6.3　Jacketed Piping Fabrication

6.3.1　Adjusting spools shall be reserved for jacketed piping，and adjusting allowance should be within 50mm-100mm.

Method:measurements checking.

6.3.2　100% of radiographic test shall be performed for concealed butt welds of inner pipe of jacketed piping.Acceptance criteria shall meet the requirements for corresponding piping class specified in Article 9.3.1 of this code.

Method:check radiographic test reports.

6.3.3　Spacers between inner pipe and outer pipe of jacketed piping shall be erected according to the design documents.Gap shall be uniform and coaxiality shall be 3mm.

Method:visual examination and measurements checking.

6.3.4　Pressure test shall be performed according to Chapter 10 of this code after inner pipes and spacers of jacketed piping are fabricated and welded，and all welds are NDE tested and accepted.All welds of inner pipes shall be exposed during pressure test.

Method:in-process examination.