There has been some concerns raised around water availability to manage the fire, and suggestions that the main along William Street was dry, when NSW Fire and Rescue arrived at the scene.
Council has undertaken an investigation of the matter and found that while there was water in the main, it was insufficient to meet the demands presented and was outside what should have been available.
Orange City Council General Manager Garry Styles said Council staff have been involved in a preliminary debrief with NSW Fire and Rescue and have also been in discussions with the Rural Fire Service which also attended the fire.
“A further debrief is scheduled for next week. In the meantime this event has triggered a number of actions from Council. An immediate city-wide audit and inspection program for valves and hydrants has begun. Additionally a review of protocols around opening and closing valves is under way and will continue,” Mr Styles said.
NSW Fire and Rescue advised Council staff that they arrived on site at approximately 2pm on Saturday. Council’s on-call Water Maintenance Crew were subsequently called out and arrived on site at approximately 2.30pm.
The Water Maintenance Crew discovered that the valves on the Dalton/McLachlan Street roundabout were closed. These valves were closed due to a substantial leak under the roundabout.
The Water Maintenance Crew reopened these valves, immediately improving water flows to the fire site in William Street.
Between the arrival of NSW Fire and Rescue and the valves being reopened, alternative water sources were provided by Council in a water tanker and a minimum of six Rural Fire Service tankers.
NSW Fire and Rescue also relayed water from hydrants in March Street. Council staff also opened the stand pipe at the McLachlan St Works Depot for the Rural Fire Service and managed traffic control. It is also understood that power to Transgrid lines needed to be cut off before firefighting could procced in full as the live powerlines presented a significant hazard if sprayed with water.
The water main in William Street is a ring main which under normal operations provides water from both ends. With the roundabout valves closed, water was only being charged from the March Street end.
Design criteria for fire flows in water reticulation modelling instructs that 20 litres per second needs to be available (10 litres per second at two hydrants).
This week Council staff have been on site to test the system. Those tests found that when the roundabout valves are open 30 litres per second is available in the main. The test found that when the valves at the roundabout are closed the flows are 7.6 litres per second across two hydrants.