Wollongong Hospital Car Park Massive space saving with Geberit Pluvia

Plumbing: DM Plumbing
Specified products: Geberit Pluvia and Geberit HDPE

A clever siphonic roofing solution from Geberit has reduced the need for piping in Wollongong Hospital’s car park redevelopment. By using Pluvia siphonic drainage, the number of downpipes were reduced by 90% from 26 to only 2 downpipes. This created more space for car parking.

The innovative design of the Geberit Pluvia siphonic drainage system overcame design and cost challenges, including:

• A significant reduction in penetrations through concrete slabs for downpipes and roof outlets, thereby reducing installation costs.
• Pipes were laid flat to maximise ceiling height and car park capacity.
• Fewer downpipes reduced the risk of damage in high traffic areas.

Conventional drainage systems require equal volumes of air to pass through the pipe when draining water from roofs, this limits the velocity and volume of water, resulting in larger pipe sizes. In a Pluvia siphonic drainage system, air is prevented from entering the system and a suction develops within the pipework, thereby increasing velocity and quickly draining large volumes of rainwater from the roof through the pipework to the stormwater system.

The combination of the Pluvia outlet design and robust HDPE increases the flow capacity at each outlet. The flow velocity within the system increases the efficiency of rainwater drainage significantly. Pluvia outlets have a capacity of up to 100 L/s, meaning fewer outlets were required than in a conventional drainage system. The HDPE pipework is capable of withstanding high negative pressures and flowrates resulting in fewer downpipes and smaller diameters than a conventional drainage system. As fewer pipes had to be installed, so fewer bollards were required for protection against impact damage in car parking accidents. Overall, Geberit Pluvia siphonics achieved savings of 500m of pipe and more than 200 labour hours.