There is always some discussion when you have a pressure vessel which has a flame inside, but the vessel is equipped with refractory. In that case the vessel is considered unfired as there is no risk of flame impingement on the pressure retaining parts.
I have not found this properly explained in ASME code. Does anybody have any reference of where this situation is well described/classified?
What would be the proper code of construction for a pressure vessel which is heated by flue gases, but has no direct flame contact; section VIII Div 1?
PS: this pressure vessel does not contain water, nor does it have any relation/comparison with a steam boiler. The process in my case is something completely different.
Perhaps a brief review of BPV code development might help...
The founders of the original ASME code recognized the increased danger to the public of a fired (heated) pressure vessel. In the mid to late 1800s, explosions in factories and on steamships were common. There were no uniform rules across the states for matters such as settings or even for the need for relief valves.
It was recognized that overheating of the boiler was a constant possibility.
Boiler repairs were haphazard, up to the craftsman and dangerous...
After many deaths and property destruction, a code to address "fired pressure vessels" was developed.
Mandatory relief devices were required, quality materials were defined and approved methods of assembly (riveting and eventually welding) were specified.
LATER, a similar section of the code (unfired vessels) was developed with slightly higher allowable stresses and slightly more liberal rules was developed.
