Fire Engineering Research Report 98/02

A comparison is made between CAFS (compressed air Foam), HPD (High Pressure Discharge) and HPD with Class A Solution on unshielded post flashover compartment fires. Extinguishment was carried out by trained fire fighters using hand held lines, whilst the method of attack was carried out following New Zealand Fire Service operating procedures. The effectiveness of each method was determined, by recording the heat release rate using the method of Oxygen Calorimetry. Knockdown effectiveness was also evaluated by recording internal compartment temperatures with the use of thermocouples. In addition comments from firefighters have been recorded and video footage reviewed so that a qualitative assessment could also be made. It was found that CAFS performed more effectively than HPD or Class A solution, in that less water was needed to obtain a similar knockdown performance. No noticeable benefit was obtained when Class A solution was added to the unmodified HPD line. The biggest advantage of CAFS over the other methods was the ability in being able to attack the compartment indirectly from a distance, which has additional benefits with respect to fire fighter safety