Boiler Overheat Accident

[Maltelec]

The following link is to a report into a boiler overheating accident after a passenger train on the Kirklees Light Railway on Sunday 3 July 2011 ran low on water in the boiler.


http://www.raib.gov.uk/cms_resources.cf ... rklees.pdf


Its an interesting read and goes through different scenarios that could have resulted in the accident happening. No one was hurt in the accident.

[gondolier88]

Very interesting.

If this had been a marine passenger boat it's passenger license would have been revoked until such time it was deemed that all crew and staff had been trained to a competent level with all risk assessments and training undertaken logged and proof of examination to prove competency- yet it seems that the RAIB were very happy for the railway to continue it's passenger carrying role knowing full well that it's training and risk assessments were unsatisfactory.

Greg

[Lopez Mike]

What jumps out at me in that report is that the fusible plug melted and it was still possible to even have a fire. I'm sort of horrified that the opening in the plug was that small.

The whole point of a such a plug is to scare the rat poop out of the crew and douse the fire. The plug on the 90 ton Shay locomotive failed once due to a faulty plug and it scared me half to death. A jet of soot and steam came whooshing out of the inspection port in the firebox door, all sorts of crud and commotion blew back down through the damper and the noise was frightening.

That all it did in this case was to make the engineer try to fire harder and to make a 'whistling sound' is alarming. I mean, what's the point of a safety device if all it does is send a warning to a person who already is overloaded with an unfamiliar situation. You might as well replace the safety valve with a penny whistle. "Someone deal with that teakettle please!"

Also, I read in the report that the railroad involved designed and installed its own plug. Bad design?

[gondolier88]

What jumps out at me in that report is that the fusible plug melted and it was still possible to even have a fire. I'm sort of horrified that the opening in the plug was that small.
Also, I read in the report that the railroad involved designed and installed its own plug. Bad design?

A good point- I've never seen a steel fusible plug for a start- a brass one's body would also fail under extreme heat and further reduce pressure. Nabic type every time for me!

[RogerV]

Two or three things occurred to me:

1) Almost all accidents are due to human error, and human error can include the installation of inadequate safety devices or the failure to maintain and test equipment properly.

2) Liquid or gas fuel have an advantage over solid fuel because they allow the fire to be put out almost instantly (assuming someone notices there is a problem and cuts the fuel supply).

3) I wonder about the feasibility of using a dry chemical fire extinguisher to put out a solid fuel fire aboard a steam launch during an emergency. Good idea, or not?

[Lopez Mike]

Dead on.

In the case of the locomotive, I was the fireman and I instinctively closed the firing valve (oil fired locomotive) to the spot fire setting and then, within seconds, shut down the fire all the way. We then looked at each other and said, "Lost a flue?"

We carefully opened up the fire door a bit and figured out what had happened. We had enough pressure left to ease the locomotive and the one flat car of passengers a length or two to where they could get off and walk the few hundred yards to get their money back. Then, after they were out of panic range, we opened the blow down and waited for things to cool down. It took overnight before I could inspect the firebox and fix the problem. It happened at noon on a Saturday and we were hauling people by ten a.m. on Sunday. I couldn't believe we had a spare fusible plug!

When I have used a dry extinguisher on automotive or electrical fires we have been advised to wash down the area as soon as possible as the powder is mildly corrosive (caustic?). I don't know if this is true. I suspect the normal combustion products of our fires are far more horrible than any such chemical.

Human error will always be with us but we try to design around it as much as we can. When I took possession of my boat, there was a shut off valve between the boiler and the safety valve!! Made my scalp tingle a bit.

[RogerV]

As I think about it, standing to one side would be a good idea if using a fire extinguisher to douse a boiler fire. The force of the pressurized propellant could blow assorted (and possibly hot) kinds of crap back out of the firebox door.

I've heard of the potential corrosivenes of the dry chemicals used in fire extinguishers, but my thinking is that if you're already in an emergency situation, that's probably the last thing to be worried about.

Nobody would tell you it was a good idea to aim a 250-gallon a minute fire hose into the window of a house that's not on fire. However, the situation changes drastically if the house IS on fire.

[Lopez Mike]

On my primitive boat, the plan for a low water emergency is to open up the fire door and use a cup to throw water from the hot well on the wood fire. Then leave the fire door open so that cool air can circulate. Then clean out my pants.

I wouldn't worry about using salt water to douse my fire. Compared to some of the combustion products from wood, salt water is small potatoes.

I don't know about the rest of you but bringing my boiler up to pressure after a layup is a mildly nervous time. I hydro test to 225 or so (150 safety valve) after any significant work or after an idle period of over a few months. But even then, I'm always half expecting the sight glass or some stupid little fitting to let loose and scare me half way out of my skin. Creakings and simmering noises.

Once I got cocky and decided to create a boiler explosion for fun. I took an old spray can and brazed a 1/4 inch pipe fitting to it for a gauge. I set it out in the field and propped my weed burner up aimed at it. When it got up to around 100 psi, I shot it with my 22 target rifle from about 50 yards. Having shot any number of mostly full spray cans just for the heck of it, I thought I was ready. Whooo Haw! Impressive. Don't do it. The cat was gone all night.

[farmerden]

As a trustee in our local fire dept ,I was concerned about our firemen attending a boiler situation.So Iasked the traction engine guys for opinions.Here's the senario -The engineer has collapsed at his station,full fire,no water showing on glass.Obviously taking an 1 1/2 in hose to the boiler might not be the best approach! Basically ,as I recall ,the advice was ,clear the site of people,smother the fire and get the engineer out of there! As our guys ,due to lack of knowledge of steam,wouldn't know what valve does what,other than smothering the fire nothing else was recommended.I would assume locomotives would be the same.First thing I do to anyone on my boat is show how to shut the fuel down and leave the engine running which should continue to pump water in the boiler and use up steam. As most of us in steam boats are young at heart but long in the tooth-one must prepare for human emergencies not nessessarily steam emergencies

[fredrosse]

Good points about the possibility of the operator dropping dead (or falling overboard!) while underway with passengers aboard.

If possible some basic training for a willing passenger might save the day, although many passengers find the steam plant way too complicated to deal with. At steam meets there is often a passenger who is a steam enthusiast, and that person should at least be informed of the locations of basic system valves, so they could take over in a pinch.

I have thought of putting a foot pedal which must be pushed down in order to have fuel flow, I think there was similar type safety controls on locomotives? If the engineer does not push the pedal down, the fire goes to pilot flame only. Of course this will only work for oil/gas firing. The propane weed burner that I use to fire the boiler has a spring return hand lever to give high fire, and this could easily be adapted to this service.