The ventilation requirement for dwellings is defined in part F of the Irish building regulations.
The key requirements and recommendations may be summarised as follows:
- The indoor sir quality (IAQ) must not be a threat to the health of the people using the building. Sufficent ventilation must be provided to ensure that the moisture content and concentration of pollutants does not reach harmful levels.
- Extraction of air will be required from kitchens, bathrooms and other areas where water vapour is generated. Harmful pollutants must also be removed from areas
where they are produced in significant quantities.
There are two methods by which the requirements may be met:
a) Natural fresh air supply via vents with extract ventilation provided by fans or passive stack vents.
Natural Ventilation with Mechanical Extract
While this method is permissible, it may not be compatible with achievment of an acceptable energy rating for the dwelling
b) Mechanical ventilation with heat recovery (MVHR).
Mechanical ventilation with heat recovery (MVHR)
Also known as 'Heat Recovery Ventilation', this has the advantage of enhancing the energy rating if suitable equipment is selected.
When using either method the following points are important:
- Provision must be made for air transfer between rooms. Typically a 10mm gap should be provided under doors.
- Extract vents should be positioned as high as possible in each room and not more than 400mm from the ceiling.
- Cooker Hoods should be located 650-750mm above the hob surface unless otherwise recommended by the manufacturer.
- The installation of ducting must comply with the requirements of Part B of the Building Regulations (Fire Safety)
- All habitable rooms should have a minimum ceiling height of 2.1m