- Dimensions are in millimeters, except for bolts and bolt holes.
- Weld neck flanges NPS 3 and smaller are identical to Class 300 flanges except
for bolting and may be used for such service.
- All other dimensions are in accordance with ASME B16.5.
- Ring joint flange in NPS 24 will require an angular meter tap.
- Other NPT sizes may be furnished if required.
- Bolt lengths for raised face flanges include allowance for orifice and gasket thickness
of 6 mm (0.25 in.) for NPS 1 to NPS 12 and 10 mm (0.38 in.) for NPS 14 to NPS 24.
Bolt lengths for ring-type joint flanges include allowance of 15 mm (0.62 in.) for NPS 1 to NPS 10,
19 mm (0.75 in.) for NPS 12 to NPS 18, and 22 mm (0.88 in.) for NPS 20.
- Bore (B) is to be specified by the purchaser.
- The length of the Stud Bolt does not include the height of the chamfers (points).
Tolerances on all dimensions shall be as shown in ASME B16.5 except for those shown below.
Pressure Tap Location
Tolerance on location of center of pressure tap hole from flange face shall be:
- ±0.5 mm (±0.02 in.) for flanges smaller than NPS 4
- ±0.8 mm (±0.03 in.) for flanges NPS 4 and larger
- Bore diameter tolerance (Welding Neck flanges only) is ±0.5% of nominal value.