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ASME BTH-1-2017 pdf download

ASME BTH-1-2017 pdf download.Design of Below-the-Hook Lifting Devices.
1-1 PURPOSE This Standard sets forth design criteria for ASME B30.20, Below-the-Hook Lifting Devices. This Standard serves as a guide to designers, manufacturers, purchasers, and users of below-the-hook lifting devices. 1-2 SCOPE This Standard provides minimum structural and mechanical design and electrical component selection criteria for ASME B30.20, Below-the-Hook Lifting Devices. The provisions in this Standard apply to the design or modification of below-the-hook lifting devices. Com- pliance with requirements and criteria that may be unique to specialized industries and environments is outside the scope of this Standard. Lifting devices designed to this Standard shall comply with ASME B30.20, Below-the-Hook Lifting Devices. ASME B30.20 includes provisions that apply to the marking, construction, installation, inspection, testing, maintenance, and operation of below-the-hook lifting devices. The provisions defined in this Standard address the most common and broadly applicable aspects of the design of below-the-hook lifting devices. A qualified person shall determine the appropriate methods to be used to address design issues that are not explicitly covered in the Standard so as to provide design factors and/or performance consistent with the intent of this Standard. 1-3 NEW AND EXISTING DEVICES The effective date of this Standard shall be one year after its date of issuance. Lifting devices manufactured after the effective date shall conform to the requirements of this Standard. When a lifter is being modified, its design shall be reviewed relative to this Standard, and the need to meet this Standard shall be evaluated by the manufacturer or a qualified person. 1 1-4 GENERAL REQUIREMENTS 1-4.1 Design Responsibility Lifting devices shall be designed by, or under the direct supervision of, a qualified person. 1-4.2 Units of Measure A dual unit format is used. Values are given in U.S. Customary units as the primary units followed by the International System of Units (SI) in parentheses as the secondary units. The values stated in U.S. Customary units are to be regarded as the standard. The SI units in the text have been directly (softly) converted from U.S. Customary units. 1-4.3 Design Criteria All below-the-hook lifting devices shall be designed for specified rated loads, load geometry, Design Category (see section 2-2), and Service Class (see section 2-3). Resolution of loads into forces and stress values affecting structural members, mechanical compo- nents, and connections shall be performed by an accepted analysis method. 1-4.4 Analysis Methods The allowable stresses and stress ranges defined in this Standard are based on the assumption of analysis by classical strength of material methods (models), although other analysis methods may be used. The anal- ysis techniques and models used by the qualified person shall accurately represent the loads, material properties, and device geometry; stress values resulting from the analysis shall be of suitable form to permit correlation with the allowable stresses defined in this Standard. 1-4.5 Material The design provisions of this Standard are based on the use of carbon, high-strength low-alloy, or heat- treated constructional alloy steel for structural members and many mechanical components. Other materials may be used, provided the margins of safety and fatigue life are equal to or greater than those required by this Standard.
All ferrous and nonferrous metal used in the fabrica- tion oflifting device structural members and mechanical components shall be identified by an industry-wide or written proprietary specification. 1-4.6 Welding All welding designs and procedures for lifters fabri- cated from steel, except for the design strength of welds, shall be in accordance with the requirements of AWS D14.1/D14.1M. The design strength of welds shall be as defined in para. 3-3.4. Whenconflicts exist between AWS D14.1/D14.1M and this Standard, the require- ments of this Standard shall govern. Welding of lifters fabricated from metals other than steel shall be performed in accordance with a suitable welding specification as determined by a qualified per- son, provided the quality and inspection requirements are equal to or greater than those required by this Standard.

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