This standard replaces CJ/T 3002-1992 from the date of implementation. This standard is revised on the basis of CJ/T 3002-1992 "Polyurethane Foam Plastic Prefabricated Insulation Pipe". In order to adapt to the "Technical Code for Urban Direct Buried Heating Pipe Engineering", the standard adds relevant content related to the product and uncompensated direct buried laying technology. The revised standard name is "High-density polyethylene outer sheath polyurethane foam plastic prefabricated direct buried insulation pipe". This standard specifies the structure, technical requirements, test methods and inspection rules of prefabricated direct buried insulation pipes composed of high-density polyethylene outer sheath, polyurethane rigid foam plastic insulation layer and steel pipe. This standard is applicable to the manufacture and acceptance of insulation pipes with a medium temperature (continuous working temperature) not higher than 120℃, an occasional peak temperature not higher than 140℃, and a working pressure not greater than 2.5MPa. CJ/T 114-2000 High-density polyethylene outer protective pipe Polyurethane foam plastic prefabricated direct buried insulation pipe CJ/T114-2000 Standard download decompression password: www.bzxz.net

CJ/T 114—2000
This standard is revised on the basis of CJ/T3002—1992 "Polyurethane Foam Plastic Prefabricated Insulation Pipe". In order to adapt to the "Technical Code for Direct Buried Heating Pipe Engineering in Cities and Towns", the standard adds more content related to the product and non-compensated direct buried laying technology. The revised standard name is "High Density Polyethylene Outer Pipe Polyurethane Foam Plastic Prefabricated Direct Buried Insulation Pipe". During the revision process, the experience of the original standard in the past 6 years was carefully summarized, and the opinions of construction, design, scientific research and colleges and universities were widely listened to. The European standard EN253:1994 and its latest scientific research results were referred to, and some new items and new testing methods with relatively mature technology were added. The revision focuses on the use function and structural quality, and the performance is quantified as much as possible. The cited standards are all national standards or industry standards, and a considerable part of them are equivalent or equivalent to international standards. This standard adopts the European standard EN253:1994 in a non-equivalent manner. This standard has the following major differences from EN253:1994 in terms of technical content: All the referenced standards adopt Chinese standards;
3 product structures are added;
4.1 Steel pipes are basically different, mainly based on national standards or industry standards; 4.2.2 The performance of raw materials for outer sheath pipes is basically different, and thermal stability, long-term mechanical properties of raw materials, and melt flow rate are cancelled.
- 4.2.3 The performance of outer sheath pipes is basically different, and melt flow rate is added; 4.3.2 Foam density is basically different, and the core density and overall density are replaced by the foam density at any position of the insulation layer; - 4.3.5 Thermal conductivity is basically different, and the insulation pipe performance is adjusted to the insulation layer performance; - 4.4 Insulation pipes are basically different, and the anti-deformation performance is cancelled, and the axial shear strength in the expected life and long-term heat resistance is retained;
- 6 inspection rules are added:
The text layout structure is basically different.
Appendix A and Appendix B of this standard are both informative appendices, and both are equivalent to Appendix A and Appendix B of EN253:1994 standard. This standard replaces CJ/T3002-1992 from the date of implementation. This standard is proposed by the Standard Estimation and Rating Research Institute of the Ministry of Construction. This standard is under the jurisdiction of the Ministry of Construction's Urban Construction Research Institute, the Ministry of Construction's urban construction standard technology management unit. The drafting units of this standard are Harbin Dongguang Machinery Factory, Tianjin Pipeline Engineering Group Co., Ltd. Insulation Pipe Factory, Beijing Haotenai Central Heating Equipment Co., Ltd., and the Fourth Testing Institute of Beijing Engineering Quality Testing Center. The main drafters of this standard are Wang Zhongsheng, Wang Tiejun, Zhang Yumin, Pu Chengchun, Dong Zhiwu, and Cao Xiaoqiang. Harbin Dongguang Machinery Factory is entrusted with the interpretation of this standard. 593
1 Scope
People's Republic of China Urban Construction Industry Standard High-density polyethylene outer protective pipe Polyurethane foam plastic prefabricated straight insulation pipe
Preformed directly buried insulating pipesfor polyurethane [PUR I foamed-plastics andhigh density polyethylene [PE] protect pipesCJ/T 114—2000
neq EN 253:1994
Replaces CJ/T3002--1992
This standard specifies the structure, technical requirements, test methods and inspection rules of prefabricated directly buried insulation pipes (hereinafter referred to as insulation pipes) composed of high-density polyethylene outer protective pipe, polyurethane (hereinafter referred to as polyurethane) rigid foam plastic insulation layer and steel pipe. This standard is applicable to the manufacture and acceptance of insulation pipes with a medium temperature (continuous working temperature) not higher than 120C, an occasional peak temperature not higher than 140, and a working pressure not greater than 2.5MPa. The calculation of the shortest expected life of polyurethane rigid foam plastics working at different temperatures is shown in Appendix B (suggestive Appendix).
2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T1033-1986Test method for density and relative density of plasticsGB/T2828-1987Batch inspection counting sampling procedure and sampling table (applicable to inspection of continuous batches)GB/T 3682-1983
Test method for melt flow rate of thermoplasticsGB/T 4217---1984
GB/T 6342-1996
GB/T 6343-1995
Nominal outer diameter and nominal pressure of thermoplastic pipes (metric series)Determination of linear dimensions of cellular plastics and rubberDetermination of apparent (bulk) density of cellular plastics and rubberGB/T 6671. 2-1986
Determination of longitudinal shrinkage of polyethylene (PE) pipesGB/T 8163—1987
Seamless steel pipe for conveying fluids
GB/T8804.2—1988
Test method for tensile properties of thermoplastic pipesPolyethylene pipesMeasurement method for dimensions of plastic pipesWww.bzxZ.net
GB/T 8806—1988
GB/T 8813—1988
GB/T 8923—1988
Compression test method for rigid foam plastics
Surface rust grade and rust removal grade of steel materials before paintingGB/T 9711.1—1997
Technical delivery conditions for steel pipes for transportation in petroleum and natural gas industryPart 1: Grade A steel pipeGB/T 10297--1998
Determination of thermal conductivity of non-metallic solid materialsHot wire methodGB/T 10799—1989
Test method for volume percentage of open and closed cells for rigid cellular plastics GB/T 12811—1991
Test method for average cell size for rigid cellular plastics GB/T 13018--1991
Limit deviations of outer diameter and wall thickness of polyethylene (PE) pipes GB/T 13021—1991
Determination of carbon black content of polyethylene pipes and fittings by thermal gravimetric method GB/T 14152--1993
Test method for external impact resistance of thermoplastic plastic pipes True impact rate method Approved by the Ministry of Construction of the People's Republic of China on April 12, 2000 594
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CJ/T3022-1993
3 Product structure
CJ/T114—2000
Spiral seam submerged arc welded steel pipe for urban heating
3.1 The structure of the insulation pipe is shown in Figure 1.
Urinary ester rigid foam insulation layer
2463:
Alarm line
3.2 The insulation pipe is a prefabricated pipe that is tightly combined with a steel pipe, a polyurethane rigid foam insulation layer and a high-density polyethylene outer sheath. There may be alarm lines and brackets in the insulation layer.
4 Technical requirements
4.1 Steel pipe
4.1.1 The material, dimensional tolerance and performance of the steel pipe shall comply with the standards of CJ/T3022 or GB/T9711.1 or GB/T8163. 4.1.2 The outer diameter and minimum wall thickness of the steel pipe shall comply with the provisions of Table 1. Table 1
Outer diameter D
Minimum wall thickness
Other specifications of steel pipe outer diameter D may be used according to the requirements of the user unit
Steel pipes with other technical requirements may be used according to the requirements of the user unit, but the mechanical properties of the steel pipe must have an obvious yield limit. 2
Minimum wall thickness
4.1.3 The surface of the steel pipe should be cleaned before foaming to remove rust, rolled steel scales, grease, dust, paint, moisture or other contaminants. mm
The rust level of the steel pipe surface shall comply with the AB.C provisions in GB/T8923--1988, and the rust removal level shall comply with the good provisions in GB/T8923-1988595
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4.2 Outer sheath
CJ/T 114 - 2000
4.2.1 The operating temperature of the outer sheath shall be controlled at -50℃～+50℃. 4.2.2 Raw material properties of the outer sheath
4.2.2.1 Density and composition
The outer sheath shall be made of high-density polyethylene plastic. The density of polyethylene resin shall be 935kg/m~950kg/m. Additives that are helpful for the production of the outer sheath and improve the performance of the outer sheath shall be used, such as antioxidants, UV stabilizers, carbon black (or masterbatch prefabricated with carbon black), etc.
The added carbon black should meet the following requirements:- Density:1 500 kg/m2~2000kg/m2-Toluene extraction amount: ≤0.1% (mass percentage): - Average particle size: 0.01μm~0.025m. 4.2.2.2 Recycled materials
No more than 15% (mass percentage) of clean recycled materials can be used, but the recycled materials must be produced by the manufacturer's own products. 4.2.3 Performance of outer sheath
4.2.3.1 The density of the outer sheath should not be less than 940kg/m. The carbon black content should be 2.5%±0.5% (mass percentage), and the carbon black should be evenly distributed in the parent material. When tested according to 5.2.2, the following requirements should be met:
The size of carbon black agglomerates, bubbles, cavities or impurities should not be greater than 100um. Color difference stripes are not allowed on the outer sheath.
4.2.3.2 Melt flow rate
The supplier of the outer sheath shall indicate the melt flow rate value of the outer sheath for reference when welding the outer sheath. When two outer sheaths are welded, the difference in their melt flow rates shall not be greater than 0.5g/10min. 4.2.3.3 Appearance of the outer sheath
The outer sheath shall be black, and there shall be no grooves on its inner and outer surfaces that may affect its performance. No defects such as bubbles, cracks, depressions, impurities, and uneven colors are allowed.
The two ends of the tube shall be cut flat and perpendicular to the axis of the tube, and the angle error shall be less than 2.5°. 4.2.3.4 Tensile yield strength and elongation at break The tensile yield strength at any position of the outer sheath shall not be less than 19MPa, and the elongation at break shall not be less than 350%. 4.2.3.5 Longitudinal shrinkage
The longitudinal shrinkage of any section of the outer sheath shall not be greater than 3%. At the end of the longitudinal shrinkage test, there should be no cracks, cavities, bubbles or other defects on the pipe surface.
4.2.3.6 Long-term mechanical properties of outer protective pipe
The long-term mechanical properties of outer protective pipe shall meet the requirements of Table 2. Table 2
Tensile force, MPa
4.2.4 Specifications of outer protective pipe
Minimum windproof time.h
4.2.4.1 The nominal outer diameter and minimum wall thickness of the outer protective pipe for prefabricated thermal insulation pipe shall comply with the requirements of Table 3. .596
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Test temperature, ℃
Nominal outer diameter
Minimum wall thickness
Nominal outer diameter
Minimum wall thickness
CJ/T 114-—2000
Note: Outer protective pipes with other nominal outer diameters can be used according to the requirements of the user unit, and their minimum wall thickness should be determined by interpolation according to this table. 1)) The outer diameter of the pipe marked is a specification other than GB/T4217. 4.2.4.2 The allowable limit deviation of the outer diameter and wall thickness of the outer protective pipe shall comply with the provisions of GB/T13018. 4.3 Insulation layer
The insulation layer material is urethane rigid foam plastic. 4.3.1 Foam structure
The foam body should be free of stains, shrinkage, delamination and cracking. The pores should be uniform and dense. When tested according to the requirements of 5.3.1, the average size of the pores measured in the radial direction shall not be greater than 0.5mm.
When tested according to the requirements of 5.3.2, the closed cell rate of the foam shall not be less than 88%. The foam shall evenly fill the annular space between the working steel pipe and the outer protective pipe. When tested according to the requirements of 5.3.3, the sum of the areas of cavities and bubbles on any section of the insulation layer shall not exceed 5% of the total cross-sectional area; the size of a single cavity in any direction shall not exceed 1/3 of the thickness of the insulation layer at the same position.
4.3.2 Foam density
When tested according to the requirements of 5.3.4, the foam density at any position of the insulation layer shall not be less than 60kg/m. 4.3.3 Compression strength
When tested according to the requirements of 5.3.5, the radial compression strength of the insulation layer foam or the compressive stress when the radial relative deformation is 10% should not be less than 0.3 MPa.
4.3.4 Water absorption
After soaking in boiling water at normal pressure for 90 minutes, the water absorption of the foam should not be greater than 10%. 4.3.5 Thermal conductivity
The thermal conductivity A5 of the foam insulation layer that has not been aged at 50℃ should not be greater than 0.033W/(m?K). 4.4 Insulation pipe
4.4.1 The thickness of the insulation layer of the insulation pipe should ensure that the outer protective pipe can be used normally within the temperature range of -50℃～+50℃. 150mm~～250mm of exposed non-insulation area should be left at both ends of the steel pipe for welding. 4.4.2 Increase rate of outer diameter of outer protective pipe
Before and after the insulation pipe is foamed, the increase rate of the outer diameter of the same section at any position of the outer protective pipe should not be greater than 2%. 4.4.3 Axis eccentricity
The distance between the axis of the outer protective pipe and the axis of the steel pipe at any position of the insulation pipe shall comply with the provisions of Table 4. Table 4
Outer diameter of outer protective pipe
≤160
180~400
450～630
≥710
4.4.4 Expected life and shear strength
4.4.4.1 The life of the insulation pipe in normal use is at least 30 years of continuous operation at 120℃. Maximum axis eccentricity
CJ/T 114—2000
4.4.4.2 The axial shear strength and test method of the insulation pipe shall comply with the provisions of Table 5. Table 5
Test temperature, ℃
140±2
4.4.5 Impact resistance
When tested according to 5.4.3, there should be no visible cracks on the outer protective tube. Test method
5. 4.3. 3
4.4.6 The resistance between the alarm line and the alarm line, and the alarm line and the steel pipe is 20MQ~5Test method
5.1 General
Minimum axial shear strength, MPa
If the test requirements in this product standard are inconsistent with the references provided by other standards, the provisions of this standard shall prevail. All specimens shall be representative of the product. 5.1.1 Samples
5.1.1.1 The performance samples of the outer protective tube shall be extracted from the outer protective tube after being stored at room temperature (23℃±2℃) for 16 hours; the samples of the insulation layer and the insulation tube shall be extracted from the insulation tube after being stored at room temperature (23℃±2℃) for 72 hours. 5.1.1.2 To test the performance of the insulation layer and the overall performance of the insulation tube, the samples shall be extracted from both ends of the same insulation tube, and the sampling point shall be greater than 500mm from the end face of the insulation layer.
5.1.1.3 When sampling from the insulation layer of the insulation pipe to test the foam structure (4.3.1), foam density (4.3.2), compression strength (4.3.3), water absorption (4.3.4) and thermal conductivity (4.3.5), the foam skin close to the steel pipe and the outer protective pipe should be removed, and the thickness of the removed layer should be 5mm and 3mm respectively.
At least three samples are required for each test item, and the samples should be evenly distributed on the same cross section of the annular insulation layer. The outer dimensions of the sample are determined in accordance with GB/T6342. The measurement accuracy is 0.02mm. 5.2 Outer protective pipe
5.2.1 Density
The density test should be carried out in accordance with GB/T1033.
5.2.2 Carbon black dispersion
The carbon black dispersion should be determined by observing the plastic slice under a microscope. The slice thickness is about 25μm and the area is about 15mm. Prepare 6 slices for each test, and take samples from the same section of the outer protective tube. The magnification of the microscope should be 100 times. 5.2, 3 Carbon black content
Carbon black content test should be carried out according to GB/T13021. 5.2.4 Melt flow rate
The melt flow rate test should be carried out according to test condition 4 in GB/T3682-1983. 5.2.5 Appearance
The inner and outer surfaces of the outer protective tube are visually inspected without magnification (see 4.2.3.3). 5.2.6 Tensile yield strength and elongation at break The tensile yield strength and elongation at break test should be carried out according to GB/T8804.2. 5.2.7 Longitudinal shrinkage rate
The longitudinal shrinkage rate test should be carried out according to GB/T6671.2. 5.2.8 Long-term mechanical properties of the outer protective tube
The specimen is made according to Figure 2 and Table 6. The test is conducted by immersing the test sample in an aqueous solution containing 2.0% surfactant at a constant temperature of 80℃±1℃ and a constant tension of 4.0MPa±0.04MPa.
The surfactant should be hydroxyphenol polyglycol ether or sec-octyl polyvinyl chloride ether [TX-10];598
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The solution should be stirred continuously to ensure uniformity and prevent precipitation of the surfactant: 6 samples should be cut for testing, and the samples should be cut along the axis of the outer protective tube. The sampling positions should be evenly distributed on the same section: record the failure time, and the timing should be accurate to ±12h; calculate the geometric mean of the 6 samples, and the test data with a deviation exceeding twice the standard deviation should be deleted. If the sample is not damaged after 1500h of the test, the test can be stopped and the sample is judged to meet the requirements. Figure 2
5.2.9 Outer sheath size
Parallel part length
Minimum total length
Initial distance between clamps
Parallel part width
End width
Outer sheath size detection shall be carried out in accordance with GB/T8806. 5.3 Test methods for rigid foam plastics
5.3.1 Cell size
Cell size detection shall be carried out in accordance with GB/T12811. Samples shall be taken radially from the center of the insulation layer, and the sample length shall be at least 20mm. 5.3.2 Foam closed cell rate
Foam closed cell rate detection shall be carried out in accordance with GB/T10799 Size
≥150
Pipe wall thickness
May differ from the sample size specified in GB/T10799. If it is not possible to cut a sample that meets the size requirements from the insulation layer according to 5.1.1.3, the size can be 25×25×t (mm), where t is the maximum allowable radial thickness of the insulation layer. 5.3.3 The percentage of voids and bubbles on the cross section of the insulation layer can be determined by cutting 5 times at a distance of 1.5m from the end of the outer protective pipe to form 4 annular blocks (the annular blocks include the outer protective pipe and the foam insulation layer), each of which is 100mm long. The section surface must be flat and intact, and the section surface must be perpendicular to the axis of the insulation pipe. Sequentially peel off the 4 100mm long annular blocks to expose the annular section of the insulation layer, and measure the size of the voids and bubbles on the annular section. For voids and bubbles larger than 6mm (measured in any direction on the plane), their size should be measured in two mutually perpendicular directions, and the product of these two sizes is defined as the area of ​​the void or bubble. Cavities and bubbles smaller than 6mm are not measured. The percentage of the sum of the areas of all tested cavities and bubbles to the cut surface area of ​​the insulation layer is taken as the measurement result. 5.3.4 Foam density. The foam density test shall be carried out in accordance with GB/T6343, 599. CJ/T 114 -- 2000. According to 5.1.1.3, 3 samples shall be taken from the center of the foam (samples containing cavities and bubbles shall be discarded). The size of each sample is: 30×30×t (mm), which is the maximum allowable radial thickness of the insulation layer, but shall not be greater than 30mm. Similarly, the sample can also be taken as a 30mm long cylinder (in the axial direction), with a diameter of d, which is the maximum allowable radial size of the insulation layer, but shall not be greater than 30mm. 5.3.5 Compression strength. The compression strength test shall be carried out in accordance with GB/T8813. The sample is a cube of 30×30×t (mm) or a cylinder of 30mm in diameter and t in height, which is the maximum allowable radial dimension of the insulation layer, but should not be less than 20 mm.
5.3.6 Water absorption
5.3.6.1 Instrument
Balance, sensitivity 0.01g;
Drying box,
Dryer;
Soaking bucket, loose container or pool.
5.3.6.2 Sample
Sample size: 25mm×25mm×25mm cube or 30mm in diameter and 25mm in height cylinder. The surface of the sample is polished with fine sand.
The number of samples in each group is 3.
5.3.6.3 Sample treatment
a) Place the sample in a drying oven at 50℃±3℃ for 24h; b) Take out the sample and place it in a desiccator to cool to room temperature, weigh it, and weigh it to an accuracy of 0.01g; c) Place the sample in the drying oven again for 4h, take it out and place it in a desiccator to naturally cool to room temperature (23℃±2℃), weigh it, and weigh it to an accuracy of 0.01g:
d) Compare the results of the above two weighings. When the difference between the two weighing values ​​is less than 0.02g, it can be considered that the sample has reached constant weight, and the latter weighing value is taken as the sample mass (m). When the difference between the two weighing values ​​is greater than 0.02g, repeat according to c) until the constant weight requirement is reached. 5.3.6.4 Test steps
Measure the linear dimensions of the sample, accurate to 0.02mm. Calculate the sample volume (V.), accurate to 0.01cm. Place the sample in the soaking bucket and press the sample with a net. Pour fresh distilled water into the soaking bucket. The water level should be 50mm higher than the upper surface of the sample (the sample must be fully in contact with the water. The two samples should be kept at a certain distance and should not touch each other). Use a short-bristled brush to remove bubbles on the sample. Heat the distilled water to immerse the sample in 1atm boiling water for 90min, and then immediately immerse it in 23℃±2C water for 1h. Take out the sample, gently absorb the surface water with filter paper, and weigh it immediately (m), accurate to 0.01g
Calculate the water absorption rate according to formula (1), and the value is rounded to three significant digits. o
Where: \——water absorption rate of the sample
mo—mass of the sample before water absorption, g;
ml—mass of the sample after water absorption, g;
Va—original volume of the sample, cm,
P—density of distilled water, g/cm.
The test results are the arithmetic mean of each group of data. 5.3.7 Thermal conductivity
The thermal conductivity test shall be carried out in accordance with GB/T10297 5.4 Test method for thermal insulation pipe
5.4.1 Increase rate of outer diameter of outer protective pipe
mi —m.
%×100%
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CJ/T 114 - 2000
By measuring the circumference of the same position of the outer protective pipe before and after foaming, calculate the percentage of the diameter increase to the original diameter. Outer diameter growth rate II
Where: D1——outer diameter after foaming;
D. ——outer diameter before foaming.
5.4.2 Expected life
D, - D.
×100%
5.4.2.1 The expected life test can be carried out according to the insulation pipe aging test. The calculated life is shown in Appendix A (suggested Appendix). 5.4.2.2 Insulation pipe aging test
For insulation pipe systems with a conveying medium temperature (continuous operating temperature) higher than 110°C, before measuring the axial shear strength of the insulation pipe, the insulation pipe sample should be subjected to the following aging treatment: When the nominal diameter of the steel pipe is DN>500, the insulation pipe aging sample length should be 3m; when the nominal diameter of the steel pipe is DN≤500, the insulation pipe aging sample length should be 2m; before aging, the end face of the foam insulation layer should be sealed; aging process: the outer protective pipe should be exposed to room temperature of 23°C ± 2°C, and the steel pipe should be kept at a high temperature. The aging conditions are shown in Table 7. Table 7
Steel pipe temperature,
Aging time, h
Steel pipe heating rate: When the temperature is less than 100℃, it is 25℃/h; when the temperature is greater than 100℃, it is 50℃/h; the temperature of the steel pipe should be continuously recorded during the aging process, and the temperature deviation is ±0.5℃C; after aging, the sample is naturally cooled to the room temperature of 23℃±2℃. 5.4.3 Shear strength of insulation pipe after aging
5.4.3.1 Test method
Sampling: Cut the sample on the insulation pipe that meets the requirements of 5.4.2.2. The sample should be obtained at least 1000mm away from the pipe end, and its length is 2.5 times the thickness of the insulation layer, but not less than 200mm. The end face of the sample should be perpendicular to the axis of the insulation pipe. Test process: The test is carried out on the testing machine, and the sample is placed according to Figure 3. Apply axial force to the end of the steel pipe, and the speed of the testing machine is 5mm/min until the sample is damaged. Record the maximum axial force and calculate the axial shear strength. The test can be carried out in two cases where the axis of the sample is placed in the horizontal direction or in the vertical direction. When the axis of the sample is placed in the vertical direction, the mass of the steel pipe should be considered. The average value of the test results of the three samples is taken as the test result. Shear strength calculation formula:
Ix =Fax/LXdXπ
Where: tax—
Axial shear strength, MPa;
d—Outer diameter of steel pipe, mm
Axial force, N (including steel pipe mass when vertical); L—Length of specimen, mma
（3）
CJ/T 114—2000
Polyurethane rigid foam insulation layer
Sang vinyl outer protective pipe
Location ring
Testing machine table
Axial force
A way to apply axial force
5.4.3.2 The axial shear strength under room temperature conditions shall be tested according to 5.4.3.1. All specimens shall be kept at room temperature (23℃±2℃). 5.4.3.3 The axial shear strength under high temperature conditions shall be tested according to 5.4.3.1. During the test, the outer protective tube should be exposed to room temperature (23°C ± 2°C), and the temperature of the steel tube should be controlled at 140°C ± 2°C. Steel tube heating rate: when the temperature is less than 100°C, it is 25°C/h; when the temperature is greater than 100°C, it is 50°C/h. After 30 minutes of constant temperature, axial force is applied for testing. 5.4.4 Impact resistance
The sample is cut from the insulation tube, and the sample length should be 5 times the outer diameter of the outer protective tube, but should not be greater than 1.5m. The test should be carried out in accordance with GB/T14152. The test temperature is -20°C, and the drop weight is 3.0kg, drop height 2000mm. Mark the insulation pipe sample with equal distances, and determine the number of equal distances according to Table 1 in GB/T14152-1993. Place the sample in a -20℃±1℃ environment for 3h before the test, and start the test within 10s after taking the sample out of the insulation facility. The test should be completed as quickly as possible.
6 Inspection rules
This rule is formulated in accordance with GB/T2828.
6.1 Batch
The insulation pipes of the same specification produced with the same raw materials, the same formula and the same process conditions are regarded as a batch, and the quantity of each batch shall not exceed 50. 6.2 Sampling inspection plan
6.2.1 Plan 1: Qualified quality level AQL6.5, general inspection level 1. The batch number, the number of sample units and the number of qualified judgments are shown in Table 8.
Batch quantity N
Number of samples taken n
Number of qualified judgments for batch Ac
Number of unqualified judgments for batch Re
6.2.2 Scheme 2: Qualified quality level AQL-4.0, special inspection level S-3. The number of batches, number of sample units taken and number of qualified judgments are shown in Table 9.
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CJ/T114—2000
Number of samples taken n
6.2.3 Inspection items and sampling schemes can also be agreed upon by both the supply and demand parties. 6.3 Factory inspection
Batch qualified judgment number Ac
Batch unqualified judgment number Re
6.3.1 The density, tensile yield strength, elongation at break of the outer protective tube of the insulation pipe and the increase rate of the outer diameter of the insulation pipe shall be inspected in accordance with the relevant provisions of 4.2.2.1, 4.2.3.4 and 4.4.2. The batch qualified judgment number is shown in Table 8. 6.3.2 The density of the insulation layer of the insulation pipe, the dimensional deviation, axial eccentricity and insulation resistance value of the insulation pipe shall be inspected in accordance with the relevant requirements of 4.3.2, 4.4.1, 4.4.3 and 4.4.6. The batch qualified judgment number is shown in Table 9. 6.4 Type inspection
6.4.1 If any of the following situations occurs, type inspection should be carried out. When the new product is being tested for trial production or when the old product is transferred to another factory for production: after formal production, if there are major changes in structure, materials, processes, etc., which may affect product performance; when the product is resumed after one year of suspension; when the results of the export inspection are significantly different from the last type inspection; when the national quality supervision agency proposes the requirement for type inspection: - During normal production, periodic type inspection should be carried out every two years or when the cumulative output reaches 300km (measured in extended meters). 6.4.2 Type inspection shall be carried out in accordance with the full-item inspection specified in Chapter 4. 6.5 Judgment rules
6.5.1 When the number of unqualified sample units inspected in the sample does not exceed the number of qualified batch quality judgments specified in Table 8 and Table 9, the delivery batch is judged to be qualified; when it exceeds the number of qualified batch quality judgments, the delivery batch is judged to be unqualified. 6.5.2 If the unqualified batch has not been eliminated, it shall not be submitted for inspection again. The number of sample units and the batch quality judgment shall be determined according to Table 8 and Table 9 for re-inspection. The re-inspection results shall serve as the final basis for judgment. 7 Marking, transportation, storage
7.1 Marking
The insulation pipe can be marked by any method that does not damage the performance of the outer protective pipe, and the marking should withstand the transportation, storage and use environment. 7.1.1 Outer protective pipe
The outer protective pipe manufacturer should mark the outer protective pipe as follows: the commodity name and code of the raw material of the outer protective pipe; the melt flow rate (MFR) value;
-the outer diameter size and wall thickness of the outer protective pipe;
-the production date:
-the Guangshang mark.
7.1.2 Insulation pipe
The insulation pipe manufacturer should mark the outer protective pipe as follows: the outer diameter and wall thickness of the steel pipe;
the steel specification and grade;
-the manufacturer's mark,
the product standard code;
-the foaming date or the production batch number.
7.2 Transportation
CJ/T 114-2000
The insulation pipe must be hoisted with a sling or other method that does not damage the insulation pipe. It is strictly forbidden to hoist it directly with a wire rope; during loading and unloading, it is strictly forbidden to avoid collision, throw, and drag and roll on the ground. During long-distance transportation, the insulation pipe must be firmly fixed. The outer protective pipe and insulation layer should not be damaged. 7.3 Storage
7.3.1 The insulation pipe stacking site should meet the following requirements: 1. The ground should be flat and free of hard debris such as gravel; the ground should have sufficient bearing capacity to ensure that there will be no collapse and dumping accidents after stacking; drainage ditches should be dug in the stacking site, and water accumulation is not allowed in the site; a pipe support should be set up in the stacking site, and the pipe support should ensure that the lower surface of the outer protective pipe of the insulation pipe is 150mm above the ground. 7.3.2 The stacking height of the insulation pipe should not be greater than 2.0m. 7.3.3
The insulation pipe shall not be exposed to the scorching sun, rain or soaking. It is advisable to cover it with tarpaulin when it is stored outdoors. The stacking place should be away from heat and fire sources.2 Transportation
CJ/T 114-2000
The insulation pipe must be hoisted with a sling or other method that does not damage the insulation pipe. It is strictly forbidden to hoist it directly with a wire rope; during loading and unloading, it is strictly forbidden to avoid collision, throw, and drag and roll on the ground. During long-distance transportation, the insulation pipe must be firmly fixed. The outer protective pipe and insulation layer should not be damaged. 7.3 Storage
7.3.1 The insulation pipe stacking site should meet the following requirements: 1. The ground should be flat and free of hard debris such as gravel; the ground should have sufficient bearing capacity to ensure that there will be no collapse and dumping accidents after stacking; drainage ditches should be dug in the stacking site, and water accumulation is not allowed in the site; a stacking site should be equipped with a pipe support, and the pipe support should ensure that the lower surface of the outer protective pipe of the insulation pipe is 150mm above the ground. 7.3.2 The stacking height of the insulation pipe should not be greater than 2.0m. 7.3.3
The insulation pipe shall not be exposed to the scorching sun, rain or soaking. It is advisable to cover it with tarpaulin when it is stored outdoors. The stacking place should be away from heat and fire sources.2 Transportation
CJ/T 114-2000
The insulation pipe must be hoisted with a sling or other method that does not damage the insulation pipe. It is strictly forbidden to hoist it directly with a wire rope; during loading and unloading, it is strictly forbidden to avoid collision, throw, and drag and roll on the ground. During long-distance transportation, the insulation pipe must be firmly fixed. The outer protective pipe and insulation layer should not be damaged. 7.3 Storage
7.3.1 The insulation pipe stacking site should meet the following requirements: 1. The ground should be flat and free of hard debris such as gravel; the ground should have sufficient bearing capacity to ensure that there will be no collapse and dumping accidents after stacking; drainage ditches should be dug in the stacking site, and water accumulation is not allowed in the site; a stacking site should be equipped with a pipe support, and the pipe support should ensure that the lower surface of the outer protective pipe of the insulation pipe is 150mm above the ground. 7.3.2 The stacking height of the insulation pipe should not be greater than 2.0m. 7.3.3
The insulation pipe shall not be exposed to the scorching sun, rain or soaking. It is advisable to cover it with tarpaulin when it is stored outdoors. The stacking place should be away from heat and fire sources.
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