Carpark Ventilation Systems

When designing for a mechanical ventilation system, engineers follow the requirements of the NZ Building Code which stipulates AS1668 as an acceptable solution. AS1668 dictates the use of supply or extract air ducting or both with stringent requirements on the placement of supply and extract air grilles to achieve compliance often based on extract rates of 3.0 litres/s/m2 of car park area.

An alternative solution lies with NZS4303. Whilst the ventilation rate is double at 7.5 litres/s/m2, the use of ductwork, supply and extract air grilles is not mandatory. This approach yields a simple solution of a number of plate type extract fans fixed to the car park external walls strategically located to ensure a good “sweep” of the car park floor with fresh air. The absence of ductwork provides for an economic, uncomplicated and simple design with maximum available floor to ceiling heights.