Design of

Below-the-Hook Lifting Devices

AN A MERICAN NA TIONAL S T AND ARD

ASME BTH-1–2017

(Revision of ASME BTH-1–2014)

ASME BTH-1–2017

(Revision of ASME BTH-1–2014)

Design of Below-the-Hook Lifting Devices

AN AMERICAN NA TIONAL S T AND ARD

Two Park Avenue • New York, NY • 10016 USA

Date of Issuance: February 10, 2017

The next edition of this Standard is scheduled for publication in 2020. This Standard will become effective 1 year after the Date of Issuance.

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

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CONTENTS

Foreword v

Committee Roster vi

Correspondence With the BTH Committee vii

Summary of Changes ix

Nonmandatory Appendices

1. Commentary for Chapter 1: Scope, Definitions, and References 49

2. Commentary for Chapter 2: Lifter Classifications 53

3. Commentary for Chapter 3: Structural Design 55

4. Commentary for Chapter 4: Mechanical Design 64

5. Commentary for Chapter 5: Electrical Components 67

6. Commentary for Chapter 6: Lifting Magnet Design 69

FOREWORD

There have been many formal requests for interpretation of the limited structural design criteria stated within ASME B30.20, Below-the-Hook Lifting Devices, a safety standard. As a consequence, industry has for quite some time expressed a need for a comprehensive design standard for below-the-hook lifting devices that would complement the safety requirements of ASME B30.20. All editions of ASME B30.20 have included structural design criteria oriented toward the industrial manufacturing community requiring a minimum design factor of 3, based on the yield strength of the material; recent editions have also included design criteria for the fatigue failure mode. However, members of the construction community expressed the need for design criteria more suitable to their operating conditions, including a lower design factor, and the necessity to address other failure modes such as fracture, shear, and buckling, and design topics such as impact and fasteners.

A Design Task Group was created in 1997 to begin work on a design standard as a companion document to ASME B30.20. The ASME BTH Standards Committee on the Design of Below-the- Hook Lifting Devices was formed out of the Design Task Group and held its organizational meeting on December 5, 1999.

ASME BTH-1–2005, Design of Below-the-Hook Lifting Devices, contained five chapters: Scope and Definitions, Lifter Classifications, Structural Design, Mechanical Design, and Electrical Components. This Standard, intended for general industry and construction, set forth two design categories for lifters based on the magnitude and variation of loading, and operating and environ- mental conditions. The two design categories provided different design factors for determining allowable static stress limits. Five Service Classes based on load cycles were provided. The Service Class establishes allowable stress range values for lifter structural members and design parameters for mechanical components. ASME BTH-1–2005 was approved by the American National Stan- dards Institute (ANSI) on October 18, 2005.

ASME BTH-1–2008 incorporated editorial revisions and two new mechanical design sections for grip ratio and vacuum lifting device design. ASME BTH-1–2008 was approved by ANSI on September 17, 2008.

ASME BTH-1–2011 incorporated revisions throughout the Standard and the addition of a new mechanical design section for fluid power systems. ASME BTH-1–2011 was approved by ANSI on September 23, 2011.

ASME BTH-1–2014 incorporated into Chapter 4 a section on lifting magnets. Other technical revisions included new requirements for fluid pressure control and electrical system guarding. Along with these technical changes, the nonmandatory Commentary for each chapter was moved to its own respective Nonmandatory Appendix. ASME BTH-1–2014 was approved by ANSI on June 24, 2014.

This revision of ASME BTH-1 includes the addition of Chapter 6: Lifting Magnet Design, an accompanying Nonmandatory Appendix with commentary for the new chapter, and other revi- sions. Following the approval by the ASME BTH Standards Committee, ANSI approved this edition as an American National Standard, with the new designation ASME BTH-1–2017, on January 6, 2017.

ASME BTH STANDARDS COMMITTEE

Design of Below-the-Hook Lifting Devices

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

STANDARDS COMMITTEE OFFICERS

D. R. Verenski, Chair

D. Duerr, Vice Chair

G. Bolan, Secretary

STANDARDS COMMITTEE PERSONNEL

B. B. Bacon, Tennessee Valley Authority

G. Bolan, The American Society of Mechanical Engineers

G. A. Bond, Wood’s Powr-Grip Co., Inc.

P. W. Boyd, The Boeing Co.

D. Duerr, 2DM Associates, Inc.

J. D. Edmundson, Konecranes/P&H

A. Faris, Braun Intertec

M. T. Gaunce, SCHUNK

K. M. Jankowski, Walker Magnetics

T. C. Mackey, Washington River Protection Solutions

D. L. McCabe, Babcock and Wilcox Co.

B. A. Pickett, Systems Engineering and Forensic Services

D. T. Rebbin, Bradley Lifting Corp.

J. E. Rea, Alternate, Bradley Lifting Corp.

J. W. Rowland III, Consultant

R. S. Stemp, Lampson International, LLC

M. P. Zerba, Alternate, Lampson International, LLC

P. D. Sweeney, Riverside Engineering, LLC

D. R. Verenski, Hunter Lift Ltd.

T. J. Brookbank, Alternate, Hunter Lift Ltd.

T. D. Waterworth, ENERPAC

S. Barton, Contributing Member, Consultant

HONORARY MEMBERS

R. A. Dahlin, Walker Magnetics

1. W. Downs, Jr., Downs Crane and Hoist Co.

   
   

   CORRESPONDENCE WITH THE BTH COMMITTEE

   
   

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

   Secretary, BTH Standards Committee

   The American Society of Mechanical Engineers Two Park Avenue

   New York, NY 10016-5990

   https://go.asme.org/Inquiry

   
   

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

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

   Interpretations. Upon request, the BTH Standards Committee will render an interpretation of any requirement of the Standard. Interpretations can only be rendered in response to a written request sent to the Secretary of the BTH Standards Committee.

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   If the Inquirer is unable to use the online form, he/she may mail the request to the Secretary of the BTH Standards Committee at the above address. The request for an 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 in one or two words.

   Edition: Cite the applicable edition of the Standard for which the interpreta- tion 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. Please provide a condensed and precise question, composed in such a way that a “yes” or “no” reply is acceptable.

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   Background Information: Provide the Committee with any background information that will assist the Committee in understanding the inquiry. 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 the format described above may be rewritten in the appropriate format by the Committee prior to being answered, which may inadvertently change the intent of the original request.

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   and/or telephone conference should contact the Secretary of the BTH Standards Committee.

   
   

   ASME BTH-1–2017 SUMMARY OF CHANGES

   
   

   Following approval by the ASME BTH Standards Committee and ASME, and after public review, ASME BTH-1–2017 was approved by the American National Standards Institute on January 6, 2017.

   ASME BTH-1–2017 includes editorial changes, revisions, and corrections identified by a margin note, (17).

   
   

   Page 2–5	Location 1-5.1	Change (1) Definitions of applied load(s), dead load,
   		load cycle, maximum stress, minimum

   stress, and rated load added

   1. Definitions of cycle, load; load(s), applied; load, dead; load, rated; rigging hardware; sling; stress, maximum; and stress, minimum deleted

   2. Definitions of shall and should and location where design factor is first used revised

1-5.3 (1) Definitions of equalizing sheave and

running sheave added

1. Definitions of sheave, equalizing and

   sheave, running deleted

2. Location where back-driving, L10 bearing life, and vacuum pad are first used revised

1-5.4 (1) Definitions of electrical power supply, electric motor, externally powered electromagnet, and master switch added

1. Definitions of electromagnet, externally powered; motor, electric; power supply, electrical; and switch, master deleted

2. Location where brake, control system, rectifier, and sensor(s) are first used revised

1-5.5 Added

Fig. 1-5.5-1 Added

6–10 1-6.1 (1) Units for a, Dp, and and nomenclature for hc, hp, My , Sxc, and Sxt added

1. Nomenclature for Fr, Fyf, and Fyw

   deleted

2. Nomenclature for ni revised

1-6.2 (1) Units for A and added

(2) Nomenclature for Su and Sy revised

1-6.3 Added

1-7 References updated