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Flanges · Size & tolerance table

ASME B16.5 Class 150 flange dimensions (NPS ½–24)

Standard: ASME B16.5 (Class 150)

The flange dimensions that make two Class 150 flanges bolt together, whatever the type — weld neck, slip-on, socket weld, threaded, lap joint or blind. Outside diameter, bolt circle and drilling are common to all types of one size and class; hub dimensions and bore differ by type and are not shown.

Inch values are the standard's own; millimetre values are those of the metric tables of ASME B16.5. The flange thickness tf is a minimum and excludes the 1.6 mm (0.06 in) raised face, as in ASME B16.5 since the 2003 edition — older catalogues printed it with the raised face included, about 1.6 mm more.

Class 150 — dimensions common to all flange types

Size Outside diameter O Thickness tf (min.) Bolt circle Drilling
NPS in DN O in O mm tf in tf mm W in W mm Bolts Bolt size in Hole in
½ 15 3.50 90 0.38 9.6 2.38 60.3 4 ½ 0.62
¾ 20 3.88 100 0.44 11.2 2.75 69.9 4 ½ 0.62
1 25 4.25 110 0.50 12.7 3.12 79.4 4 ½ 0.62
1¼ 32 4.62 115 0.56 14.3 3.50 88.9 4 ½ 0.62
1½ 40 5.00 125 0.62 15.9 3.88 98.4 4 ½ 0.62
2 50 6.00 150 0.69 17.5 4.75 120.7 4 ⅝ 0.75
2½ 65 7.00 180 0.81 20.7 5.50 139.7 4 ⅝ 0.75
3 80 7.50 190 0.88 22.3 6.00 152.4 4 ⅝ 0.75
3½ 90 8.50 215 0.88 22.3 7.00 177.8 8 ⅝ 0.75
4 100 9.00 230 0.88 22.3 7.50 190.5 8 ⅝ 0.75
5 125 10.00 255 0.88 22.3 8.50 215.9 8 ¾ 0.88
6 150 11.00 280 0.94 23.9 9.50 241.3 8 ¾ 0.88
8 200 13.50 345 1.06 27.0 11.75 298.5 8 ¾ 0.88
10 250 16.00 405 1.12 28.6 14.25 362.0 12 ⅞ 1.00
12 300 19.00 485 1.19 30.2 17.00 431.8 12 ⅞ 1.00
14 350 21.00 535 1.31 33.4 18.75 476.3 12 1 1.12
16 400 23.50 595 1.38 35.0 21.25 539.8 16 1 1.12
18 450 25.00 635 1.50 38.1 22.75 577.9 16 1⅛ 1.25
20 500 27.50 700 1.62 41.3 25.00 635.0 20 1⅛ 1.25
24 600 32.00 815 1.81 46.1 29.50 749.3 20 1¼ 1.38

Notes

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