Discharge-system tests of Halon 1301 test-gas simulants. Memorandum report Jun-Sep 88

All new and retrofit installations of Halon 1301 total flooding systems in shipboard machinery spaces require an acceptance discharge test. It is desirable to use a simulant instead of Halon 1301 in view of current and future restrictions regarding the discharge of Halons into the atmosphere. Two candidate simulants; sulfur hexafluoride (SF6) and chlorodifluoromethane (R-22) were evaluated on the basis of flow through the piping networks of both modular and banked systems. A modular system with two different fill densities and six banked systems were used in this evaluation. Sulfur hexafluoride was found to discharge at a similar rate to Halon 1301, while R-22 discharged faster in all tests. The flow splits for both candidate simulants in banked systems were similar to those of Halon 1301. Together with work on leakage from an enclosure and initial mixing, these tests have shown that sulfur hexafluoride is an excellent simulant for Halon 1301. These conclusions will be confirmed in full scale tests.