ASME B16.21:2005 pdf free download

ASME B16.21:2005 pdf free download.Nonmetallic Flat Gaskets for Pipe Flanges.
2.3 Pressure Class Designation
Class, followed by a dimensionless number, is the designation for common flange pressure-temperature ratings as given by the referenced flange standards.
3 MATERIALS
3.1 Composition
Gaskets shall be made of resilient or pliable materials. Metal or nonmetal composites may be incorporated as reinforcement or filler material.
3.2 ServIce Requirements
Selection of a material suitable for a given service application is the responsibility of the user subfrct to the requirements of any applicable code or government regulation. The material selected shall be compatible with the fluid and suitable for the pressure-temperature conditions of the service.
4 DIMENSIONS AND TOLERANCES
4.1 Dimensions
Gasket dimensions shall be in accordance with Tables I through 9 (Tables 1-1 through 1-9 of Appendix D for the flanges standards, sizes, and classes indicated. Selection of gasket thickness is the responsibility of the user,considering the properties of the gasket materialas well as the intended service application.
4.2 Tolerances
(a) Outside Diamefer
(1) NPS 12 and smaller:
+0.0，一1.5 mm (+0.0，—0.06 in.)
(2)NPS 14 and larger:
+0.0，—3.0 mm (+0.0，一0.12 in.)
(b) Inside Diameter
(c) NPS 12 and smaller:±1.5 mm (±0.06 in.)
(2) NPS 14 and larger: ±3.0 mm (±0.12 in.)
(3) Bolt Circle Diameter: ±1.5 mm(±0.06 in.)
(4) Center to center of adjacent bolt holes:±1.0 mm(±0.03 in.)