Report of the Task Group on Halon Options International Aircraft Systems Fire Protection Work Group, R.E. Tapscott, L.C. Speitel, eds.

This report contains a summary of available fire suppression agents and their properties. The applicability of various technologies for each major onboard aircraft application is assessed. Classes of agents, with presently available agents listed, are recommended for use in the development of test protocols. The test protocol developed for a class of agents can be used, with minor modifications, to test all agents belonging to that class.

John W. Reinhardt

This report documents the full-scale evaluation tests of a water mist system, with and without nitrogen that would be available from an onboard inert gas generation system (OBIGGS) against a series of standardized aircraft cargo fires. These evaluation tests followed the testing protocols specified in the Minimum Performance Standard for Aircraft Cargo Compartment Gaseous Fire Suppression Systems modified with a draft new protocol for an exploding aerosol can fire scenario that would be applicable to nongaseous systems. The developmental work was performed in conjunction with the International Aircraft Systems Fire Protection Working Group. The results showed that a hybrid water mist and nitrogen system met the minimum performance standard, with lower cargo compartment temperatures than either plain water mist or halon, and with less weight of water consumed than halon.

Robert Z. Filipczak

A new fire extinguisher concept, the adiabatic expansion nozzle, extends the usefulness of fire extinguishing compounds by lowering the temperature and discharge pressure of the agent. This allows total flood type halon replacements to be used in hand-held applications and, in the instance of carbon dioxide, produces a low-pressure dry ice snow.

Timothy Marker

A task group assembled under the auspices of the International Aircraft Materials Fire Test Working Group examined issues involving fire test approval of previously qualified interior material systems following renovation or alteration. A major problem associated with the alteration of interior system components is the difficulty in conducting certification tests that would determine if the altered interior component is still compliant with the heat release, smoke, and flammability certification requirements. In many instances, the appropriate substrates for conducting these follow-up certification tests are unavailable. As discussed in an earlier report, DOT/FAA/AR-TN95/83, International Aircraft Materials Fire Test Working Group, Material Systems Renovation and Repair Subgroup, the use of surrogate materials is the most feasible method for conducting certification tests following renovation, when samples of the actual buildup materials are unavailable. In order to validate the accuracy of using surrogate materials as heat release, smoke, and flammability predictors, tests were conducted in which several similar surrogate panels were compared. The surrogate panels were manufactured by three independent suppliers according to a common specification. Heat release and vertical Bunsen burner tests were conducted on the surrogate panels, which were finished with one of three paints or one of two laminates. The heat release test results indicate that each of the three surrogates reacts slightly different when tested without finish paint or laminate. When tested with a finished surface, the heat release results are even more scattered, providing evidence of the interrelationship between the substrate panels and the finish.

Richard Johnson and Lindsey Wuethrich

Child restraint seat used in aircraft are based on automotive designs that are required to pass a horizontal burn rate test method. The flammability of child seat materials was gauged against the Federal Aviation Administration (FAA) vertical Bunsen burner tests method. Basically, the vertical test prescribed in Federal Aviation Regulation (FAR) 25.853 (a)(1)(ii) allows a burn length of 8 inches and flame time of 15 seconds after exposure to a Bunsen burner flame for 12 seconds.

Eight child restraint seats were purchased from a retail store. The seats were disassembled in order to cut test specimens from the various seat components. Because of the size of the seat and use of materials, in most cases it was not possible to prepare the required sample size and replicates. However, this did not impact the overall conclusions regarding the flammability of the materials tested.

The test results indicated that the large majority of materials would not meet the FAA vertical fire test criteria. Also, some of the failed materials burned across the entire sample length, and others produced high flames or dense smoke. The findings are consistent with the knowledge that a horizontal burn test is far less severe than a vertical burn test.