Storage vessel design

Basics of API 650

1. STORAGE VESSELS Ministry of Electricity, Iraq By MASU KUMARA Chartered Mechanical Engineer Consultant, GPP Projects

2. Storage Vessel Design Storage of Petroleum oils Biogenic oil Fertilizers Food Grains Plastic Pellets etc. liquids Solids

3. Petroleum Oil Storage Cylindrical Tanks designed and constructed based on API codes of practice API Standard 650 – Welded Steel Tanks for Oil Storage API Standard 651- Cathodic Protection of Aboveground Storage Tanks API Standard 653 , Tank Inspection, Repair, Alteration, and Reconstruction And other API standards also useful

4. API STANDARD 650 (API 650) Chapter 01. Scope Chapter 02. Materials Chapter 03. Design Chapter 04. Fabrication Chapter 05. Erection Chapter 06. Methods of Inspecting Joints Chapter 07. Welding Procedure and Welder Qualifications Chapter 08. Markings Appendices A to U

5. Chapter 01. Scope Scope of this standard (API 650) Limitations and references Tanks with internal pressures approximately in the region of atmospheric pressure ( Appendix F gives provisions for smaller pressure storages ) The entire bottom should be uniformly supported In non refrigerated services Maximum operating temperature 90 o C (Appendix M gives provisions for the operating temperature range from 90 o C to 260 o C ) In SI units or US customary units

6. Chapter 01. Scope COMPLIANCE The manufacturer is responsible for complying with all provisions of this standard. Inspection by the purchaser’s inspector (the term inspector as used herein) does not negate the manufacturer’s obligation to provide quality control and inspection necessary to ensure such compliance.

7. Chapter 02 Materials (Plates) Group i through iiiA is lower stress steels Group v through viA is higher stress steels

8. Chapter 02. Materials Killed steel is steel that has been completely deoxidized by the addition of an agent before casting, so that there is practically no evolution of gas during solidification. They are characterized by a high degree of chemical homogeneity and freedom from gas porosity . The steel is said to be "killed" because it will quietly solidify in the mould, with no gas bubbling out . It is marked with a "K" for identification purposes

9. Chapter 02. Materials Semi-killed steel is mostly deoxidized steel, but the carbon monoxide leaves blowhole type porosity distributed throughout the ingot. The porosity eliminates the pipe found in killed steel and increases the yield to approximately 90% by weight. Semi-killed steel is commonly used for structural steel with a carbon content between 0.15 to 0.25% carbon.

10. Chapter 02. Materials (Lower Stress Group) Group I Group II Group III Group IIIA Semi killed Killed or semi killed As rolled, killed fine grain practice Normalized Killed, fine grain practice A 283 C A 131 B A 573-58 A 131 CS A 285 C A 36 A516-55 A 573-58 A 131 A G40.21M-26-M A516-60 A 516-55 A 36 Grade 250 G40.21M-260W A 516-60 Grade 235 Grade 250 G40.21M-260W Grade 250 Grade 250

11. Chapter 02. Materials (Higher Stress Group)

12. Chapter 02: Materials ( SA 283/SA 283M Plates ) Chemical Requirement Grade A Grade B Grade C Grade D C , Max % 0.14 0.17 0.24 0.27 Mn , Max % 0.90 0.90 0.90 0.90 P , Max % 0.035 0.035 0.035 0.035 S , Max % 0.04 0.04 0.04 0.04 Si , Max % 40mm & Under 0.40 0.40 0.40 0.40 Over 40 mm 0.15-0.40 0.15-0.40 0.15-0.40 0.15-0.40 Cu , Max % 0.2 0.2 0.2 0.2 Tensile requirement Tensile strength ( MPa ) 310-415 345-450 380-515 415-550 Yield Point ( MPa ) 165 185 205 320

13. Chapter 02: Materials ( SA 285/SA 285M Plates ) Chemical requirement Grade A Grade B Grade C C , Max % 0.17 0.22 0.28 Mn , Max % 0.90 0.90 0.90 P , Max % 0.035 0.035 0.035 S , Max % 0.035 0.035 0.035 Tensile requirement Tensile strength ( MPa ) 310-450 345-485 380-515 Yield Point ( MPa ) 165 185 205

14. Chapter 02: Materials ( Colours Designated)

15. Chapter 02 Materials (Piping)

16. Chapter 02 Materials (Flanges)

17. Chapter 02 Materials (Bolting)

18. Chapter 02 Materials (Welding Electrodes)

19. Chapter 03. Design No Description 1 Joints 2 Design Considerations 3 Special Considerations 4 Bottom Plates 5 Annular bottom plates 6 Shell Design 7 Shell Openings 8 Shell Attachments and Tank appurtenances 9 Top and intermediate wind girders 10 Roofs 11 Wind Load on Tanks 12 Tank Anchorage

20. Chapter 03 Design (Joints) some terminologies tack weld: A weld made to hold the parts of a weldment in proper alignment until the final welds are made. fillet weld: A weld of approximately triangular cross section that joins two surfaces at approximately right angles , as in a lap joint, tee joint, or corner joint . full-fillet weld: A fillet weld whose size is equal to the thickness of the thinner joined member . butt-weld: A weld placed in a groove between two abutting members. Grooves may be square, V-shaped (single or double), or U-shaped (single or double), or they may be either single or double beveled . lap joint: A joint between two overlapping members butt joint: A joint between two abutting parts lying in approximately the same plane

21. Chapter 03 Joint Design BUTT JOINT STRAP JOINT LAP JOINT FILLET JOINT CORNER JOINT

22. Chapter 03 Design (joints) Fusion Weld Zones

23. Chapter 03 Design (Joints) Shell joints (Vertical and horizontal) shall be butt joints with complete penetration and complete fusion. Bottom joints may be butt welded or lap welded Butt welded bottom joints with or without backing strips Complete penetration At least 3mm backing strip when use Root opening less than 6 mm Three-plate joints in the tank bottom shall be at least 300 mm ( 12 in.) from each other and from the tank shell.

24. Chapter 03 Design (Joints) Bottom Joints may be Butt welded or Lap welded Lap welded bottom joints Complete penetration Reasonably rectangular and square edged Full fillet on all seams Three-plate laps in tank bottoms shall be at least 300 mm (12 in.) from each other, from the tank shell, from butt-welded annular-plate joints, and from joints between annular plates and the bottom .

25. Chapter 03 Design (Joints) Shell to bottom Fillet Welds If shell plates less than 12.5 mm, shall be continuous fillet weld on both sides of shell. If shell plate are grater than 12.5 mm, either the legs of the fillet welds or the groove depth plus the leg of the fillet for a combined weld is of a size equal to the annular-plate thickness Nominal thickness of shell plate Minimum size of fillet weld 5 mm 5 mm 5 mm to 20 mm 6 mm 20 mm to 32 mm 8 mm 32 mm to 45 mm 10 mm

26. Chapter 03 Design Bottom plates and annular plates Minimum thickness of bottom plates 6mm, if any corrosion allowance is specified by the purchaser, add c.a. to 6mm Unless otherwise agreed, plates shall be of minimum width of 1800 mm (72 ft ) at least a 25 mm (1 in.) width will project beyond the outside edge of the weld attaching the bottom to the shell plate

27. Chapter 03 Design

28. Chapter 03. Design Shell Design Above thickness is the minimum, and hence could be altered based on other parameters as well Minimum nominal plate width shall be of 1800mm The design shell thickness shall be computed on the basis that the tank is filled to a level with a liquid that has a specific gravity specified by the purchaser Nominal Tank Diameter (m) Nominal Plate thickness (mm) Less than 15 5 Between 15 to 36 6 Between 36 to 60 8 Above 60 10

29. Chapter 03 Design

30. Chapter 03. Design

31. Chapter 03 Design Calculation of Thickness by the 1-Foot Method Calculation of Thickness by the Variable Design-Point Method Calculation of Thickness by Elastic Analysis

32. Chapter 03 Design Shell Openings Shell Manholes Shell nozzles and flanges Flush-Type Cleanout Fittings Spacing of Welds Around Connections Reinforcement and Welding

33. Chapter 03 Design SHELL ATTACHMENTS AND TANK APPURTENANCES Shell Attachments Bottom Connections Cover Plates Roof Manholes Roof Nozzles Water Drawoff Sumps Scaffold-Cable Support Threaded Connections

34. Chapter 03 Design Wind Girders Draw off sumps Wind girders are stiffening rings to maintain roundness when the tank is subjected to wind loads. Wind girders may be made of structural sections, formed plate sections, sections built up by welding, or combinations of such types of sections assembled by welding. Minimum structural member sizing would be 65x65x6 and may cross vertical tank weld seam welds with coping of stiffening rings at vertical seam. Could be used as a walkway if minimum width of stiffening ring to be 610 mm and to be located 1100mm below the top angle.

35. Chapter 03 Design Top wind girders Intermediate wind girders Top angle and curb angle Dome roof, umbrella roof Tank anchorage

36. Chapter 04 Fabrication

37. Chapter 04 Fabrication

38. Chapter o4 Fabrication

39. Chapter 04 Fabrication

40. Chapter 05 Erection Tank Bottom

41. Chapter 05 Erection Two methods used From bottom to roof – using cranes From roof to bottom – using hydraulic jacks

42. Chapter 05 Erection

43. Chapter 05 Erection Tank Shells Some other guide lines are also there in the code

44. Chapter 05 Shell to bottom welds The initial welds pass inside of the shell have to be examined by using applicable method agreed by the purchaser and manufacturer

45. Chapter 05 Erection

46. Chapter 05 Erection

47. Chapter 06 Method of Inspecting Joints 1. Radiographic Method 2. Magnetic Particle Examination 3. Ultrasonic Examination 4. Liquid Penetrant Examination 5. Visual Examination 6. Vacuum testing

48. Chapter 06 Radiographic Method

49. Chapter 06

50. Chapter 06 Inspection of joints

51. Chapter 06 Inspection of joints Magnetic Particle Examination Liquid Penetrant Examination

52. Chapter 07 Welding Procedure Welding Procedure Specification (WPS) Procedure Qualification Records (PQR) Welder Performance Qualification (WPQ)

53. Chapter 08 Marking

54. Thank you very much