Standard Toughness Requirements for Piping

ASME Code for Pressure Piping, B31

AN INTERNA TIONAL PIPING C ODE®

ASME B31T-2015

(Revision of ASME B31T-2010)

ASME B31T-2015

(Revision of ASME B31T-2010)

Standard Toughness Requirements for Piping

ASME Code for Pressure Piping, B31

AN INTERNA TIONAL PIPING C ODE ®

Two Park Avenue • New York, NY • 10016 USA

Date of Issuance: August 12, 2016

This Code will be revised when the Society approves the issuance of a new edition.

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The American Society of Mechanical Engineers Two Park Avenue, New York, NY 10016-5990

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CONTENTS

Foreword iv

Committee Roster v

Correspondence With the B31 Committee vi

Summary of Changes vii

Nonmandatory Appendices

1. Flowchart of Requirements 41

2. Guidelines for Establishing T-Number Group 43

   
   

   FOREWORD

   
   

   In 2000, the B31 Code for Pressure Piping, Materials Technical Committee (MTC), determined that there was a need to develop a standard set of toughness requirements for piping components that can be adopted by reference by the various piping codes and other codes and standards. At the time, the requirements of the B31 Code books varied, with some having no requirements at all. This Code is intended to provide requirements for evaluating the suitability of materials used in piping systems for piping that may be subject to brittle failure due to low-temperature service

   conditions.

   Under direction of ASME Standards and Certification, both SI and U.S. Customary units are provided. The 2010 edition of this Code was approved by the American National Standards Institute (ANSI) on April 20, 2010.

   This edition of the Code was approved by ANSI on October 21, 2015.

   
   

   ASME B31 COMMITTEE

   Code for Pressure Piping

   (The following is the roster of the Committee at the time of the approval of this Code.)

   
   

   STANDARDS COMMITTEE OFFICERS

   J. E. Meyer, Chair

   J. W. Frey, Vice Chair

   1. P. Maslowski, Secretary

R. J. T. Appleby, ExxonMobil Pipeline Co.

C. Becht IV, Becht Engineering Co., Inc.

K. C. Bodenhamer, TRC Pipeline Services

STANDARDS COMMITTEE PERSONNEL

W. J. Mauro, American Electric Power

J. E. Meyer, Louis Perry Group

T. Monday, Team Industries, Inc.

R. Bojarczuk, ExxonMobil Research and Engineering Co.

C. J. Campbell, Consultant

J. S. Chin, TransCanada Pipeline US

D. D. Christian, Victaulic

R. P. Deubler, Fronek Power Systems, LLC

1. Eskridge, Jr., Jacobs Engineering

2. J. Fetzner, BP Exploration Alaska, Inc.

P. D. Flenner, Flenner Engineering Services

J. W. Frey, Stress Engineering Services, Inc.

D. R. Frikken, Becht Engineering Co., Inc.

R. A. Grichuk, Fluor Enterprises, Inc.

R. W. Haupt, Pressure Piping Engineering Associates, Inc.

G. A. Jolly, Flowserve/Gestra, USA

A. P. Maslowski, The American Society of Mechanical Engineers

M. L. Nayyar, NICE

G. R. Petru, Acapella Engineering Services, LLC

E. H. Rinaca, Retired

M. J. Rosenfeld, Kiefner/Applus—RTD

J. T. Schmitz, Southwest Gas Corp.

S. K. Sinha, Lucius Pitkin, Inc.

W. J. Sperko, Sperko Engineering Services, Inc.

J. Swezy, Jr., Boiler Code Tech, LLC

F. W. Tatar, FM Global

K. A. Vilminot, Black & Veatch

G. Antaki, Ex-Officio Member, Becht Engineering Co., Inc.

L. E. Hayden, Jr., Ex-Officio Member, Consultant

A. Livingston, Ex-Officio Member, Kinder Morgan

J. S. Willis, Ex-Officio Member, Page Southerland Page, Inc.

R. A. Grichuk, Chair, Fluor Enterprises, Inc.

B31 MATERIALS TECHNICAL COMMITTEE

C. J. Melo, Technip USA, Inc.

C. E. O’Brien, Secretary, The American Society of Mechanical Engineers

W. P. Collins, WPC Solutions, LLC

R. P. Deubler, Fronek Power Systems, LLC

C. Eskridge, Jr., Jacobs Engineering

A. A. Hassan, Power Generation Engineering and Services Co.

G. A. Jolly, Flowserve/Gestra, USA

M. L. Nayyar, NICE

M. B. Pickell, Retired

D. W. Rahoi, Consultant

R. A. Schmidt, Canadoil

H. R. Simpson, PM&C Engineering

J. L. Smith, Consultant

1. Djilali, Contributing Member, Sonatrach

   
   

   CORRESPONDENCE WITH THE B31 COMMITTEE

   
   

   General. ASME Codes are developed and maintained with the intent to represent the consensus of concerned interests. As such, users of this Code may interact with the Committee by requesting interpretations, proposing revisions, and attending Committee meetings. Correspondence should be addressed to:

   Secretary, B31 Standards Committee

   The American Society of Mechanical Engineers Two Park Avenue

   New York, NY 10016-5990

   Proposing Revisions. Revisions are made periodically to the Code to incorporate changes that appear necessary or desirable, as demonstrated by the experience gained from the application of the Code. Approved revisions will be published periodically.

   The Committee welcomes proposals for revisions to this Code. Such proposals should be as specific as possible, citing the paragraph number(s), the proposed wording, and a detailed descrip- tion of the reasons for the proposal, including any pertinent documentation.

   Interpretations. Upon request, the B31 Materials Technical Committee will render an interpreta- tion of any requirement of the Code. Interpretations can only be rendered in response to a written request sent to the Secretary of the B31 Standards Committee.

   The request for interpretation should be clear and unambiguous. It is further recommended that the inquirer submit his/her request in the following format:

   Subject: Cite the applicable paragraph number(s) and the topic of the inquiry.

   Edition: Cite the applicable edition of the Code for which the interpretation is being requested.

   Question: Phrase the question as a request for an interpretation of a specific requirement suitable for general understanding and use, not as a request for an approval of a proprietary design or situation. The inquirer may also include any plans or drawings that are necessary to explain the question; however, they should not contain proprietary names or information.

   Requests that are not in this format may be rewritten in the appropriate format by the Committee prior to being answered, which may inadvertently change the intent of the original request.

   ASME procedures provide for reconsideration of any interpretation when or if additional information that might affect an interpretation is available. Further, persons aggrieved by an interpretation may appeal to the cognizant ASME Committee or Subcommittee. ASME does not “approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity. Attending Committee Meetings. The B31 Standards Committee regularly holds meetings that are open to the public. Persons wishing to attend any meeting should contact the Secretary of

   the B31 Standards Committee.

   
   

   ASME B31T-2015 SUMMARY OF CHANGES

   
   

   Following approval by the B31 Committ ee and ASME, and af t e r p ub li c rev ie w, ASME B31T-2015 was approved by the American National Standards Institute on October 21, 2015.

   ASME B31T-2015 contains editorial changes, revisions, and corrections identified by a margin note, (15), placed next to the affected areas.

   
   

   Page 1	Location 1	Change (1) Footnote added
   		(2) References to “this Standard” changed

   to “this Code”

   1. 3.3 Reference to “this Standard” changed to “this Code”

      1. Reference to “this Standard” changed to “this Code”

      2. First paragraph revised

      3. Title revised

      3.6.1 First paragraph revised

   2. 3.6.2 Last two paragraphs moved to end of 3.6.1

      3.7.1 Second paragraph revised

      3.7.2.2 Reference to “this Standard” changed to “this Code” in second paragraph

   3. 3.7.2.3 References to “this Standard” changed to “this Code” in first paragraph and paras. (a) and (c)

7 4.4.2 Revised

10, 15 Table 3.1-1 (1) Columns 4, 6, 8, and 10–14 revised for CS B  11.9 mm

1. Columns 4, 6, 8, and 10–14 revised for CS B  14.5 mm

2. Columns 4, 6, 8, and 10–15 revised for CS B  17.3 mm

3. Columns 4, 6, 8, and 10–14 revised for CS B  0.47 in.

4. Columns 4, 6, 8, and 10–14 revised for CS B  0.57 in.

5. Columns 4, 6, 8, and 10–15 revised for CS B  0.68 in.

22, 23–25 Table 3.2-1 (1) First two A351 entries updated, last three added

1. New Note (8) added, and remaining Notes renumbered accordingly

2. Second A671 entry revised, fourth and fifth added

3. First A672 entry revised, fourth and fifth added

rows 4–8 and 10–19

36–38 Mandatory Appendix III (1) Twelfth and 14th CS B entries revised,

13th and 15th added

1. Third and fifth CS D entries added

2. Seventh SS −425 entry added

3. Sixteenth and 17th SS −325 entries added

4. Third SS −60 entry added

5. Twenty-second SS −20 entry deleted, 23rd revised

“this Code”

ASME B31T-2015

STANDARD TOUGHNESS REQUIREMENTS FOR PIPING

(15) 1 INTRODUCTION

This Code provides requirements for evaluating the suitability of materials used in piping systems for piping that may be subject to brittle failure due to low- temperature service conditions. While low-temperature service is usually considered to be below ambient tem- perature, brittle failure can occur at temperatures above ambient temperature for certain combinations of materi- als, thicknesses, and stress levels. The definition of “low- temperature service” as used in this Code, therefore, varies widely across the many applications for which piping systems are used. For a building service air line, low temperature may be 0°C (32°F), whereas for a cryo- genic piping system, it could easily be −185°C (−300°F).1 However, the principles used to evaluate the suitability of a piping system as related to service temperature by evaluating the toughness of the material can be applied across a wide temperature range, and this Code has been established to provide uniform guidance in this area. This Code may be invoked in whole or in part by various piping codes and/or specifications and is only mandatory when so invoked.

Suitability of piping systems for low-temperature ser- vice is a function of several variables, including material properties, design loadings, and fabrication procedures. The three primary factors that generally control the sus- ceptibility for brittle fracture are material toughness, crack size, and tensile stress level. There are a wide variety of services where low-temperature suitability need not even be considered; however, a screening crite- rion is necessary to determine this.

One objective of this Code is to provide a simple approach to evaluate whether additional consideration is necessary to evaluate suitability for low-temperature service. This is done by establishing a low-temperature service limit for various materials. Services at or warmer than this limit are not considered low temperature, and additional considerations relative to suitability are not required.

For services colder than this limit, various require- ments are provided that, when met, qualify the material for low-temperature services. These requirements include impact testing, qualification of welding and other fabrication procedures, and limiting the design loadings.

1 For guidance on cryogenic valves, refer to MSS SP-134, Valves for Cryogenic Service Including Requirements for Body/Bonnet Extensions.

The low-temperature service limit established herein is based on a reasonable degree of assurance that at this temperature the material will have a ductile failure mode. The actual ductile-to-brittle transition tempera- ture for a given material specification will vary based on actual heat chemistry of the material and subsequent processing. For critical applications, the design engineer can select materials with a lower low-temperature ser- vice limit, or require impact testing. On less-critical applications, material with a higher low-temperature service limit may be acceptable. The final selection is left to the referring code and the design engineer (when permitted by the referring code).

To keep the number of sets of requirements to a mini- mum, material groupings have been established, and a unique set of requirements have been provided for each group. These groups are assigned “T-numbers” for easy reference. Although most materials used in piping sys- tems are listed, some are not, and these unlisted materi- als are not addressed in this Code. Where permitted by code or specification invoking this Code, these require- ments may be used for unlisted materials. The invoking code or specification may establish the correct T-number group for the material or may invoke the testing and other requirements of this Code using the worst-case assumption that the design minimum temperature is colder than the temperatures that would allow exemp- tion from any of the requirements of this Code. The guidelines for establishing the correct T-number group are provided in Nonmandatory Appendix B.

2 GLOSSARY

CVN: abbreviation for Charpy V-notch.

design minimum temperature: the lowest component tem- perature expected in service.

fully deoxidized steel: steel that has been deoxidized either by the addition of strong deoxidizing agents or by vac- uum treatment, to reduce the oxygen content to such a level that no reaction occurs between the carbon and oxygen during solidification. Also known as killed steel. Steels that are not fully deoxidized include rimmed, semi-killed, and capped steels. Limitations on the use of steels that are not fully deoxidized may be imposed by the applicable piping code or specification.

lower critical temperature: the temperature at which the first phase change occurs when heating a metal.

1