Pressure piping code - Industrial piping - Part 5: Inspection and testing
1 Scope
This part of GB/T 20801 specifies the basic safety requirements for pressure piping inspection, examination and test.
This part is applicable to the inspection, examination and test of pressure piping defined by GB/T 20801.1.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 20801.1-2020 Pressure piping code - Industrial piping - Part 1: General
GB/T 20801.2-2020 Pressure piping code - Industrial piping - Part 2: Materials
GB/T 20801.3-2020 Pressure piping code - Industrial piping - Part 3: Design and calculation
GB/T 20801.4-2020 Pressure piping code - Industrial piping - Part 4: Fabrication and assembly
GB/T 20801.6-2020 Pressure piping code - Industrial piping - Part 6: Safeguarding
NB/T 47013.1 Nondestructive testing of pressure equipment - Part 1: General requirements
NB/T 47013.2 Nondestructive testing of pressure equipment - Part 2: Radiographic testing
NB/T 47013.3 Nondestructive testing of pressure equipment - Part 3: Ultrasonic testing
NB/T 47013.4 Nondestructive testing of pressure equipments - Part 4: Magnetic particle testing
NB/T 47013.5 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
NB/T 47013.7 Nondestructive testing of pressure equipments - Part 7: Visual testing
NB/T 47013.8-2012 Nondestructive testing of pressure equipments - Part 8: Leakage testing
NB/T 47013.10 Nondestructive testing of pressure equipments - Part 10: Ultrasonic time of flight diffraction technique
NB/T 47013.11 Nondestructive testing of pressure equipment - Part 11: Standard practice for X-ray digital radiography
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 20801.1-2020, GB/T 20801.2-2020, GB/T 20801.3-2020, GB/T 20801.4-2020, GB/T 20801.6-2020 as well as the following apply.
3.1
inspection
compliance review process conducted by the owner or an inspection body independent of the piping builder to verify whether the product or piping construction meets the requirements of code and engineering design
3.2
inspector
full-time staff of the owner or inspection body engaging in inspection work
3.3
examination
process of manufacturing plant as well as fabrication, construction and erection units fulfilling quality control responsibilities by carrying out necessary inspection and test on materials, components, processing, fabrication and erection to verify whether the product or piping construction meets the requirements of relevant standards and engineering design
3.4
examination personnel
full-time staff of manufacturing plant as well as fabrication, construction and erection units engaging in examination work, who shall be the staff independent of the manufacturing, fabrication and erection departments
4 Examination requirements
4.1 General requirements
4.1.1 This clause specifies the piping erection, including the requirements for examination of each component and its fabrication process, any additional examination required by the engineering design and acceptance criteria. The examination of chromium-molybdenum alloy steel piping in GB/T 20801.2-2020, Table A.1 shall be carried out after all heat treatment has been completed. For the welding of branch pipes and the reworking of pressure-bearing welded joints, they shall be completed before the welding of reinforcing ring or saddle reinforcing part.
4.1.2 The examination and test of piping components (or their subassembly) processed by the factory shall meet the requirements of relevant product standards and design documents.
4.2 Acceptance criteria
The examination and test requirements given in this part are basic safety requirements. If there are special examination and test requirements in the design documents, the examination, test and acceptance shall be carried out according to the requirements of the design documents.
4.3 Treatment of unacceptable defect
If it is found that the parts under examination have defects beyond the acceptance criteria of this part, reworking or replacement shall be carried out. New parts shall be examined in the same way and scope and with the same acceptance criteria as required by original parts.
4.4 Progressive examination
In case of unacceptable defects found in local or sampling examination, the following requirements shall be followed:
a) Take another two identical parts (in case of welded joints, they shall be welded joints welded by the same welder from the same batch) for the same examination;
b) If the two parts required by a) pass the examination, the batch represented by the additional examination shall be regarded as acceptable, but the parts with defect shall be reworked or replaced and then re-examined;
c) If it is found that any one of the two parts required by a) has unacceptable defects, two identical parts shall be added for each defect item for examination;
d) If the two parts required by c) pass the examination, the batch represented by the additional examination shall be regarded as acceptable, but the parts with defect shall be reworked or replaced and then re-examined;
e) If it is found that any one of the two parts required by c) has unacceptable defects, the whole batch shall be subject to examination, with the rejected ones reworked or replaced and then re-examined;
f) If the parts with defects still have unacceptable defects in re-examination after having been reworked or replaced, it is not necessary to carry out the progressive examination according to a), c) and e) for the defects found during reworking, but the parts with unacceptable defects shall be reworked or replaced and then re-examined until they meet the acceptable criteria of this part. If possible, local or sampling examination may also be carried out on other welded joints having not been examined.
4.5 Examination personnel
If there is no special indication, the construction unit shall be responsible for the examination and test of on-site fabrication and welding. The examination personnel shall meet the definition in 3.4.
5 Examination method
5.1 General requirement
5.1.1 This clause specifies the main examination methods that meet the requirements of this part, engineering design or inspector. If methods other than those specified in this clause are used, the acceptance criteria shall be specified in the engineering design.
5.1.2 The examination ratio includes 100% examination, sampling examination and local examination, which are defined as follows:
a) In a specified batch of piping, all the piping are examined for a specific item, which is called 100% examination;
b) In a specified batch of piping, certain percentage of the piping are examined for a specific item, which is called sampling examination;
c) In a specified batch of piping, the specified part of each piping is examined for a specific item, which is called local examination.
Notes:
1 The specified batch refers to the quantity of piping required for examination in this part. The size and degree of specified batch should be agreed by both parties before work starts.
The determination principles of specified batch are as follows:
——The size of "batch" should not be too large;
——The parts under examination with the same piping grade, same material or same inspection proportion may be regarded as a "batch";
——For the welded joint, the welding time should be controlled within 2 weeks;
——Different "batches" may be specified for different kinds of works for piping fabrication and erection.
2 Sampling or local examination will not guarantee the quality level of manufactured products. In a batch of piping which are represented for examination, the part of piping having not been examined may show defects in further examination. If it is required that there is no welding unacceptable defect specified for radiographic testing for a certain batch of piping, it shall be specified that 100% radiographic testing shall be carried out for examination.
5.2 Visual examination
Visual inspection refers to the observation carried out before, during or after the manufacture, fabrication, assembly, erection, examination or test of components, joints and parts of other pipework components that are easy to observe or can be visually examined. Visual inspection shall include verifying whether the quality of materials, components, dimensions, joint preparation, fitting up, welding, bonding, brazing, flange connection, threaded or other connection methods, supports, assembly and erection meet the requirements of relevant standards and engineering design. The visual examination shall be carried out in accordance with NB/T 47013.7.
5.3 Non-destructive testing
Non-destructive testing of welded joints includes radiographic testing, ultrasonic testing, magnetic particle testing, penetrant testing, ultrasonic time of flight diffraction technique and standard practice for X-ray digital radiography, and the testing shall be carried out using the methods specified in NB/T 47013.1, NB/T 47013.2, NB/T 47013.3, NB/T 47013.4, NB/T 47013.5, NB/T 47013.10 and NB/T 47013.11.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Examination requirements
5 Examination method
6 Examination scope and acceptance criteria
7 Process examination
8 Examination of certificates and records
9 Tests
10 Records