When loosening the bolts on a flange, which bolts should you loosen first?

When loosening bolts on a flange, it is essential to follow a proper procedure to avoid distorting the flange, which could lead to leaks or damage. The correct approach often involves loosening the bolts in a pattern that promotes equal pressure release across the flange.

Loosening the far bolts first allows for an even distribution of force as the pressure is relieved from the flange. This reduces the risk of misalignment and prevents the flange faces from becoming warped. By starting with the bolts that are situated farthest from the point of application, you create a more balanced and controlled loosening process. This ensures that any residual pressure is gradually released, minimizing the chances of unexpected movements of the flange or pipe.

In contrast, loosening bolts that are located at the top, bottom, or near the flange first could lead to uneven stress on the flange, increasing the likelihood of leaks or damage to the sealing surfaces. Therefore, the chosen method of loosening the far bolts first is rooted in best practices for maintaining the integrity of the piping system.