API 608-2008 pdf free download

API 608-2008 pdf free download.Metal Ball Valves—Flanged, Threaded and Welding Ends.
1 Scope 1.1 This standard specifies the requirements for metal ball valves suitable for petroleum, petrochemical and industrial applications that have: — flanged ends in sizes NPS 1 / 2 through NPS 20 (DN 15 through DN500); — butt-welding ends in sizes NPS 1 / 2 through NPS 20 (DN 15 through DN 500); — socket-welding ends in sizes NPS 1 / 4 through NPS 2 (DN 8 through DN 50); — threaded ends in sizes NPS 1 / 4 through NPS 2 (DN 8 through DN 50). Corresponding to the nominal pipe sizes in ASME B36.10M. 1.2 This standard applies to metal ball valves with pressure classes as follows: — flanged ends in Classes 150, 300 and 600 (PN 16, 25, 40 and 100); — butt-welding ends in Classes 150, 300 and 600 (PN 16, 25, 40 and 100); — socket-welding ends in Classes 150, 300, 600 and 800 (PN 16, 25, 40 and 100); — threaded ends in Classes 150, 300, 600 and 800 (PN 16, 25, 40 and 100). 1.3 This standard establishes requirements for bore sizes described as: — full bore; — single reduced bore; — double reduced bore. 1.4 This standard applies to floating ball valve designs (Figure B.1) and trunnion ball valve designs (Figure B.2). These figures are to be used only for the purpose of establishing standard nomenclature for valve components— other floating and trunnion designs also exist. 1.5 This standard establishes additional requirements for ball valves that are otherwise in full conformance to the requirements of ASME B16.34, Standard Class. 2 Normative References The following referenced documents form a part of this standard. If references are dated, only that revision applies; for undated references, the most current edition or revision applies. API Standard 598, Valve Inspection and Testing API Standard 607, Testing of Valves—Fire-type Testing Requirements ASME B1.1 1 , Unified Inch Screw Threads
3 Terms and Definitions 3.1 Class An alphanumeric designation that is used for reference purposes relating to valve pressure/temperature capability, taking into account valve material mechanical properties and valve dimensional characteristics. It comprises the letters Class followed by a dimensionless whole number. The number following the letters Class do not represent a measurable value and are not used for calculation purposes except where specified in this Standard. The allowable pressure for a valve having a Class number depends on the valve material and its application temperature and is to be found in tables of pressure/temperature ratings. Class usage is applicable to steel valves bearing NPS nominal size designations. 3.2 NPS An alpha numeric designation of size that is common for components used in a piping system, used for reference purposes, comprising the letters NPS followed by a dimensionless number indirectly related to the physical size of the bore or outside diameter of the end connection as appropriate. The dimensionless number may be used as a valve size identifier without the prefix NPS. The dimensionless size identification number does not represent a measurable value and is not used for calculation purposes. Prefix NPS usage is applicable to steel flanges bearing Class designations. 3.3 DN An alpha numeric designation of size that is common for components used in a piping system, used for reference purposes, comprising the letters DN followed by a dimensionless number indirectly related to the physical size of the bore or outside diameter of the end connection as appropriate. The dimensionless number following DN does not represent a measurable value and is not used for calculation purposes except where specified in this international standard. DN usage is applicable to steel valves bearing PN designations.
3.4 PN An alphanumeric designation that is used for reference purposes relating to valve pressure/temperature capability, taking into account valve material mechanical properties and valve dimensional characteristics. It comprises the letters PN followed by a dimensionless whole number. The number following the letters PN do not represent a measurable value and are not used for calculation purposes except where specified in this international standard. The allowable pressure for a valve having a PN number depends on the valve material and its application temperature and is to be found in tables of pressure/temperature ratings. PN usage is applicable to steel valves bearing DN nominal size designations 4 Pressure-temperature Ratings 4.1 Valve Rating The valve pressure-temperature rating shall be the lesser of the shell rating or the seat rating. 4.2 Shell Rating The valve shell pressure-temperature rating shall be the rating for the shell material as listed for Standard Class in ASME B16.34 (see 6.1 for definition of shell and description of shell materials). 4.3 Seat and Seal Rating 4.3.1 Seat Ratings for PTFE and R-PTFE Valves employing PTFE (polytetrafluoroethylene) or Modified PTFE seats and valves employing R-PTFE (reinforced polytetrafluoroethylene) or modified R-PTFE seats shall have pressure-temperature ratings equal or higher than the values shown in T able 1 and Table 2.