API Spec 7NRV-2006 pdf free download

API Spec 7NRV-2006 pdf free download.Specification for Drill String Non-return Valves.
This standard has been developed by users/purchasers and suppliers/manufacturers of Drill String Non-return Valve equipment intended for use in the petroleum and natural gas industry worldwide. This Standard is intended to give requirements and infor- mation to both parties in the selection, manufacture, testing and use of Drill String Non-return Valve equipment. Further, this Standard addresses requirements that set the minimum parameters with which the supplier/manufacturer must comply to claim conformity with this standard. Users of this standard should be aware that further or differing requirements might be needed for individual applications. This standard is not intended to inhibit a supplier/manufacturer from offering, or the user/purchaser from accepting, alternative equip- ment or engineering solutions. This may be particularly applicable where there is innovative or developing technology. Where an alternative is offered, the supplier/manufacturer should identify any variations from this standard and provide details. This document does not cover maintenance and inspection once the NRV has left the manufacturer and is in operation. These are important to the safety and reliability of the equipment and should be considered. 1 Scope This standard was formulated to provide the minimum acceptable requirements for Drill String Non-return Valve (NRV) equip- ment. It covers Drill String Non-return Valves, 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 interchange- ability of the NRV equipment. Non-return Valve Subs, Non-return Valve landing nipples, Non-return Valve Equalizing Heads and NRVs manufactured by different facilities or manufacturers may be supplied as separate items. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this stan- dard.
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.
Note: Metallic materials suitable for Class 2C service are dependent on specific well conditions. No national or international standards exist for the application of metallic materials for this class of service. 4.3 FUNCTIONAL CONSIDERATIONS NRV design shall permit prediction and repeatability of rates, pressures or other conditions required for operation.