The procedure replaces periodic hydro-test, providing improved safety, reduced costs, and reduced environmental impact. Bottles are warmed in a temperature controlled environment whilst being monitored by six sensors for acoustic emission, any problems with the material or welds are located so the bottles can be removed from service. The best feature of the test is that good bottles do not need to have the halon removed, be filled with water, and hydro-tested, a process that is costly and yet gives no information on sub-critical defects.