ASME B16.48:2020 pdf free download – Line Blanks
1 SCOPE
This Standard covers pressure-temperature ratings.materials, dimensions, tolerances, marking.and testingfor operating line blanks in sizes NPS vz through NPS24 for installation between ASME B16.5 flanges in the150,300,600,900,1500,and 2500 pressure classes.
2 GENERAL
2.1 Definitions
2.1.1 Figure-8 Blank. A figure-8 blank (also called aspectacle blank) is a pressure-retaining plate with onesolid end and one open end connected with a web ortie bar (see Figure 2.1.1-1).
2.1.2 Paddle Blank.A paddle blank is similar to thesolid end of a figure-8 blank. It has a plain radial handle. It is generally used in conjunction with apaddle spacer in large sizes.
2.1.3 Paddle Spacer. A paddle spacer is similar to theopen end of a figure-8 blank.It has a plain radial handle. Itis generally used in conjunction with a paddle blank.
2.2 References
Codes, standards, and specifications, containing provi-sions to the extent referenced herein, constitute require-ments of this Standard. These reference documents are listed in Mandatory Appendix L.
2.3 Quality Systems
Nonmandatory requirements relating to the productmanufacturer’s Quality System Program are describedin Nonmandatory Appendix A.
2.4 Relevant Units
This Standard states values in both Sl (Metric) and U.S.Customary units.These systems of units are to be regarded separately as standard. within the text, theU.S. Customary units are shown in parentheses. The values stated in each system are not exact equivalents;therefore, it is required that each system of units be used independently of the other. Combining valuesfrom the two systems constitutes nonconformancewith the Standard.
2.5 Convention
For determining conformance with this Standard, theconvention for fixing significant digits where limits(maximum and minimum values) are specified shall beas defined in ASTM E29.This requires that an observedor calculated value be rounded off to the nearest unit in thelast right-hand digit used for expressing the limit. Decimalvalues and tolerances do not imply a particular method ofmeasurement.and pressure class. For intermediate temperatures, linearinterpolation between temperatures within a pressureclass is permitted by ASME B16.5.
3.2.2 System Pressure Testing.
Line blanks may besubjected to system tests at a pressure not to exceed1.5 times the 38°C (100°F) rating rounded off to thenext higher 1 bar (25 psi) increment.Testing at anyhigher pressure is the responsibility of the user, takinginto account the requirements of the applicable codeor regulation.
3.2.3 Mixed Material Joints.
Should either the twoflanges or the line blank in a flanged line blank assemblynot have the same pressure-temperature rating, therating of the assembled joint at any temperature shallbe the lower of the flange or line blank rating at thattemperature.
4 DESIGN
4.1 Handle
The handle or web (tie bar) may be integral or attachedto the line blank or spacer. The web and its attachmentshall be capable of supporting the weight of the blank orspacer in all orientations without permanent deformationto the web.
4.3 Facing
4.3.1 Raised Face Joint Blanks.The gasket-seatingsurface and dimensions for line blanks used with raised face flanges shall be in accordance with ASMEB16.5.A raised face may be specified for these blanksat the option of the purchaser. The height of the raisedfaces shall be in addition to the thicknesses, t, listed inTables 4.3.1-1 through 4.3.1-6.
4.3.2 Female Ring-Joint Blanks.Female ring-jointgrooves shall be shaped with the groove side wall surface finish not exceeding 1.6 um (63 uin.) Ra roughness.The finish of the gasket contact faces shall be judged byvisual comparison with Ra standards (see ASME B46.1)and not by instruments having stylus tracers and electron-ic amplification.
4.3.3 Male Ring-Joint Blanks. The gasket shape (ring)for male ring-joint blanks shall not exceed 1.6 um (63 uin.)Ra roughness. The finish of the gasket contact faces shallbe judged by visual comparison with Ra standards (seeASME B46.1) and not by instruments having stylustracers and electronic amplification.