New Year's Eve Generator Fire

[Mark (Basspig) Weiss]

This was a totally unexpected incident, as I had run this generator on 95°F days and no fires resulted. It's been raining all week and everything is wet and 35°F and the fire happened.

Ran the generator for an hour (as usual) to bring the battery banks up (been raining for weeks on end here) and as I approached the generator building to shut it down, I noticed peculiar lights. First thought was maybe wife put some more warm white holiday lighting up on the other side of the bush, but when I got a clear view, I nearly had a heart attack. There was fire coming out of the generator building! I thought the windings on the genset had caught on fire, but it was the wooden door and frame that were on fire. Generator was still running. Ran back inside, turned on the garden hose and ran out and put out the fire, then shut down the generator.

Perplexing as it seems, I suspect the generator hadn't been aligned properly or had shifted away from the wall exhaust pipe inlet and hot exhaust gas had build up in the corner, drying out and eventually igniting the door frame. The door came off its hinges and was burnings when I got there. It must have been burning for quite some time. Fortunately all the rain made the wood damp, so the fire burned slowly.

Next non-rainy day, I will have to pull the genset and do a thorough inspection. The fan housing looks a little melted, and may need replacing. This could have been much worse, if a fuel line broke or the main fuel tank ignited.

Fortunately, the building is all concrete except the door and door frame, which are oak and plywood filled with concrete.

I will have to build a steel frame and steel door in the spring.

I really need a quiet diesel genset that doesn't need this elaborate noise mitigation.

 

[Another Johnson]

Looks like an enclosure rather than a building.

If it’s for noise containment, it is also containing the engine heat.

I have used this type of generator, and would not be comfortable enclosing it as your picture depicts.

I eventually bit the bullet and had a 22kw unit with load shedding software installed. It runs on propane, and its enclosure is factory built as part of the unit.

Although it was not audible at my main listening room, it was audible if you listened for it in the living room. To make it less noisy, it could have been ibstalled further away from the structure of the main house.

Yours was probably working very hard … it sounds like you use it to charge depleted batteries when a solar charging system isn’t able to work. With a week of no sun, the batteries probably presented quite a stout load. You might check the load to see if there’s a problem beyond depletion due to bad weather.
Best of luck with your repair.

 

[Mark (Basspig) Weiss]

I didn't mention that there are two fans--an input and an exhaust-- 1000CFM that kept this generator cool in 95F August heat during a dry spell. This concrete structure was built in 1986. The only thing I could not make fire resistant was the door. I did not have the tools or materials to make a steel frame and door at the time. There never was a problem in all these decades, but the freak accident was that the genset muffler outlet was not aligned and pressed up against the flue pipe after the last refueling. Hot exhaust gas was blowing and that corner had the least ventilation. The temperature was 35F and it had been raining for the past two weeks, which made this a surreal event, remembering that it ran 90 minutes in 95F summer heat with no fire.

One of my four projects this summer will be to weld a steel frame together and fabricate a steel door.
Aside from some melting of the plastic cowling, the generator is undamaged, thankfully.

I wanted to get an Aurora quiet diesel (58dB @ 3'), but in 2010, there was no way to get it delivered up the mountain. Now that I have a truck and an excavator to move it, the price tripled and it is beyond my ability to finance on social security retirement.