VENTILATION – WHY DO WE NEED IT?
Problems associated with inadequate Ventilation
Over time, stale air, dampness and condensation all contribute to the deterioration of buildings, causing unpleasant, uncomfortable and unhealthy living conditions.
Stale air is caused by inadequate ventilation and often made worse by humidity, steam, smoking, cooking and, of course, odours remaining in toilets and bathrooms, resulting in areas becoming dank and uninviting. Condensation occurs when moist warm air comes into contact with a cooler surface such as walls, ceilings and windows. This often leads to mould growth, peeling wallpaper, damage to painted surfaces or even more serious structural damage such as timber decay. These problems are a result of poor ventilation but can be resolved through the correct selection and application of fans.
Where steam is involved, run-on timers are also recommended to ensure the area is thoroughly purged of damp air. This will protect surface finishes as well as limiting the growth of mould.
Regulations for Bathroom & Toilet Ventilation
All of the fans within the Fantech Trade range comply with Australian Standard AS 1668.2 – 2012 for ventilation rates when utilised correctly.
Odour Requirements (Based on Australian Standards)
The standard requires the minimum flow rate to be no less than 90m³/hr (25L/s) for a toilet, shower or bathroom area with a single fixture.
Steam Requirements (Recommended)
To effectively exhaust water vapour (steam) from a shower, air flows of 270 – 360m³/hr (75 – 100L/s) are required, depending on the climatic conditions and room size.
Air flow rates equal to or above the defined minimums will ensure odours and stale air will be exhausted quickly, enhancing the environment for the occupants of the building.
Regulations for ventilating directly into the roof space
As detailed below, in dwellings with a metal roof, or where the roof is lined with sarking, ventilating directly into the roof space is not permitted by building codes unless the roof space is adequately ventilated by open eaves or roof vents. The Fantech Trade range offers many ducted solutions to exhaust to atmosphere through the wall, roof or eaves to comply with the latest building codes.
Paragraph 22.214.171.124 of the Building Code of Australia states:
Performance requirement P2.4.5 is satisfied for a mechanical ventilation system if it is installed in accordance with AS 1668.2 “Mechanical ventilation for acceptable indoor air quality”, except that any contaminated air from a sanitary compartment or bathroom must: –
(a) Exhaust directly to outside the building by way of ducts; or
(b) Exhaust into the roof space provided:
(i) It is adequately ventilated by open eaves, and /or roof vents; or
(ii) The roof is clad in roofing tiles without sarking or similar materials, which would prevent venting through gaps between tiles.
Paragraph G4/AS 1 1.3.1 (c) (ii)* in New Zealand states:
1.3.1 Mechanical ventilation systems must satisfy the following conditions:
(c) Extract ventilation shall:-
(ii) Where provided to remove moisture and other contaminants from kitchens, bathrooms, toilet spaces and laundries in housing, exhaust the air to the outside at flow rates given in AS1668.2, Table B1.
* This paragraph is part of the Acceptable Solutions G4/ASI contained in the Approved Document G4: Ventilation and is used with the permission of the Building Industry Authority.