API STD 602:2009 pdf download.Steel Gate, Globe, and Check Valves for Sizes NPS 4(DN 100)and Smaller for the Petroleum and Natural Gas Industries.
3 Terms and Definitions
For the purposes of this document, the following definitions apply,
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 dwnensional characteristics. It comprises the letters CIass 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 pressureitemperature ratings. Prefix Class usage is applicable to steel valves bearing NPS nominal size designations.
3.2
diameter nominal
DN
An alphanumeric designation of &ze 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 standard. Prefix DN usage is applicable to steel valves bearing PN designations.
3.3
nominal pipe size
NPS
An aiphanumenc 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.
4 Pressurel Temperature Ratings
4.1 Valve Ratings
4.1.1 Applicability
The pressure/temperature ratings applicable to valves specified in this standard shall be in accordance with those specified in the tables of ASME B 16.34 for standard class for the applicable material specification and class designahon
4.1.2 ApplIcable Valve Materials
The ASME B16.34 Material Group 1 and Material Group 2 forging and casting ASTM identifications acceptable for valves constructed under this standard are listed in Table 1. The Table 1 notes apply to the applicable valve material where noted.
4.1.3 Interpolated Ratings
The pressureltemperature ratings for Intermediate CLass 800 valves shall be as shown in Table 2a and Table 2b. The pressure/temperature ratings in Table 2a and Table 2b are a linear interpolation of Standard Class 600 and Standard Class 900 pressure/temperature ratings listed in ASME B16.34 for the appropriate valve material.
API STD 602:2009 pdf download
