API Spec 8A pdf download.Specification for Drilling and Production Hoisting Equipment
1.1 DESIGN RATING BASIS This specification provides a basis for establishing the ratings of main load carrying components of certain hoist- ing equipment used in drilling and production operations as follows: 1.1.1 Maximum Load Rating This is a calculated maximum load rating using a pre- scribed design safety factor on the minimum yield strength of the material used in the equipment. This load rating is not intended to fix the expected service life other than by provid- ing a reasonable margin of safety against failure. CAUTION: The terms safety factor or design safety factor are intended as design criteria and should not under any circum- stances be construed as allowing loads in excess of the maxi- mum load rating as established under this specification. 1.1.2 Bearing Load Rating This is a calculated maximum load main-bearing rating for traveling blocks, and swivels. This bearing rating is intended primarily to achieve consistency of ratings, but is also intended to provide a reasonable service life for such main bearings when used at loads within the equipment rating. 1.1.3 Design Criteria This specification provides for a method of rating main load carrying components of certain hoisting equipment used in drilling and production operations, predicated on normal field loading in which the following conditions are assumed to exist: a. The maximum load rating includes all static loads encoun- tered in the operation of the equipment. It should be recognized that dynamic loads exist and if the combined static and dynamic loads exceed the maximum safe working load, the safety factor will be reduced accordingly. b. The fatigue limit of the material in the equipment and the effect of stress risers are recognized as important factors in design. c. The ratings determined herein are intended to apply to new equipment only.1.2 RATING ASSURANCE—MANUFACTURED UNITS This specification provides the manufacturer with a means for adequately assuring that manufactured units will meet the design load ratings established in accordance with 1.1 as follows: 1.2.1 Material Controls The use of material controls by the manufacturer provides assurance that the materials used in the equipment will be suitable for its intended use. Material controls verify compli- ance with the requirements of Section 4, Materials. 1.2.2 Process Controls The use of process controls by the manufacturer provides assurance that the equipment has been manufactured in a man- ner resulting in a consistent level of quality and reliability. 1.2.3 Non-Destructive Examination (NDE) NDE and/or test controls provide for uniformity in meth- ods, procedures and standards of acceptance. 1.3 SUPPLEMENTARY REQUIREMENTS This specification also covers a group of supplementary requirements which may be applied to equipment manufac- tured under the provisions of this specification. These are meant to be used when additional testing or inspection is desired and apply only when specified individually by the purchaser in the inquiry, contract, and order. Details of these requirements shall be as agreed to by the manufacturer and purchaser.
4 Material Requirements
4.1 CASTINGS Steel castings used in the manufacture of the main load carrying components of the equipment covered in this specifi- cation shall conform to ASTM A781: Common Requirements for Steel and Alloy Castings for General Industrial Use , and either an individual material specification listed therein or a proprietary material specification that as a minimum con- forms to ASTM A781. 4.2 FORGINGS Steel forgings used in the manufacture of the main load carrying components of the equipment covered in this spec- ification shall conform to ASTM A668: Steel Forgings, Car- bon and Alloy, for General Industrial Use and ASTM A788: Steel Forgings, General Requirements. A material specifica- tion listed in ASTM A788 or a proprietary specification con- forming to the minimum requirements of ASTM A788 may be used. 4.3 PLATES, SHAPES, AND BAR STOCK Structural material used in the manufacture of main load carrying components of the equipment covered in this specifi- cation shall conform to applicable ASTM or API specifica- tions covering steel shapes, plates, bars, or pipe, or a proprietary specification conforming to the minimum require- ments of applicable ASTM or appropriate standard. Struc- tural steel shapes having a specified minimum yield strength less than 33,000 psi, or steel pipe having a specified mini- mum yield strength less than 35,000 psi shall not be used.