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APPLYING THE ASME CODES:PLANT PIPING AND PRESSURE VESSELS

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James A. Wingate is a practicing Mechanical Engineer and technical author. After graduation (BSME, 1964 & MSME, 1965,both from Clemson University) he served 6 years in the U.S. Air Force as a development engineering officer in tactical missileweapons systems. Since then he has performed various M.E. roles in heavy industry and in engineering design/construction firms.More than half of his 4+ decades of practice have been as an independent consultant to those activities, as well as in forensicanalysis and as a legal expert-witness in capital loss litigations involving failures in piping/hydraulic systems and pressure vessels.He is a long-time member of the ASME and has been very active in its Professional Development series of Continuing Educationprogram courses, concentrating in the ASME Piping Codes and the Boiler and Pressure Vessel Codes, B31.1, B31.3, etc. He hasbeen a registered Professional Engineer for more than 30 years. He and his family reside in the Greenville, South Carolina area.Jim’s main leisure-time activity is fine woodworking, building scratch reproductions of antique furniture museum pieces from theColonial period in America.

His first book (Mister MechMentor Volume I), also published by the ASME, serves as an information source and problems-solution guide for novice and recently begun Mechanical Engineers starting work in process industries, utilities plant design, andin engineering/construction firms. Its emphasis is on those topics most often required on the job of junior engineers in thoseenvironments: basic hydraulics, environmental control (HVAC), and pipe flow systems of various types. Utility systems engineeringconcepts involving those topics are explained in a personal down-to-earth manner in Volume I, with an emphasis on “lessonslearned” and the design of safe and conservative utilities systems. This book, (Mister MechMentor Volume II) places emphasis onthe ASME Code applications of piping systems for boilers and pressure vessels and for heavy industrial process and utilitiesengineering. Pipe stress analysis and Code application issues dominate this volume, which deals mostly with stress/strain andmechanics of materials design-and-analysis topics, and, therefore, Volume II is aimed more at the mid- and senior-level engineersand technical managers consistent with those types of advanced responsibility. However, Volume II retains the same friendly andpersonal communication approach used in Volume I. Both volumes are intended to help fill the voids in modern on-the-job personaltraining and technical assistance that have resulted in many firms from corporate staff down-sizing and out-sourcing policies;hence, the “MechMentor” book titles and the fatherly conversational styles in which they are written.


APPLYING THE ASME CODES:PLANT PIPING AND PRESSURE VESSELS

By

James A. Wingate


© 2007 by ASME Press, Three Park Avenue, New York, NY 10016

All rights reserved. Printed in the United States of America. Except as permitted under the United StatesCopyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by anymeans, or stored in a database or retrieval system, without the prior written permission of the publisher.

INFORMATION CONTAINED IN THIS WORK HAS BEEN OBTAINED BY THE AMERICAN SOCI-ETY OF MECHANICAL ENGINEERS FROM SOURCES BELIEVED TO BE RELIABLE. HOWEVER,NEITHER ASME NOR ITS AUTHORS OR EDITORS GUARANTEE THE ACCURACY OR COM-PLETENESS OF ANY INFORMATION PUBLISHED IN THIS WORK. NEITHER ASME NOR ITSAUTHORS AND EDITORS SHALL BE RESPONSIBLE FOR ANY ERRORS, OMISSIONS, OR DAM-AGES ARISING OUT OF THE USE OF THIS INFORMATION. THE WORK IS PUBLISHED WITHTHE UNDERSTANDING THAT ASME AND ITS AUTHORS AND EDITORS ARE SUPPLYINGINFORMATION BUT ARE NOT ATTEMPTING TO RENDER ENGINEERING OR OTHER PROFES-SIONAL SERVICES. IF SUCH ENGINEERING OR PROFESSIONAL SERVICES ARE REQUIRED,THE ASSISTANCE OF AN APPROPRIATE PROFESSIONAL SHOULD BE SOUGHT.

ASME shall not be responsible for statements or opinions advanced in papers or . . . printed in publications(B7.1.3). Statement from the Bylaws.

For authorization to photocopy material for internal or personal use under those circumstances not fallingwithin the fair use provisions of the Copyright Act, contact the Copyright Clearance Center (CCC), 222Rosewood Drive, Danvers, MA 01923, tel: 978-750-8400, www.copyright.com.

Library of Congress Cataloging-in-Publication Data

Wingate, James A.Applying the ASME codes: plant piping and pressure vessels / James A. Wingate.

p. cm.Includes index.

1. Mechanical engineering. 2. Mechanical engineering—Standards. 3. American Society of MechanicalEngineers. I. Title.

TJ145.W47 2007621—dc22

2007010224

ISBN 978-0-7918-0255-7


CONTENTS

temperature ratings, allowable stresses, leakage vs. stressVOLUME TWOloadings, pipe code requirements, ring-type gasket criteria,Applying the ASME Codes: Plant Piping andillustrations, actual flange detail dimensions, examples andPressure Vesselscalculations.

Chapter 6: Thermal Restraint Stress 105Preface viiInternal and external restraint of thermal expansion and con-Foreword ixtraction will induce mechanical stresses and can lead to fa-

Chapter 1: ASME B31.3 Process Piping Stress tigue stress cracking of various object shapes, single- andAnalysis Requirements 1 multidimensional geometry.

Complete listing, definition, and description of the equationsdictated for pipe stress analysis code compliance; pipe wall Chapter 7: The Types and Amounts of Mechanicalthickness, flange pressure/temperature rating, thermal expan- Stresses to Be Expected in Common Utilitysion restraint—anchor displacement strain, cyclic fatigue, Piping Systems 117sustained and occasional longitudinal loads, correlation of

What the everyday mechanical engineer needs to understanddesign loads with failure mode and method of analysis, con-about piping stresses and strains to interface intelligentlydensed correlation table; allowable excursions above opera-with piping professionals; uses basics of elasticity andtional design temperature and pressure.Mohr’s Circle to demonstrate how a common steel piping

Chapter 2: Bellows-Type Pipe Expansion Joints: system responds to the typical loadings it receives in practice.Pressure Thrust and Other Pitfalls 9

Chapter 8: Pressure (Hydro-) Tests 133Physical illustrations of the various types, how they work,how they must be carefully applied and installed, and why Codes, vessel test requirements, safety considerations, andthey fail when this is not done; illustrated example, require- tips.ments for safe use.

Chapter 9: Issues and Codes Concerning Piping and VesselChapter 3: Supports Determine Loads on Piping,Overpressure Protection and Safety 139Connecting Equipment, the Level of Pipe Stress, and

Load Reactions on Supporting Structure 17 Guidance on sizing and selecting pressure relief and safetyrelief devices, application tips, relationships to ASME B&Piping contractors, piping design and plant engineers, struc-PV CODES Section VIII Division 1 and the API 520-21tural engineers, and all designers for piping and support

structure MUST have a good working understanding of this standards, and working data sheets for recording the flowrate/material, for safety’s sake! This topic is covered in great pressure calculations and device sizing criteria.detail, designed for self-study, and you don’t have to be apipe stress analyst to understand and apply these principles. Chapter 10: Jacketed Piping Issues 181

Identification and explanation of some of the unique, nastyChapter 4: Spring Constants of Elastic Shapesproblems that plague these miserable (jacketed) piping ar-in Contact 61rangements. They can be done safely, but you better knowMostly for pipe support design and pipe stress analysis, mod-how! Based on first-hand knowledge of real-life system fail-els of elastic structural shapes in compression, tension, canti-ures with big-bucks damage consequences.levered beam in bending, sphere on flat plate, cylindrical

rod between flat plates, pure torsion.Selected References 199

Chapter 5: Pipe Flange Leakage and Stress 67

A complete primer, with types of flanges, their pressure– Index 201

v


vi • Contents

VOLUME ONE: (PUBLISHED SEPARATELY) VOLUME ONE involves more entry-level and less specializedprofessional information than does VOLUME TWO. VOL-UME ONE is more basic, and is intended primarily for theengineering novitiate, to keep him or her out of trouble on thatVOLUME ONE’s topics cover these main areas of mechanicalfirst important job. Its contents were collected as a predecessorengineering practice:and companion piece to VOLUME TWO.

• HYDRAULICS OF PIPE FLOW• INDUSTRIAL HVAC SPECIALTIES• UTILITY SYSTEMS• CHILLED WATER LOOPS, OVERALL SYSTEM DE-

SIGN, AND CONTROL


PREFACE

Mister MechMentor is a collection of technical chapters, pub- Primarily involving mechanical process and utility pipingdesign and analysis, fluids handling (pumping and flow con-lished in two separately bound volumes, written in a friendly,

first-person style, meant to help people solve certain mechanical trol), real-world hydraulic transients, and useful solutions ofmechanical stress and strain problems often related to theseengineering problems.

Its title reflects its intent, which is to augment the reader’s systems, the book’s selected topics are commonly encounteredon the job by folks who work in these engineering fields:necessary training in the way a caring mentor might. It explains

“why” as well as “how,” with the goal of helping the novitiatelearn certain potentially dangerous lessons in physics and engi- 1. Engineering design/construction firms;neering design application, safely and convincingly, without 2. Contract engineers and designer/technicians;subjecting him or her to the suffering and embarrassment of 3. Architect/engineer/planner/consulting firms;learning the hard way. 4. Mechanical contracting firms: process, facility, utility,

It seems that life’s (and engineering’s) most important heating, ventilation, and air conditioning (HVAC),lessons are learned by making painful mistakes; the author and plumbing;insists that it is far better to learn from the past mistakes of 5. Environmental firms especially involved with mechani-others than to repeat the mistakes himself. Whenever actual cal equipment and piping;examples of such cases are helpful, they are included in a frank 6. Forensic loss consultants;and colorful way most will appreciate. 7. Staff engineers in plant projects, both direct engineering

Although its primary readership is intended to be mainly and management, and in utilities, maintenance, safety,younger people who have yet to gain certain vital engineering and environmental departmental duties, and especiallyexperiences, and who do not have access to a senior “flesh and the chemical/manufacturing process hazardous opera-blood” on-the-job mentor, the more seasoned engineer may tions (HAZOPS) team members.also find it helpful as a quick refresher and source of organizedsolutions to the ubiquitous problems it embraces. Code refer-ences are especially valuable.

vii



FOREWORD

Because this is my book, and because it pretends a claim, operators and maintainers, and especially by myself, then I goback and simplify the design to the point at which it will behowever modest, on mentorhood, then I suppose I am duty-

bound to offer you my own points of view on our chosen 100% understood. If I have to, I will make those changes onmy own time and expense. I will never be rich, and don’t care;profession, engineering, and that is what I will try to do

here. Of course, my opinions are just that—opinions. Every- however, I will sleep well at night.As experienced technicians and professionals, we knowone has them. It remains the prerogative, in fact the profes-

sional duty of each of us to strive toward finding his or her what we know, and what we can do, and we are expectedand paid to do “good engineering” within our range of actualown personal truths.

Any personal guidelines that I share here for your consider- competence. And indeed, we do try our best to be clever andinnovative and thrifty and thorough and sophisticated and braveation are necessarily taken from my personal experience. Fall-

ing personally and quite remarkably short of genius, I have had and true-blue and all those other neat things we want ouremployers and clients to think of us. And being human, manyto master the important lessons of my profession and my life

as most folks do; by learning from my own mistakes, when times we are tempted to stretch just a bit beyond, to take alittle chance, maybe to want to brag a little, or bite off a tadunavoidable, and from the mistakes of others, whenever possi-

ble. I sincerely hope that all your learning experiences will be more than we can comfortably chew. You know the drill. Ournature makes us want to promote ourselves, to continuallyof the latter kind, and that your pilgrimage will be more worthy

than was my own. market our abilities, to advertise our strengths both real andimagined, and by all means to hide our weaknesses and fearsI like to make simplifying assumptions as much as the

next guy does, and my point of view in design will always be at all times, all the while exuding cool self-confidence, andmaybe even a general aura of salty seaworthiness. All of whichconservative, but not ridiculously so. Rather, my degree of

conservatism in any technical matter is always assigned in is perfectly natural. Perfectly human.But we have taken upon ourselves the professional respon-sensible proportion to the particular consequential dangers

which might accrue if I made errors of judgment or calculation. sibility to do a certain kind of work, ostensibly one whichgreatly benefits mankind but which, if not done properly, hasKnowing where to draw the line with yourself is the key.

That knowledge will come with practice and observation and the potential to do great harm instead. And because of that, wemust act professionally, responsibly, at all times in our work.experience. You were not born knowing where the line should

be drawn; none of us were. But you were born with a head Even when to do so would seem contrary to our own personaladvancement. We must not try to practice outside the bound-full of common sense and valuable human intuition, and a heart

full of the inner voice of conscience. Use all of these gifts aries of our own limitations, all by our intellectual selves alone.No. To grow our abilities safely, we need to take our first stepswithout hesitation or apology. Weave them into the framework

of your professional practice and of your life as well, and the on strange new ground with someone else present, someonewho knows the ropes, to check us and guide us and keep usrest will come with time.

I try to be efficient and productive, to create refined systems as well as our potential benefactors-nee-victims safe from ourfledgling efforts. We must swallow our human vanity and askwithout putting too fine a point on things, and will avoid gilding

lilies and reinventing wheels as best I can. I strive for maximum for help when we need it. And trust me, the oldest and best ofus need help much more frequently than you are led to imagine.simplicity and understandability in the things I design, because

it seems to me that these are the source springs of elegance. Those who blissfully ignore their personal limitations andpress on into unknown territory alone, without first achievingThey are without question two of safety’s necessary ingredients.

If I find that I cannot in plain language explain my design a truly satisfactory upgrading in knowledge sufficient to theundertaking, are truly dangerous to themselves and the publicprecisely, completely, and clearly enough for its operational

physical principles, means of control, range of safe operation, whom they are charged with serving.Every true profession recognizes this principle. Prac-design intent, natural physical limitations, expected service life,

and requirements for proper safe operation and maintenance to titioners of education, law, medicine, those who serve us in themilitary, the guardians of public health and safety, and all thebe thoroughly understandable by its intended owners, builders,

ix


x • Foreword

rest; all know this, whether or not it receives much public At present, engineering lacks the grueling internship sojustifiably prized and touted by the medical profession. Asmention.

The key word here is “alone.” Do not hesitate to ask for fledglings we are given typically nowhere near the kind ofscrutiny that lawyers invest in their new hires. And we surelyguidance when you sense it is needed. Do not allow yourself

to be forced into giving snap explanations or making hasty don’t give our people the kind of gutsy, realistic, no-punches-pulled training that the professional military must receive indecisions, thinking that, if you do not you may damage your

reputation. Far from it! It has been my life experience that order to do their job with even a prayer of personal survival!No, the “onus” of self-policing is definitely sitting squarelyreally bad screw-ups do not happen unless the opportunity to

prevent them falls upon every weak link in the project’s entire upon our own shoulders. And that is where it should be anyway,if we are to be truly worthy of professional status. We have tochain of production.

Each organization involved in that chain will have one de make it our own final responsibility to know exactly where ourown personal limits of competence end, and where the vast seafacto decision-maker; sometimes, that person will be you. Don’t

you become a weak link due to fear of speaking out, or shyness of unknowns, our remaining uncertainties, begins. And believeyou me, we all have limits, great bunches and gobs ofabout asking questions which you fear might seem “stupid” to

the others. When it is your turn to act, when the problem has uncertainty.After all, are we not merely human? The more we poorrolled up to your workstation and you see that a problem exists

in the project and that sooner or later there will be trouble if creatures see and experience and learn, the more we realize thetrue depths of our own ignorance and human frailty. Its justsomeone doesn’t do something to fix it, then by all means,

blow the whistle on it! It is your professional responsibility to that the professional keeps on trying to improve the situation,realizing his quest is finally beyond human endeavor and cando so. And, yes, it might cause some “big guy” to look bad

somewhere in the chain, and he might cause you trouble and never truly end, right up until his day of death.And truly, the quest needs to come ahead of personaltry to get you taken off the project, or even fired.

Well friend, that is just an inevitable human experience. aggrandizement. The best professionals, the best engineers, thebest people of all walks of life whom I have been privilegedIt is a test of your mettle. Sooner or later, it is going to happen

to you on the job. When it does, do what you know is right, to know during a lifetime of practice, have been those whofrankly admit their limitations, appearances be damned! Theyand stick to your guns. And if you in fact turn out to be correct

but lose the argument anyway, if the organization knows you most certainly do not refrain from asking questions or beggingassistance when they face something that frightens them, wayare right but fails to support you or spits you out, whatever the

reason, then FINE! It simply proves that they themselves are down inside. They will put the actual welfare of others aheadof their own personal ambition every time.seriously flawed and not worthy of employing professionals.

You shouldn’t be working there anyway. Move on to another Finally, I am compelled to give you my honest appraisalof engineering. It is my long-term opinion that this professionplace where people are willing to act professionally and will

invariably do the right thing on principle! demands more actual brain sweat and more acceptance of tangi-ble responsibility, yet repays one’s effort with proportionatelyWhat is a professional engineer? I say he or she is an

engineer who possesses necessary minimum levels of profes- less money and with more grinding of teeth during the late-night hours, than any other job that I know. The single importantsional judgment consistent with adequate computational ability,

plus an adequate base of scientific and technical knowledge exception is the professional soldier, who must add real mortaldanger to the list of professional living conditions, and getsgained through accredited formal education, plus the ability to

master complicated abstract procedures, plus common sense less in return for his tangible sacrifices than do all other men.I think you have to enjoy this work for its own sake, andpracticality plus emotional maturity plus a well-developed sense

of duty and responsibility, plus the ability and willingness al- have a fair share of intellectual curiosity and the impetus tocontinually seek more insight into the workings of the universe,ways to continue the personal learning and improvement pro-

cess, not only to teach himself or herself through continual for engineering to make sense as a career. And on those terms,I think it does.self-study aimed at professional growth but also to seek out

the wisdom and valuable experience of those who have provento have it.


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