A stairwell smoke ventilator is an AOV which provides at least 1.0m2 of free area when open. It usually serves one of two purposes;
- to evacuate any smoke that gets in the stairwell of small buildings,
- or, more commonly, it provides replacement air for a lobby smoke extract system in large buildings.
The most common product types of stairwell ventilators are illustrated below.
The louvre provides discharge of smoke and fumes through motorised blades along the length of the frame. A choice of blades are available with standard and insulated aluminium, 8mm or 16mm polycarbonate (transparent or opal) and single or double-glazed panels.
It is recommended that insulated blades and frames are used to prevent future condensation problems.
Louvred ventilator with weatherproof ventilation
The louvre provides discharge of smoke and fumes though the motorised blades along the length of the frame. Different styles of blades are available with standard and insulated aluminium, 8mm or 16mm polycarbonate (transparent or opal) and single or double-glazed panels.
These weatherproof ventilators also contain separate 24V, side-mounted daily ventilation louvres to allow fresh air input without opening the whole louvre. This means that daily ventilation can be provided even in wet weather.
Actuated vertical window
It is preferable and more effective for the window to be bottom hung and outward opening.
To meet standards it must always provide the required free area as specified in Approved Document B. A range of actuators are available, including chain drives, linear and folding arms.
These should be tested and CE marked to EN12101:2.
Guidance on Stairwell AOVs
For more guidance on stairwell AOVs, download our useful pocket guide to stairwell AOVs.
Under the Construction Products Regulations (CPR) it is a legal requirement to use only certified products for smoke ventilation. For more information see SCS Group's Technical Bulletin here.