The Amron Model 240 Hyperbaric Water Based Fire Extinguisher is a modified Class 2-A extinguisher and is tested to ANSI/UL711 and 626 standards and is designed for the pressures and confines of a hyperbaric chamber. The Model 240 has been fully tested and approved for use in all U.S. Navy standard double lock chambers.
In actual operation the Model 240 is filled with potable water and then pressurized to 150 psig. The unit comes complete with a fill valve, pressure gauge and a pressure relief valve factory set at 173 psig to prevent over pressurization. The Model 240 can be used in a chamber pressurized to a maximum depth of 225 FSW. If the unit is activated at the maximum depth, and held until the water is exhausted, the pressure inside the extinguisher will equal the chamber pressure. With the chamber and extinguisher at equilibrium, the fire extinguisher cannot implode or crush.