1.0.1 This national standard specifies the basic technical requirements of steel pipe flanges (PN designated), including nominal dimension, nominal pressure, material, pressure-temperature rating, flange type, dimension, seal contact face, tolerance and marking.
1.0.2 This Standard is applicable to steel pipe flanges and blind flanges in nominal pressure of PN2.5~PN160. The nominal flange pressure grades are denoted by PN, including the following nine grades: PN2.5, PN6, PN10, PN16, PN25, PN40, PN63, PN100 and PN160.
1.0.3 Nominal dimension and outside diameter of the steel pipe
Outside diameter of the steel pipe applicable to this Standard includes two series: A and B, where A designs for the international purposes (it is commonly referred to as "John Guest"), while B designs for the domestic adopting series (it is commonly referred to as "metric pipe"). Its nominal dimension DN and outside diameter of the steel pipe are in accordance with those specified in Table 1.0.3.
The flanges adopting B series steel pipe shall be marked with "B" at the back of the number of nominal dimension DN for differentiation. However, the flange adopting A series steel pipe must not be marked with "A" at the back of the number of nominal dimension DN, for more details, see Chapter 13 and Chapter 14 of this Standard.
Table 1.0.3 Nominal Dimension and Outside Diameter of the Steel Pipe (mm)
Nominal dimension DN 10 15 20 25 32 40 50 65 80
Outside diameter of the steel pipe A 17.2 21.3 26.9 33.7 42.4 48.3 60.3 76.1 88.9
Outside diameter of the steel pipe A 610 711 813 914 1016 1219 1422 1626 1829 2032
B 630 720 820 920 1020 1220 1420 1620 1820 2020
1.0.4 This Standard is also applicable to valve, pump, chemical engineering machinery, pipeline fittings and equipment spares with flange being used as its coupling mode.
1.0.5 This Standard excludes selection principle for materials under particular fluid operating conditions.
1. General provisions 2. Normative references 3. Flange type and flange seal contact face 3.1 Flange type 3.2 Flange seal contact face 4. Materials 5. Gaskets and bolting for flange 6. Fitting of flange joint 7. Pressure-temperature rating 8. Dimensions 8.1 Flanged coupling dimension 8.2 Physical dimension of the flange 8.3 Flange neck 8.4 Pipe thread 9. Welding joint and groove dimension 9.1 Plate-type flat welding flange and flat welding ring loose flange 9.2 Slip on neck flange 9.3 Welding joint of the socket welding flange connecting to the steel pipe 9.4 Weld neck flange 9.5 Butt welding ring 10. Dimension tolerance 11. Test 12. Inspection and acceptance 13. Marking and marking illustration 14. Packaging and steel seal label Appendix A (Normative) Steel Orifice Flange Appendix B (Informative) Steel Jacket Flange Appendix C (Informative) Assorted Pipe Flanges' Standard Appendix D (Informative) Approximate Mass of the Flange Appendix E (Informative) Approximate Distance between Ring Joint Face Flanges
