Calculation for root gap according to tihckness of pipe

asme

is also called section IX. it is the qualification for welders for pressure pipe and vessels. it covers both brazing and welding and it is pretty much the industry standard for testing of pipe welders for power plants and such.

WPS does not provide dimensional allowances for joint design.

Piping codes address engineering design.

ASME B31.1, B31.3. are the primary piping codes and give the dimensional tolerances for 

piping alignment. 

Generally your Construction Procedures should address all code requirements with adequate

figures, (drawings). The Construction Procedures are taken directly from the applicable code and should reference the page, drawings etc. that they were taken from. Shop and field fabrication and welding of pipe will be delineated in a Pipe / Welding Fabrication Procedure 

These Construction Procedures are generally approved by QC before the start of construction. These Construction Procedures are provided to the field engineers, inspectors,

foreman etc who need them to do their work. These Construction Procedures are much easier

to use than the code book they were taken from.

Gene Matsko