Standard No.:	SY/T 5921-2024
English Name:	Specification for operating, maintenance and repairof vertical cylindrical welded steel oil tank
Chinese Name:	立式圆筒形钢制焊接油罐 运行维护修理规范
Professional Classification:	SY    Professional Standard - Oil & Gas
Source Content Issued by:	Nation Energy Administration
Issued on:	2024-12-25
Implemented on:	2025-6-25
Status:	valid
Superseding:	SY/T 5921-2017 Specification for operating, maintenance and repair of vertical cylindrical welded steel oil tank
Target Language:	English
File Format:	PDF
Word Count:	30000 words
Translation Price(USD):	900.0
Delivery:	via email in 1~10 business day

SY/T 5921-2024 Specification for operating, maintenance and repairof vertical cylindrical welded steel oil tank English, Anglais, Englisch, Inglés, えいご This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered. ICS E Professional standard of the People's Republic of China SY/T 5921-2024 Replaces SY/T 5921-2017 Specification for operating, maintenance and repair of vertical cylindrical welded steel oil tank 立式圆筒形钢制焊接油罐 运行维护修理规范 (English Translation) Issue date: 2024-12-25 Implementation date: 2025-06-25 Issued by National Development and Reform Commission, P.R.C Contents Foreword 1 Scope 2 Normative References 3 Terms and Definitions 4 Tank Operation 4.1 General Rules 4.2 Tank Inspection 4.3 Tank Operation Procedures 4.4 Safety Management Requirements 5 Maintenance 5.1 General Rules 5.2 Routine Maintenance 5.3 Quarterly Maintenance 5.4 Annual Maintenance 6 Repair 6.1 General Rules 6.2 Tank Cleaning 6.3 Off-line Inspection and Evaluation 6.4 Tank Repair 6.5 Tank Body Corrosion Protection 6.6 Tank Wall Insulation 6.7 Foundation Repair 6.8 Testing and Acceptance Appendix A (Informative) Common Tank Faults, Accidents, and Handling Methods Appendix B (Normative) Safety Regulations for Manual Tank Cleaning Operations Appendix C (Normative) Inspection and Evaluation of Tank Body Settlement Appendix D (Normative) Off-line Inspection and Evaluation Appendix E (Normative) On-line Tank Repair Appendix F (Normative) Technical Requirements for Complete Replacement of Tank Components and Accessories Bibliography Specification for Operation, Maintenance and Repair of Vertical Cylindrical Steel Welded Oil Tanks 1 Scope This document specifies the technical requirements for the operation, maintenance, and repair of vertical cylindrical steel welded oil tanks. This document applies to the operation, maintenance, and repair of vertical cylindrical steel welded oil tanks with a capacity of 15×10⁴ m³ and below. 2 Normative References The following documents contain provisions which, through normative reference in this text, constitute essential provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies. GB/T 706 Hot rolled section steel GB/T 3007 Test method for moisture content of refractories GB/T 3186 Paints, varnishes and raw materials for paints and varnishes — Sampling GB/T 3880 (all parts) Wrought aluminium and aluminium alloy plates, sheets and strips for general engineering GB/T 5210 Paints and varnishes — Pull-off test for adhesion GB/T 5285 Hexagon head self-tapping screws GB/T 6891 Aluminium and aluminium alloy profiled sheets GB/T 8923.1 Preparation of steel substrates before application of paints and related products — Visual assessment of surface cleanliness — Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings GB/T 10299 Test method for hydrophobic nature of thermal insulation GB/T 12754 Prepainted steel sheet and strip GB/T 12755 Profiled steel sheets for building GB/T 15856.5 Hexagon flange head self-drilling screws with tapping screw thread GB/T 17393 Specification for thermal insulation materials for covering austenitic stainless steel GB/T 18570.3 Preparation of steel substrates before application of paints and related products — Tests for the assessment of surface cleanliness — Part 3: Assessment of dust on steel surfaces prepared for painting (pressure-sensitive tape method) GB/T 30583 Specification for post weld heat treatment of pressure equipment GB 30871 Safety code for special operations in hazardous chemical enterprises GB 50128 Specification for construction of vertical cylindrical steel welded storage tanks GB 50341 Code for design of vertical cylindrical steel welded oil tanks GB/T 50393 Technical standard for anti-corrosion engineering of steel petroleum tanks AQ/T 3042 Safety requirements for mechanical cleaning of external floating roof crude oil tanks AQ 3058 Safety specification for repair of internal floating roof tanks JB/T 10765 Non-destructive testing — Magnetic flux leakage testing method for atmospheric metal storage tanks JGJ 7 Technical specification for space frame structures NB/T 47013 (all parts) Non-destructive testing of pressure equipments NB/T 47014 Welding procedure qualification for pressure equipment NB/T 47015 Welding specification for pressure vessels SY/T 0407 Standard of steel surface treatment before painting SY/T 5225 Safety technology code for fire and explosion prevention in drilling, development and storage of petroleum & natural gas SY/T 6306 Safety specification for operation of steel crude oil storage tank SY/T 6696 Specification for tank mechanical cleaning 3 Terms and Definitions For the purposes of this document, the following terms and definitions apply. 3.1 off-line inspection Inspection carried out on the interior and exterior of an oil tank after emptying the medium inside the tank. 3.2 on-line inspection Inspection carried out on an oil tank without removing the medium inside the tank. 3.3 floating roof tank A collective term for external floating roof tanks and internal floating roof tanks. 4 Tank Operation 4.1 General Rules 4.1.1 Before the tank is put into service, the operation management unit shall establish corresponding inspection tour systems, the process parameter tables for the operation of the tanks under its management, and technical files for the tanks. 4.1.2 Newly built or repaired tanks shall be accepted according to the requirements of the design documents and may only be put into service after passing acceptance. 4.2 Tank Inspection 4.2.1 Pre-service Inspection 4.2.1.1 Process Inspection The inspection items and requirements are as follows: a)Valves in all process systems and heating systems related to the tank shall operate flexibly without leakage. Connections between valves and pipeline flanges shall be secure and reliably sealed, and the valve status shall be correct. b) The remote and local emergency shut-off function of the tank root valve shall be in good condition. The valve closing time should not exceed 180 s. c) The high-high level and low-low level detection instruments and the interlock protection program functions of the tank shall pass functional tests. The execution of the interlock program shall be consistent with the design documents. d) The connection of the compensator before the tank shall be reliable. The adjustment of the auxiliary tie rods for bellows compensators shall comply with the equipment instruction manual. e) For tanks with cathodic protection systems, the insulating flange connected to the process pipeline shall have no damage to the insulation layer, and the insulation performance test shall be qualified. 4.2.1.2 Tank Body Inspection The inspection items and requirements are as follows: a) The conclusions of inspection and test reports, such as those for tank welds, geometric shape, and water filling test, shall be qualified. The geometric shape and dimensions of the tank shell plates and the local concave-convex deformation of the floating roof shall comply with the provisions of GB 50128. b) Parts such as the insulation layer shall be installed securely. The anti-corrosion coating on the tank body shall have no defects. 4.2.1.3 Accessory Inspection The inspection items and requirements are as follows: a) The no-load rotation direction of the side wall mixer motor shall be correct. The barring rotation shall be flexible without jamming. The mixer shall be in a standby state. The rotating nozzle of the jet mixer shall rotate flexibly. b) Components such as the tank staircase, tank roof handrails, platforms, and inspection walkways shall be securely welded. c) Detection instruments such as level gauges, level switches, thermometers, and flame detectors shall function normally and be verified as qualified. d) The manhole and light hole cover plates on the tank roof shall be installed securely. The light hole windows shall be intact, undamaged, and provide good light transmission. e) The protective mesh for the annular vents of internal floating roof tanks shall be installed intact. f) There shall be no debris on the guide rail of the rotating floating ladder. The floating ladder shall rotate flexibly without jamming with the guide rail. The copper cladding on the rollers shall be intact and undeformed. g) Tank accessories such as breather valves, flame arresters, and safety valves shall be installed securely and verified as qualified. h) The automatic bleeder vent shall be installed securely. The gasket of the valve cap shall be flat and clean. i) The central sump shall be free of debris. The filler at the bottom of the sump shall be intact and not missing. The float (disc) check valve shall operate without jamming. j) The floating roof drain pipe shall pass the test and be securely connected. k) The water seal tank of the emergency drain device shall be filled with water to the design liquid level. l) The sealing device shall fit tightly against the tank wall. There shall be no light penetration observed during internal inspection of the tank. m) The wax scraper mechanism shall be installed securely. The scraper plates shall be evenly distributed and fit tightly against the tank wall, with no overlap between adjacent plates. n) The foam dam shall be free of deformation. The opening area of the drain shall comply with the requirements of the design documents. o) The floating roof static electricity discharge device shall be installed securely and flexibly extend and retract. The static electricity discharge wire of the internal floating roof tank shall have a natural sag and be free from entanglement or obstacles along its lifting path. rollers of the floating roof guide device shall rotate flexibly without jamming.