Approved Document F provides guidance on meeting building regulations that specifically apply to ventilation. It states that adequate ventilation needs to be provided to prevent excess condensation buildup which could damage the structure of the property. It also ensures then, that air properly flows through the property maintaining good levels of indoor air quality.
When building a new property it is important to comply with requirements in building regulations for installation, inspection, testing, commissioning and provision of information when installing fixed ventilations systems in your new and existing property. Approved Documents provide guidance on how to meet these building regulations.
Passive stack ventilation (PSV) is the most effective natural ventilation strategy as it uses a combination of cross ventilation, buoyancy (warm air rising) and the venturi (wind passing over the terminals causing suction) effect. Each new room in a house should have adequate ventilation for general health reasons. The type of room will determine how much ventilation is required.
When inserting a new internal wall care should be taken not to make any other matters, such as ventilation, worse. If a new room is being created as a result of the addition of an internal wall then care should also be taken to ensure that the existing room is ventilated adequately. The general rules for ventilating a room are:
Purge - this is achieved by opening the window. The opening should have a typical area of at least 1/20th of the floor area of the room served, unless it is a bathroom which can be any openable size.
Whole building - this is also known as trickle ventilation which can be incorporated in to the head of the window framework, or by some other means. The area varies on the type of room:
- habitable room - 5,000 mm² equivalent area
- kitchen, utility, bathroom (with or without toilet) - 2,500 mm² equivalent area
Both of these forms of ventilation are normally required, however alternative approaches to ventilation may also be acceptable, subject to agreement with the building control body.
Due to the increasing complexity of the Regulations, ventilation strategies and system design must be considered at the earliest stages of building design.
Any new kitchen, bathroom (or shower room), utility room or toilet should be provided with a means of extract ventilation to reduce condensation and remove smells.
For toilets only, ‘purge ventilation’ (an opening window/door on an external wall) meeting the requirements specified in Appendix 2 of ‘Approved Document F - Ventilation’ can instead be used to provide ventilation if security is not an issue.
If you are refurbishing a kitchen or bathroom, you will need to ensure that any existing extract ventilation is retained or replaced. If there is no existing ventilation system, you need not provide one (though you can if you wish).
Any extract ventilation system you install should meet the requirements specified in ‘Approved Document F - Ventilation’.
In England and Wales, requirements for ventilation are contained in Approved Document F and can be downloaded from www.planningportal.gov.uk. The Building Regulations Approved Document F 2010 considers ventilation through a combination of infiltration and purpose-provided ventilation. Regulations are constantly being reviewed, with the aim to improve building standards, so it is worth checking the Planning Portal website for any updates to Building Regulations.
A uncontrollable air exchange between the inside and outside of a building.
A controllable air exchange between the inside and outside of a building.
Approved Document F looks at different systems for ventilation. The performance rates for each of the “System” approaches set out in Approved Document F are the minimum requirements needed to ensure that adequate air quality is provided for people indoors. The occupant's health could be at risk if these ventilation rates are compromised.
The following systems are outlined which satisfy the performance standard: