Misalignment of nozzle-to-header joint : any tolerance ?
Misalignment of nozzle-to-header joint : any tolerance ?
(OP)
Dear all,
Refer to thread292-290132: misalignment of tube to header weld (misalignment of tube to header weld). In this thread it was answered by Metengr that such misplace / misalignment of joint between tube and header is a non-conformance. I fully understand this. Now my question : is there any tolerance on how much the mis-alignment is still considered acceptable ?
For example : I have nozzle to header joint. The nozzle is NPS 4 Sch XXS - grade91, header NPS 8 Sch 160 - grade91. Is misalignment of 8 mm (0.31") still acceptable ?
Refer to thread292-290132: misalignment of tube to header weld (misalignment of tube to header weld). In this thread it was answered by Metengr that such misplace / misalignment of joint between tube and header is a non-conformance. I fully understand this. Now my question : is there any tolerance on how much the mis-alignment is still considered acceptable ?
For example : I have nozzle to header joint. The nozzle is NPS 4 Sch XXS - grade91, header NPS 8 Sch 160 - grade91. Is misalignment of 8 mm (0.31") still acceptable ?





RE: Misalignment of nozzle-to-header joint : any tolerance ?
Fabrication tolerances for piping and pressure vessels are not contained within the codes. They are a commercial matter to be resolved between the purchaser and the supplier
For pressure vessel fabrication tolerances, the pressure vessel handbook contains some good information:
http://www.inspection-for-industry.com/pressure-ve...
Engineering companies also develop thier own standards.... I have some older versions.
Also, reportedly, you can also refer the PD 5500 Annex L
http://65.57.255.42/ubbthreads/ubbthreads.php?ubb=...
Hope that this helps.....
Let us know about your final call on this matter....
RE: Misalignment of nozzle-to-header joint : any tolerance ?
However there is a widely accepted "Standard"
The Pipe Fabrication Institute "PFI ES3" Covers Fabrication Tolerances.
Go here for a complete list of all PFI Standards
http://www.pfi-institute.org/products.php
prognosis: Lead or Lag
RE: Misalignment of nozzle-to-header joint : any tolerance ?
I appreciate your advice. I think I need to learn more about this.
As for now, we decided to cut and replace the nozzle with a new one.
RE: Misalignment of nozzle-to-header joint : any tolerance ?
Does anyone know of a (PFI or other) standard for tolerances on VIII-1 vessels, other than whats listed in VIII-1 w/ respect to tolerances?