When replacing a gasket in a six-bolt flanged joint, in what order should the bolts be tightened?

Correct Answer: Option A — Install and tighten bolts in pairs which are opposite each other in the flange (1-4, 2-5, and 3-6).

Proper flange bolting requires a cross-pattern tightening sequence to ensure even compression of the gasket. By tightening opposite bolts in pairs, you prevent cocking or uneven loading of the flange faces, which maintains uniform pressure across the gasket surface and prevents leaks in high-pressure piping systems.