Piping materials for boiler at low ambient temperatures

[coolniks37]

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?

 

[XL83NL]

First off, be more specific/provide more details.
Is the minimum temp. a site condition, and is it operated at that temp.?
What are the normal/design/environmental conditions? Whats the size range?

What is your design code? If it's ASME, I suspect posting in the ASME section has more potential for reply.
If your scope falls under PED 97/23/EC (i.e. if thats the reasoning for posting in CEN section), then keep in mind PED's ESR's from Annex I.

 

[coolniks37]

Hi XL83NL

Minimum temp is a site condition. Very snowy conditions, temperature can drop to -40 deg C. (2 months in an year max)
Normal conditions would be 25-30 deg C.
Pipe sizes are 368x50; 406.4x70mm etc.

The design shall be as per BS EN 12952 and has to satisfy PED.
ESR doesnt give a clear idea about this problem.

 

[OSIRIS7]

According to PED you are allowed to use materials that do not suffice the toughness requirements provided that you cleared the risk of brittle fracture by e.g. electrical (sandwich) tracing of the piping or maybe keep a constant hot gas flowing with low flow and low pressure or prevent fast start-up. There are probably more ways to eliminate the risk. This should be taken care of when you do the risk analysis (at the beginning of a project).