Farewell and best of luck

[Thumpalumpacus]

POL fire?

"Petroleum/Oil/Lubricants" fire.

POLs are nasty fighting with pure water because they're all lighter than straight water. They will float on top of the water, and remain burning, and worse, the water can and will lift them above any local containment and aid the spread of the fire unless one is very careful.

AFFF (aqueous film-forming foam) lowers the specific gravity so that the mixture of foam and water will float atop any pooled liquid POLs, and because it's basically supercharged dish-soap, it will spread out, forming the film referred to in the name. In so doing, it separates the fuel from the oxygen and smothers the fire that way.

You still have to be very careful with AFFF, specifically taking care to never, repeat never, disturb your foam blanket once you've laid it down and gotten your smother on. In artillery terms, when shooting foam you're always shooting indirect fire, never direct fire. You rain the foam down onto the blaze using a fog setting on your nozzle or turret, no straight-streams allowed. You work to grow the blanket once you've blanketed the rescue side (port side of most a/c) or other egress paths that may be present.

 

[gumbyk]

"Petroleum/Oil/Lubricants" fire.

POLs are nasty fighting with pure water because they're all lighter than straight water. They will float on top of the water, and remain burning, and worse, the water can and will lift them above any local containment and aid the spread of the fire unless one is very careful.

AFFF (aqueous film-forming foam) lowers the specific gravity so that the mixture of foam and water will float atop any pooled liquid POLs, and because it's basically supercharged dish-soap, it will spread out, forming the film referred to in the name. In so doing, it separates the fuel from the oxygen and smothers the fire that way.

You still have to be very careful with AFFF, specifically taking care to never, repeat never, disturb your foam blanket once you've laid it down and gotten your smother on. In artillery terms, when shooting foam you're always shooting indirect fire, never direct fire. You rain the foam down onto the blaze, no straight-streams allowed. You work to grow the blanket once you've blanketed the rescue side (port side of most a/c) or other egress paths that may be present.

As you said - it can be done with straight water, and is surprising what they do use straight water for, mainly in fixed sprinkler systems. My wife designs the systems, and it is surprising what they do use water for - transformers, fuel (incidental amounts), even data centers.

Better even than AFFF is to chemically disrupt the combustion (halon type extinguishers, etc). There are saponifiers which basically turn the oil into soap.

 

[Thumpalumpacus]

As you said - it can be done with straight water, and is surprising what they do use straight water for, mainly in fixed sprinkler systems. My wife designs the systems, and it is surprising what they do use water for - transformers, fuel (incidental amounts), even data centers.

Better even than AFFF is to chemically disrupt the combustion (halon type extinguishers, etc). There are saponifiers which basically turn the oil into soap.

I never worked with saponifiers, but we had two truck models in service at my base with 500-lb Halon systems on-board, for use on jet engines and computer facilities, mainly, as well as hand-held portable halon extinguishers for operator-use in the latter spots. We also maintained wheeled 508-lb halon exts on the flightline, with one assigned for every two aircraft. Neither engines nor computers care much for massive water-dumps, lol.

As an aside, I got called off by the assistant chief from a joint training exercise (w/ Fort Worth FD) by putting out an open fire using a 508-lb flightline portable on about 300 gallons of JP-4 ... he came over the PA in his truck and called out loud "Save some fire for the rookies, Gossett." I was an insufferable sonofabitch around the station for a couple of days after that, heh.

I just got upwind, aimed low, and swept like an Uzi, letting the wind blow the halon down over everything. That shit's good. 1211, iirc. 1301 was for computer rooms.

 

[gumbyk]

I never worked with saponifiers, but we had two truck models in service at my base with 500-lb Halon systems on-board, for use on jet engines and computer facilities, mainly, as well as hand-held portable halon extinguishers for operator-use in the latter spots. We also maintained wheeled 508-lb halon exts on the flightline, with one assigned for every two aircraft. Neither engines nor computers care much for massive water-dumps, lol.

As an aside, I got called off by the assistant chief from a joint training exercise (w/ Fort Worth FD) by putting out an open fire using a 508-lb flightline portable on about 300 gallons of JP-4 ... he came over the PA in his truck and called out loud "Save some fire for the rookies, Gossett." I was an insufferable sonofabitch around the station for a couple of days after that, heh.

I just got upwind, aimed low, and swept like an Uzi, letting the wind blow the halon down over everything. That shit's good. 1211, iirc. 1301 was for computer rooms.

1211 was for hand-held, 1301 was for gas-flood. You're not allowed to use it any more other than aviation and marine
I hope you had BA on while using it - it produces toxic byproducts. The extinguishers supplied in a new C-172 a customer bought had the warning not to discharge in a room less than 120 cubic feet...
There are newer, safer products that work just as well, or better on the market.

If a computer catches fire, it's already beyond recovery, you need to protect the adjacent ones. Preventive systems are used to practically eliminate the fire threat as well - hypoxic (low oxygen) is the main one. It reduces the oxygen level to the equivalent of 10,000ft so it is still safe for people to work in.

 

[Thumpalumpacus]

I hope you had BA on while using it - it produces toxic byproducts.

On emergencies, we always had SCBA donned; and usually for training as well, especially after 1990 when we lost our brotha A1C James White to a nozzle failure; a bolt failed under pressure, the recoil blew the nozzle under his hood, and a lungful of halon knocked him unconcious. As he fell he opened the dry-chem side of the double-nozzle on the P-10, and inhaled a bunch of dry-chem, killing him.

Before that, on open training fires, we didn't always mask up; the drooping hood was considered sufficient. After that, we always did.

If a computer catches fire, it's already beyond recovery, you need to protect the adjacent ones.

The idea of 1301 as I understood it was to extinguish structural fires for the building housing the computers. Back in 1991/92, our bases had computer labs crammed with the things, and 1301 was used to snuff out the building fire without damaging the systems themselves.

Of course many other buildings, my fire dept included, had computers with zero-point-zero halon coverage. But the hand-held portable 1301s and installed 1301 systems were reserved for data-processing centers with a concentration of computers for group- or wing-level ops. The rest of us had dry-chem or in worst case pressurized water exts.

 

[gumbyk]

On emergencies, we always had SCBA donned; and usually for training as well, especially after 1990 when we lost our brotha A1C James White to a nozzle failure; a bolt failed under pressure, the recoil blew the nozzle under his hood, and a lungful of halon knocked him unconcious. As he fell he opened the dry-chem side of the double-nozzle on the P-10, and inhaled a bunch of dry-chem, killing him.

Before that, on open training fires, we didn't always mask up; the drooping hood was considered sufficient. After that, we always did.



The idea of 1301 as I understood it was to extinguish structural fires for the building housing the computers. Back in 1991/92, our bases had computer labs crammed with the things, and 1301 was used to snuff out the building fire without damaging the systems themselves.

Of course many other buildings, my fire dept included, had computers with zero-point-zero halon coverage. But the hand-held portable 1301s and installed 1301 systems were reserved for data-processing centers with a concentration of computers for group- or wing-level ops. The rest of us had dry-chem or in worst case pressurized water exts.

Dry chem will permanently fry computers - corrosive and conductive

 

[Thumpalumpacus]

Dry chem will permanently fry computers - corrosive and conductive

Indeed, ammonium phosphate is some ugly stuff. It will also screw up anything with moving parts, like engines of any sort.

Our internal plan if the alarm room caught fire was to pull a P-10 into the Chief's stall and use its halon.

 

[gumbyk]

Indeed, ammonium phosphate is some ugly stuff. It will also screw up anything with moving parts, like engines of any sort.

Our internal plan if the alarm room caught fire was to pull a P-10 into the Chief's stall and use its halon.

makes a good fertiliser though

 

[Thumpalumpacus]

makes a good fertiliser though

Dammit Jim, I'm a firefighter, not a farmer!

 

[ThomasP]

We used 1301 Halon systems for potential magnesium alloy (and a couple of other pyrophoric alloy) fires in a few of the manufacturing plants I worked in. Most of the time it was due to the possibility of a fire starting in the fine metal chips generated by a machine tool (CNC milling/machining or lathe/turning center). In effect, if the crew was not careful to clean out the machines properly - between work on magnesium, steel, aluminum, etc - they could end up creating a thermite fire. Usually this would be due to the fine chips starting on fire, but sometimes a solid magnesium alloy blank could start on fire if the crew was not alert.

One of the companies had a serious 'thermal event' about 6 months before I started work there. A CNC machining center had started on fire, either due to the oil based coolant running low or the system becoming clogged, causing an intermittent coverage of the area being cut by the tool. This was enough to start the .75" x 2" x 2.5" magnesium alloy blank (a soon to be hard disk drive reader head arm) on fire The fire then spread to the pile of magnesium chips in the lower part of the machine, the heat then becoming high enough to start the steel sheet metal of the enclosure on fire, etc. I got to see the video of the 'thermal event'. It took only about 2.5 sec to go from no visible fire at the machine, to a flare so bright that it bloomed out the CCD camera. The fire spread to to the near machine after about 5 seconds. Fortunately there was not enough fuel for the fire to spread wide enough to start fires in any more neighboring machines. But the fire triggered the overhead sprinkler system over half the shop area (about 20 machining centers), and the vaporized metal particles and metal-oxides combustion products contaminated the entire facility (~30,000 ft2). I am not sure how much damage the Halon itself did, if any. All the personnel got out safely. 4 months and $6,000,000 (mid-1990s) later they were back up and running - with dedicated single-shot Halon systems for each machining/turning center, and the distance between machines increased from 4-5 ft to 10 ft..

 

[GrauGeist]

Perhaps now's not the time to mention that we'd place VW type I engine cases under a stack of pallets at the beach for our bonfire parties.
The oak pallets would eventually ignite the magnesium alloy and start an epic display that could have been seen by the Space Station (and every beach ranger for miles).

 

[fastmongrel]

I attended a fire fighting course at work once. The instructor set up the demonstration to show what happens when you use a water extinguisher on an oil fire. He must have done it thousands of times but on this day I don't know what he did but when he sprayed the fire instead of the spectacular but harmless whumpf and a small fireball shooting upwards there was a WHUMPF and instead of the flames going up it spread at ground level. We were all standing well back but the safety instructor with the fire extinguisher got singed boots.