Container supervision

For the supervision of container manufacturing and tank construction on site, it is necessary to define: the objectives of supervision, the tasks involved in supervision, the methods and procedures for supervision, as well as organizational and coordination aspects. It is crucial to identify the key control points. Here are two examples – going a bit overboard here! ! Container Supervision Project Table Supervision Project Number Supervision Project Category Remarks 1 Materials Cylinder, head, access pipe, flange, elbow ； Welding materials for welds. 1-1 Certificates of material for main pressure-bearing components and welding materials W 1-2 Reinspection reports for main pressure-bearing components and welding materials H 1-3 Transferring of material markings E 1-4 Approval for material substitution W 2 Welding 2-1 Welders and weld qualification 2-1-1 List of welders W 2-1-2 List of weld qualification items W 2-1-3 Welding procedure qualification report W 2-1-4 Welding specifications W 2-2 Manufacturing process 2-2-1 Process flow diagram W 2-2-2 Marking, cutting, GW, and shaping of cylinders E 2-2-3 Shaping of end caps E 2-2-4 Marking, gas cutting, and GW of cylinders and end caps E 2-3 Welding of Class A, B, and D welds 2-3-1 GW, FU, DT E 2-3-2 Records of weld process inspection W 2-3-3 ISR W 2-3-4 Weld VT, DT, RT W 2-3-5 Repair of welds W 3 Non-destructive testing 3-1 List of non-destructive testing personnel E 3-2 RT and UT testing procedures E 3-3 20% reinspection of RT films; resolution of suspicious findings through consultation. For W 3-4, UT testing of steel plates is carried out at 100%, and any suspicious results are resolved through consultation. W 4 Hydrostatic test H 5 Inspection of internal components 5-1 Joint inspection of internal components before leaving the factory W 5-2 Preliminary assembly of internal components W 5-3 Assembly inspection of internal components W 6 Appearance quality and geometric dimensions 6-1 Inner diameter, length W 6-2 Position and size of openings in the connectors W 6-3 Misalignment amount at the joints W 7 Documentation for handover W Note: Symbol explanation E – Inspection point ； W - Witness Point ； H - Stop point ； UT - Ultrasonic testing ； RT - Ray detection ； VT - Visual inspection ； ISR - Intermediate Stress Relief Heat Treatment ； GW - Notch machining ； NT – Mechanical property testing ； DT - Dimension inspection ； FU – Assembly and construction supervision of storage tanks: Detailed control points are established first.
　　　　　　　　　　　　　　　　　　　　　　　　　　　
Serial Number | Control Point | Control Point Level
--- | --- | ---
I. Construction Preparation | 1. Review of the construction plan for tank installation | A
| 2. Inspection of certification documents for raw materials and tank accessories | A
| 3. Inspection items related to the foundation | A
| (1) Foundation elevation and slope
| (2) Asphalt sand, unevenness, penetrating cracks
| (3) Ellipticity of the ring beam, width deviation, levelness of the ring beam
| 4. Prefabrication | B
| 5. Inspection of welders’ qualifications | B
| 6. Welding procedure qualification | A
| 7. Inspection of concealed works (sandblasting for rust removal and anti-corrosion inspection of the tank bottom plate) | A
| 8. Inspection of openings and connections on the tank wall | B

II. Tank Bottom Construction | 1. Inspection of the layout plan for the tank bottom plate | B
| 2. Quality of alignment of the tank bottom plate | B
| 3. Distance between adjacent welds on the tank bottom plate | B
| 4. Check whether the anti-corrosion layer is damaged during installation | B
| 5. Inspection of unevenness after welding of the tank bottom | A
| 6. Weld flaw detection | B
| 7. Vacuum test | A
| 8. Inspection of large-angle welds on the ring plates and side plates | B

III. Tank Wall Construction | 1. Inspection of the layout plan for the wall plates (distance between adjacent ring plate welds) | B
| 2. Inspection of the distance between the butt welds of side plates and the longitudinal welds of the first ring plate | B
| 3. Levelness, verticality, and ellipticity of the upper edge of the first ring plate | B
| 4. Verticality of each layer of ring plates | B
| 5. Grinding of weld scars on the inner surface of the welds | B
| 6. Inspection of levelness, ellipticity, height, and radius deviations after welding of the tank | A
| 7. Inspection of the visual quality of welds | B
| 8. Non-destructive testing of welds | B

IV. Tank Top Construction | 1. Inspection of the layout plan for the top plate | B
| 2. Quality of alignment of the grooves in the top plate | B
| 3. Distance between adjacent welds on the top plate | B
| 4. Check whether the anti-corrosion layer is damaged during installation | B
| 5. Unevenness after welding | A
| 6. Weld flaw detection | B
| 7. Vacuum test | B
| 8. Kerosene leak test | B
| 9. Inspection of the location of openings | B
| 10. Inspection of the welding quality of reinforcement rings and wind-resistant rings | B
| 11. Inspection of the appearance of ladder platforms | B
| 12. Assembly of accessories | C

V. Anti-Corrosion Measures | 1. Rust removal | A
| 2. Painting | B

VI. Overall Tests | 1. Water filling test | A
| 2. Monitoring of foundation settlement | A

VII. Construction of equipment insulation layers | B

It’s written in great detail and comprehensively upstairs. However, in actual work, it is rare that we can truly implement it comprehensively. The amount of work required to do this is simply too great. Therefore, when supervising the manufacture of pressure vessels on a per-unit-time basis, our focus is primarily on controlling the key aspects: the material and thickness of the pressure-bearing components, as well as the pressure testing, which require personal involvement. If it’s a small factory, don’t trust the material lists and test records they provide. A little experience for your reference.

The most important thing is whether the rules were actually followed during the execution process.

The supervision details are a refinement of the supervision plan, serving as a work guide for providing supervision services. It takes into account the scope, objectives, contents of supervision as well as the specified processes and methods outlined in the supervision plan, and further breaks down these processes and objectives into more specific details regarding inspection and supervision activities, requirements, methods, and guidelines, to facilitate the work of supervision engineers. It generally must be completed before each supervision service is provided! Taking the detailed rules for equipment engineering supervision in equipment manufacturing projects as an example, the main contents of such rules are as follows: 1. Scope of expertise and characteristics; 2. Basis for supervision; 3. Equipment manufacturing process and determination of inspection and verification points; 4. Content and methods for each inspection and verification point (such as document verification point R, on-site verification point W, and halt-for-inspection point H); 5. Filling out of supervision records. Note: During implementation, various changes due to different factors may occur, such as schedule deviations, quality issues, design or process modifications, and substitution of materials. Therefore, it is necessary to adjust the detailed rules accordingly. Generally, an application form for adjusting the detailed rules is filled out by the professional supervision engineer after conducting a thorough analysis of the specific changes, and it can only be put into effect after approval by the chief supervision engineer. For reference!