Thankyou, SP5103.


>> .......and so is way too expensive.
> Expensive compared to what? To a boiler failure? To a boiler explosion?


Expensive compared to actually available resources; which often means that Steam engines get parked for long periods of time, until those resources can be found. I did not mean to imply that they shouldn't have to be done.

The intent of the question was - what is it about boilers (construction, metallurgy, or whatever), that says it should be done on a 15 year cycle, rather than, say 10 years, or some other time period. One not in the know, like me, might think that it was just an arbitrary pick (you got to do it sometime), and maybe it was. But there might also be a very good reason behind the specific 15 year number -

That is what I wanted to find out. And also what are the wear factors in a boiler that the inspections are looking for; that would not have already caused a boiler explosion within those 15 years (cracks for instance).

Thanx