ASME B31.1-2010

(Revision of ASME B31.1-2007)

Power Piping

ASME Code for Pressure Piping, B31

A N A M E R I C A N N A T I O N A L S T A N D A R D

Copyright 2010 by the American Society of Mechanical Engineers.

No reproduction may be made of this material without written consent of ASME.

c

INTENTIONALLY LEFT BLANK

ASME B31.1-2010

(Revision of ASME B31.1-2007)

ASME B31.1-2010

(Revision of ASME B31.1-2007)

Power Piping

ASME Code for Pressure Piping, B31

AN AMERICAN NA TIONAL S T AND ARD

Three Park Avenue • New York, NY • 10016 USA

Date of Issuance: December 31, 2010

The next edition of this Code is scheduled for publication in 2012. This Code will become effective 6 months after the Date of Issuance. There will be no addenda issued to this edition.

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Copyright © 2010 by

THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS

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CONTENTS

Foreword vi

Committee Roster vii

Introduction xi

Summary of Changes xiii

iii

1. Postweld Heat Treatment 91

2. Stamping 99

1. Assembly 99

   Chapter VI Inspection, Examination, and Testing 101

2. Inspection and Examination 101

3. Pressure Tests 105

   Chapter VII Operation and Maintenance 108

4. General 108

5. Operation and Maintenance Procedures 108

6. Condition Assessment of CPS 108

7. CPS Records 109

Figures

100.1.2(A.1) Code Jurisdictional Limits for Piping — An Example of Forced Flow

Steam Generators With No Fixed Steam and Water Line 2

100.1.2(A.2) Code Jurisdictional Limits for Piping — An Example of Steam Separator Type Forced Flow Steam Generators With No Fixed Steam and Water

Line 3

100.1.2(B) Code Jurisdictional Limits for Piping — Drum-Type Boilers 4

100.1.2(C) Code Jurisdictional Limits for Piping — Spray-Type Desuperheater 5

102.4.5 Nomenclature for Pipe Bends 17

104.3.1(D) Reinforcement of Branch Connections 24

104.3.1(G) Reinforced Extruded Outlets 28

104.5.3 Types of Permanent Blanks 31

104.8.4 Cross Section Resultant Moment Loading 33

122.1.7(C) Typical Globe Valves 55

122.4 Desuperheater Schematic Arrangement 59

127.3 Butt Welding of Piping Components With Internal Misalignment 78

127.4.2 Welding End Transition — Maximum Envelope 79

127.4.4(A) Fillet Weld Size 82

127.4.4(B) Welding Details for Slip-On and Socket-Welding Flanges; Some

Acceptable Types of Flange Attachment Welds 83

127.4.4(C) Minimum Welding Dimensions Required for Socket Welding

Components Other Than Flanges 83

127.4.8(A) Typical Welded Branch Connection Without Additional

Reinforcement 83

127.4.8(B) Typical Welded Branch Connection With Additional Reinforcement 83

127.4.8(C) Typical Welded Angular Branch Connection Without Additional Reinforcement 83

127.4.8(D) Some Acceptable Types of Welded Branch Attachment Details

Showing Minimum Acceptable Welds 84

127.4.8(E) Some Acceptable Details for Integrally Reinforced Outlet Fittings 85

127.4.8(F) Typical Full Penetration Weld Branch Connections for NPS 3 and

Smaller Half Couplings or Adapters 86

127.4.8(G) Typical Partial Penetration Weld Branch Connection for NPS 2 and

Smaller Fittings 87

135.5.3 Typical Threaded Joints Using Straight Threads 100

Tables

102.4.3 Longitudinal Weld Joint Efficiency Factors 16

1. Bend Thinning Allowance 17

   102.4.6(B.1.1) Maximum Severity Level for Casting Thickness 41⁄2 in. (114 mm) or

   Less 18

   102.4.6(B.2.2) Maximum Severity Level for Casting Thickness Greater Than 41⁄2 in.

   (114 mm) 18

   iv

   
   

   102.4.7	Weld Strength Reduction Factors to Be Applied When Calculating the Minimum Wall Thickness or Allowable Design Pressure of Components Fabricated With a Longitudinal Seam Fusion Weld ......	20
   104.1.2(A)	Values of y ............................................................	22
   112	Piping Flange Bolting, Facing, and Gasket Requirements ...............	38
   114.2.1	Threaded Joints Limitations ............................................	42
   121.5 121.7.2(A) 122.2	Suggested Pipe Support Spacing ....................................... Carrying Capacity of Threaded ASTM A 36, A 575, and A 576 Hot-Rolled Carbon Steel ............................................. Design Pressure for Blowoff/Blowdown Piping Downstream of BEP Valves ..............................................................	48 49 55
   122.8.2(B)	Minimum Wall Thickness Requirements for Toxic Fluid Piping .........	62
   126.1	Specifications and Standards ...........................................	70
   127.4.2	Reinforcement of Girth and Longitudinal Butt Welds ...................	81
   129.3.1	Approximate Lower Critical Temperatures .............................	89
   132	Postweld Heat Treatment ..............................................	92
   132.1 136.4	Alternate Postweld Heat Treatment Requirements for Carbon and Low Alloy Steels .................................................... Mandatory Minimum Nondestructive Examinations for Pressure Welds or Welds to Pressure-Retaining Components ...................	97 103
   136.4.1	Weld Imperfections Indicated by Various Types of Examination .........	104
   Mandatory Appendices
   A	Table A-1, Carbon Steel ................................................	112
   	Table A-2, Low and Intermediate Alloy Steel ...........................	124
   	Table A-3, Stainless Steels .............................................	134
   	Table A-4, Nickel and High Nickel Alloys ..............................	164
   	Table A-5, Cast Iron ...................................................	176
   	Table A-6, Copper and Copper Alloys ..................................	178
   	Table A-7, Aluminum and Aluminum Alloys ...........................	182
   	Table A-8, Temperatures 1,200°F and Above ............................	190
   	Table A-9, Titanium and Titanium Alloys ..............................	196
   	Table A-10, Bolts, Nuts, and Studs .....................................	200
   B	Table B-1, Thermal Expansion Data ....................................	206
   	Table B-1 (SI), Thermal Expansion Data ................................	210
   C	Table C-1, Moduli of Elasticity for Ferrous Material .....................	214
   	Table C-1 (SI), Moduli of Elasticity for Ferrous Material ................	215
   	Table C-2, Moduli of Elasticity for Nonferrous Material .................	216
   	Table C-2 (SI), Moduli of Elasticity for Nonferrous Material .............	218
   D	Table D-1, Flexibility and Stress Intensification Factors ..................	220
   	Chart D-1, Flexibility Factor, k, and Stress Intensification Factor, i .......	224
   	Chart D-2, Correction Factor, c .........................................	225
   	Fig. D-1, Branch Connection Dimensions ...............................	226
   F	Referenced Standards ..................................................	227
   G	Nomenclature .........................................................	231
   H	Preparation of Technical Inquiries ......................................	237
   J	Quality Control Requirements for Boiler External Piping (BEP) .........	238

   Nonmandatory Appendices

   1. Rules for the Design of Safety Valve Installations 240

   2. Rules for Nonmetallic Piping and Piping Lined With Nonmetals 260

   3. Corrosion Control for ASME B31.1 Power Piping Systems 280

   4. Recommended Practice for Operation, Maintenance, and

      Modification of Power Piping Systems 284

   5. Approval of New Materials 294

   6. Procedures for the Design of Restrained Underground Piping 295

Index 306

v

FOREWORD

The general philosophy underlying this Power Piping Code is to parallel those provisions of Section I, Power Boilers, of the ASME Boiler and Pressure Vessel Code, as they can be applied to power piping systems. The Allowable Stress Values for power piping are generally consistent with those assigned for power boilers. This Code is more conservative than some other piping codes, reflecting the need for long service life and maximum reliability in power plant installations. The Power Piping Code as currently written does not differentiate among the design, fabrication, and erection requirements for critical and noncritical piping systems, except for certain stress calculations and mandatory nondestructive tests of welds for heavy wall, high temperature applications. The problem involved is to try to reach agreement on how to evaluate criticality, and to avoid the inference that noncritical systems do not require competence in design, fabrication, and erection. Someday such levels of quality may be definable, so that the need for the many

different piping codes will be overcome.

There are many instances where the Code serves to warn a designer, fabricator, or erector against possible pitfalls; but the Code is not a handbook, and cannot substitute for education, experience, and sound engineering judgment.

Nonmandatory Appendices are included in the Code. Each contains information on a specific subject, and is maintained current with the Code. Although written in mandatory language, these Appendices are offered for application at the user’s discretion.

The Code never intentionally puts a ceiling limit on conservatism. A designer is free to specify mor