ASME B16.21:2005 pdf download Nonmetallic Flat Gaskets for Pipe Flanges
1.1 General
This Standard covers types, sizes, materials, dimensions, tolerances, and markings for nonmetallic flat gaskets. These gaskets are dimensionally suitable for usewith flanges described in the referenced flange standards
1.2 Relevant Units
This Standard states values both in metric and U.Scustomary units. As an exception, diameter of bolts ancflange bolt holes are expressed in inch units only. Thescsystems of units are to be regarded separately as standard. Within the text, the US. customary units areshown in parentheses or in separate tables. The valuesstated in each system are not exact equivalents; therefore, it is required that each system of units be used in-dependently of the other. Except for diameter of boltsand flange bolt holes, combining values from the twosystems constitutes nonconformance with the Standard
1.3 Quality Systems
Requirements relating to the product manufacturersquality system programs are described in Nonmandatory Appendix A
1.4 References
Standards and specifications adopted by reference inthis Standard are shown in Mandatory Appendix Il.
2 TYPES AND SIZES
2.1 Types
Dimensions are provided for the following types ofgaskets, which are suitable for use with the flange facesindicated:
Gasket Type
Full faceFlat ring
Flange FacingFlat faceRaised face
2.2 Size
NPS, followed by a dimensionless number, is the designation for normal pipe size,NPS,as described in ASME B36.10M; and is related to the reference nominal diameter, DN, used in international standards. The re- lationship is as follows:
GENERAL NOTE: For NPS 三 4, the related DN is DN = 25 XNPS
2.3 Pressure Class Designation
Class, followed by a dimensionless number, is thedesignation for common flange pressure-temperatureratings as given by the referenced flange standards.
3 MATERIALS
3.1 Composition
Gaskets shall be made of resilient or pliable materi-als. Metal or nonmetal composites may be incorporatedas reinforcement or filler material.
3.2 Service Requirements
Selection of a material suitable for a given service application is the responsibility of the user subject to therequirements of any applicable code or government regulation. The material selected shall be compatible withthe 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 Tables1 through 9 (Tables I-1 through I-9 of Appendix I) forthe flanges standards, sizes, and classes indicated. Selection of gasket thickness is the responsibility of the