Sutherland Shire Council – D&C Exclusion Bars Tea Tree Place

Council installed a GPT at Tea Tree Place in Kirrawee. But because the pipes were 1200mm and 1350mm diameter it made it reasonably easy for kids to play in the pipes and therefore climb up the pipes and play in the GPT diversion chamber.

This was an OH&S risk that Council did not need, so they decided to have exclusion bars located over the outlet.

The problem with this is that in a large event, if these bars were to block due to pollution bypassing the GPT, then the system would blow itself apart, and cause surcharging and flooding all over the place.

It required a tried and tested design from Murray Powell at Optimal Stormwater, to be customised for the site, fabricated, galvanised and installed. The “Fail Open” exclusion bars are hinged and essentially locked in place with a piece of sacrificial polymer tube. When the pressure gets too much the thin polymer tube will give way and the exclusions bars open right up, and provide minimal hydraulic resistance for the flows. Replacement polymer tubing costs about $1, and replacements are supplied by Optimal Stormwater.