Boiler approval and testing

Not in the UK nor in small non commercial boiler sizes in the US or Canada as far as I am aware. Nor do I see any need for a formal licence to operate the boilers within the scope of the British code. It is not as if we have boilers bursting left right and centre! Thus any legislation would be a complete waste of time, should there be an accident or a series of accidents involving injury or fatalities no doubt that would change but I would argue the risk is well managed and controlled at present.

There are competence standards on heritage railways evidenced by training, logs and assessments to qualify firemen and again this seems to work. There was one incident a few years ago that involved a narrow gauge loco that ran short of water and the HSE were involved, their conclusion was the driver / fireman was inadequately trained and experienced due to non compliance with the training that was in place - case closed, there was no consternation and knee jerk reaction at gobbermint level.

The decision on whether to add water or not to a boiler with a low level is a subjective one also dependant on the type of boiler. Locomotive style boilers as fitted to railway loco’s and TE’s do not fall into the same class and risk as a water tube or an industrial unit. Normally an industrial boiler will be run close to its maximum rate of evaporation. Boilers in our world and even in most full size heritage operations are rarely operated at those levels and if they are only intermittently. If you take the case of a loco sitting in a station for 45min waiting for the train to depart and maybe with steam heat running, it could drop the water out of the glass if not properly supervised, however the rate of evaporation compared to say working up a 1:50 would be low and the chance of overheating the crown to red heat levels would be very low so adding water would not be a problem. Your blanket industrial licence procedure would be relevant to a boiler running hard, it’s not necessarily correct in all circumstances.

Paul

Edited By Paul Kemp on 09/07/2022 23:31:19

Hopper -

The legal requirements apply particularly to boilers built commercially, but it's more the insurers require them being tested. However, if the event of a serious accident the investigators would want to verify that the society concerned had followed all the appropriate rules and practices.

There are no formal "driving licences" for models, thank goodness! There is enough bureaucracy in the world as it is, and if the legal types whose only connection with leisure activities is commercially exploiting their accidents, managed to enforce it, it would achieve nothing useful. It would probably do far more harm than good. (Several years ago now, some of them wanted all amateur workshops "licensed" in some way, after the conviction of one criminal who had made a gun, or re-activated a non-working one, at home.)

Although in the UK, if you drive a miniature traction-engine on the public road it needs to be registered as a vehicle and you need have appropriate insurance - and that is only valid if the separate boiler tests are in date. It does not appear very hard to obtain though, presumably because most owners of such engines are already motorists anyway.

Clubs do have their own by-laws though, for establishing who are "passed drivers" for public passenger-carrying events on their permanent and portable railway tracks. I daresay some might be rather formal about it but others might prefer simple peer-review.

There are no legal requirements for operating model boilers in Australia that have a volume of less than 50 litres and a max. working pressure of 100psi. Many model clubs have their own certification requirements and the boiler has to have a current test certificate. Insurance is included with your club membership. Difficult to get registration to run on a public road except on special street parades when there is no car traffic.

A high risk Class BS National Licence is required to operate bigger boilers and traction engines with a piston diameter of less than 10 inches, like a 10 ton 4NHP Fowler. I also drive a 7NHP Fowler and had to get a Class ES ticket, allowing me to drive bigger reciprocating engines.

I'd like to see any old locomotive drivers handbooks that advised adding water to a boiler with nothing in the glass. You might get away with it, but it's a very risky practice. Of course,they were less risk averse in those days.

On the topic of full sized heritage steam, they can still go awfully wrong, as this tragic example shows Link due to low water and crown plate failure. I have been very wary of going to amateur steam events since! But I think most places have stricter inspection and licensing regimes for old equipment than in the state where this happened.

I vaguely remember another incident in Australia years ago where a worker on a heritage railway screwed the fusible plug in cross threaded and it blew out mid-run, filling the cab with superheated steam and broiling the driver and fireman alive. I don't recall if they survived. I think not.

But at model size, yes we never hear of such mini-explosions, and further bureaucracy, we do not need. Just interesting that there are some formal rules for boilers but not the operators. Hopefully they are not following outdated advice like the Victorian views that SOD unearthed!

Both the clubs I am a member of have testing and retesting regimes for driving and being a guard when carrying members of the public but when they are not present these are relaxed to allow training and practice to take place.

The Medina incident is not a good example to use for low water level failure as the boiler was clearly structurally unsound in the first place and also that there were no surviving witnesses to provide account of the events. There was also some dissent between the professional boiler inspectors on whether low water was the cause or contributory factor.

They were agreed that the crown sheet had extensive wastage of up to 77%, that the crown stays had wastage and the thread engagement due to crown sheet thinning was only about 30% of what would be required in some areas. The crown also showed signs of “bagging” (quilting in the uk) that may have been pre-existing. The pressure gauge was under reading, the safety valve rated for 125 psi did not lift until 253psi when tested after the event. The fusible plug was in place but was insulated on the water side by a build up of scale and was intact. Parts of the crown sheet towards the front of the firebox showed signs of overheating, those at the rear did not.

Taking all of the info and comments the one thing I did not see was a record of any inclination of the ground the engine was stood on at the time of failure - uphill slightly could lead to a circumstance where there was water over the back of the crown (where the fusible plug was located) but little or none to the front of the crown. My conclusion from all the evidence is if low water was the cause at the point of failure it can’t be proven (boiler had undoubtably experienced low water at some point though). What is beyond doubt is irrespective of the water level the boiler was structurally in a dangerous condition, had not been well maintained and thus a failure at some point was inevitable.

I will try and find the narrow gauge loco report I referred to earlier.

Paul.