Sunday, October 10, 2010

Adventures with Antarctic ARFF trucks

Catch 22: AFD has something like $200,000 for an ARFF truck that can be driven onto a C-130 and flown to the South Pole.
No ARFF truck that costs $200,000 and fits on a C-130 will work in Antarctica.
(Also, we later discover that ARFF trucks that cost $200,000 and fit on a C-130 and don't work in Antarctica - which is, by necessity, what we bought- ONLY fit on a C-130 if driven in- not back in. This lesson costs about $1mil and results in a C-130 sitting on the ramp at Pole with a 'For Sale' sign pasted on it. Fortunately, it was the loadmaster's fault, not ours.
The Renegades:
It's an F-550 with a 300gal CAFS/ 500 lb dry chem fire package on back. The trimax fire package is a pretty nifty patented system in which big high pressure nitrogen cylinders pressurize dry chem and foam tanks, enabling agent flow, and simulaneously injects air into the foam stream to create CAFS. Because the nitro cools when it expands, the agent comes out almost at freezing temperature. The trucks have about 90 secs worth of agent out the turret, and up to 8 mins out the handline. The forest service, loggers, etc buy a lot of these systems, and they work quite well. Everywhere but Antarctica.

Fatal Flaws of the Renegades:
Fire Package - Foam must be used as a concentrate and is therefore very corrosive. All brass fittings and certain areas of inappropriate soft hose replaced after they blew apart when charged at a fire.
- the fire package is surrounded by a metal box. The undiluted foam will freeze below -40F, so the truck has to be heated. Current heaters are inadequate and there isn't capacity at the air field right now for high-voltage plug ins.
- 5 psi check valves between the nitro and foam system are inadequate and allow foam to back up and render the electrical actuating system inoperable. One of my favorite AFD catches: while the foam can be cleaned out by breaking down the entire system and taking apart the solenoids, the system must then be tested, which puts more foam into the system.
- THE SYSTEM HAS NO MANUAL OVERRIDE. In order to manually activate the system, a 5' nitro cylinder would have to be moved to the side, air hoses disconnected from the foam line valve, and the valve manually pulled and held open. System failed at a truck fire due to lack of manual activation capability.
- Hoseline is a 100' rubber hose reel that hardens in cold temps. This means that the truck will have to back up right to the door of a C-130 or C-17 for good reach inside the plane.
The truck - F550 is not a tough enough platform for this system.
- back overloaded - suspension system has pretty much zero spring left.
- transmission is not heavy enough for the tracks. Much time at VMF.
- trucks can go about 6 miles at 20mph before their coolant boils. Spills are a no-no here.
- trucks were nearly impossible to steer in close quarters/ low speeds due to track friction. This resulted in excessive wear and tear and a few really good years for the Ford steering pump division, until VMF rigged up a hydraulic enhancement.
- Although the trucks are used very little, the Mattracks are not very durable and end up with rips fairly frequently

- Smurf hut, winter (2007?) - warming hut at Pegasus catches fire. Glow is seen from town, a Renegade responds over the ice road. On arrival, handline is pulled, system is charged, and the corroded brass fittings in the package blow apart. Package fills with foam, hut burns while crew waits for a second truck to drive out. Total loss.

- Van fire - Pegasus, summer 2010 - Renegade works beautifully. Van total loss.
- Truck fire - Ice Runway, winter 2010 -Solenoids on foam side of system fail, system unchargeable, fire eventually put out with PKP and shovelfulls of snow. Total loss.

Testing - After the failure of Red 4 at the winter 2010 truck fire, AFD was mandated to test all ARFF apparatus. Testing of the 4 Renegades was informative, fun, and resulted in the following unique photo ops:
Foam explosion #1: Foam system switch was wired backwards -> 'off'='on'. Unfortunately handline was open in the back, so when the ignition key was turned, the package got filled with foam. Fortunately for, I left that evening for the Castle Rock manhaul and missed the cleanup.

Foam Explosion #2 - malfunction causes foam discharge out the turret. The fates present this disaster in an artistic way to me. We have just returned from building inspections, and open the bay door to back the truck in. As I signal the truck back, I turn and stare as the door slowly rises to reveal a heavy stream shooting from the turret and a huge expanding pool of white foam rapidly spreading across the bay. Perfect timing. Cleanup takes the rest of the afternoon. Note how our noble fire crew is still smiling.
Foam Explosion #3 - A similar event causes a similar spill the next day - picture a slightly smaller bubbly puddle and a few less smiles.

Eventually all 6 ARFF trucks were returned to serviceable condition, for now. Plans are being worked on for fixing the unintended foam-air system interface, and adding manual overrides. Two new units will be ordered for Pole, and these will be dragged on sleds to reduce the strain on the F550s. Their packages will feature compressor-generated CAFS and full manual overrides.

PKP Explosion - The grand finale. I've lost track of the details on this one, but it was a big cleanup for the other shift, with lots of 55 gal drums, masks, and brooms. A fine purple film can still be found by running one's finger along most any horizontal surface in the firehouse.

Testing the Chieftons: 25 years old and still going strong

Red 1 - separate pump and generator in back package. Passes flow test without a hitch. Package was completely rewired in back last month after being plugged into the wrong phase power source.

Red 2 - PTO pump and separate generator in package. Everything is nice and solid, heavy and old. It doesnt break easy. It isnt simple. Steps to use this truck during our test:

1) Pre-startup truck check... outer 30" of water intake pipe is frozen solid. Two hours of thawing necessary.

2) Unplug 2 power cords from under engine.

3) Climb up on tread and turn on front battery switch.

4) Start engine by turning ignition and holding ignition cutoff switch for at least 30 seconds.

5) Turn off outside breaker for package power

6) unplug cannon plug from truck

7) climb into package and start generator by turning on fuel, turning off circuit breaker, pulling out choke, and turning key for electric start. Use pull start when electric start fails to work.

8) Unplug and re-plug 3 cords to transfer all package heater to generator power.

9) Open main valve and recirculate valve to get pump wet.

10) Return to cab and follow normal steps to engage PTO: place air brake on, truck in neutral, engage PTO, put truck in drive, switch on high idle.

11) Truck stalls. Experiment until you figure out this is the order needed: Truck in neutral, parking brake, high idle, PTO, drive.

12) Climb back into package and open the valve to the turret if you havent already.

13) Climb back into the front and use turret controls. For handline, pull handline, then charge with valve at back of package. Remember that you only have 1000 or 1100 of the 1200 gals that could fit in the tank , since the agent sloshes out the top vent if the tank is filled all the way.

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