Types of Standards Industry Standards of the People’s Republic of China Standard Issuing Units Approved by the Ministry of Light Industry of the People’s Republic of China on January 06, 1994 Standards Standards 1 Subject content and scope of application
This standard specifies the product classification, technical requirements, test methods, inspection rules and signs, packaging, transportation, and storage of poly (PP) as the main raw material and extruded poly pipes (hereinafter referred to as pipes).
This standard applies to water supply pipes with a nominal pressure of 0.25MPa, 0.4MPa, 0.6MPa, 1.0MPa, 1.6MPa, 2.0MPa, a nominal outer diameter of 16-630mm, and a buried water supply pipe with a conveying water temperature of 95°C or less.
2 Reference standards
GB 9688 Hygienic standards for polymolded products for food packaging
GB 2918 Standard environment for condition adjustment and testing of plastic samples
GB 8806 Plastic pipe size measurement method
GB 6671.3 Poly(PP) pipe longitudinal shrinkage determination
GB 6111 Thermoplastic pipes with constant internal pressure for long-term determination of damage resistance time
GB 5009.60 Analytical method for the hygienic standards of polyethylene, polyethylene and polymolded products for food packaging
GB/T 14152 Thermoplastic pipe resistance to external impact test method Real impact rate method
GB 2828 Sampling procedure and sampling table for batch-by-batch inspection by attributes (applicable to continuous batch inspection)
3 Product classification
3.1 The pipes are classified into six grades according to the maximum continuous working pressure: 0.25MPa, 0.4MPa, 0.6MPa, 1.0MPa, 1.6MPa and 2.0MPa.
3.2 The maximum continuous working pressure of the pipe changes with temperature and service life, see Table 1 (omitted).
3.3 The pipe specifications are represented by de×e (see Figure 1). The nominal outer diameter, wall thickness and deviation of the pipe are shown in Table 2 (omitted). See Appendix A (reference piece) for its imperial series.
4 Technical requirements
4.1 The color of the pipe should be black, and it can also be determined by negotiation between the supplier and the buyer.
The inner and outer walls of the pipe should be smooth and flat. No bubbles, cracks, discoloration lines, obvious grooves, depressions, impurities, etc. are allowed. The cut of the pipe should be basically perpendicular to the axis of the pipe.
4.3 Pipe specifications and dimensions
4.3.1 The size and deviation of pipe specifications should meet the requirements of Table 2 (omitted).
4.3.2 The standard length of the pipe is 4m, which can also be negotiated between the supplier and the buyer according to the user’s requirements. The limit deviation of pipe length is% of pipe length.
4.4 The physical mechanism performance of the pipe should meet the requirements of Table 3 (omitted).
4.5 The sanitary performance of drinking water pipes should meet the requirements of GB 9688.
5 Test method
5.1 Standard environment for sample condition adjustment and testing
According to GB 2918, the temperature is 23±2℃, the state adjustment time is not less than 24h, and the test is carried out under this condition (unless otherwise required).
5.2 Color and appearance inspection
Observe with the naked eye under the light source.
5.3 Dimension measurement
5.3.1 Average outer diameter
GB 8806 stipulates measurement.
5.3.2 Wall thickness
is measured according to GB8806 regulations.
Measured with a measuring tool with an accuracy of 10mm at room temperature.
5.4 Vertical shrinkage rate
Test according to method A or B in GB 6671.3. The test temperature is 110±2℃.
5.5 Hydraulic test
5.5.1 The hydraulic test method shall be carried out in accordance with GB 6111.
5.5.2 The temperature, ring stress and test time of the hydraulic test shall be as specified in Table 3 (omitted).
5.6 Drop hammer impact test
The drop hammer impact test is tested in accordance with GB/T 14152.
The test temperature is 0℃, and the drop weight and drop height are shown in Table 4 (omitted).
The first batch of 10 impacts, if all the samples are not damaged, then pass.
If 4 or more samples are damaged in 10 impacts, it is not passed.
If 1 or 2 or 3 samples are damaged after 10 impacts, 20 impacts need to be added. If 5 or more samples are damaged in the accumulated 30 impacts, it is not passed.
5.7 The measurement of hygienic performance shall be carried out in accordance with the provisions of GB 5009.60.
6 Inspection rules
6.1 Products must be inspected by the quality inspection department of the manufacturer and have a qualified mark before they leave the factory.
6.2 Group batch
Use the same specifications of pipes produced with the same raw material, formula and process as a batch, and the quantity of each batch shall not exceed 10t. One delivery can consist of one batch or multiple batches, and the batch number should be indicated at the time of delivery. Products with the same delivery batch number are one delivery inspection lot.
6.3 Factory inspection
6.3.1 The inspection items are the longitudinal retraction rate and the 1h hydraulic test in 4.1, 4.2, 4.3 and 4.4.
6.3.2 For the inspection of 4.1, 4.2 and 4.3, the GB 2828 normal inspection sampling plan is adopted, IL is the general inspection level I, and the acceptable quality level (AQL) is 6.5. Among them, N, n, Ac, Re are shown in Table 5 (omitted) .
6.3.3 Among the qualified products by counting and sampling, sufficient samples are randomly selected, and the longitudinal retraction rate and the 1h hydraulic test in 4.4 are tested.
6.4 Type inspection
6.4.1 Type inspection items are all technical requirements items.
6.4.2 Conduct inspections to 4.1, 4.2 and 4.3 in accordance with 6.3.2 of this standard. Take samples according to the provisions of 6.3.3 of this standard to inspect other technical requirements.
6.4.3 In general, a type inspection shall be carried out at least once a year. Type inspection should also be carried out in one of the following situations.
A. Trial-making appraisal of new products or old products transferred to factory production;
B. After formal production, if there are major changes in structure, materials, and processes, the product performance may be affected;
C. When the product has been suspended for any reason for more than three months and resumed production;
D. When there is a big difference between the factory inspection result and the last type inspection;
E. When the state-owned quality supervision agency requests for type inspection.
6.5 Judgment Rules
If any of 4.1, 4.2 and 4.3 does not meet the requirements, the unit sample shall be judged as unqualified. The batch is qualified according to the provisions of Table 5 (omitted). When one of the other items fails to meet the specified indicators, a double sample can be randomly selected for re-inspection of the project. If it is still unqualified, the batch will be judged as unqualified. .
7 Marking, packaging, transportation and storage
The pipes should be permanently marked, and the marking interval should not exceed 3m. The manufacturer’s name or trademark, product name and specifications (de×e) should be marked in sequence; the product packaging should be marked with the standard number, batch number, quantity, production date and The code of the inspector, and the product quality certificate of the inspection department is attached.
The pipes should be bundled according to different specifications. The weight of each package is generally not more than 50kg, and it can also be negotiated and determined according to user requirements.
During transportation, the pipe shall not be subject to severe impact, throwing and sunlight.
The pipes should be stored in a warehouse with a temperature not exceeding 40°C. They should not be stored in the open air, and the distance from the heat source should not be less than 1m. The storage date should not exceed one year from the date of production.
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