Boiler Repair Standards

Is there one national organisation that sets the standards that boilers should be repaired to or does it just depend on the whim of the individual insurance company?

 

i think it comes under goverment law and the insurance company the eu has something to play in it too

 

But who determines the maximum limit of corrosion that is acceptable on a firebox side sheet or the correct way to flare a fluetube?

 

Shouldn't this topic be moved the new "Loco Engineering MIC" forum?

 

yes it should
and the boiler inspector determins plate thicknesses using non destructive testing (NDT) using a ultrasound meter or xrays i think ians the best person for itas he knows them off by heart

 

HG29 is a useful document concerning boilers, also MT276 should help for the rest of the loco.
both documents tell you what you should be maintaining things to a minimum standard.
ultimately it up to the boiler inspector with your boiler responible person
no one wants any accidents at the end of the day.

Richard.

 

what loco is this for

 

Link here: http://www.rail-reg.gov.uk/upload/pdf/locomotiveboilers.pdf

There is also the group standard no. GM/RT2003 from Jan '96 (still current according to the rssb website), but all this really does is refer you to MT/276. http://www.rgsonline.co.uk/docushare/dsweb/Get/Rail-38802/Rt2003.pdf

There are various national codes & standards for pressure vessels, such as PD5500 and ASME VIII, but these are aimed at design aspects and are really not applicable to fired boilers such as found on locos.

 

Actually ASME was designed around Coal fired Loco boilers in the late 1800's as a result of the numerous boiler explosions thaat happened at that time. It is still a design code for all pressure vessels, fired and un fired. PD5500 is for unfired only.

The minimum plate thickness is determined in the calculations of the design, as i depends on the grade of steel used (there are several boiler grades), but there is still discression by the inspector. ASME does state that you cannot use a plate thinner than 6mm for pressure vessels in Steel, that includes a corrosion allowance as required.

It is a subject which i want to get into, as i would like to become a boiler inspector given time!!!

Craig G

 

At the moment there is no national standard and it is at the whim of a Boiler inspector backed up by his head office. In practice it is often a combination of considered opinion of the boiler repairer, Boiler Inspector and head office. Different people have differing ideas on how to repair things and what is acceptable in some quarters is not in others. As an example, patches were originally fitted to the copper firebox sides of 61264 (I think they still are) when initially restored but it now seems that welding in inserts is the preferred option. Both have advantages and disadvantages. Another example is seal welding of riveted seams. This was quite common, then seems to have fallen out of favour with some Inspectors and now again seems to be a preferred option. At the end of the day there are often several ways to repair something and, as long as the repair is fit for purpose, it doesn't matter.

 

My experience of industrial boilers is that the boiler inspector (employed by an insurance company)is a very useful bloke, well worth spending time with.
They were (not sure if they still are) recruited from the ranks of sea going engineers (more Merchant Navy than Royal Navy) with a breadth of knowledge and experience. As with all people each one has his favourite little area that he wants to be just so, but their general knowledge and proper engineering training does give them the right background to make judgments on boiler condition.
These days not all have experience of loco type boilers, but I can think of 2 who I knew (both sadly passed on) who helped me no end on pressure vessels, and who were the source of many stories about people who wouldn't spend a penny more than they absolutely had to on plant. If you're going to tell a factory owner that you're going to shut down his boiler plant or air compressors, you need to be right and confident.
I do know that with the "rationalisation" of insurance companies that may of the Engineer Surveyors were getting very disheartened, and were waiting to get out, which is a sad reflection on the roles of engineers and bean counters in industry today.

Rob