Api spec 12d 2017 (american petroleum institute)

Specification for Field welded Tanks for Storage of Production Liquids API SPECIFICATION 12D TWELFTH EDITION, JUNE 2017 EFFECTIVE DATE DECEMBER 1, 2017 Special Notes API publications necessarily addre[.]

Specification for Field-welded Tanks for Storage of Production Liquids

API SPECIFICATION 12D

TWELFTH EDITION, JUNE 2017

EFFECTIVE DATE: DECEMBER 1, 2017

API publications are published to facilitate the broad availability of proven, sound engineering and operating practices These publications are not intended to obviate the need for applying sound engineering judgment regarding when and where these publications should be utilized The formulation and publication of API publications

is not intended in any way to inhibit anyone from using any other practices

Any manufacturer marking equipment or materials in conformance with the marking requirements of an API standard

is solely responsible for complying with all the applicable requirements of that standard API does not represent, warrant, or guarantee that such products do in fact conform to the applicable API standard

All rights reserved No part of this work may be reproduced, translated, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher Contact the

Publisher, API Publishing Services, 1220 L Street, NW, Washington, DC 20005

Copyright © 2017 American Petroleum Institute

Nothing contained in any API publication is to be construed as granting any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or product covered by letters patent Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent.Shall: As used in a standard, “shall” denotes a minimum requirement in order to conform to the specification

Should: As used in a standard, “should” denotes a recommendation or that which is advised but not required in order

to conform to the specification

This document was produced under API standardization procedures that ensure appropriate notification and participation in the developmental process and is designated as an API standard Questions concerning theinterpretation of the content of this publication or comments and questions concerning the procedures under which this publication was developed should be directed in writing to the Director of Standards, American PetroleumInstitute, 1220 L Street, NW, Washington, DC 20005 Requests for permission to reproduce or translate all or any part

of the material published herein should also be addressed to the director

Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years A one-timeextension of up to two years may be added to this review cycle Status of the publication can be ascertained from theAPI Standards Department, telephone (202) 682-8000 A catalog of API publications and materials is published annually by API, 1220 L Street, NW, Washington, DC 20005

Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW, Washington, DC 20005, standards@api.org

iii

Page

1 Scope 1

1.1 General 1

1.2 Compliance 1

2 Normative References 1

3 Terms and Definitions 2

4 Materials 3

4.1 General 3

4.2 Plates 3

4.3 Sheets 3

4.4 Welding Electrodes 3

4.5 Structural Shapes 4

4.6 Piping 4

4.7 Flanges 4

4.8 Couplings 4

4.9 Bolting 4

5 Design 4

5.1 General 4

5.2 Tank Size 5

5.3 Weld Size 5

5.4 Joints 6

5.5 Bottom Design 6

5.6 Shell Design 8

5.7 Roof Design 9

5.8 Cleanout 10

5.9 Connections 10

5.10 Center Roof Nozzle 11

5.11 Center Support 11

5.12 Anti-channel Drain Baffle 11

5.13 Downcomer Pipe 12

5.14 Walkways, Stairways, and Ladders 12

6 Venting Requirements 12

6.1 Normal Venting 12

6.2 Emergency Venting 12

7 Construction, Testing, and Painting 12

7.1 Construction 12

7.2 Welding 12

7.3 Testing 13

7.4 External Painting 13

7.5 Internal Coating 13

7.6 Clean Up 13

8 Marking 13

9 Inspection and Rejection 14

9.1 Inspection Notice 14

9.2 Inspection 14

9.3 Rejection 14

v

Page

Annex A (informative) Use of Monogram by Licensees 15

Annex B (normative) Walkways, Stairways, and Ladders 18

Annex C (informative) Suggestions for Ordering Field-welded Tanks 20

Figures 5.1 Tank Dimensions 7

5.2 Cone Bottom 8

5.3 Gauge/Thief Hatch Cutout Details 11

8.1 Nameplate Format 14

Tables 5.1 Tank Dimensions 5

vi

This specification is under the jurisdiction of the API Subcommittee on Aboveground Storage Tanks

This specification is based on the accumulated knowledge and experience of purchasers and manufacturers of welded steel storage tanks of various sizes and capacities for internal pressures approaching atmospheric This publication provides a purchase specification to facilitate the manufacture and procurement of storage tanks for production service, such as storage of crude oil, condensate, hydrocarbon products, and nonpotable water If tanks are purchased in accordance with this specification, the purchaser is expected to specify certain basic requirements.This specification shall become effective on the date printed on the cover

field-

vii

Specification for Field Welded Tanks for

Storage of Production Liquids

1.1 General

This specification covers material, design, fabrication, and testing requirements for vertical, cylindrical, aboveground, closed top, welded steel storage tanks in various standard sizes and capacities for internal pressures of approximately atmospheric, not to exceed those listed in Table 5.1, Column 2

This specification provides the oil production industry with tanks of adequate safety and reasonable economy for use in the storage of crude petroleum and other liquids commonly handled and stored by the production segment of the industry This specification is for the convenience of purchasers and manufacturers in ordering and fabricating tanks

1.2 Compliance

The manufacturer is responsible for complying with all provisions of this specification The purchaser may make any investigation necessary to be satisfied that the manufacturer is in compliance and may reject any material that does not comply with this specification It is urged that the purchaser exercise this right

by providing an inspection independent of any supervisory inspection furnished by the manufacturer, and that the purchaser’s inspector closely monitor all of the details of shop fabrication and/or field construction and testing herein specified that may affect the integrity and safety of the completed structure

The following referenced documents are indispensable for the application of this document For dated references, only the edition cited applies For undated references, the latest edition of the referenced document applies including any amendments

API Specification 5L, Specification for Line Pipe

API Standard 650, Welded Tanks for Oil Storage

API Recommended Practice 652, Lining of Aboveground Petroleum Storage Tank Bottoms

API Standard 2000, Venting Atmospheric and Low-pressure Storage Tanks

ASME Boiler and Pressure Vessel Code, Section IX 1, Welding, Brazing, and Fusing Qualifications ASME B16.5, Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard

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

ASTM A36/A36M 2, Standard Specification for Carbon Structural Steel

ASTM A53/A53M, Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless

ASTM A106/A106M, Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service

ASTM A563, Standard Specification for Carbon and Alloy Steel Nuts

ASTM A1011/A1011M, Standard Specification for Steel, Sheet and Strip, Hot-Rolled, Carbon, Structural, High-Strength Low-Alloy, High-Strength Low-Alloy with Improved Formability, and Ultra-High Strength

AWS A5.1 3, Specification for Mild Steel Arc-Welding Electrode

AWS A5.18/A5.18M:2005, Specification for Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding

AWS D1.1, Structural Welding Code—Steel

AWS D1.6, Structural Welding Code—Stainless Steel

NACE SP0178-2007 4, Design, Fabrication, and Surface Finish Practices for Tanks and Vessels to Be Lined for Immersion Service

3 Terms and Definitions

For the purposes of this document, the following terms and definitions apply to joints

3.1

double-welded butt joint

A joint between two abutting parts lying in approximately the same plane welded from both sides A joint with filler metal added from one side only is considered equivalent to a double-welded butt joint when means are provided for a complete penetration and reinforcement on both sides of the joint

3.2

single-welded butt joint with backing

A joint between two abutting parts lying in approximately the same plane and welded from one side only, with a backing strip, bar, or other suitable material

3.3

double-welded lap joint

A joint between two overlapping members in which the overlapped edges of both members are welded with fillet welds

3.4

single-welded lap joint

A joint between two overlapping members in which the overlapped edge of one member is welded with a fillet weld

S PECIFICATION FOR F IELD W ELDED T ANKS FOR S TORAGE OF P RODUCTION L IQUIDS 3

4.2 Plates

4.2.1 Plates shall conform to ASTM A36/A36M or ASTM A516/A516M

4.2.2 Shell plates for which minimum thicknesses have been fixed for practical reasons (greater than required by computation) and that will not underrun the required computed thickness by more than 0.01 in., as well as all roof and bottom plates, may be purchased on a weight basis The plate thicknesses

or weights, as stipulated herein are minimums; thicker or heavier material may be required in the order at the option of the purchaser

4.2.3 Rimmed or capped steels are not permitted

4 API S PECIFICATION 12D

Section IX of the ASME Code Welding shall be performed in a manner that ensures complete fusion with

the base metal

4.4.2 Welding procedures for ladder and platform assemblies, handrails, stairways, and other miscellaneous assemblies, but not their attachments to the tank, shall comply with either AWS D1.1;

AWS D1.6; or Section IX of the ASME Code, including the use of standard WPSs

4.5 Structural Shapes

Structural shapes shall be of the open hearth, electric furnace, or basic oxygen process and shall conform

to ASTM A36/A36M or ASTM A529/A529M

4.9 Bolting

4.9.1 Bolting shall conform to ASTM A307, Grade A or B

4.9.2 Nuts, when used with bolting, shall conform to ASTM A563

4.9.3 Unless otherwise specified on the purchase order, black finish bolts and nuts shall be furnished

4.9.4 When specified to be galvanized, bolts and nuts shall be zinc coated in accordance with ASTM A123/A123M

4.9.5 Alternative materials and/or finish, conforming to recognized standards for bolting, may be furnished by agreement between the purchaser and the manufacturer

5.1 General

Tanks covered by this specification have been designed using established engineering calculations to determine minimum metal thickness and bolting requirements for each size tank filled with water (62.37 lb/ft3 at 60°F) and at the internal pressures specified in Table 5.1, Column 2 In order to ensure structural stability and integrity, additional metal thickness has been added to that determined by calculation The minimum metal thickness, specified in Table 5.1, shall not be decreased

NOTE For pressures beyond those stated in Table 5.1 or for other conditions not covered by this specification, API650, Annex F should be used for the design

S PECIFICATION FOR F IELD W ELDED T ANKS FOR S TORAGE OF P RODUCTION L IQUIDS 5

(ft, in.)

A

Nominal Height

(ft, in.)

B

Height of Overflow-line Connection b (ft, in.)

C

Height of Walkway Lugs

(ft, in.)

D

Location of Fill-line Connection b

(in.)

E

Size of Connections (in.)

a

Pressure

b Vacuum

208 bbl for the 55 ft diameter tanks

a

See 5.7.5 for frangible roof limitations

b

Viscous oil option When so specified on the purchase order, tanks shall be furnished for viscous oil service On such tanks,

dimension C of the overflow-line connections shall be 6 in less than shown in Column 6 above, and dimension E of the fill-line connection shall be 6 in., ± 1/ 8 in

6 API S PECIFICATION 12D

5.3.2 Fillet Welds

5.3.2.1 For equal leg fillet welds, weld size shall be based on: the leg length of the largest isosceles right

triangle that can be inscribed within the fillet-weld cross section

5.3.2.2 For unequal leg fillet welds, weld size shall be based on: the leg lengths of the largest right

triangle that can be inscribed within the fillet-weld cross section

5.4 Joints

5.4.1 General

See Section 3 for the definitions of terms related to joints as used in this specification

5.4.2 Joint Restrictions

The following restrictions on the type and size of joints or welds shall apply

5.4.2.1 Tack welds shall not be considered as having any strength value in the finished structure

5.4.2.2 The minimum size of fillet welds shall be as follows:

a) Plate 3/16 in., in thickness: full-fillet welds;

b) Plates over 3/16 in thick: not less than one-third the thickness of the thinner plate at the joint, with a minimum of 3/16 in., except as otherwise noted

5.4.2.3 Single-welded lap joints shall not be used on shell plates

5.5 Bottom Design

5.5.1 Type

Tank bottoms shall be flat or of the cone design, as specified on the purchase order In addition, if cone bottoms are used, they shall conform to Figure 5.2

S PECIFICATION FOR F IELD W ELDED T ANKS FOR S TORAGE OF P RODUCTION L IQUIDS 7

Figure 5.1—Tank Dimensions

5.6.1.1.2 The thickness of the first 8 ft of shell plates for 10,000 bbl tanks shall not be less than

1

/4 in (10.20 lb/ft2)

5.6.1.2 The width of the shell plates shall be determined by the manufacturer, but preferably should not

be less than 60 in

S PECIFICATION FOR F IELD W ELDED T ANKS FOR S TORAGE OF P RODUCTION L IQUIDS 9

b) For roofs larger than 15 ft 6 in in diameter, added structural supports in the form of rafters shall be provided

5.7.5 Shell Attachment for Frangible Roofs

When specified by the purchaser, the tank may be provided with a frangible roof In that case, the design pressure shall not exceed the weight of the roof, including rafters, if external The roof shall be attached to the compression ring by a single-fillet weld not to exceed 3/16 in and applied to the top side only Internal rafters, if used, shall not be welded to the roof plates The applicable requirements of API 650 shall apply

for frangible roof design

5.7.6 Roof Support

In addition to the dead load, roof supports shall be designed to support a live load of 20 lb/ft2 Allowable design stresses shall be as follows

Rolled Structural Shapes:

1 + L2/20,000 r2

where

L is the unbraced length in inches;

r is the governing radius of gyration, in inches