5. Mechanical Ventilation (Refer to Topic 9 Mechanical Services)

5.1 Mechanical ventilation systems for wet areas must function properly to remove MOISTURE created in the room which impacts on ceilings, mirrors, joinery etc. A common complaint is that the fan is either too noisy (where located in the ceiling) or not working (usually a fan on the roof and they cannot hear anything) if installed and isolated from the structure correctly.

5.2 Mechanical exhausts in laundries were previously designed at 20L/s, clothes dryers put out at 40L/s of humid area (unless a condensing dryer is used) – which means the room becomes humid and condensates. This creates mould. The NCC2013 & new AS1668.2 (2012) change this to 40l/s for condensing dryers.

5.3 Review the systems in place prior to commencement. In-ceiling fans will need ACCESS panels for servicing and maintenance post construction.

5.4 Fans should run permanently (common riser systems for multi residential or commercial offices), or be on a common switch with the lights with a timer to allow the fan to continue running for a 10 minutes AFTER the light is switched off to clear remaining moisture in the air and hooked through a relay to provide a second input to operate the fan – a thermal sensor to operate the fan if heat builds up in the laundry. If the dryer is operated without a light on, the fan will exhaust once temperature builds up. This eliminates the condensation and mould caused when the dryer is used without the light/fan on.

5.5 If the laundry is not designed with a mechanical ventilation (using approved natural ventilation) a sign must be provided “leave door open when drier is in use”.