Based on info received from a mechanic who was rebuilding a pair of V12's in a 66 Princess due to halon discharge to put out a fire...destroyed the engines.
Maybe the fire and smoke did the damage? I've never heard of engine damage caused by the halon itself. Seems odd that an agent that destroys the engines would be the choosen fire protection when there are other options that don't.
Then I found this bit of info. Sounds interesting and plausible.
http://www.marinefireequipment.com/Q006.html
Does halon damage my engine?
There are actually two different halon gasses used in the fire protection industry that consumers would be familiar with. The type used in portable fire extinguishers was called 1211 and was actually bromochlorodifluoromethane. It usually had a warning on the side that limited it's use to spaces over a certain cubic ft. because the agent does break down into hydrogen fluoride when exposed to temperatures above 900 degrees. These extinguishers are common in aviation applications because they are a clean agent, leaving no residue on sensitive electronic instruments. The warning is particular to it's common use in the cockpits of airplanes.
The second type of halon seen is the 1301 which is typically a system gas. It is actually monobromotrifluoromethane. Both agents were marketed as clean agents ideal for use in computer rooms, marine engine rooms and normally occupied spaces because in the proper concentration the agent itself is harmless to humans. After seeing for myself the effects of halon on the stainless steel in engine compartments after several fires, and hearing repeatedly from guys repairing engines that had ingested halon, it is true that these agents can cause damage. The salesmen of these agents use to swear it wasn't the agent itself but the "byproducts" that are produced at the high temperatures that is in fact damaging to the engine, as well as the damage seen on the surface of all unpainted metals in the engine compartments. Halon 1301 gas does break down into hydrogen fluoride and hydrogen bromides and apparently produces enough of it before the fire goes out to damage the engine. That is why it is very important to have automatic engine shut-down capability with halon systems. Under normal conditions the agent does extinguish the fire very rapidly and very little of those harmful gasses are produced.
Of note- the new agents are FM-200 which is actually heptafluoropropane (producing hydrogen fluoride at 1292 degrees F) and FE-241 which is actually chlorotetrafluorine. FE-241 is not approved as a halon alternative by the European Union. Only FM-200 is approved for occupied spaces, and is the propellant used in asthma inhalers.
Halon Alternatives Research Corporation Kyoto Protocol Info
