Smoke Vent Installation

Smoke Vent Installation

Smoke control is an important life safety feature of any building. Equipment and systems relating to smoke control and ventilation must be designed and installed correctly for the building to ensure safety of occupants and where appropriate, fire fighters.

Mechanical smoke shaft systems are commonly installed as part of a fire engineered approach to safety in buildings and the presentation by contractors and acceptance of these by Building Control Officers is a key event in the handover process of construction projects. These are routinely conducted in an ad hoc manner with little structure, evidence of commissioning, or record of performance data. It is common for demonstrations to be repeated several times for to a variety of reasons including system non performance, absence of key personnel and incomplete interfaces with other systems.

A stairwell smoke ventilator is an automatic opening ventilator (AOV) which provides at least 1.0m2 of free area when open. It usually serves one of two purposes;

  1. To evacuate any smoke that gets in the stairwell of small buildings
  2. Or more commonly it provides replacement air for a lobby smoke extract system in large buildings

There are two main types of smoke ventilators, used at the head of a stairwell – they are louvred vents and hatch vents. Both types of vents are able to perform the expectations of an AOV, however each have individual benefits which will influence the selection process.

For comprehensive information on stairwell ventilators see the Easivent’s pocket guide to stairwell AOV’s

Hatch
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Louvred vent benefits

  • Louvred ventilators can be used for daily ventilation, either by adding a rain sensor to the control system, or by selecting a louvre with separate 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.
  • Louvred vents have a low profile when installed, which means the vent is less likely to incur wind damage when open. This is a frequent cause of damage to hatch ventilators which are opened in high winds.
  • Even when open, intruders will not be able to gain access to the building through the vent.

Hatch vent benefits

  • The lid opens to over 120o to ensure smoke exhaust benefits from cross winds and has no obstructions.
  • The free area of a hatch vent is maximised as there are no obstructions to airflow therefore the roof opening size is slightly smaller than the equivalent louvre.
  • An insulated hatch vent will have a better u value than the equivalent louvre giving a better insulation performance.
  • Hatch vents may also be used for roof access.
    • Using hatch vents for roof access will require the opening mechanism to be designed in such a way that it doesn’t obstruct access through the hatch. In addition, manual controls to facilitate the opening and closing both from inside and from the roof can be installed. For more information see our blog using stairwell smoke ventilators (AOV) for roof access.

A range of hatch and louvred vents are available on the Easivent webstore, or download our guide for more information.

National Domelight Company
Pyramid House
52 Guildford Road
Lightwater
GU18 5SD