Might be worth looking into. I was not thinking of doing a massive job that met all required standards for a public building, more along the lines of running some 3/4" copper and adding 3-4 sprinkler heads with perhaps one over my gun safe. If it is a run of pipe with no other taps for hose, whatever, it would probably provide a decent degree of protection that might supress a fire or limit its effect. I believe it would be easy enough to put a pressure detector on the line to sound some kind of an alarm when the water started to flow.
A home bulit "safety system" that could be worthwhile that I would not rely on 100%.

This site has good information on halon

http://www.h3r.com/

Forget portable fire extinguishers to put out fires in your OWN car (you'll still need them to help someone else). Take a look at these (quick google search "vehicle fire suppression"):

Crown Victoria Police Interceptor Fire Suppression

Levitt-Safety Custom Fire Suppression

Amerex Custom Fire Suppression

Deist Safety On Board Fire Suppression

Fire Fox

Safecraft Vehicle Fire Suppression Systems

Note: Several webpages indicate HALON is dangerous, and should not be used in confined areas where someone may breath it in.

On the topic of keeping an extinguisher in your vehicle, when I was involved in the sport up to world rally standard back in the 70s, it was compulsory under race and rally regulations to carry such an item. We always had a powder extinguisher with steel holder bolted to the floor by the navigator's seat in rally cars. You failed scrutineering if you didn't have one. Along with a big red battery/ignition isolation switch for use if and when the car rolled.
No doubt the Group One world rally cars today have even more sophisticated fire retard systems. And for good reason..

Looks like it is safe:

"It is a common misconception that halon "removes oxygen from given space." This is what C02 does, not halon. According to the Halon Alternative Research Corporation (www.harc.org): "Halons are low-toxicity, chemically stable compounds that have been used for fire and explosion protection throughout this century. Today, Halon 1211 (a liquid streaming agent) is used mainly in hand-held fire extinguishers and Halon 1301 (a gaseous agent) is used mainly in total flooding systems. These halons have proven to be extremely effective fire suppressants, which are clean (leave no residue) and remarkably safe for human exposure. Three things must come together at the same time to start a fire. The first ingredient is fuel (anything that can burn), the second is oxygen (normal breathing air is ample) and the last is an ignition source (high heat can cause a fire even without a spark or open flame). Traditionally, to stop a fire you need to remove one side of the triangle - the ignition, the fuel or the oxygen. Halon adds a fourth dimension to fire fighting - breaking the chain reaction. It stops the fuel, the ignition and the oxygen from dancing together by chemically reacting with them. Many people believe that halon displaces the air out of the area it is dispensed in. Wrong! Even for the toughest hazards, less than an 8% concentration by volume is required. There is still plenty of air to use in the evacuation process."


The EPA recognizes that that halon remains the most effective extinguishing agent available, and it continues to allow its use despite its ozone depleting potential. All halon available now is recycled, so it is not an environmentally irresponsible choice. In addition, due to its effectiveness and relatively low toxicity, the FAA also continues to require halon extinguishers for use on commercial aircraft.

Finally, there are no federal or state regulations prohibiting the buying, selling or use of halon extinguishers."

Also, these guys sell them as well.

http://www.performanceproducts.com/
http://www.madvet.com/shop?frame=1.6272