Emergency response personnel from the EPA Division joined forces last Wednesday 3 June with their counterparts from the Tasmanian Fire Service (TFS) and TasPorts to trial the use of TasFire’s new Compressed Air Foam System (CAFS) in marine water within TasPorts’ dockside precinct in order to assess the environmental outcomes. The joint exercise provided valuable operational knowledge to all three agencies in responding to a major fire in the marine environment and showed that the CAFS could be used effectively on water with minimal environmental harm.
With a consistency like shaving foam, the foam produced by CAFS is significantly more effective at smothering hydrocarbon-based fire than conventional water retardants. It is very effective in dealing with hard to extinguish fires such as tyre, vehicle and boat fires and is also known to have good fire protective properties if sprayed onto adjacent assets.
The use of CAFS would be an advantage therefore, in the event of a boat fire in the Hobart wharf area, particularly during peak usage times such as at end of the Sydney to Hobart yacht race or during the Wooden Boats Festival. A possible drawback however, may be some environmental impact if the foam was left in the marine environment to breakdown naturally.
Hence the EPA was keen to work with TasFire and TasPorts to investigate the potential environmental impact of CAFS ahead of any emergency response. Specifically, the EPA wanted to know how the foam would behave in the marine environment, how long it would take to break down or mix with saltwater, and whether it could be recovered effectively from the water after its use in extinguishing a fire.
In trials of CAFS last year, the EPA discovered that the foam maintained its consistency for hours when contained in a tub of fresh water before it broke down naturally but this process could be sped up using a water mist spray. The results showed a very low impact of CAFS on dissolved oxygen levels in the water within the tub over a 24 hour period, probably because the foam tended to sit on top of the water with little or no mixing.
During this marine exercise, TasFire officers sprayed the CAFs from the TFS fire truck onto an area of water in the slipway, which had been cordoned off by TasPorts using two sets of oil spill booms – an outer hard boom and an inner absorbent boom. Emergency response personnel then tested the methods required to recover the foam using a vacuum hose connected to a waste disposal truck and several types of specially designed floating vacuum heads. The foam, along with surface water, was completely removed, collected in the waste disposal truck and transported to the TFS Cambridge facility where the solution was observed to break down naturally.
The results of the trial, therefore, showed that the foam could be contained in the marine environment with the use of the booms, that it remained on top of the water without extensive mixing, and could be recovered using a specialised vacuum hose and head attached to a standard waste removal truck. Further trials will be conducted on the CAFS to develop this new capability and joint emergency response pre-planning will continue amongst the three agencies. This is good news for Tasmania, with the State being better prepared for an emergency response in the event of a major fire-on-water emergency whilst ensuring satisfactory environmental outcomes.