How should you assemble a four-bolt flange?

Assembling a four-bolt flange correctly is critical for ensuring a proper seal and alignment between the connected pipes. The correct approach is to set up opposite bolts fairly tight and then tighten the bolts equally in a crossing pattern. This technique is known as "cross-tightening," and it helps distribute the load evenly across the flange. By tightening opposite bolts first, you create a balanced pressure around the flange, which minimizes the risk of warping or misalignment.

Tightening in a crossing pattern ensures that no single point is subjected to excessive stress, which can lead to leaks or failures. It is a method that allows for an even distribution of forces and helps maintain the integrity of the connection.

Other methods, such as tightening all bolts in a clockwise manner, may lead to uneven forces and can cause the flange to distort. Starting nuts and tightening in a counterclockwise direction or following a specific order (like top, side, bottom) may apply uneven pressure on the flange, which compromises the seal and could lead to operational issues. The cross-tightening method reflects best practices in flange assembly, emphasizing the importance of load distribution for achieving a secure and effective joint.