FOREWORD These specifications@ for pumping@ cable tool@ and rotary drilling rigs and derricks were prepared by the Special A.P.I. Committee on the Standardization of Standard Rigs and Derricks and are recommended for the use of the oil industry in all districts of the United States. This Committee@ which is composed of representatives from all districts@ first collected and tabulated various dimensions of derricks and standard rigs used throughout the industry. A process of consolidating similar dimensions resulted in the elimination of a great many different height and base sizes. Derrick and Standard Rig manufacturers have been represented at all meetings of this Committee@ so that the industry as a whole@ including manufacturers as well as users@ has aided in this standardization work.