API Spec 7NRV-2006 pdf download.Specification for Drill String Non-return Valves.
3.6 failure: Any condition of NRV equipment that prevents it from performing the design function. 3.7 fit: The geometric relationship between parts. 3.8 form: The essential shape of a product including all its component parts. 3.9 function: The operation of a product during service. 3.10 functional test: Test performed to confirm proper operation of NRV equipment. 3.11 heat treatment/heat treating: Alternate steps of controlled heating and cooling of materials for the purpose of chang- ing physical or mechanical properties. 3.12 interchangeable: Conforming in every detail, within specified tolerances, to both fit and function of a safe design but not necessarily to the form. 3.13 manufacturer: The principal agent in the design, fabrication and furnishing of NRV equipment, who chooses to comply with this Standard. 3.14 model: NRV equipment with unique internal part(s) and operating characteristics which differentiate it from other NRV equipment of the same type. 3.15 NDE: Nondestructive examination. 3.16 NRV: A Drill String Non-return Valve. 3.17 NRV Equalizing Head: Used to equalize the NRV on surface, venting any trapped pressure prior to the removal of the NRV from the drill string. 3.18 NRV equipment: The Drill String Non-return Valve, Non-return Valve Subs, Non-return Valve landing nipples, Non- return Valve Equalizing Heads and all components that establish tolerances and/or clearances which may affect performance or interchangeability of the NRV equipment. 3.19 NRV Sub / NRV Landing Nipple: A receptacle with internal sealing surfaces in which an NRV may be installed. 3.20 operating manual: A publication issued by the manufacturer which contains detailed data and instructions related to the design, installation, operation and maintenance of NRV equipment. 3.21 operator: A user of NRV equipment. 3.22 production test: Test performed to qualify any size, type and model of NRV equipment for any class of service.
4.2 DESIGN REQUIREMENTS 4.2.1 Drawings, manufacturing specifications and the verification test results shall be retained by the manufacturer for a period of ten years after NRVs of that size, model and type are discontinued from the manufacturer’s product line. NRV equipment con- forming to this Standard shall be manufactured to drawings and specifications that are substantially the same as those of the NRV equipment that has passed the verification test. 4.2.2 Documentation of designs shall include methods, assumptions, calculations and design requirements. Design require- ments shall include but not be limited to those criteria for size, test and operating pressures, material, environmental and other per- tinent requirements upon which the design is based. Design documentation shall be clear, legible, reproducible and retrievable. 4.2.3 Design documentation shall be reviewed and verified by a qualified individual other than the individual who created the original design. 4.2.4 Changes to the design acceptance criteria which may affect verification test performance or interchangeability of NRV equipment shall require re-qualification, except that seals which have passed the applicable verification test requirements of clause 7 shall be considered interchangeable among the NRV equipment of any one manufacturer for a particular class of service. 4.2.5 NRV equipment manufactured in accordance with this Standard shall conform to one or more of the following classes of service: Class 1: standard service. This class of NRV equipment is intended for use in wells which do not exhibit the detrimental effects caused by sand or corrosive agents. Class 2: stress corrosion cracking service. This class of NRV equipment is intended for use in wells where corrosive agents could be expected to cause stress corrosion cracking. Class 2 equipment shall meet the requirements for Class 1 and be manufactured from materials which are resistant to stress corrosion cracking.