ASME B16.21:2005 pdf download

ASME B16.21:2005 pdf download Nonmetallic Flat Gaskets for Pipe Flanges
1 sCOPE1.1 General
This Standard covers types,sizes,materials,dimen-sions,tolerances, and markings for nonmetallic flat gas-kets. 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.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 stan-dard. Within the text,the U.s. customary units areshown in parentheses or in separate tables. The valuesstated in each system are not exact equivalents; there-fore, 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 manufacturers’quality system programs are described in Nonmanda-tory Appendix A.
1.4 References
Standards and specifications adopted by reference inthis Standard are shown in Mandatory Appendix II.
2TYPES AND SIZES
2.1 Types
Dimensions are provided for the following types ofgaskets, which are suitable for use with the flange facesindicated:
2.2 Size NPS, followed by a dimensionless number, is the designation for normal pipe size, NPS, as described in ASME B16.21-2005 1 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 DN25 NPS
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 materi- als. 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 ap- plication is the responsibility of the user subject to the requirements of any applicable code or government reg- ulation. The material selected shall be compatible with the fluid and suitable for the pressure-temperature con- ditions of the service.
4 DIMENSIONS AND TOLERANCES
4.1 Dimensions Gasket dimensions shall be in accordance with Tables 1 through 9 (Tables I-1 through I-9 of Appendix I) for the 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.
4.2 Tolerances
(a) Outside Diameter
(1) NPS 12 and smaller:0.0, 1.5 mm (?0.0, ?0.06 in.)
(2) NPS 14 and larger:0.0, 3.0 mm (?0.0, 0.12 in.)
(b) Inside Diameter
(1) 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.)
5 MARKINGS 5.1 Material Marking Unless otherwise specified by the purchaser, gasket material shall be marked with the material manufacturer’s name or trademark and material designation.
5.2 Gasket Marking Gaskets shall be packaged with NPS, Class, gasket manufacturer’s name, material designation, thickness, and ASME B16.21 marked or tagged on the package or gasket. At the option of the manufacturer, the DN des- ignation may be included.