Piping Class and Design Pressure
Piping Class and Design Pressure
(OP)
Hi,
If the design pressure for a piping spec is somewhere between the ASME Class 300 and 600 pressure/temperature ratings can it be labelled a "Class 600" piping spec? Class 600 flanges will be specified in the spec, but the piping wall thickesses will be calculated using the design pressure. I think it is dangerous to label the spec Class 600, but I have seen this happen several times.
Thanks
If the design pressure for a piping spec is somewhere between the ASME Class 300 and 600 pressure/temperature ratings can it be labelled a "Class 600" piping spec? Class 600 flanges will be specified in the spec, but the piping wall thickesses will be calculated using the design pressure. I think it is dangerous to label the spec Class 600, but I have seen this happen several times.
Thanks





RE: Piping Class and Design Pressure
Calling a spec "class 600" when it has a MAWP less than class 600 is potentially confusing- but not necessarily dangerous. In reality, your spec is possibly good for class 600 to a certain diameter or temperature. In that case, is it really wrong to call it class 600? But you could call it by any acronym you want if you fear confusion.
RE: Piping Class and Design Pressure
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Piping Class and Design Pressure
If it ain't broke, don't fix it. If it's not safe ... make it that way.
RE: Piping Class and Design Pressure
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Piping Class and Design Pressure
Then special services will have their own specs, say for stainless lube oil piping, etc.
Then all lines on the P&IDs will be labled with something like 10"-A1-XXXX-YYYY, where XXXX is an system designation (with it's own numbering system) and YYYY is the line designation.
There's a gazillion ways to do it, and everyone does it differently.
RE: Piping Class and Design Pressure
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Piping Class and Design Pressure