celsius;
- The ability to operate at low temperatures (zero degrees Celsius);
- Durability of (testing for) a minimum of 1,000 open/close cycles, if used exclusively for smoke extraction, or a minimum of 10,000 cycles, if the motor is used for both smoke extraction and daily ventilation.
If whoever is selling you the motor cannot provide the documents (test reports, classification reports, issued by a notified body) proving the above characteristics, it’s most likely a ventilation window motor, which is not suitable for smoke extraction in case of fire.
KADRA offers you complete and certified organized natural draft smoke extraction solutions, staircase smoke extraction solutions, electric or pneumatic smoke vents, automation for smoke extraction windows, and our over 30 years of experience is the guarantee that we can advise you on choosing the optimal solution, ensure correct installation, and provide maintenance and servicing with qualified specialists.
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