When tightening bolts on a flanged connection, what is the recommended procedure?

The recommended procedure when tightening bolts on a flanged connection is to take up each bolt gradually, alternating between bolts. This method is crucial because it ensures that the flange is pulled together evenly and avoids introducing stress concentrations that could lead to flange warping or gasket failure.

By alternating the bolts, you allow the flange surfaces to make contact progressively, which helps distribute the load evenly across the flanges and maintains a consistent and effective seal. This approach minimizes the risk of distorting the flange or damaging the gasket material thus ensuring a better long-term sealing performance.

Starting with the bolt closest to the flange can lead to uneven tightening, which may create gaps and increase the risk of leaks. Tightening in a random order lacks any systematic approach, which can similarly result in poor seal integrity. Fully tightening all bolts at once and then checking again may not allow for proper alignment and could result in uneven tension across the connection, increasing the likelihood of failure at the interface.