Smoke Shaft Vent Kits
Smoke Shaft AOV Kits
Ventilation systems in the lobbies of tall buildings, commonly known as smoke shafts, are used to maintain safe escape routes in the event of a fire. Smoke shaft Ventilators are used for natural ventilation where the head of the shaft ends with an automatic opening ventilator (AOV). The complete AOV system is controlled by an addressable control system that provides automatic operation of the ventilation by interfacing with the fire alarm system or smoke detectors.
Compliance with Building Regulations
Smoke shaft compliance comes under the requirements for natural smoke shafts (BRE shafts). Paragraphs 3.5.1 b of Approved Document B of the Building Regulations 2019 details the requirements as follows:
They should discharge into a vertical smoke shaft, closed at the base, that meets all of the following criteria.
The shaft should conform to the following conditions.
- Have a minimum cross-sectional area of 1.5m² (minimum dimension 0.85m in any direction).
- Open at roof level, minimum 0.5m above any surrounding structures within 2m of it horizontally.
- Extend a minimum of 2.5m above the ceiling of the highest storey served by the shaft.
The free area of all the following vents should be a minimum of 1m² in the following places.
- From the corridor or lobby into the shaft.
- At the opening at the head of the shaft.
- At all internal locations within the shaft (e.g. safety grilles).
The smoke shaft should be constructed from a class A1 material. All vents should either be a fire doorset (see Appendix C, Table C1, item 2.e for minimum fire resistance) or fitted with a smoke control damper achieving the same period of fire resistance and designed to operate as described below. The shaft should be vertical from base to head, with a maximum of 4m at a maximum inclined angle of 30 degrees.
If smoke is detected in the common corridor or lobby, both of the following should occur.
Simultaneous opening of vents on the storey where the fire is located, at the top of the smoke shaft and to the stair.
Vents from the corridors or lobbies on all other storeys should remain closed, even if smoke is subsequently detected on storeys other than where the fire is located.
The current draft of BS 9991 – Fire safety in the design, management and use of residential buildings. Code of practice specifies that vents into smoke shafts should be multi-compartment smoke control dampers certified to BS EN 12101-8:2011 – Smoke and heat control systems – Smoke control dampers and specifically excludes the use of non-certified products as follows (from clause A.5.3.2)
Note 1 Products tested as “smoke rated fire doors” are not acceptable replacements for smoke control dampers (e.g. BS EN 12101-2 products with additional tests)
Note 2 The fitting of actuators to other components to “make” natural smoke vents or smoke control dampers is not acceptable as no performance has been tested.
Smoke shaft control requirements
Smoke shaft vents must be provided with a standby power source, CE marked to BS EN 12101-10:2005 – Smoke and heat control systems. Power supplies. This will usually take the form of a battery backup supply housed within a control unit. Additionally, control panels should be certified to ISO 21927-9:2012 – Smoke and heat control systems. Specification for control equipment.
Once a ventilator has opened due to smoke being detected in one lobby, then all other lobby vents shall remain closed. The stairwell vent and head of smoke shaft vent should be activated automatically when a lobby ventilator is opened so all controls will be networked.
The EV-301 control panel that features in the AOV kit range meets all of the above standards and is designed to be networked to give the correct control sequence. There are many additional features that can be added to the panel including thermostatic control and wind and rain-sensing control for summer ventilation.
Smoke Shaft AOV Kit options
There are three models available within the AOV kit range which provide code-compliant solutions for a BRE natural smoke shaft system. An EN 12101-8 certified smoke damper provides the AOV into the shaft and a choice of EN 12101-2 louvres or hatch vents are available to provide the roof-mounted automatic opening vent.
View alternative AOV Kits
AOV Kits A, B, C & H are suitable for stairwell ventilation. Find out more about each kit.
Automatic Opening Vent Kits D & I are suitable for lobby vents. Find out more about each kit.