Flanges and Fittings
1. Flange bolt holes are to be oriented as follows, unless otherwise indicated on the piping drawings:
a. Flange face vertical: Bolt holes to straddle vertical centerline.
b. Flange face horizontal: Bolt holes to straddle north-south centerline.
Note: Fabricator shall ensure that this information is included on the fabrication drawings.
2. Where jack screws (such as at a spectacle blind) are called for on a piping drawing, the shop Fabricator shall drill, tap, and supply jackscrews.
3. Orifice flanges shall be fabricated with the taps in the exact orientation shown on the piping drawings. The up and down stream sections of pipe to which the orifice flanges are attached may be standard mill run pipe, but each piece shall be a choice hand-selected piece, and the interior of the pipe shall be round, smooth, and free from blisters and scale; welds shall be ground flush. Field welds shall be kept at a maximum distance from the face of the orifice.
4. Where line taps are required, first attach the connection fitting; drill the hole for the line tap square to the axial centerline. All line taps are to be clean, sharp, and free from burrs, wire edges, or other irregularities.