Inspection Practices for Piping System Components

Downstream Segment

API RECOMMENDED PRACTICE 574 THIRD EDITION, NOVEMBER 2009

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Users of this RP should not rely exclusively on the information contained in this document. Sound business, scientific, engineering, and safety judgment should be used in employing the information contained herein.

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Copyright © 2009 American Petroleum Institute

Foreword

This recommended practice (RP) is based on the accumulated knowledge and experience of engineers, inspectors, and other personnel in the petroleum and petrochemical industry. It is intended to supplement API 570, Piping Inspection Code: Inspection, Repair, Alteration, and Rerating of In-service Piping Systems.

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 the interpretation 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 Petroleum Institute, 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Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years.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-time extension of up to two years may be added to this review cycle. Status of the publication can be ascertained from the API 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

Contents

Page

1. Scope 1

2. Normative References 1

3. Terms, Definitions, Acronyms, and Abbreviations 3

   1. Terms and Definitions 3

   2. Acronyms and Abbreviations 7

4. Piping Components 8

   1. Piping 8

   2. Tubing 16

   3. Valves 17

   4. Fittings 21

   5. Flanges 24

   6. Expansion Joints 24

5. Pipe-joining Methods 24

   1. General 24

   2. Threaded Joints 24

   3. Welded Joints 24

   4. Flanged Joints 25

   5. Cast Iron Pipe Joints 25

   6. Tubing Joints 25

   7. Special Joints 25

   8. Nonmetallic Piping Joints 26

6. Reasons for Inspection 29

   1. General 29

   2. Safety 29

   3. Reliability and Efficient Operation 29

   4. Regulatory Requirements 29

7. Inspection Plans 29

   1. General 29

   2. Developing an Inspection Plan 30

   3. Monitoring Process Piping 32

   4. Inspection for Specific Damage Mechanisms 34

   5. Integrity Operating Envelopes 47

8. Frequency and Extent of Inspection 47

   1. General 47

   2. Online Inspection 48

   3. Offline Inspection 48

   4. Inspection Scope 49

9. Safety Precautions and Preparatory Work 49

   1. Safety Precautions 49

   2. Preparatory Work 49

   3. Investigation of Leaks 51

10. Inspection Procedures and Practices 51

    1. External Visual Inspection 51

    2. Thickness Measurements 54

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    3. Internal Visual Inspection 60

    4. Nonmetallic Piping. 64

    5. Pressure Tests 65

    6. Hammer Testing 68

    7. Tell-tale Hole Drilling 68

    8. Inspection of Piping Welds 69

    9. Other Inspection Methods 69

    10. Inspection of Underground Piping 69

    11. Inspection of New Fabrication, Repairs and Alterations 78

11. Determination of Minimum Required Thickness 80

    1. Piping 80

    2. Valves and Flanged Fittings 83

12. Records 84

    1. General 84

    2. Sketches 85

    3. Numbering Systems 86

    4. Thickness Data 86

    5. Review of Records 86

    6. Record Updates 86

    7. Audit of Records 86

Annex A (informative) External Inspection Checklist for Process Piping 88

Figures

1. Cross Section of a Typical Wedge Gate Valve 18

2. Cross Section of a Typical Globe Valve 18

3. Cross Sections of Typical Lubricated and Nonlubricated Plug Valves 19

4. Cross Section of a Typical Ball Valve 19

5. Cross Section of a Typical Diaphragm Valve 20

6. Typical Butterfly Valve 20

7. Cross Sections of Typical Check Valves 21

8. Cross Section of a Typical Slide Valve 22

9. Flanged-end Fittings and Wrought Steel Butt-welded Fittings 23

10. Forged Steel Threaded and Socket-welded Fittings 23

11. Cross Section of a Socket-welded Tee Connection 26

12. Flange Facings Commonly Used in Refinery and Chemical Plant Piping 26

13. Types of Flanges 27

14. Cross Section of a Typical Bell-and-spigot Joint 27

15. Cross Sections of Typical Packed and Sleeve Joints 27

16. Cross Sections of Typical Tubing Joints 28

17. Piping Circuit Example 35

18. Erosion of Piping 36

19. Corrosion of Piping 36

20. Internal Corrosion of Piping 37

21. Severe Atmospheric Corrosion of Piping 37

22. Injection Point Circuit 39

23. S/A Interface Corrosion 42

24. Radiograph of a Catalytic Reformer Line 59

25. Radiograph of Corroded Pipe Whose Internal Surface is Coated with Iron Sulfide Scale 59

26. Sketch and Radiograph of Dead-end Corrosion 60

27. Underground Piping Corrosion Beneath Poorly Applied Tape Wrap 70

28. Pipe-to-soil Internal Potential Survey Use to Identify Active Corrosion Spots in Underground Piping . 71

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29. Example of Pipe-to-Soil Potential Survey Chart 72

30. Wenner Four-pin Soil Resistivity Test 74

31. Soil Bar Used for Soil Resistivity Measurements 75

32. Two Types of Soil Boxes Used for Soil Resistivity Measurements 76

33. Typical Isometric Sketch 85

34. Typical Tabulation of Thickness Data 87

Tables

1. Nominal Pipe Sizes (NPSs), Schedules, Weight Classes, and Dimensions of Steel Pipe 9

2. Nominal Pipe Sizes (NPSs), Schedules, and Dimensions of Stainless Steel Pipe 13

3. Permissible Tolerances in Diameter and Thickness for Ferritic Pipe 15

4. Damage Mechanisms Associated with Nonmetallic Piping 47

5. Comparison of Common Nonmetallic Piping NDE Techniques 66

6. Minimum Thicknesses for Carbon and Low-alloy Steel Pipe 83

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Inspection Practices for Piping System Components

1. Scope

   This recommended practice (RP) supplements API 570 by providing piping inspectors with information that can improve skill and increase basic knowledge and practices. This RP describes inspection practices for piping, tubing, valves (other than control valves), and fittings used in petroleum refineries and chemical plants. Common piping components, valve types, pipe joining methods, inspection planning processes, inspection intervals and techniques, and types of records are described to aid the inspector in fulfilling their role implementing API 570. This publication does not cover inspection of specialty items, including instrumentation and control valves.

   
   

2. Normative References

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 (including any amendments) applies.

API 570, Piping Inspection Code: Inspection, Repair, Alteration, and Rerating of In-service Piping Systems API Recommended Practice 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry API Recommended Practice 577, Welding Inspection and Metallurgy

API Recommended Practice 578, Material Verification Program for New and Existing Alloy Piping Systems

API 579-1/ASME FFS-1 1, Fitness-For-Service

API Recommended Practice 580, Risk-Based Inspection

API Recommended Practice 581, Risk-Based Inspection Technology

API Specification 5L, Specification for Line Pipe

API Standard 594, Check Valves: Flanged, Lug, Wafer and Butt-welding

API Standard 598, Valve Inspection and Testing

API Standard 599, Metal Plug Valves—Flanged, Threaded and Welding Ends

API Standard 600, Steel Gate Valves—Flanged and Butt-welding Ends, Bolted Bonnets

API Standard 602, Steel Gate, Globe and Check Valves for Sizes DN 100 and Smaller for the Petroleum and Natural Gas Industries

API Standard 603, Corrosion-resistant, Bolted Bonnet Gate Valves—Flanged and Butt-welding Ends

API Standard 608, Metal Ball Valves—Flanged, Threaded and Welding Ends

API Standard 609, Butterfly Valves: Double Flanged, Lug- and Wafer-Type

API Recommended Practice 651, Cathodic Protection of Aboveground Petroleum Storage Tanks

API Recommended Practice 751, Safe Operation of Hydrofluoric Acid Alkylation Units

API Recommended Practice 932-B, Design, Materials, Fabrication, Operation, and Inspection Guidelines for Corrosion Control in Hydroprocessing Reactor Effluent Air Cooler (REAC) Systems

API Recommended Practice 936, Refractory Installation Quality Control Guidelines—Inspection and Testing Monolithic Refractory Linings and Materials

API Recommended Practice 941, Steels for Hydrogen Service at Elevated Temperatures and Pressures in Petroleum Refineries and Petrochemical Plants

1. ASME International, 3 Park Avenue, New York, New York 10016, www.asme.org.

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2. API RECOMMENDED PRACTICE 574

API Recommended Practice 945, Avoiding Environmental Cracking in Amine Units

API Publication 2217A, Guidelines for Work in Inert Confined Spaces in the Petroleum and Petrochemical Industry

ASME B1.20.1 2, Pipe Threads, General Purpose (Inch)

ASME B16.20, Metallic Gaskets for Pipe Flanges—Ring-Joint, Spiral-Wound, and Jacketed

ASME B16.25, Buttwelding Ends

ASME B16.34, Valves—Flanged, Threaded, and Welding End

ASME B16.47, Large Diameter Steel Flanges

ASME B16.5, Pipe Flanges and Flanged Fittings NPS 1/2 Through NPS 24 Metric/Inch Standard

ASME B31.3, Process Piping

ASME B31G, Manual for Determining the Remaining Strength of Corroded Pipelines

ASME B36.10M, Welded and Seamless Wrought Steel Pipe

ASME B36.19M, Stainless Steel Pipe

ASME Boiler and Pressure Vessel Code (BPVC), Section V: Nondestructive Examination

ASME Boiler and Pressure Vessel Code (BPVC), Section V: Nondestructive Examination; Article 11: Acoustic Emission Examination of Fiber Reinforced Plastic Vessels

ASME RTP-1, Reinforced Thermoset Plastic Corrosion Resistant Equipment

ASTM A53 3, Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless

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

ASTM A530, Standard Specification for General Requirements for Specialized Carbon and Alloy Steel Pipe

ASTM B88, Standard Specification for Seamless Copper Water Tube

ASTM D2583, Standard Test Method for Indentation Hardness of Rigid Plastics By Means of a Barcol Impressor ASTM E1118, Standard Practice for Acoustic Emission Examination of Reinforced Thermosetting Resin Pipe (RTRP) ASTM G57, Standard Test Method for Field Measurement of Soil Resistivity Using the Wenner Four-Electrode Method MTI Project 129-99 4, Self-help Guide for In-service Inspection of FRP Equipment and Piping

MTI Project 160-04, Guide for Design, Manufacture, Installation & Operation of FRP Flanges and Gaskets NACE RP 0169 5, Control of External Corrosion on Underground or Submerged Metallic Piping Systems NACE RP 0274, Standard Recommended Practice High-Voltage Electrical Inspection of Pipeline Coatings NACE Publication 34101, Refinery Injection and Process Mixing Points

OLF 6, Recommended Guidelines for NDT of GRP Pipe Systems and Tanks

Title 29 Code of Federal Regulatiosn (CFR) Part 1910.119 7, Process Safety Management of Highly Hazardous Chemicals

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

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

3. Materials Technology Institute, 1215 Fern Ridge Parkway, Suite 206, St. Louis, Missouri 63141-4405, www.mti-link.org.

4. NACE International (formerly the National Association of Corrosion Engineers), 1440 South Creek Drive, Houston, Texas 77218-8340, www.nace.org.

5. Norwegian Oil Industry Association, P.O. Box 8065, 4068 Stavanger, Norway, www.olf.no.

6. The Code of Federal Regulations is available from the U.S. Government Printing Office, Washington, DC 20402.