BS 4504 Standard Flanges Dimensions and Tolerances

PDF:  BS 4504 Standard Flanges Dimensions and Tolerances

BS 4504 Standard Flanges Dimensions and Tolerances

 

Dimension

Range

Tolerance

mm

Flange Facings

Eccentricity of machined facing diameters

< DN 100

1.0

> DN 100

2.0

a  (type B facing height)

2 mm

+0, -1.0

3 mm

+0, -2.0

4 mm

+0, -3.0

5 mm

+0, -4.0

6 mm

+0, -5.0

b (type C and E facing height)

All

+0.5, -0

b (type G facing height)

All

+0, -0.5

b (type H facing height, outer)

All

+0.2, -0

c (type D and F facing height)

All

+0, -0.5

d (type H facing height, inner)

All

+0.5, -0

B and E (facing diameters)

All

+0, -0.5

C and D (facing diameters)

All

+0.5, -0

Surface Finish

Facing types A, B, E and F

All, turning

Ra = 3.2 µm min 12.5 µm max

All, other than turning

Ra = 3.2 µm min 6.3 µm max

Facing types C, D, G and H

All

Ra = 0.8 µm min 3.2 µm max

Flange Drilling Details

B (diameter of bolt circle)

Bolt sizes M10 to M24

±0.9

Bolt sizes M27 to M45

±1.4

Centre to centre of adjacent bolt holes

Bolt sizes M10 to M24

±0.45

Bolt sizes M27 to M45

±0.7

All

A (outside diameter)

< DN 150

±2.0

> DN 150 < DN 500

±3.0

> DN 500 < DN 1200

±5.0

> DN 1200 < DN 1800

±7.0

> DN 1800

±10.0

C (flange thickness, machined on both faces)

< 18 mm thickness

±1.0

> 18 mm < 50 mm thickness

±1.0

> 50 mm thickness

±1.0

C (flange thickness, machined on front face)

< 18 mm thickness

+2.0, -1.0

> 18 mm < 50 mm thickness

+4.0, -1.5

> 50 mm thickness

+7.0, -2.0

Weld Neck Flanges, Code 111

B (outside diameter of hub at welding end)

< DN 125

+3.0, -0

> DN 125 < DN 1200

+4.5, -0

> DN 1200

+6.0, -0

F (hub diameter)

< DN 50

+0, -2.0

> DN 50 < DN 150

+0, -4.0

> DN 150 < DN 300

+0, -6.0

> DN 300 < DN 600

+0, -8.0

> DN 600 < DN 1200

+0, -10.0

D (length through hub)

< DN 80

±1.5

> DN 80 < DN 250

±2.0

> DN 250

±3.0

Slip on, Code 112 and Threaded,Code 113

E (slip on flange hub diameter)B (threaded flange hub diameter)

< DN 50

+1.0, -0

> DN 50 < DN 150

+2.0, -0

> DN 150 < DN 300

+4.0, -.0

> DN 300 < DN 600

+8.0, -0

> DN 600 < DN 1200

+12.0, -0

> DN 1200 < DN 1800

+16.0, -0

> DN 1800

+20.0, -0

B (slip on bore diameter)

< DN 100

+0.5, -0

> DN 100 < DN 400

+1.0, .0

> DN 400 < DN 600

+1.5, .0

> DN 600

+3.0, -0

D (length through hub)

Same as Weld Neck D

Blank Flanges, Code 105

B (flange thickness)

Same as C for all other flanges

C (unmachined centre portion)

Maximum specified

X

skype
email