UG-14 Limits
UG-14 Limits
(OP)
What constitutes 4" NPS.
As an example, we produce a pressure vessel from 4" sch80 pipe and a flat head weld ed to one end. My interpretation is that the flat end can be made from forged bar (ensuring that the grain flow of the hub is in the correct direction).
However, we produce a stronger model machined entirely from forged bar, it has a larger OD but the same bore. My inrepretation is that this is still 4" NPS.
What would your interpretation be?
As an example, we produce a pressure vessel from 4" sch80 pipe and a flat head weld ed to one end. My interpretation is that the flat end can be made from forged bar (ensuring that the grain flow of the hub is in the correct direction).
However, we produce a stronger model machined entirely from forged bar, it has a larger OD but the same bore. My inrepretation is that this is still 4" NPS.
What would your interpretation be?





RE: UG-14 Limits
RE: UG-14 Limits
If you cut flat caps off the bar like "cookies" you will have problems.
RE: UG-14 Limits
if you modify a pipe in any way size or chemical components, it is not pipe anymore.
you will have to comply with the forging specification.
which you can probably use NPS certified by the forging mfr.
(what about female forging specs) they are heavier than 4in. NPS pipe!
RE: UG-14 Limits
I do think that ASME have been a little hasty, there will be a lot of manuafcturers of small vessels out of titanium or other materials with small grain sizes that are going to struggle to make one-off bespoke vessels because of this new ruling when they don't get any benefit from having the grain formed in the stress directions.
Maybe they should consider who uses the code and how before they jump in like this.
RE: UG-14 Limits