Compressed air foam (CAF) is among the many suppression technologies in the fire service that is often met with both praise and doubt. With varying accounts of success and challenges, many fire service agencies are often unsure of embracing the technology. As a result, hands-on testing can be a way for individual fire service agencies to make decisions about how CAF can meet their fire suppression needs.
The Tasmania Fire Service (TFS) sought to determine the effectiveness of Class A compressed air foam for its fire suppression needs at the Hazelwood open cut coal mine in Tasmania. As part of the endeavour, firefighters conducted a brown coal batter test that encompassed an area approximately 10,000 square meters. The team tested ground temperature before and after the test to determine the cooling effect of CAFS, and monitored foam solution use to compare against typical water usage.
For approximately 75 minutes, the TFS delivered CAFS to completely extinguish the fire ground. Immediately following the application, firefighters tested the ground temperature, which measured between 120 degrees C and 150 degrees C. Before applying the compressed air foam, the ground temperature registered between 350 degrees C and 400 degrees C, displaying a dramatic drop in temperature following the CAF delivery.
Reports indicated that 45 minutes after the application, the ground temperature dropped to between 17 degrees C and 20 degrees C and offered no evidence of hotspots or re-ignition, according to thermal imaging testing methods. Overall, the compressed air foam offered fast suppression and cool-down traits at the testing site.
“The success of CAF at the Hazelwood open cut coal mine fire has led to a lot of interest in regard to the application and potential for CAF integration into urban and land management agencies within Australia,” said Leon Smith, manager, engineering services with the Tasmania Fire Service.
When it came to water usage, the firefighters determined that the same duration of delivery with a similar flow rate would have consumed 337,500 litres of water, compared with the 40,000 litres of compressed air foam used in the test.
Following the testing, the TFS has been contacted by several agencies to provide information in regard to the specification and configuration of their appliance as well as the role that the team designed the appliance to undertake in the trials. “I have been asked to a forum that has been organized by the CFA (County Fire Authority) to discuss the trials, allowing them to consider this information relative to their risks and assist in their direction in regard to building a CAF capability,” Smith said. “Other agencies are convening such groups to discuss and explore the same option.”
Smith noted the exceptional extinguishing capabilities of CAFS as well as misconceptions surrounding the technology. “Many agencies have not previously embraced CAF capability due to a lack of easily accessible research and information pertaining to the medium as well as well engrained misconceptions about the issues and the technology,” he said. “The opportunity to convey relevant, meaningful and accurate information to agencies will allow them to walk away fully informed and confident in their decision-making process in regard to CAF.”
With this particular account of successful CAF testing, the TFS has embraced CAF technology and is spreading the word to its colleagues so individual fire service agencies can make educated, clear decisions about how CAF can be a useful tool for effective fire suppression. For the trials, the TFS used a Waterous CXVT 1250 GPM integrated cross-mount pump system and a Waterous foam injection system rated at 4750 litres-a-minute.
TFS CAFS Heavy Tanker –8,200 litres of water, 200 litres of Class A foam concentrate, Waterous pump set with foam injection system rated at 4750 litres-a-minute, 200 cfm compressor, and two FTF remote control monitors.
For more information, go to www.waterousco.com