Engine Compartment Fire Extinguisher (1 Viewer)

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@Mandrake can you suggest any fire detection devices that would be suitable for the engine bays? It sounds like you have relevant experience and there are plenty of flame detectors on the market but at their cost point I'm concerned about them triggering a false discharge if the sun hits the photo eye.
 
Those look promising thanks!.

I'd like to make it automatic w/ manual override. But false detection is a concern, so maybe I will need to put multiple sensors in as a fail safe.

If one sensor detects then an alarm is set off, if a second detector is set off then it triggers the system.

I'm planning on installing the system and running it dry for a good while through the summer so I can work out the bugs.
 
One nice thing about a CO2 system is that a false activation will only shut you down for a few minutes. Once it dissipates you are back in business. No residue, no cleanup. Easy peasy. It may shut off the engine by displacing the ambient oxygen though, that's how we usually shut down run-away combustion engines- by discharging a CO2 extinguisher into the air intake. Snuffs them right out.

That may be something to think about if you are in traffic or at speed though, the engine shutting down may not be what you want until you can make a controlled stop. A snorkel would pretty much keep this from happening unless you wanted to put another nozzle in the airbox specifically for shutting off the engine quickly without damage in case an electrical meltdown resulted in run-on. A manual system would give you this option, of course, and I'd second that recommendation.

One thing you may wish to consider is a circuit that would engage when the vehicle is in 'Park' that connects the notification system to the extinguisher system. That would keep you from losing your rig if it was unattended while remaining safe if you are driving it. That might give you the best of both worlds. You may even wish to connect it to your alarm system if you have one for more theft deterrent. They can't drive it off if it won't run, but a false alarm would drain your extinguisher system, so that may not be the best idea unless your alarm is pretty sophisticated.

And your nozzle map looks just about right, all the critical areas seem covered. Nice work.
 
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Another thought would be connecting one small CO2 line through an air horn under the hood. You could tee it off between one of the nozzles and the valve. It would spread out the gas distribution a bit and let you(and everybody else in the vicinity) know your extinguisher system was going off. Might get you some help quicker if there was an emergency.
 
Did you end up integrating this setup? I've been wanting to do something similar.
 
It's taken a back seat. Bought a house, have to finish my yard, fence etc... and have a wedding coming up. Too many expense, but I'd still like to see this through.
 
I wouldn't use halon... ever... that stuff will kill you. I'm not even sure you can get it anymore. co2 is a good idea but it may burst the burst disc because of heat spiking pressures. you can get a large abc extinguisher and plumb it in and rig a trigger somehow. the problem with the heat or ir detectors are accidental discharges. an exhaust manifold will easily trigger an ir detector and unless you get an accurate reading of temps underhood are you wont know what temp rating to get on a heat detector. some ir detectors you can program but they also require a actual fire alarm system. my advice is, hood louvers and get an abc extinguisher and a fuel shut off. keep it simple IMO

we stopped using halon here on base years ago. us use afff now
 
Some good ideas on this thread. I've had an engine fire before in an old Volvo 240 caused by a ground short between the main power cable from the battery to alternator. On those cars it runs under the front crank seal, which mine leaked, eventually softening the insulation up enough for it to short out.

The fire was small but putting it out was hectic and unplanned. The starter kept cranking nonstop (even with the key removed) and the fire wouldn't go out with water at first since it kept arcing and restarting. I scrambled to disconnect the battery with my little 10mm wrench, dug up from the toolbox in the trunk while my passenger kept pouring water on the fire (we were about 20 years old at the time (37 now), not super experienced in life in general). I got the battery disconnected, the starter stopped spinning and we ran out of water. Luckily a passerby was literally carrying a case of bottled waters (WTF, it was in an industrial area and literally made no sense for someone to be around, especially walking down the street). We poured a few of the waters on the fire, it went out and everything cooled down. The old 240 Turbo lived to see another day (after I rebuilt the wiring harness and fusable links).

I'm not sure where most vehicle fires originate but electrical would be my guess. This reminds me I should include a quick disconnect when I replace my battery cables/terminals.
 
danthman114 said:
I wouldn't use halon... ever... that stuff will kill you. I'm not even sure you can get it anymore. co2 is a good idea but it may burst the burst disc because of heat spiking pressures. you can get a large abc extinguisher and plumb it in and rig a trigger somehow. the problem with the heat or ir detectors are accidental discharges. an exhaust manifold will easily trigger an ir detector and unless you get an accurate reading of temps underhood are you wont know what temp rating to get on a heat detector. some ir detectors you can program but they also require a actual fire alarm system. my advice is, hood louvers and get an abc extinguisher and a fuel shut off. keep it simple IMO

we stopped using halon here on base years ago. us use afff now
Click to expand...
AFFF (Aqueous Film Forming Foam) is one of the most common types of fire suppressant discharge. It is designed to fight the two most common types of fires, Class A which is normal combustibles like wood and paper, and Class B fires like those started with gasoline.
What does the US use for Class C?
 
Dissent said:
AFFF (Aqueous Film Forming Foam) is one of the most common types of fire suppressant discharge. It is designed to fight the two most common types of fires, Class A which is normal combustibles like wood and paper, and Class B fires like those started with gasoline.
What does the US use for Class C?
Click to expand...
Electrical
 
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it changes. when a class c happens and the power source is removed, it changes to class a. the extinguishers we use are abc but and the building systems in the hangers is afff. I'm not sure about class d fires tho.
 
danthman114 said:
it changes. when a class c happens and the power source is removed, it changes to class a. the extinguishers we use are abc but and the building systems in the hangers is afff. I'm not sure about class d fires tho.
Click to expand...
Gotcha. That makes sense. I've only run into one Class D, VW block (Magnesium). Couldn't do much but watch it burn.
 
A class D fire in a vehicle means it's too hot for you to go anywhere near. Burning molten metal is very difficult to extinguish.

The hardest part with a vehicle like an 80 series is creating a foolproof way to externally isolate the power system. I've talked about this before and wondered how to do it. I have dual batteries, with direct ground links and fused positive feeds going to either side of a Redarc dual-sensing solenoid.

The *only* way to completely isolate the elec system is disconnect both negative terminals. It's not good enough just to isolate the main battery negative (which is what we normally do for standard repairs and maintenance if required) as in a fire situation the second batt stays 'live'.

It's not going to help having any sort of fancy fire supression system until there's a fancy way to totally isolate the elec system safely from outside the vehicle.
 
I have a Flaming River disconnect on my only battery. You could easily add a 2nd disconnect to the 2nd battery. There's even models with remote handles and rods to disconnect from the cockpit. That's mainly for race cars but works on all cars.
 
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