ASME B16.21:2005 pdf free download

ASME B16.21:2005 pdf free download Nonmetallic Flat Gaskets for Pipe Flanges
1 SCOPE
1.1 General This Standard covers types, sizes, materials, dimen- sions, tolerances, and markings for nonmetallic flat gas- kets. These gaskets are dimensionally suitable for use with flanges described in the referenced flange standards
1.2 Relevant Units This Standard states values both in metric and U.S. customary units. As an exception, diameter of bolts and flange bolt holes are expressed in inch units only. These systems of units are to be regarded separately as stan- dard. Within the text, the U.S. customary units are shown in parentheses or in separate tables. The values stated 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 bolts and flange bolt holes, combining values from the two systems constitutes nonconformance with the Standard.
1.3 Quality Systems Requirements relating to the product manufacturers’ quality system programs are described in Nonmanda- tory Appendix A.
1.4 References Standards and specifications adopted by reference in this Standard are shown in Mandatory Appendix II. 2 TYPES AND SIZES 2.1 Types Dimensions are provided for the following types of gaskets, which are suitable for use with the flange faces indicated:
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 = 4, the related DN is DN = 25×NPS
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.
3MATERIALS
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 ap-plication is the responsibility of the user subject to therequirements of any applicable code or government reg-ulation. The material selected shall be compatible withthe fluid and suitable for the pressure-temperature con-ditions of the service.
4DIMENSIONS AND TOLERANCES4.1 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.Se-lection of gasket thickness is the responsibility of the user, considering the properties of the gasket material as well as the intended service application.