WN Tower 28 aerial fire truck, a marvel of technology

My third firefighter training beckons tonight on what is sure to be sweltering once we don our turnout suits. It’s going to hit 90 today. Thank God we’re not in Portland, Ore. where it’s going to reach 105 today!

I’ve been meaning to recount one training session last week as well a 280-slide PowerPoint presentation (the longest I’ve ever been subjected to) on the new ladder truck which while loooong was fascinating.wn-tower-281

I did not take notes, but there’s a lot I remember about the truck even after a week. And you can read more about it at manufacturer KME’s (Kovatch Mobile Equipment) web site.

What left the biggest impression is that this of 80-ton piece of equipment can be dangerous in the wrong hands (mine, right now). The aerial (the ladder and bucket) extends 95 feet into the air from it steepest angle of attack and with two firefighters in the bucket, extreme caution should used and competence exercised. I’ll get my turn to share a spot in the bucket eventually. The aerial alone weighs 50,000 pounds (25 tons).

Much of the presentation focused on the aerial and how to set up the truck’s outriggers. There were four major points which I probably don’t recall exactly right: maximize stance, center of gravity and stability and minimize height off the ground. If the truck is in excess of 5 degrees off level, you subtract 500 pounds from the maximum weight in the bucket. That would reduce it to 1,000  pounds. I also seem to recall that if the “line is charged,” you take off another 500, leaving the bucket weight at 500 pounds – still enough for two firefighters.

A green zone gauge tells the operator how level the truck is. The biggest hazard operating the truck is it tipping over with the aerial extended and firefighters in the bucket.  He also reviewed the features of the bucket from which the aerial can be controlled. However, the controls at the base of the aerial have priority and override the ones in the bucket.

There’s margin of safety built in — 2:1 structurally and 1.5:1 from a stability standpoint. Again this is from memory and those numbers could be off. The presenter who was from the dealer who sold West Newbury the truck emphatically said you “never operate in the margin.” Lives are at stake. Indeed!

The outriggers which set the truck in place and lift it off the tires are computer controlled and set level automatically although there’s overrides should the computer fail. It’s impossible to predict what kind of terrain the truck will find itself during a call. One thing he said was not to put an outrigger on top of ground covering a septic tank. You can imagine that picture – dangerous not to mention messy.

As for the 95-foot extension (actually, it might have been 94) and no building in  West Newbury being more than 40 feet high, Bob Pierce later explained that what counts is the horizontal extension. If someone is struggling in a pond 80 feet out, you don’t want a 50 foot aerial. That extension could really matter and save a life.

The truck itself is run by computers. There’s one for the engine, transmission and aerial (I’m leaving out one or two). They fail and your in trouble. I forget if he said there are overrides, but I think not. The 525 HP Cat engine and transmission are major consumers of fluids…upward of 40 quarts of engine oil and a few more quarts than that of tranny fluid. Hydraulic fluid capacity was something like 60 gallons! Think about just how much the hydraulic fluid weighs.

Another area where he spent quite a bit of time was on the alternator which maximally cranks out 320 amps. However at engine idle, it’ll only produce half that so a “fast idle” switch revs the engine to a point where the alternator will produce at full capacity. After all, there’s dozens of lights on the truck (many look to be halogen which we were warned can get very hot). There’s six interconnected batteries acting as a single unit, I think he said.

He also cautioned that if the gauge (and there were many) shows voltage to be high, pull over and call a technician. Continuing with high voltage can fry the electrical system and more importantly the computers which control everything. That’s one expensive repair. A low voltage reading is less troublesome.

Finally, he talked about how exhaust particulate is captured in a chamber nearby or in the muffler. On occasion, it has to be burnt off by soaking the particulate with diesel fuel and igniting it. This is common is all diesels now. The result is a very hot gas in excess of 1,000 degrees F. out the exhaust pipe. So the operator has to be careful about where the truck is situated. The dealer mentioned it’s a bad idea to park it next to chief’s car or truck when that procedure is underway as it leave a brown burn on the paint.

I am sure I am leaving out some aspects of this marvel of technology. It has many cabinets, additional ladders and large air tanks for to provide oxygen for the firefighters in the bucket and even some creature comforts in the cab.  As the dealer remarked, it takes the WNFD into a whole new realm of firefighting.

As for the previous evening’s training, we donned airpacks and used the masks for the first time. One trainer showed how to don air packs by lifting it over heads to put it on in a “cascading fashion.” Like donning the turnout suit, the air packs and related gear are supposed to be put on and set up in under a minute. We all will need to practice as that requires putting on the hood, the mask with airtight seal and helmet, turning on the air, cross-checking capacity using two gauges, and hooking on the air hose to the mask.

The first time I did it, I wondered if I would be able to breath. It was surpisingly easy and there were at least two ways to get air into the mask of the tank failed. We also learned how to recharge the tanks. Training three begins tonight.

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