Flange concentricity issue
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Does the ASME B16.5 standard contain any specifications regarding the concentricity of the flange bolts on the left and right sides of valves? ? I searched for a long time but couldn’t find it! If anyone knows, please let me know. Thank you!
The flange issue – is it related to the flange on the valve?
7.8 Drilling and Facing 7.8.1 Bolt Circle Diameter. The required tolerance for all bolt circle diameters is as follows: ±1.5 mm (±0.06 in.). 7.8.2 Bolt Hole to Bolt Hole. The required tolerance for the center-to-center distance between adjacent bolt holes is as follows: ±0.8 mm (±0.03 in.). 7.8.3 Bolt Circle Concentricity. The required tolerances for concentricity between the flange bolt circle diameter and the diameters of the machined surfaces are as follows: Size Tolerance – NPS ≤ 2.5: 0.8 mm (0.03 in.); NPS ≥ 3: 1.5 mm (0.06 in.)
This refers to bolt circle concentricity. The required tolerances for the concency between the diameter of the flange’s bolt circle and the diameters of the machined surfaces are as follows: For NPS ≤ 2.5, the tolerance is 0.8 mm (0.03 in.); for NPS ≥ 3, the tolerance is 1.5 mm (0.06 in.)