ASME B16.21:2021 pdf download

ASME B16.21:2021 pdf download Nonmetallic Flat Gaskets for Pipe Flanges
1 scOPE
This Standard covers types,sizes. materials, dimen-sions, tolerances, and markings for nonmetallic flatgaskets.These gaskets are dimensionally suitable foruse with flanges described in the referenced flange stan-dards.
2GENERAL
2.1 Relevant Units
This Standard states values both in Sl (metric) and u.s.Customary units.As an exception, diameter of bolts andflange bolt holes are expressed in inch units only. Thesesystems of units are to be regarded separately as standard.In this Standard, the u.S. Customary units are shown inparentheses. The values stated in each system are notexact equivalents; therefore, it is required that eachsystem of units be used independently of the other.Except for diameter of bolts and flange bolt holes,combining values from the two systems constitutesnonconformance with the Standard.
2.2 Quality Systems
Requirements relating to the product manufacturers’quality system programs are described in Nonmandatoryppendix A.
2.3 References
Standards and specifications adopted by reference inthis Standard are shown in Mandatory Appendix I.
2.4 Flanged Joints
A flanged joint is composed of separate and indepen-dent, although interrelated, components: the flanges,gasket,and bolting, which are assembled by another influ-ence,the assembler. Proper controls must be exercised inthe selection and application for all these elements toattain a joint that has acceptable leak tightness.Additionalguidelines for flange assembly can be found inASME PCC-1 (see Nonmandatory Appendix B).
2.5 Types
Dimensions are provided for the following types ofgaskets,which are suitable for use with the flangefaces indicated:
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 ofa material suitable fora given service appli- cation is the responsibility of the user subject to the re- quirements of any applicable code or government regulation. The material selected shall be compatible