1 Scope
This part specifies the basic requirements in the fabrication and assembly of pressure piping that GB/T 20801.1 applies. And the basic requirements cover fabrication, welding, pre-heating, heat treatment, assembly, erection and cleaning.
2 Normative Reference
The following standards contain provisions which, through reference in this text, constitute provisions of this code. For dated reference, subsequent amendments to (excluding correction contents), any of these publications do not apply. However, parties to agreements based on this Part are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest edition of the normative document is applicable to these specifications.
GB/T 17116.1-1997 Pipe supports and hangers - Part 1: Technical specification
GB/T 20801.1-2006 Pressure piping code - Industrial piping - Part 1: General
GB/T 20801.2-2006 pressure piping code - Industrial piping - Part 2: Materials
GB/T 20801.3-2006 Pressure piping code - Industrial piping - Part 3: Design and calculation
GB/T 20801.5-2006 Pressure piping code - Industrial piping - Part 5: Inspection and testing
JB 4708-2005 Welding Procedure Qualification for Pressure Equipment
Examination and Administrative Rules for Welders Specializing in Boilers and Pressure Vessels and Pressure Pipes
3 Terms and Definitions
3.1 Manufacture
Manufacturing process of products like pipe, piping components or pipe-supporting elements.
3.2 Fabrication
Preparation works before piping erection, including cutting, screw thread processing, grooving, forming, bending, welding and component assembling by elements; the fabrication may be conducted in workshop or on site.
3.3 Assembly
Connecting two or more piping components together with bolt, welding, cementation, screw thread, braze welding, soldering or seal element according to the requirements of the engineering design.
3.4 Erection
Erecting a pipe system on a designated position or support perfectly according to the requirements of the engineering design; the works cover all site assembling, fabrication, inspection and test required for the system by the code.
3.5 Isometric diagram
Piping aerial view, indicated by single lines through axonometric projection drawing method for each piping.
3.6 Hot bending
Pipe bending operation when the temperature is higher than the metal critical point AC1.
3.7 Cold bending
Pipe bending operation when the temperature is lower than the metal critical point AC1.
3.8 Pipe-segments to be prefabricated
Pipe segment processed in advance, that is determined according to the isometric diagram before piping fabrication.
3.9 Pipe-segments for dimension adjustment
Pipe segment processed after measuring the erection size, which is determined according to the isometric diagram before piping fabrication.
3.10 Tack weld
Welded joints that are used to ensure proper alignment of welding parts before completing final welded joints.
4 General Requirements
4.1 The piping manufacture, fabrication and erection organization shall have quality management system and administrative license that meet the relevant regulations in pressure piping safety supervision.
4.2 Necessary construction note and verification document shall be made and kept properly in the piping fabrication and erection. After completing the pressure piping erection works, the fabrication and erection organizations shall provide the owner with at least the following technical documents and data:
a) Piping completion drawing (including the design modification documents and the material substitution list). The modification in the design and material substitution shall be marked directly in the completion drawing. The following information shall be marked on the piping isometric diagram: weld position, welding seam number, welder code number, welding position, reworked weld, nondestructive testing method, randomly-inspected welded joints, further-inspected welded joints, and welded joints with heat treatment randomly hardness inspection.
b) Product qualification certificate, quality certificate or re-inspection / test report of pressure piping component, support member and welding material.
c) Construction inspection records, and inspection/test report. The format and content hereof shall meet the requirements of corresponding construction and acceptance specifications.
d) Certificate of acceptance for transfer project.
GB/T 20801.4-2006 The following standards are cited：
