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Could you please tell me the uses and locations of various valves? What is the pressure testing standard for valves? Where does it come from, at the upper seal valve?
It is recommended that the original poster check the valve selection manual written by Lu Peiwen, as it provides detailed information
Mechanical Industry Standard of the People’s Republic of China JB/T 9092—1999 Inspection and Testing of Valves. Published on July 12, 1999; came into effect on January 1, 2000. Issued by the State Machinery Industry Bureau. Preface to JB/T 9092—1999: This standard is a revision of ZB J16 006—90 \"Testing and Inspection of Valves\". Compared with ZB J16 006—90, the main technical differences of this standard are as follows: 1. The name of the standard has been changed to “Inspection and Testing of Valves”” ； 2. Add the terms “one-way sealing and two-way sealing” ； 3. The requirements for the “mandatory tests” of valves are specified separately according to nominal pressure and nominal diameter ； 4. The test items for gate valves and globe valves are specified separately ； 5. The minimum duration for the shell test and seal test of butterfly valves has been modified to be consistent with that of other valves ； 6. The minimum duration for the sealing test on valves has been modified ； 7. The maximum allowable leakage amount for the seal test has been modified in accordance with the requirements of API 598—96 ； 8. The test method for the low-pressure sealing test has been modified. This standard replaces ZB J16 006—90 as of the date of its implementation. This standard was proposed and taken under responsibility by the Standardization Technical Committee for Valves. Drafting units of this standard: Hefei General Machinery Research Institute, Shanghai General Machinery Technology Research Institute. Main drafters of this standard: Wang Xiaojun, Ning Zhongrong, Shi Jianhong. Inspection and Testing of Standard Valves in the Machinery Industry of the People’s Republic of China. Valve inspection and testing JB/T 9092—1999 replaces ZB J16 006—90. 1 Scope: This standard specifies the requirements for the inspection and pressure testing of valves. This standard applies to the inspection and pressure testing of gate valves, globe valves, plug valves, ball valves, check valves, and butterfly valves with metal sealing pairs, elastic sealing pairs, and non-metallic sealing pairs (such as ceramics). With the agreement of both the supplier and the buyer, it can also be applied to other types of valves. An elastic sealing pair refers to: (1) a soft sealing pair, or a sealing pair composed of solid and semi-solid greases (such as oil-sealed plug valves) ； (2) Sealing pairs composed of non-metallic and metallic materials ； (3) Other types of sealing pairs with elastic seal leakage rates as specified in Table 3. 2 Referenced Standards The provisions contained in the following standards become part of this standard by being referenced herein. At the time of publication of this standard, all versions listed are valid/All standards are subject to revision; those using this standard should consider the possibility of using the latest versions of the following standards. JB/T 7927—1999 Cast steel parts for valves – Requirements for visual quality 3 Terms 3.1 One-way sealing: When the valve is closed, the medium must enter from one of the two sides of the valve in order for the valve’s sealing surfaces to remain sealed ； 3.2 Double-seal: Regardless of the direction from which the medium enters the valve, the valve’s sealing elements remain sealed once the valve is closed ； 4 Inspection 4.1 Inspection at the valve manufacturing plant. The buyer specified in the order contract that the valves needed to be inspected at the manufacturing plant, and the buyer’s inspectors were allowed to enter the plant at any time during the production of the ordered valves to conduct inspections. 4.2 Inspection outside the valve manufacturer’s facility: If specified by the buyer, the inspection includes the housing components manufactured outside the valve manufacturer’s facility; such components shall be inspected by the buyer’s inspectors at their place of origin. 4.3 Inspection Notice: When the buyer requests an inspection, the valve manufacturer shall, in accordance with the test items specified, notify the buyer at the address listed in the order contract 7 days prior to the inspection. If inspection outside the valve manufacturer’s facility is required, the manufacturer shall also notify the buyer 7 days in advance. 4.4 Scope of inspection If no other additional items are specified in the purchase contract, the buyer’s inspections shall be limited to the following: a) Inspecting the valves during the assembly process using non-destructive testing tools and methods as specified in the purchase contract ； b) The visual inspection of castings shall comply with the provisions of JB/T 7929 ； c) “Mandatory” and “optional” pressure tests ； d) Other supplementary tests (see 4.6) ； e) Review the processing records and non-destructive testing records (including the required radiographic inspection records). Note: All tests shall be conducted in accordance with written procedures prepared based on the relevant standards. 4.5 Inspection 4.5.1 The valve manufacturer shall conduct a visual inspection of all castings for valve bodies, valve covers, and seals to ensure compliance with the requirements of JB/T 7929. 4.5.2 The valve manufacturer shall inspect each valve to ensure compliance with the provisions of this standard and relevant product standards. 4.6 Additional Inspections Other additional inspections are carried out only when specified in the purchase contract; the specific requirements shall follow the procedures and conditions agreed upon by the buyer and the seller. The inspections must be conducted by the manufacturer in the presence of the buyer’s inspectors. 5 Pressure Testing 5.1 Test Location Pressure testing shall be carried out by the valve manufacturer within its own facility. 5.2 Testing Equipment The equipment used for pressure testing shall not exert any external forces that could affect the seal of the valve seat during the test. 5.3 Test requirements 5.3.1 Each valve shall be subjected to a pressure test in accordance with the requirements of Table 1 or Table 2. 5.3.2 Valves with a nominal diameter of 100 mm or less and a nominal pressure of 25.0 MPa or less, as well as those with a nominal diameter of 125 mm or more and a nominal pressure of 10.0 MPa or less, shall be tested in accordance with Table 1. 5.3.3 Valves with a nominal diameter of 100 mm or less and a nominal pressure of more than 25.0 Mpa, as well as those with a nominal diameter of 125 mm or more and a nominal pressure of more than 10.0 Mpa, shall be tested in accordance with Table 2. Table 1 Pressure Testing – Test Items
Valve Types: Gate Valves, Globe Valves, Plug Valves, Check Valves, Floating Ball Valves, Butterfly Valves and Fixed Ball Valves
Body: Required, Required, Required, Required, Required, Required
Upper Seal 1): Required, Required, Not Applicable, Not Applicable, Not Applicable, Not Applicable
Low-Pressure Seal: Required, Optional, Required2) Choose 3), Required, Required
High-Pressure Seal 4): Optional, Required5) Optional
2): Required, Optional, Optional
1): All valves with upper sealing capability shall undergo an upper seal test, except for bellows-sealed valves. 2) For oil-sealed plug valves, a high-pressure sealing test is mandatory, while a low-pressure sealing test is optional ； 3) With the consent of the purchaser, the valve manufacturer may use a low-pressure sealing test in place of a high-pressure sealing test ； 4) After undergoing high-pressure sealing tests, elastomeric-sealed valves may experience a decrease in their sealing performance under low-pressure conditions ； 5) For power-driven stop valves, the test pressure for the high-pressure sealing test shall be 110% of the design pressure difference used for the selected power drive unit. Table 2 Pressure Testing – Test Items
Valve Types: Gate Valves, Globe Valves, Plug Valves, Check Valves, Floating Ball Valves, Butterfly Valves and Fixed Ball Valves
Body: Required, Required, Required, Required, Required, Required
Upper Seal 1): Required, Required, Not Applicable, Not Applicable, Not Applicable, Not Applicable
Low-Pressure Seal: Required, Optional, Required, Selective 2), Required, Required
High-Pressure Seal 3): Optional, Required 4), Optional, Required, Optional, Optional
1) All valves with upper sealing capability shall undergo an upper seal test, except for bellows-sealed valves. 2) With the consent of the purchaser, the valve manufacturer may use a low-pressure sealing test in place of a high-pressure sealing test ； 3) After undergoing high-pressure sealing tests, elastomeric-sealed valves may experience a decrease in their sealing performance under low-pressure conditions ； 4) For power-driven stop valves, the test pressure for the high-pressure sealing test shall be 110% of the design pressure difference used for the selected power drive unit. 5.3.4 Unless otherwise specified in the order contract, for valves with upper sealing performance, the upper sealing test may be a high-pressure sealing test or a low-pressure sealing test, as chosen by the manufacturer. 5.4 High-pressure sealing test In Tables 1 and 2, several types of valves are required to undergo a high-pressure sealing test. For some types of valves, although the high-pressure sealing test is optional, they should still be able to pass this test (as a test of the valve’s sealing mechanism). 5.5 Test Medium 5.5.1 The test medium for shell tests, high-pressure upper seal tests, and high-pressure seal tests shall be water, air, kerosene, or a non-corrosive liquid with a viscosity not higher than that of water. The temperature of the test medium shall not exceed 52°C. The test medium temperature for low-temperature valves can be specified in the order. 5.5.2 For the low-pressure sealing and low-pressure upper sealing tests, the test medium shall be air or an inert gas. 5.5.3 When conducting shell tests, seal tests, and upper seal tests with air or other gases, the manufacturer shall employ the correct leak detection methods. When testing with water or liquids, the air inside the valve should be removed. 5.5.4 The water used for various tests may contain water-soluble oils or rust inhibitors; when specified by the purchaser, it may also contain lubricants. When testing austenitic stainless steel valves, the chloride content in the water used should not exceed 100 mg/L. 5.6 Shell testing of high-pressure gases 5.6.1 When the purchase contract specifies that shell testing of high-pressure gases is required, such testing shall be carried out after the liquid testing of the shell, and appropriate safety measures must be in place. 5.6.2 The shell test pressure for high-pressure gases is 1.1 times the maximum allowable operating pressure at 38°C, or as specified in the order contract; no visible leakage is permitted during the test. 5.6 Test pressure 5.7.1 The shell test pressure is 1.5 times the maximum allowable operating pressure at 38°C. 5.7.2 The pressure for the high-pressure sealing test and the high-pressure upper sealing test is 1.1 times the maximum allowable operating pressure at 38°C. 5.7.3 The pressure for the low-pressure sealing test and the low-pressure upper sealing test is 0.4~0.7 MPa. 5.7.4 For butterfly valves specified in the user’s procurement specifications, the sealing test pressure is 1.1 times the design pressure difference. 5.7.5 The sealing test pressure for the check valve is the nominal pressure at 38°C. 5.8 Test Duration For each test, the minimum duration during which the test pressure is maintained is specified in Table 3. Table 3 Duration of maintaining test pressure Valve specification DN (mm) Minimum duration for maintaining test pressure t Body seal Check valve Other valves Check valve Other valves ≤50 60 15 15 60 15 65–150 60 60 60 60 60 200–300 60 120 60 120 ≥350 120 300 120 120 Note: The minimum duration for maintaining test pressure refers to the shortest time required to maintain the specified test pressure after the pressure of the test medium inside the valve reaches the specified value. 5.9 Leakage rate 5.9.1 For the shell stress test and upper seal test, no visible leakage is allowed. If the test medium is a liquid, there must be no visibly visible droplets or wet surfaces. If the test medium is air or another gas, no bubbles should escape. No structural damage shall occur during the test. 5.9.2 For both the low-pressure sealing test and the high-pressure sealing test, no visible leaks are allowed at locations such as the valve disc, the contact surfaces between the valve seat and the valve body, and there should be no structural damage. The allowable leakage rate of the test medium through the sealing surfaces during the duration of the test is shown in Table 4. Table 4 Maximum allowable leakage rates for sealing tests. Valve specification: DN in mm. All valves with elastic seals: drops/mm, bubbles/min. All valves with metal seals except check valves; check valves with metal seals. Liquid test: 1) drops/min. Gas test: bubbles/min. Liquid test: mL/min; Gas test: m3/h. ≤50: 0, 0. For 2) 65–150: 12, 24; 200–300: 20, 40; ≥350: 3) 28, 56. 1) For the liquid test, 1 mL (cm3) is equivalent to 16 drops. 2) No leakage within the specified minimum test time (see Table 3); for liquid tests, \"0\" drops indicates no visible leakage during each specified minimum test time, and for gas tests, \"0\" bubbles indicates that the amount of leakage is less than 1 bubble per specified minimum test time. 3) For check valves with a diameter larger than DN600 mm, the allowable leakage amount shall be agreed upon by both the supplier and the buyer. 5.9.3 For valves with non-metallic sealing pairs such as ceramics, the allowable leakage rate for their sealing tests shall be in accordance with the specifications for metal-sealed valves of the same type and specification given in Table 4. 5 Pressure testing methods 6.1 General requirements 6.1.1 For valves with a special design that permits the injection of emergency sealing grease into the sealing surfaces or packing areas (except for oil-sealed plug valves), the injection system must be empty and inactive during testing. 6.1.2 When conducting tests with a liquid, the air in the chamber must be completely removed. 6.1.3 Before the shell test, the valve shall not be painted or coated with any other substance that could conceal surface defects. Phosphating or similar chemical treatments used to protect the valve surface are permitted before the test, but they shall not cover up defects such as pores, voids, and sand holes. 6.1.4 When conducting seal tests on gate valves, plug valves, and ball valves, the cavity between the valve cover and the sealing surface shall be filled with the medium and pressurized to the test pressure, in order to prevent any leakage in the seals from going unnoticed as the medium and pressure are gradually introduced into those areas during the test. 6.1.5 During the sealing test, no external forces that could affect leakage at the sealing surfaces should be applied at either end of the valve, and the operating torque required to close the valve should not exceed the designed closing torque of the valve. 6.2 Shell testing 6.2.1 Pressure is applied to the cavity of the installed valve, with both ends of the valve sealed and the operating part partially opened. During testing, there should be no leaks at any connections. Except for bellows-sealed valves, the packing gland should be tightened enough to maintain the test pressure, so as to test the packing box; there should be no leakage at the packing box during the test. 6.2.2 For valves whose stem seals are not adjustable (such as \"O\"-rings, single-layer seals, or similar packings), there shall be no leakage at the sealing points during shell testing. 6.3 Valves with upper sealing performance (except diaphragm valves) shall all undergo an upper sealing test. During the upper seal test, both ends of the valve are sealed, and pressure is applied to the chamber inside the assembled valve body; the valve should open completely. The packing gland is then released, and this test is carried out after the shell test. Valve manufacturers should not use valves that have passed the upper seal test as a basis for recommending the addition or replacement of packing while the valve is under pressure. 6.4 Low-pressure sealing test 6.4.1 During the test, the sealing surfaces must be kept clean, free of oil residues (except for valves in which lubricant plays a primary role in sealing). To prevent scratching of the sealing surface, a thin oil film, no thicker than that of kerosene, can be applied. 6.4.2 Low-pressure sealing shall be carried out in one of the following methods: a) For valves with two-way sealing (except multi-channel valves and globe valves), pressure shall be applied sequentially to each end of the valve, with the other end left open to the atmosphere, in order to check for leaks at the sealing surface on the outlet side. For valves with one-way sealing and markings indicating the direction of fluid flow, pressure should be applied at the inlet side. For check valves, pressure should be applied at the outlet end. Pour clean water at the sealing surface at the open end of the valve or apply a solution similar to soapy water, and observe the bubbles to check the leakage amount at the valve seat, as well as at the contact surface between the valve seat and the valve body and in the valve’s sealing mechanism. It can also be inspected using the testing apparatus specified in the order contract, but it must be converted into the leakage volume units specified in Table 4. b) For valves with multi-channel sealing, the test medium should be introduced under pressure sequentially from the sealed channel openings, and the leakage rate of the inlet seal surface should be checked from the packing box (at which point no packing is present) or other open channel openings. During testing, the leakage rate of each sealing surface shall not exceed the leakage rate specified in Table 4. Note: For wedge-type single-plate (rigid or elastic) gate valves, the following testing methods are not permitted: such as sealing the test medium between the two sealing surfaces and filling them with clean water or applying soapy water at those sealing surfaces, and similar testing methods. 6.4.3 For butterfly valves with elastic seals, whether for one-way or two-way sealing, pressure testing is required only at the end with the most unfavorable sealing condition. 6.5 High-pressure sealing test 7 Certificate of conformity and retesting of valves 7.1 Certificate of conformity The valve manufacturer shall provide the purchaser with a certificate confirming that the valve products meet the requirements of the order. 7.2 Re-testing If the purchase contract does not stipulate that re-testing shall be carried out by the buyer, the valves that have already been tested do not need to be re-tested. For subsequent tests, the painted valves do not need to have their paint removed. Inventory valves should be retested and cleaned before shipment.
Valve Types: Gate Valves, Globe Valves, Plug Valves, Check Valves, Floating Ball Valves, Butterfly Valves and Fixed Ball Valves
Body: Required, Required, Required, Required, Required, Required
Upper Seal 1): Required, Required, Not Applicable, Not Applicable, Not Applicable, Not Applicable
Low-Pressure Seal: Required, Optional, Required2) Choose 3), Required, Required
High-Pressure Seal 4): Optional, Required5) Optional
2): Required, Optional, Optional
1): All valves with upper sealing capability shall undergo an upper seal test, except for bellows-sealed valves. 2) For oil-sealed plug valves, a high-pressure sealing test is mandatory, while a low-pressure sealing test is optional ； 3) With the consent of the purchaser, the valve manufacturer may use a low-pressure sealing test in place of a high-pressure sealing test ； 4) After undergoing high-pressure sealing tests, elastomeric-sealed valves may experience a decrease in their sealing performance under low-pressure conditions ； 5) For power-driven stop valves, the test pressure for the high-pressure sealing test shall be 110% of the design pressure difference used for the selected power drive unit. Table 2 Pressure Testing – Test Items
Valve Types: Gate Valves, Globe Valves, Plug Valves, Check Valves, Floating Ball Valves, Butterfly Valves and Fixed Ball Valves
Body: Required, Required, Required, Required, Required, Required
Upper Seal 1): Required, Required, Not Applicable, Not Applicable, Not Applicable, Not Applicable
Low-Pressure Seal: Required, Optional, Required, Selective 2), Required, Required
High-Pressure Seal 3): Optional, Required 4), Optional, Required, Optional, Optional
1) All valves with upper sealing capability shall undergo an upper seal test, except for bellows-sealed valves. 2) With the consent of the purchaser, the valve manufacturer may use a low-pressure sealing test in place of a high-pressure sealing test ； 3) After undergoing high-pressure sealing tests, elastomeric-sealed valves may experience a decrease in their sealing performance under low-pressure conditions ； 4) For power-driven stop valves, the test pressure for the high-pressure sealing test shall be 110% of the design pressure difference used for the selected power drive unit. 5.3.4 Unless otherwise specified in the order contract, for valves with upper sealing performance, the upper sealing test may be a high-pressure sealing test or a low-pressure sealing test, as chosen by the manufacturer. 5.4 High-pressure sealing test In Tables 1 and 2, several types of valves are required to undergo a high-pressure sealing test. For some types of valves, although the high-pressure sealing test is optional, they should still be able to pass this test (as a test of the valve’s sealing mechanism). 5.5 Test Medium 5.5.1 The test medium for shell tests, high-pressure upper seal tests, and high-pressure seal tests shall be water, air, kerosene, or a non-corrosive liquid with a viscosity not higher than that of water. The temperature of the test medium shall not exceed 52°C. The test medium temperature for low-temperature valves can be specified in the order. 5.5.2 For the low-pressure sealing and low-pressure upper sealing tests, the test medium shall be air or an inert gas. 5.5.3 When conducting shell tests, seal tests, and upper seal tests with air or other gases, the manufacturer shall employ the correct leak detection methods. When testing with water or liquids, the air inside the valve should be removed. 5.5.4 The water used for various tests may contain water-soluble oils or rust inhibitors; when specified by the purchaser, it may also contain lubricants. When testing austenitic stainless steel valves, the chloride content in the water used should not exceed 100 mg/L. 5.6 Shell testing of high-pressure gases 5.6.1 When the purchase contract specifies that shell testing of high-pressure gases is required, such testing shall be carried out after the liquid testing of the shell, and appropriate safety measures must be in place. 5.6.2 The shell test pressure for high-pressure gases is 1.1 times the maximum allowable operating pressure at 38°C, or as specified in the order contract; no visible leakage is permitted during the test. 5.6 Test pressure 5.7.1 The shell test pressure is 1.5 times the maximum allowable operating pressure at 38°C. 5.7.2 The pressure for the high-pressure sealing test and the high-pressure upper sealing test is 1.1 times the maximum allowable operating pressure at 38°C. 5.7.3 The pressure for the low-pressure sealing test and the low-pressure upper sealing test is 0.4~0.7 MPa. 5.7.4 For butterfly valves specified in the user’s procurement specifications, the sealing test pressure is 1.1 times the design pressure difference. 5.7.5 The sealing test pressure for the check valve is the nominal pressure at 38°C. 5.8 Test Duration For each test, the minimum duration during which the test pressure is maintained is specified in Table 3. Table 3 Duration of maintaining test pressure Valve specification DN (mm) Minimum duration for maintaining test pressure t Body seal Check valve Other valves Check valve Other valves ≤50 60 15 15 60 15 65–150 60 60 60 60 60 200–300 60 120 60 120 ≥350 120 300 120 120 Note: The minimum duration for maintaining test pressure refers to the shortest time required to maintain the specified test pressure after the pressure of the test medium inside the valve reaches the specified value. 5.9 Leakage rate 5.9.1 For the shell stress test and upper seal test, no visible leakage is allowed. If the test medium is a liquid, there must be no visibly visible droplets or wet surfaces. If the test medium is air or another gas, no bubbles should escape. No structural damage shall occur during the test. 5.9.2 For both the low-pressure sealing test and the high-pressure sealing test, no visible leaks are allowed at locations such as the valve disc, the contact surfaces between the valve seat and the valve body, and there should be no structural damage. The allowable leakage rate of the test medium through the sealing surfaces during the duration of the test is shown in Table 4. Table 4 Maximum allowable leakage rates for sealing tests. Valve specification: DN in mm. All valves with elastic seals: drops/mm, bubbles/min. All valves with metal seals except check valves; check valves with metal seals. Liquid test: 1) drops/min. Gas test: bubbles/min. Liquid test: mL/min; Gas test: m3/h. ≤50: 0, 0. For 2) 65–150: 12, 24; 200–300: 20, 40; ≥350: 3) 28, 56. 1) For the liquid test, 1 mL (cm3) is equivalent to 16 drops. 2) No leakage within the specified minimum test time (see Table 3); for liquid tests, \"0\" drops indicates no visible leakage during each specified minimum test time, and for gas tests, \"0\" bubbles indicates that the amount of leakage is less than 1 bubble per specified minimum test time. 3) For check valves with a diameter larger than DN600 mm, the allowable leakage amount shall be agreed upon by both the supplier and the buyer. 5.9.3 For valves with non-metallic sealing pairs such as ceramics, the allowable leakage rate for their sealing tests shall be in accordance with the specifications for metal-sealed valves of the same type and specification given in Table 4. 5 Pressure testing methods 6.1 General requirements 6.1.1 For valves with a special design that permits the injection of emergency sealing grease into the sealing surfaces or packing areas (except for oil-sealed plug valves), the injection system must be empty and inactive during testing. 6.1.2 When conducting tests with a liquid, the air in the chamber must be completely removed. 6.1.3 Before the shell test, the valve shall not be painted or coated with any other substance that could conceal surface defects. Phosphating or similar chemical treatments used to protect the valve surface are permitted before the test, but they shall not cover up defects such as pores, voids, and sand holes. 6.1.4 When conducting seal tests on gate valves, plug valves, and ball valves, the cavity between the valve cover and the sealing surface shall be filled with the medium and pressurized to the test pressure, in order to prevent any leakage in the seals from going unnoticed as the medium and pressure are gradually introduced into those areas during the test. 6.1.5 During the sealing test, no external forces that could affect leakage at the sealing surfaces should be applied at either end of the valve, and the operating torque required to close the valve should not exceed the designed closing torque of the valve. 6.2 Shell testing 6.2.1 Pressure is applied to the cavity of the installed valve, with both ends of the valve sealed and the operating part partially opened. During testing, there should be no leaks at any connections. Except for bellows-sealed valves, the packing gland should be tightened enough to maintain the test pressure, so as to test the packing box; there should be no leakage at the packing box during the test. 6.2.2 For valves whose stem seals are not adjustable (such as \"O\"-rings, single-layer seals, or similar packings), there shall be no leakage at the sealing points during shell testing. 6.3 Valves with upper sealing performance (except diaphragm valves) shall all undergo an upper sealing test. During the upper seal test, both ends of the valve are sealed, and pressure is applied to the chamber inside the assembled valve body; the valve should open completely. The packing gland is then released, and this test is carried out after the shell test. Valve manufacturers should not use valves that have passed the upper seal test as a basis for recommending the addition or replacement of packing while the valve is under pressure. 6.4 Low-pressure sealing test 6.4.1 During the test, the sealing surfaces must be kept clean, free of oil residues (except for valves in which lubricant plays a primary role in sealing). To prevent scratching of the sealing surface, a thin oil film, no thicker than that of kerosene, can be applied. 6.4.2 Low-pressure sealing shall be carried out in one of the following methods: a) For valves with two-way sealing (except multi-channel valves and globe valves), pressure shall be applied sequentially to each end of the valve, with the other end left open to the atmosphere, in order to check for leaks at the sealing surface on the outlet side. For valves with one-way sealing and markings indicating the direction of fluid flow, pressure should be applied at the inlet side. For check valves, pressure should be applied at the outlet end. Pour clean water at the sealing surface at the open end of the valve or apply a solution similar to soapy water, and observe the bubbles to check the leakage amount at the valve seat, as well as at the contact surface between the valve seat and the valve body and in the valve’s sealing mechanism. It can also be inspected using the testing apparatus specified in the order contract, but it must be converted into the leakage volume units specified in Table 4. b) For valves with multi-channel sealing, the test medium should be introduced under pressure sequentially from the sealed channel openings, and the leakage rate of the inlet seal surface should be checked from the packing box (at which point no packing is present) or other open channel openings. During testing, the leakage rate of each sealing surface shall not exceed the leakage rate specified in Table 4. Note: For wedge-type single-plate (rigid or elastic) gate valves, the following testing methods are not permitted: such as sealing the test medium between the two sealing surfaces and filling them with clean water or applying soapy water at those sealing surfaces, and similar testing methods. 6.4.3 For butterfly valves with elastic seals, whether for one-way or two-way sealing, pressure testing is required only at the end with the most unfavorable sealing condition. 6.5 High-pressure sealing test 7 Certificate of conformity and retesting of valves 7.1 Certificate of conformity The valve manufacturer shall provide the purchaser with a certificate confirming that the valve products meet the requirements of the order. 7.2 Re-testing If the purchase contract does not stipulate that re-testing shall be carried out by the buyer, the valves that have already been tested do not need to be re-tested. For subsequent tests, the painted valves do not need to have their paint removed. Inventory valves should be retested and cleaned before shipment.
I recommend the valve manual, which contains detailed instructions and selection criteria
Great article; I’ve been looking for it for a long time