1 General Provisions
1.0.1 This code is formulated to standardize the construction of vertical cylindrical welded steel tanks, guarantee the engineering quality and make it advanced in technology, cost-effective, safe and applicable.
1.0.2 This code is applicable to the construction of vertical cylindrical welded steel tank body at and close to normal pressure for storing petroleum and petrochemical products and other similar liquids, including accessories welded with the tank, but not applicable to the construction of buried tank, tank holding extremely and highly hazardous medium and artificial refrigerant fluid tank.
1.0.3 Tanks shall be constructed according to design documents. In case design documents are required to be revised, written consent of the original design organization shall be first obtained.
1.0.4 Prefabrication, installation and inspection of tanks shall be performed with qualified measuring tools with the same accuracy grade.
1.0.5 The construction of vertical cylindrical welded steel tanks shall not only meet those specified in this code, but also those in the current relevant standards of the nation.
2 Terms
2.0.1 Annular/sketch bottom plates
The tank bottom plates at the outermost side of the lower part of the shell plate, including annular edge plates and non-annular edge plates.
2.0.2 Fixed roofs
The tank roofs with peripheral parts connected, in fixed method, with the tank shell top, mainly including self-supporting cone roof, supporting cone roof and self-supporting dome roof etc..
2.0.3 Floating roofs
Roofs which lifts with the liquid level, including external floating roof and internal floating roof, and mainly being single-deck floating roof, double-deck floating roof, open-top bulk-headed floating roof and floating roof on floats etc..
2.0.4 Wind girder
Member arranged onto the shell to make it stronger to resist wind.
2.0.5 Auto vent
The venting device which opens/closes automatically when the floating roof rises or restores to be in bracing state.
2.0.6 Floating roof drains
Equipment which drains the rainwater on external floating roof out of the tank under normal conditions.
2.0.7 Stiffening ring
The member arranged onto the shell to enhance the stability of tank shell and protect it against instability.
3 Material Acceptance
3.0.1 Materials and accessories selected for the construction of tanks must be provided with quality certificates and meet those specified in design documents. Both steel plates and accessories shall be with clear product labels.
3.0.2 Electrode, welding wire, welding flux, shielding gas and other welding materials shall be with quality certificates, and meet not only the requirements of Technical Permission of Welding Materials for Pressure Equipment Section (NB/T 47018), but also the following requirements:
1 Electrodes shall meet the relevant requirements of the current national standards Covered Electrodes for Manual Metal Arc Welding of Non-alloy and Fine Grain Steels (GB/T 5117) and Covered Electrodes for Manual Metal Arc Welding of Creep-resisting Steels (GB/T 5118) and Stainless Steel Covered Electrodes (GB/T 983);
2 Flux-cored wires shall meet the relevant requirements of the current national standards Carbon Steel Flux Cored Electrodes for Arc Welding (GB/T 10045), Low Alloy Steel Flux Cored Electrodes for Arc Welding (GB/T 17493) and Stainless Steel Flux Cored Wires (GB/T 17853);
3 Gas shielded welding wires shall meet the relevant requirements of the current national standard Welding Electrodes and Rods for Gas Shielding Arc Welding of Carbon and Low Alloy Steel (GB/T 8110);
4 Welding wires and welding fluxes used for submerged arc welding shall meet the relevant requirements of the current national standards Carbon Steel Electrodes and Fluxes for Submerged Arc Welding (GB/T 5293), Low-alloy Steel Electrodes and Fluxes for Submerged Arc Welding (GB/T 12470) and Stainless Steel Electrodes and Fluxes for Submerged Arc Welding (GB/T 17854);
5 Shielding gas shall meet the relevant requirements of the current national standards Carbon Dioxide for Welding Use (HG/T 2537) and Argon (GB/T 4842).
3.0.3 Before construction, steel plates shall be subjected to appearance inspection piece by piece, and steel plate quality shall meet the relevant requirements of design documents and the current national standards Dimension, Shape, Weight and Tolerance for Cold-rolled Steel Plates and Sheets (GB/T 708) and Dimension, Shape, Weight and Tolerances for Hot-rolled Steel Plates and Sheets (GB/T 709).
3.0.4 Sum of negative deviations from partial reduction and scratch depth on steel plate surface to the actual thickness of the steel plate shall meet the requirements of the design documents, and not be greater than the allowable negative deviation specified in corresponding steel plate standard.
3.0.5 Imported steels and welding materials shall meet the requirements of the foreign corresponding codes for steel welded tanks and the design requirements.
3.0.6 Material re-inspection shall meet the requirements of the design documents.
3.0.7 In case of any doubt about material quality, re-inspection shall be performed by the party purchasing such material.
4 Prefabrication
Foreword I
1 General Provisions
2 Terms
3 Material Acceptance
4 Prefabrication
4.1 General Requirement
4.2 Shell Plate Prefabrication
4.3 Bottom Plate Prefabrication
4.4 Floating Roof Prefabrication
4.5 Top Plate Prefabrication of Fixed Roof
4.6 Accessories Prefabrication
5 Assembly
5.1 General Requirement
5.2 Foundation Inspection
5.3 Tank Bottom Assembly
5.4 Shell Plate Assembly
5.5 Fixed Roof Assembly
5.6 Floating Roof Assembly
5.7 Accessories Installation
6 Welding
6.1 General Requirement
6.2 Welding Procedure Qualification and Welding Procedure Specification
6.3 Welding Material
6.4 Welding Construction
6.5 Welding Sequence
6.6 Repair and Rework
7 Inspection and Acceptance
7.1 Welding Seam Appearance Inspection
7.2 Welding Seam NDT Test and Leakage Test
7.3 Tank Geometry and Dimension Inspection
7.4 Hydro-test
7.5 Project Completion
Appendix A Fillet Welding Seam Test Specimen Preparation and Inspection for T-shape Joint
Appendix B Storage Tank Foundation Settlement Observation Method
Appendix C Acceptance Forms
Explanation of Wording in This Code
List of Quoted Standards
