Specification for Bolted Tanks for Storage of Production Liquids

API SPECIFICATION 12B

SEVENTEENTH EDITION, DECEMBER 2020

API MONOGRAM PROGRAM EFFECTIVE DATE: JUNE 2021

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iii

Contents

Page

1. Scope 1

   1. Purpose 1

   2. Scope 1

2. Normative References 1

3. Terms and Definitions 2

4. Material 2

   1. Finish 2

   2. Plates 3

   3. Sheets 3

   4. Structural Shapes 3

   5. Piping 3

   6. Flanges 3

   7. Couplings 3

   8. Bolts and Nuts Used in the Tank Bottom, Shell, and Roof 3

   9. Other Bolts 4

   10. Gaskets 4

5. Design 4

   1. Loads and Load Combinations 4

   2. Dimensions 5

   3. Bottoms 5

   4. Staves (Shell Plates/Sheets) 6

   5. Roof 6

   6. Bolted Joints 12

   7. Joint Gaskets 12

   8. Cleanouts 12

   9. Inlet and Outlet Connections 14

   10. Bolting Patterns for the Gauge Hatches and Relief Valve 16

   11. Downcomer Pipe 18

   12. Walkways, Stairways, Ladders, and Platforms 18

   13. Venting 18

6. Fabrication 19

   1. Straightening 19

   2. Edges 19

   3. Tolerances 19

7. Erection 19

8. Inspection 19

   1. Notice 19

   2. Inspection by purchaser 19

   3. Compliance 19

9. Marking 19

Annex A (informative) Suggestions for Ordering Tanks 21

v

Contents

Figures

Page

1. Cone Bottoms 6

2. Bottom Elements 8

3. Bottom Elements 9

4. Stave Elements 10

5. Roof Elements 11

6. Flush-type Cleanout 13

7. Extended-neck-type Cleanout 14

8. Bolted Piping Flanges 15

9. Bolt Pattern for 8-in. Circular Gauge Hatches and Vents 17

10. Bolt Pattern for 8-in. x 18-in. Oblong Gauge Hatches and Vents 17

11. Bolt Pattern for 8-in. x 22-in. Oblong Gauge Hatches and Vents 18

12. Nameplate Format 20

Tables

1. Sizes and General Dimensions 5

2. Details of Bottoms, Shells, and Roofs 7

3. Bolted Pipe Flanges 16

vi

Specification for Bolted Tanks for Storage of Production Liquids

1. Scope

   
   

   1. Purpose

      
      

      This specification provides the oil production industry with safe, economical tanks for storing liquids.

      
      

   2. Scope

      
      

      This specification establishes minimum requirements for material, design, fabrication, erection, inspection, and marking of vertical, cylindrical, aboveground, unanchored, closed- and open-top, bolted storage tanks in standard sizes designed for the loads specified in Section 5.

      
      

2. Normative References

The following documents are referenced by this specification. For dated references, only the edition cited applies:

AISC 360-161, Specification for Structural Steel Buildings

API Standard 12R1, Installation, Operation, Maintenance, Inspection, and Repair of Tanks in Production Service, 6th Edition

API Specification 5L, Line Pipe, 46th Edition

API Specification 6A, Specification for Wellhead and Christmas Tree Equipment, 20th Edition API Standard 650, Welded Steel Tanks for Oil Storage, 12th Edition, Addendum 2

API Standard 2000, Venting Atmospheric and Low-pressure Storage Tanks, 7th Edition ASCE 7-162, Minimum Design Loads for Buildings and Other Structures

ASME B1.1-20033, Unified Inch Screw Threads, (UN and UNR Thread Form)

ASME B16.11-2016, Forged Fittings, Socket-Welding and Threaded

ASME B18.2.1-2012, Square, Hex, Heavy Hex, and Askew Head Bolts and Hex, Heavy Hex, Hex Flange, Lobed Head, and Lag Screws (Inch Series)

ASME B18.2.2-2015, Nuts for General Applications: Machine Screw Nuts, Hex, Square, Hex Flange, and Coupling Nuts (Inch Series)

ASTM A36/A36M-144, Standard Specification for Carbon Structural Steel

1 American Institute of Steel Construction, 130 East Randolph, Suite 2000, Chicago, Illinois 60601, www.aisc.org.

2 American Society of Civil Engineers, 1801 Alexander Bell Drive, Reston, Virginia 20191, www.asce.org.

3 ASME International, 2 Park Avenue, New York, New York 10016-5990, www.asme.org.

4 ASTM International, 100 Barr Harbor Drive, West Conshohocken, Pennsylvania 19428, www.astm.org.