A smoke and heat exhaust ventilation system (SHEV) must work immediately in the event of fire – even if it has only been used for ventilation or not moved at all for years. That is why standards and state law require regular maintenance and inspection. This guide shows what operators, facility managers and contractors need to know: which obligations apply, at what intervals inspections take place and what to consider when maintaining window actuators.
Maintenance and expert inspection: two different obligations
Two things are often confused with SHEV systems:
- Maintenance and inspection: regular function testing, servicing and repair by a qualified specialist company – usually once a year.
- Expert inspection: inspection by an officially recognised expert in accordance with the inspection ordinance of the respective federal state – for certain buildings before commissioning, after significant changes and at recurring intervals.
The expert inspection does not replace annual maintenance. Both obligations apply side by side.
How often must a SHEV system be maintained?
For natural smoke and heat exhaust ventilators, DIN 18232-2 stipulates that they must be inspected and maintained according to the manufacturer's instructions, usually once a year. VdS guidelines also require inspections at regular intervals, at least annually. If the manufacturer specifies shorter intervals, these apply.
Maintenance may only be carried out by a specialist company qualified for the system concerned. All work is documented in the system logbook.
When is an inspection expert required?
The inspection ordinances of the German federal states require smoke extraction systems in special buildings to be inspected by recognised experts. Typical examples are:
- Retail and exhibition spaces over 2,000 m²
- Assembly venues, schools and hospitals
- High-rise buildings and hotels
- Medium and large car parks as well as large industrial and warehouse buildings
Inspections take place before commissioning, after significant changes and at recurring intervals – every three years in most federal states, at longer intervals in some. Which rule applies to your building is stated in the building permit or fire protection concept and in the inspection ordinance of your federal state.
What is checked during maintenance?
| component | Test |
|---|---|
| RWA Central | Function, fault display, mains and emergency power supply |
| Batteries | Capacity and age; replacement as specified by the manufacturer |
| Triggering devices | Trigger and check smoke detectors, SHEV push buttons and wind/rain sensor |
| Window drives | Opening time, full opening, current consumption, fastening and brackets |
| Windows and fittings | Smooth running, seals, hinges, dirt and corrosion |
| lines | Cable routing, connections and circuit integrity |
Finally, the entire system is triggered: all windows must open fully – for SHEV usually within 60 seconds – and then close properly again.
Typical defects in window actuators
- Actuator no longer opens fully: often a worn chain, a stiff sash or an actuator that is too weak after a window replacement.
- Opening time too long: with long strokes, the running speed is not sufficient for the required opening.
- Actuator hums but does not move: gearbox damage or overload.
- Moisture and corrosion: especially on roof windows and rooflights with insufficient protection class.
- Manufacturer no longer supplies: older actuators are sometimes no longer available.
Replacing a defective actuator
If a window actuator fails during maintenance, it must be replaced promptly – until then, the SHEV system is not fully functional. Suitable replacement actuators for brands such as GEZE, Aumüller, D+H, WindowMaster, HAUTAU and Kingspan STG can be found in the guide Replacing window drives and in our replacement table.
| Mission | drive |
|---|---|
| Tilt and top-hung windows, facade | VS-KA chain drive (24 V, 250–1500 N) |
| Roof windows and skylights | Linear actuator VS-LA (600–5000 N) |
| Heavy skylights | Spindle actuator VS-SA 2500 or VS-KA 2500 (IP66) |
Important: for SHEV use, actuator, window and SHEV control panel must be matched for each project. Before replacing, check the current consumption of the new actuator and the opening time. How SHEV and NSHEV are related is explained in the article SHEV or NSHEV – the difference.
Frequently asked questions
Who is responsible for SHEV maintenance?
The building operator. They commission a qualified specialist company and ensure that maintenance and inspections are documented.
Is it enough to open the windows regularly for ventilation?
No. Daily ventilation replaces neither the maintenance of the control panel and batteries nor the trigger test of the entire system.
How long do SHEV batteries last?
That depends on the manufacturer, typically several years. The control panel manufacturer specifies when to replace them; maintenance checks capacity and age.
May I replace a SHEV actuator with another brand?
In principle yes, if force, stroke, voltage, current consumption and opening time match. For tested NSHEV, agree the replacement with the installer or expert beforehand.
Looking for a replacement actuator?
Send us a photo of the old actuator's type plate and of the window – we will name the right alternative, from stock in Hamburg. To the contact form or call +49 40 50694631.