Notice of Publication of the National Standard of the "Code for the Acceptance of Construction Quality of Industrial Metallic Piping". The Ministry of Housing and Urban-Rural Development of the People's Republic of China is charged with the administration of this code and the explanation of the mandatory provisions, China Chemical Industry Branch, Engineering Construction Standardization Association, is responsible for the routine. management of this code, and the National Administrative Center of Chemical Construction Standardization is responsible for explaining specific technical contents.
Division for Acceptance of Constructional Quality
It refers to the inspection of the inspected object by visual observation in conjunction with practical experience to judge whether the object meets those specified in this code or not. It refers to the inspection of a certain percentage of a specific item in a designated inspection lot.
Acceptance of Constructional Quality
Procedure and Organization for Acceptance of Constructional Quality
For valves of Grade GCl pipes and Class C liquid pipes with a design pressure greater than or equal to 10MPa, 100% examination shall be carried out. Among the Grade GCl pipes and Class C liquid pipes, a random sample examination must be carried out for the hardness of bolt and nut for pipes with a design pressure greater than or equal to 10MPa.
Fabrication of Bending
Examination amount: random examination of 5% of each inspection lot, which shall not be less than one. When the length of straight pipe is greater than 3m, the maximum deviation may not exceed 10mm.
Machining of Rolling Pipe
The distance between the ring and the reinforcement plate and the surrounding weld of the rotating tube should not be less than 50 mm. 2 In the longitudinal butt weld 200 mm from the end of the pipe, the gap should not be greater than 2 mm.
Flanging Edge of Pipe
4 The minimum thickness of the flange edge connection shall not be less than 95% of the minimum wall thickness of the pipe. 1 The thickness of the flange edge by welding shall not be less than the nominal wall thickness of the connected pipe.
Machining of Jacket Pipe
3 The end side with the flange must be perpendicular to the center line of the pipe and the permissible vertical deviation is 1 mm. 2 The surface quality of the edge joint with the flange matched with the gasket must meet the requirements of the standard for the matched flange.
Production of Miter Elbow
Fabrication of Piping Support and Hanger
3 When welding socket weld fittings and pipes, the size of the minimum weld leg of fillet welding shall be 1.25 times the nominal thickness of straight pipe and shall not be less than 3 mm. 3 The distance from the pipe weld to the opening edge of the branch pipe or pipe joint shall not be less than 50 mm and the hole diameter. 4 The distance from the pipe's circumferential weld to the pipe support and the bracket must not be less than 50 mm.
The distance from the heat-treated weld to pipe support and hanger shall not be less than 5 times the weld width and 100 mm.
General Requirement
Examination method: visual inspection, inspection with a check gauge and inspection of the pipe welding inspection record. 2. The distance between the center of the pipeline weld and the bending starting point of bending shall not be less than the outer diameter of the pipe and not less than 100 mm, except that a hardened elbow is used. Examination method: visual inspection, inspection of the construction record, pressure test report, investigation record for corrosive layer and hidden project record.
The pipeline must be protected by a sleeve or construction culvert when passing through a road, wall, floor slab or structure and must meet the requirements of the current relevant national standards and design documents.
Prefabrication of Piping
Examination method: performing visual inspection, detecting spark coil leaks, measuring with a thickness gauge, and inspecting construction and anti-corrosion coating test data. The construction quality of the supporting substrate and the foundation must meet the requirements of the current relevant national standards and design documents. Examination method: performing a visual inspection, inspection of the record of the construction of the substrate and the foundation, as well as the inspection report of the treatment of the foundation or bearing capacity.
Installation of Steel Piping
Examination method: performing visual inspection and adopting methods such as spectral analysis or other material re-inspection if necessary. Flanges must maintain parallel to each other and the deviation must not be greater than 0.15% of the flange's outer diameter and not greater than 2mm. Bolts must close to the flange after tightening and must be free of any wedge seam.
Surveying method: surveying with gradient, theodolite, plane, level, drag line or hanging line.
Installation of Piping for Connecting Equipment
Study method: monitoring the displacement of mobile equipment by setting up the dial gauge on the coupling.
Installation of Cast Iron Piping
After connecting the interface, the connecting part and fittings must be free of deformation and damage. 3 The installation position of the rubber ring must be correct, and the rubber ring must not be distorted and exposed part; points around the perimeter must be at the same distance from the front side of the socket with a tolerance of ±3 m. 1 The depth of hammering of series-coated jute must be 1/3 of the total depth of the socket and must not exceed the inner edge of the triangular groove of the socket; the rubber ring filler must be flat, compressed and free of any defects such as looseness, curvature, fracture, etc.
2 The interface cement must be dense and full; the depth of the interface cement surface sunk into the socket edge shall not be greater than 2 mm and the cement strength shall meet the requirements of design documents.
Installation of Stainless Steel Piping and Non-ferrous Piping
The depth of the mold push must meet the requirements of the design or product technical document. The final tightening torque of the connecting bolts must meet the requirements of the design or product technical document. 1 The pipe connected to the flange must be coaxial; when the nominal dimension is less than or equal to 50 mm, the deviation must not be greater than 1 mm; when the nominal dimension is greater than 50 mm, the deviation should not be greater than 2 mm.
2 For the threaded pipe, graphic motor oil should be applied to the threaded part.
Installation of Heating Piping
3 When installing the copper bellows expansion joint, the length of the straight pipe should not be less than 100 mm.
Installation of Jacket Pipe
If no requirements are given in the design, the interconnecting pipe must be free of accumulated liquid.
Installation of Anticorrosive Lining Piping
Installation of Valves
Installation of Expansion Joint
Installation of Piping Support and Hanger
Installation of Static Electricity Grounding
Inspection method: resistance measurement and inspection of the pipeline static grounding test record. Inspection method: conducting a visual inspection and reviewing the record of the pipeline static grounding test.
Visual Inspection of Weld
For pipes with static electricity grounding requirements, the resistance between each pair of flanges or other connections must be less than or equal to 0.03Ω. Examination method: measure the resistance and inspection of the test record of pipes' static electricity grounding. IV (1) Medium toxic and light hazard liquid pipes with a design pressure of less than 4MPa;. V Non-flammable and non-toxic liquid pipes with a design pressure of less than or equal to 1.0MPa and a design temperature of more than -20℃ but not more than 185℃.
The color and gloss inspection result of titanium and titanium alloy welds shall be in accordance with those specified in Table 8.1.2.
Radiographic and Ultrasonic Examinations of Weld
In the sampling or local sampling survey, a random sampling survey shall be conducted for welds of each weld in accordance with the specified ratio. The inspection lot and location of the random or local sampling survey are determined by the quality inspector. 1 When there is one unqualified weld, 2 welds in the same inspection lot of this welder must be reexamined;
3 When the unqualified weld is detected again in the re-examination, 100% examination shall be performed for the welds in the same inspection lot of this welder.
Non-destructive Examination of Weld Surface
3 The examination fee must meet the requirements of the design document and the following provisions: . 1) The ratio of non-destructive examination of pipe welds shall correspond to that specified in Table 8.2.1. When the circumferential weld intersects the longitudinal weld, the intersection points with longitudinal weld should be included in the maximum range, of which the examination length of longitudinal welds should not be less than 38mm. 6) The random or local sampling survey is carried out according to the inspection party. 2 If one of the 2 welds is again unqualified, 2 welds in the same inspection lot of this welder must be reexamined.
After repair of unqualified welds detected by magnetic particle examination or penetrant examination, the repaired positions shall be reexamined according to the methods originally determined.
Hardness Examination and Other Inspections
The criterion of acceptance of the quality of welds must not be lower than level I, specified in the applicable professional standards. Inspection method: inspection of the inspection report of magnetic particles or penetrants and the axonometric drawing of the pipe. Scope of inspection: in accordance with the requirements of the current relevant national standards and project documents.
Pressure Test
For pipes with a large potential difference, the static pressure of the test medium must be included in the test pressure. 3. The test pressure of steel pipes and non-ferrous pipes carrying internal pressure shall be 1.15 times the design pressure. 4 A pressure relief device shall be provided during the pneumatic test and the set pressure shall not exceed 1.1 times the test pressure.
5 Before the pneumatic test, a trial test with air should be performed, and the test pressure should be 0.2 MPa.
Water Flushing
2 The leakage test shall be performed after the pipes have passed the pressure test and the test medium shall be air. 4 The leak test pressure must be increased slowly step by step; when the test pressure is reached, it must be maintained for 10 min. patrol inspection shall be carried out for sealing positions such as valve stuffing box, flange or thread connection point, discharge valve, exhaust valve and drain valve; the inspection is considered qualified if no leakage is detected. Investigation method: Performing visual inspection with foaming agent and inspection of the leak test protocol.
If no requirement is specified in the construction document, it is considered qualified if the color and transparency of the water flush at the outlet are consistent with those at the inlet by visual observation.
Air Blowing
Steam Blowing
2 Target exercise duration 15 minutes for each blowing time (both blowing times apply). After 15 minutes of blowing, the target plate will be free of iron rust, dirt and other foreign substances.
Degreasing of Piping
Inspection method: conducting a visual inspection and reviewing the degreasing record, water quality report, etc.
Chemical Cleaning
Oil Cleaning
Notes: The inspection records for subsection design and quality control data in this table must be completed by the construction organization and the acceptance conclusion must be completed by the development (supervision) organization. The comprehensive acceptance conclusion must be approved by all parties participating in the acceptance and must be completed by the development organization. Note: the data name and number of copies must be filled in by the construction organization; the inspection report and the inspector must be completed by the development (supervision) organization.
Both parties agree to the decision and it is supplemented by the development organization.
