Pipe materials for boilers at low ambient conditions
Pipe materials for boilers at low ambient conditions
(OP)
Hi what pipe materials i need to use for boiler piping, in places having low ambient temp?
For example boiler when operating, will have temp, above 500 deg C
But when it is shut down, the piping comes down to ambient conditions say -10 deg C
What ASME Section I or any other codes says about this?
Will th material be prone to brittle fracture then?
What conditions shall be considered and how safety shall be incorporated?
For example boiler when operating, will have temp, above 500 deg C
But when it is shut down, the piping comes down to ambient conditions say -10 deg C
What ASME Section I or any other codes says about this?
Will th material be prone to brittle fracture then?
What conditions shall be considered and how safety shall be incorporated?





RE: Pipe materials for boilers at low ambient conditions
The only concern is for pressure testing. Here, the NBIC provides guidance for elevating the temperature of the water for pressure testing to reduce the risk of brittle fracture. Again, this is a non-operating condition and only relates to pressure testing of weld repairs.
RE: Pipe materials for boilers at low ambient conditions
I understand that boilers operate at high temp. but lets say during a shut down or during erection, or during storage of items at site, if atmpospheric temp falls down , then there is a chance of ductile to brittle fracture..
How it is taken care by code? I think this seasonal variations are common in russia, uk, etc..
RE: Pipe materials for boilers at low ambient conditions
RE: Pipe materials for boilers at low ambient conditions
I believe most materials dont have very low nil ductility point.
COuld you pls give some reference or standards, talking about such temperatures for boiler materials.
have you seen bsen codes which specify some minimum charpy value at -20 deg C ? How to calculate the same for still lower temperatures?
What ASME Section 8 talks about this scenario?
RE: Pipe materials for boilers at low ambient conditions
RE: Pipe materials for boilers at low ambient conditions
RE: Pipe materials for boilers at low ambient conditions
In ASME VIII-1 this can be illustrated with the MDMT reduction curves of Fig UCS-66.1. If you look at these charts, and consider the no-pressure case, your stress ratio will be 0, and you end up with an allowable MDMT reduction of 140°F. This would provide you an MDMT well below your required -10°C.
RE: Pipe materials for boilers at low ambient conditions
RE: Pipe materials for boilers at low ambient conditions
What IS important is the pre-weld, inner-pass, and post-weld temperatures for the welding itself! Those HAVE to be met for every weld regardless of the "pipe" temperature while erecting.