API Spec 4F

Please note that the API Monogram Program effective date for the this document's next edition is December 2020. Until then, this edition will still be considered active and not historical.Please note: Addendas and/or errata may not be included in the non-English translations of this publication.Effective date: August 1, 2013This specification states requirements and gives recommendations for suitable steel structures for drillingand well servicing operations in the petroleum industry, provides a uniform method of rating the structures,and provides two Product Specification Levels (PSLs).This specification is applicable to all new steel derricks, masts (including masts with guy lines and servicerig masts), substructures, and crown block assemblies with a date of manufacture after the effective dateof this specification.Annex A provides a number of standard Supplementary Requirements (SRs) that apply only if specifiedby the purchaser. Annex B is an informative Annex to assist in an understanding/application of this APIspecification. Annex C is an informative Annex regarding the API Monogram Program and the APIMonogram marking requirements. Annex D is an informative Annex providing guidelines to assist thePurchaser with purchasing equipment manufactured to the requirements in this API document.