ASME B16.48 pdf download Line Blanks
1 SCOPE This Standard covers pressure–temperature ratings, materials, dimensions, tolerances, marking, and testing for operating line blanks in sizes NPS 1 ∕ 2 through NPS 24 for installation between ASME B16.5 flanges in the 150, 300, 600, 900, 1500, and 2500 pressure classes.
2.1.1 Figure-8 Blank. A figure-8 blank (also called a spectacle blank) is a pressure-retaining plate with one solid end and one open end connected with a web or tie bar (see Figure 2.1.1-1).
2.1.2 Paddle Blank. A paddle blank is similar to the solid end of a figure-8 blank. It has a plain radial handle. It is generally used in conjunction with a paddle spacer in large sizes.
2.1.3 Paddle Spacer. A paddle spacer is similar to the open end ofa figure-8 blank. Ithas a plain radial handle. It is 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 I.
2.3 Quality Systems Nonmandatory requirements relating to the product manufacturer’s Quality System Program are described in Nonmandatory Appendix A.
2.4 Relevant Units This Standard states values in both SI (Metric) and U.S. Customary units. These systems of units are to be regarded separately as standard. Within the text, the U.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 values from the two systems constitutes nonconformance with the Standard.
2.5 Convention For determining conformance with this Standard, the convention for fixing significant digits where limits (maximum and minimum values) are specified shall be as defined in ASTM E29. This requires that an observed orcalculatedvalueberoundedofftothenearestunitinthe lastright-hand digitused forexpressingthe limit. Decimal values and tolerances do notimply a particular method of measurement.
2.6 Size NPS, followed by a dimensionless number, is the designation fornominal blanksize. NPS is related to the refer- ence nominal diameter, DN, as defined in ISO 6708. The relationship is typically as follows:
GENERAL NOTE: For NPS ≥ 4, the related DN = 25 multiplied by the NPS number.
2.7 Service Conditions Criteria for selection ofmaterials suitable forparticular fluid service are not within the scope of this Standard.
3 PRESSURE–TEMPERATURE RATINGS
3.1 Pressure Classes Line blanks covered by this Standard are for the following pressure classes: 150, 300, 600, 900, 1500, and 2500 as listed in ASME B16.5.
3.2 Pressure–Temperature Ratings
3.2.1 Ratings. Ratings are the maximum allowable working gage pressure at the temperature shown in ASME B16.5, Tables 2 and 2C for the appropriate material and pressure class. For intermediate temperatures, linear interpolation between temperatures within a pressure class is permitted by ASME B16.5.
3.2.2 System Pressure Testing. Line blanks may be subjected to system tests at a pressure not to exceed 1.5 times the 38°C (100°F) rating rounded off to the next higher 1 bar (25 psi) increment. Testing at any higher pressure is the responsibility of the user, taking into account the requirements of the applicable code or regulation.
3.2.3 Mixed Material Joints. Should either the two flanges or the line blank in a flanged line blank assembly not have the same pressure–temperature rating, the rating of the assembled joint at any temperature shall be the lower of the flange or line blank rating at that temperature.
4.1 Handle The handle or web (tie bar) maybe integral or attached to the line blank or spacer. The web and its attachment shall be capable of supporting the weight of the blank or spacerin all orientations withoutpermanentdeformation to the web.
4.2 Edge Preparation In addition to machining, flame, plasma, saw cutting, and press punching are acceptable methods for forming the inside and outside diameters of line blanks. Surfaces shall be free of projections that would interfere with gasket seating.
4.3.1 Raised Face Joint Blanks. The gasket-seating surface and dimensions for line blanks used with raised face flanges shall be in accordance with ASME B16.5. A raised face may be specified for these blanks at the option of the purchaser. The height of the raised faces shall be in addition to the thicknesses, t, listed in Tables 4.3.1-1 through 4.3.1-6.