A company’s valve pressure testing procedures

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I. Overview of Valves: The valves in the process pipelines of Company X’s XX unit are classified into high-pressure valves, medium-pressure valves, and low-pressure valves based on their nominal pressure. In the process pipelines of the XX unit, there are 202 high-pressure valves, 838 medium-pressure valves, and 157 low-pressure valves. There are 102 high-pressure valves, 2,340 medium-pressure valves, 496 low-pressure valves, 24 steam traps, and 29 safety valves in the process pipelines of the XX plant area. II. Compliance with standards: SH3518 \"Procedures for Inspection and Management of Valves\", SH3501 \"Specifications for Construction and Acceptance of Pipelines for Highly Toxic and Flammable Media in the Petrochemical Industry\", GB50235 \"Specifications for Construction and Acceptance of Industrial Metal Pipelines\", SH3064 \"Selection, Inspection, and Acceptance of General Steel Valves in the Petrochemical Industry\", SH3505 \"Technical Regulations for Safety in Petrochemical Construction\", HGJ209 \"Specifications for Construction and Acceptance of Medium and Low Pressure Chemical Equipment\", GB12220 \"Marking of General Valves“. III. Scope of application: These regulations apply to the inspection and pressure testing of valves in the process pipelines of XX unit at a certain company. IV. Construction Preparation 4.1 After the valves arrive, a tripartite inspection should be conducted. Only when there are no visual defects, all quality certification documents are present, and all accessories are available can a pressure test be carried out. 4.2 Before pressure testing, the tools required for removing the valve and the pressure testing fixtures are all ready, and the pressure testing pump meets the on-site requirements. 4.3 For blind plates used on valves at the site, the thickness of the steel plate must be calculated to meet the pressure testing requirements. 4.4 Before the pressure test, the bolts and nuts required to secure the valve must meet the requirements of the test; it is also necessary to check whether the interior of the valve is clean and free of any foreign objects. 4.5 The materials and dimensions of the auxiliary components used for valve pressure testing shall meet the load requirements generated during the pressure test. 4.6 The thickness of the temporary blind plates used for pressure testing can be selected according to the appendix in HGJ209 \"Code for Construction and Acceptance of Medium and Low Pressure Chemical Equipment\". V. General Provisions 1.1 These regulations apply to the inspection and testing activities prior to installation of general-purpose cast iron, carbon steel, alloy steel, stainless steel, as well as non-ferrous metals such as copper, aluminum, and titanium valves used in the petrochemical industry, for which the design pressure ranges from 400 Pa to 42 MPa (gauge pressure) and the design temperature ranges from -196°C to 850°C. 1.2 If the design documents specify additional requirements for valve inspection, those requirements shall be followed. 1.3 For valves manufactured according to foreign standards, the corresponding foreign inspection standards shall be applied during inspection. 1.4 The safety techniques and labor protection measures to be applied during valve inspection work shall comply with **the relevant current regulations, standards, as well as the provisions of the ‘Safety Technical Regulations for Petrochemical Construction’ SH3505. 1.5 In accordance with the requirements of SH3501 \"Code for Construction and Acceptance of Pipelines for Highly Toxic and Flammable Media in Petrochemical Industries\" and GB50235 \"Code for Construction and Acceptance of Industrial Metal Pipelines\", and considering the importance of production in the two plant areas as well as the small number of valves used in the utility systems, each valve shall be tested individually. VI. Valve Inspection 6.1 General Provisions 6.1.1 Valves must be accompanied by quality certification documents. The valve body shall be equipped with a manufacturer’s nameplate. The nameplate and the valve body must bear indications such as the manufacturer’s name, valve model, nominal pressure, and nominal diameter, and these requirements shall comply with the provisions of GB12220 \"General Marking for Valves\". 6.1.2 The product quality certification document for valves shall contain the following information: (1) Name of the manufacturer and date of manufacture; (2) Product name, model, and specifications; (3) Nominal pressure, nominal diameter, applicable medium, and applicable temperature; (4) Applicable standards, inspection results, and inspection date; (5) Factory serial number; (6) Signatures of the inspectors and persons in charge of inspection; (7) For stainless steel valves that require intergranular corrosion testing as stipulated in the design documents, the manufacturer must provide a certificate proving that the intergranular corrosion test has been passed. (8) Cast steel components used for the welds of SHA-class pipeline valves, or for the valve bodies and bonnets, shall be accompanied by a non-destructive testing certificate that complies with the requirements specified in SH3064, \"Selection, Inspection, and Acceptance of General Steel Valves in the Petrochemical Industry\". 6.1.3 A visual inspection must be conducted on the valve before testing. 6.2 Visual inspection of valves 6.2.1 The open or closed position of valves during transportation shall meet the following requirements: (1) Valves such as gate valves, globe valves, throttle valves, control valves, butterfly valves, and bottom valves shall be in the fully closed position. (2) The closing elements of plug valves and ball valves should be in the fully open position. (3) The diaphragm valve should be in the closed position, but not closed too tightly to prevent damage to the diaphragm. (4) The valve disc of the check valve should be closed and secured. 6.2.2 The valve must not have any damage, missing parts, corrosion, or detached nameplates, and the valve body must be free from dirt. 6.2.3 The ends of the valve shall be protected by covers. The handle or handwheel should operate smoothly and easily, without any sticking. 6.2.4 When the valve body is a casting, its surface shall be smooth and even, free from defects such as cracks, shrinkage cavities, sand holes, pores, and burrs; when the valve body is a forging, its surface shall be free from defects such as cracks, laminations, double layers, spots, and missing shoulders. 6.2.5 The valve disc or spool of the check valve shall operate smoothly and accurately, without any eccentricity, displacement, or skewing. 6.2.6 Spring-type safety valves shall be equipped with lead seals; lever-type safety valves shall have a weight positioning device. 6.2.7 The sealing surface of the valve flange shall meet the requirements and must be free of radial scratches. 6.2.8 Spectral analysis should be employed for alloy steel valves to recheck the material of each valve body individually and apply markings. Valves that do not meet the requirements shall not be used. 6.2.9 Before installing alloy steel valves and valves for pipelines carrying highly toxic or flammable media, it is necessary to conduct random inspections of the valve body, sealing surfaces, as well as the materials of gaskets and packing that have special requirements, in accordance with the \"Valve Specification\" specified in the design documents; at least one sample from each batch should be inspected. If any are unqualified, no valves from that batch shall be used. 6.3 Inspection and Testing of Valve Actuation Devices 6.3.1 For valves equipped with gear or worm gear actuation systems, their actuation mechanisms shall be inspected and cleaned in accordance with the following requirements. (1) The worm and worm gear should mesh properly, operate smoothly, without any jamming or excessive wear. (2) The gear meshing surfaces and bearings of open-type mechanisms should be cleaned thoroughly, and new lubricant should be applied. (3) For valves with closed-type mechanisms, 10% of them should be inspected randomly, with a minimum of one valve; the mechanism parts must be complete, the interior must be clean without any dirt, the moving parts must be free of burrs, and the gaps and meshing surfaces must meet the required standards. If any problems are found, the transmission mechanisms of those valves should be checked one by one. (4) Upon opening the cover for inspection, if it is found that the lubricating grease has deteriorated, the lubricating grease of that batch of valves shall be replaced. 6.3.2 For valves equipped with a sprocket mechanism, the center planes of the chain frame and the sprocket should be aligned. Check the condition of the chain in its operating position; the chain should move smoothly without coming out of its track. The chain must not have any defects such as open links, weld failures, rust, or a mismatch between the sprocket pitch and that of the chain links. 6.3.3 For valves driven by air or hydraulic pressure, testing for opening and closing should be carried out using air or water as the medium, based on the operating pressure of the piston. If necessary, the valves should also be tested for their sealing properties. 6.3.4 In addition to being cleaned and inspected in accordance with the provisions of this specification, the gearbox of electric valves shall also have its coupling concentricity rechecked. Then, upon connecting a temporary power supply, the limit devices of the valves shall be checked and adjusted while the valves are in the fully open or fully closed state. This test shall be conducted no less than three times; the electric system must operate reliably and provide accurate indications. 6.3.5 The electromagnetic valve shall be connected to a temporary power supply to conduct opening and closing tests, with at least three trials. If necessary, a sealing test shall be carried out on the valve while it is in the closed state. 6.3.6 Valves equipped with mechanical interlock devices shall be tested and adjusted on a mock-up at the installation location. The opening and closing actions of the two valves should be coordinated, the operation should be smooth, and the positioning should be accurate. VII. Valve Testing 7.1 General Provisions 7.1.1 Valve testing includes shell pressure testing, sealing testing, and safety valve adjustment testing. 7.1.2 Valves shall undergo shell pressure tests and sealing tests in accordance with the number of inspections specified in the relevant standards; valves equipped with an upper sealing structure shall also undergo an upper sealing test. 7.1.3 The liquid pressure test and upper seal test of valves shall be conducted using clean water as the medium. When conducting a hydraulic pressure test on stainless steel valves, the chloride ion content in the water must not exceed 100 mg/L. 7.1.4 Unless otherwise specified, the temperature of the test medium should be 5–50°C. 7.1.5 Before testing the valve, oil stains and dirt on the sealing surface must be removed; it is strictly prohibited to apply any anti-leakage grease on the sealing surface. 7.1.6 The pressure gauges used for testing must be certified and within their periodic inspection period. Their accuracy should not be lower than Class 1.5. The full-scale value of the gauges should preferably be 1.5 to 2 times the maximum pressure to be measured. There should be no fewer than two pressure gauges in the test system; they should be installed at the storage tank, equipment, and the inlet of the valve under test, respectively. 7.1.7 When the test medium is a liquid, the air inside the valve must be removed; after the pressure testing of the valve is complete, any liquid that has accumulated inside it should be drained promptly. 7.2 Pressure test of valve housing 7.2.1 Test pressure for the valve housing pressure test: 1.5 times the nominal pressure of the valve. 7.2.2 The minimum holding time for the pressure test of the valve shell shall be 5 minutes. If the test medium is clean water, there must be no dripping or moisture on the outer surface of the shell, and no leaks at the joints between the valve body and its lining, as well as between the valve body and the valve cover; the absence of any leaks indicates that the test has been passed. 7.2.4 For gate valves with a nominal pressure of less than 1 MPa and a nominal diameter of 600 mm or more, the shell pressure test may not be conducted separately; it can be carried out as part of the pipeline system test. 7.2.5 Pressure testing of valve housings: For valves with the same nominal pressure and nominal diameter, they can be connected in series to test their housing pressure as a whole. A pressure gauge should be installed at each of the inlet and outlet ports to ensure that the requirements for valve pressure testing are met. A steel pipe is used to lead from the blind flange of the valve, with a stop valve attached to it. A stop valve is also installed at the outlet of the pressure testing pump. 7.3 Valve Sealing Test The basic steps of the sealing test are as follows: seal the inlet and outlet of the valve, loosen the packing gland, open the valve while keeping the seal closed, fill the chamber with the testing medium, gradually increase the pressure to the specified test level; if there is no leakage after maintaining this pressure for the required time, the test is considered successful. 7.4 The adjustment and testing of safety valves shall be entrusted to a qualified unit for commissioning and testing. VIII. Valve Marking 8.1 Form of Marking 8.1.1 The materials of the valves used in this project shall be identified by means of labels attached directly to them. 8.1.3 Any missing or lost markings shall be supplemented before the product is released from storage, after being verified by the inspectors from the Materials Department of the project team. 8.2 Valve marking: Valves that pass the testing shall be marked with a “√” directly on them using a paint pen, while those that fail the testing shall be marked with an “×”. Records of the valve testing shall also be kept. Valves that are in the stage of \"to be verified and confirmed\" during incoming inspection and pressure testing are not labeled, and a \"To Be Verified and Confirmed\" sign is hung on them. 8.3 Labeling of products released on an emergency basis: For valves that are released for installation due to urgency during the incoming inspection and testing phases, without time to conduct verification, a “Emergency Release Request Form” label should be filled out, and such products should be tracked and managed as products released on an emergency basis. 8.4 Product identification during construction (1) The original identification of the valves should be preserved intact to prevent damage or loss. The re-applied markings shall be confirmed by the quality inspector. (2) For non-conforming products that require evaluation and handling after inspection and pressure testing, a “Inspection Failed” label shall be attached, and a “Non-Conforming Product Control Record” shall be kept; the label shall be removed once the product passes rework or is accepted on a concession basis. IX. Safety Technical Regulations 1. A no-entry zone should be established around the valves during pressure testing, and a dedicated person should be assigned to monitor it; persons other than those involved in the testing are not allowed to enter. 2. Valves that are subjected to pressure testing should be protected, with covers on the inlet and outlet to prevent dirt from entering. 3. Before and during the pressure testing, it is necessary to carefully inspect the blind plates on the valve under test, the installation of pressure gauges, as well as any deformation that may occur during the testing process. Voltage boosting can only be performed when the conditions for boosting are indeed met. 4. During the pressure test, it is strictly prohibited to bump or strike the valve. If any leakage or other abnormal phenomena occur during the pressure testing, the testing must be stopped immediately; inspections should not be carried out while under pressure. Before draining, the pipe at the top of the heat exchanger should be opened first to equalize pressure with the atmosphere, and then drainage should be carried out from the bottom to prevent the equipment from becoming vacuumed. 5. During the hydrostatic test, a vent valve shall be installed at the highest point of the valve, and a globe valve shall be fitted at the lowest point. When filling with water or sealing it for waterproofing, the drain valve should be opened first. 6. During pressure testing, if the equipment under pressure emits abnormal noises, experiences a drop in pressure, or its surface paint peels off, the test should be stopped immediately to determine the cause. 7. During the valve pressure testing process, the testing water should be reused as much as possible to ensure conservation. It is strictly prohibited to discharge pressure test water indiscriminately. 8. During the testing process, attention should be paid to environmental protection and noise reduction. X. Construction machinery and equipment XI. List of materials for use XII. Construction workers