What pattern is recommended when tightening bolts on an eight-bolt flange?

• A. In a circular pattern
• B. In a cross over pattern
• C. In a straight line
• D. In a diagonal sequence

Answer: (B)

Even distribution of clamping force around the flange is the essential idea. Tightening in a cross‑over pattern means alternately pulling opposite sides of the flange and then moving around the circle. This method keeps the flange flat as the gasket seats, prevents one side from tightening ahead of the other, and reduces the chance of bending or distortion that could cause leaks or misalignment. After snugging, you apply final torque in the same cross pattern, stepping up gradually to the specified value to maintain even compression.

A circular pattern can create load concentrations around the ring and may warp the flange. A straight-line sequence tends to pull in one direction, risking misalignment. A diagonal sequence doesn’t provide the systematic opposite pulls needed for even distribution.