Research and testing of halon replacement agents for use in aircraft cargo compartments has led to the development of three basic test conditions. These include surface burning, bulk or loose loaded luggage, and containerized luggage simulations. The surface burning scenario utilizes a small pan of kerosene, while shredded-paper-filled cardboard boxes comprise the fire load in both the bulk and containerized luggage simulations. A forth test condition representing an exploding aerosol can will be added.

Several years ago the aerosol can manufacturers began phasing out the use of CFC type propellants due to their ozone depleting characteristics. The newer generation propellants, although non-ozone-depleting, are very flammable. Propane, butane, and iso-butane are the most common choice of propellants used in today's aerosol cans. Recent full-scale tests have shown that cans utilizing the newer propellants can rupture with explosive force when subjected to a fire. This is of particular concern in the cargo compartment fire protection arena, since a rupture force has the capability of dislodging the cargo liner, which is responsible for containing not only the fire, but the agent used to suppress the fire. Although testing has displayed the potential dangers of aerosol cans in cargo compartment fires, the actual rupture/explosion sequence is very erratic and unpredictable. Many of the tests result in primarily flaming combustion, others in violent explosions yielding high pressure waves, but in most instances the results can not be repeated. For this reason, the Fire Safety Section has been developing an exploding aerosol can simulator, which could replicate the typical heating, rupturing/explosion event. Once a finalized event(s) is established using the simulator, the effectiveness of the halon replacement agents could be measured against this, as 1301 has already proven to be very effective at mitigating this sequence of events.

The main thrust behind the simulator is not only to develop a repeatable test condition, but a representative one as well. In order to gain more insight into the propellant quantities/constituents used in aerosol products, the Fire Safety Section met with members of both CSMA (Consumers Specialties Manufacturing Association), and CTFA (Consumers Toiletries & Fragrance Association). These two industry groups represent a majority of the manufacturers of products packaged in aerosol form. With the assistance of CTFA and CSMA, a representative and repeatable simulator device will be developed for use in halon replacement agent evaluation.

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LAST UPDATED 7/12/99