All to often we hear "the gasket leaks". This is not strictly true. It is the joint that leaks and the gasket is one component of several that make up the joint. Unfortunately, the gasket is expected to make up for any and all deficiencies in design, improper installation procedures, and to compensate for all flange movement due to thermal changes, pressure changes, vibrations, etc. In many cases the gasket will do these things but only when careful attention is given to all aspects of gasket selection, design and installation. Experience in investigating leaky joints over the years has indicated the most common cause of leaky joints improper installation procedures being followed.

A few simple precautionary measures must be observed during installation to ensure the most satisfactory joint.

• Center the gasket on the flange. This is extremely vital where raised faces are involved.
• Be sure surface finish and flatness are satisfactory.
• Tighten the bolts to compress the gasket uniformly. This means going from side to side around the joint. See Figure 1.
• Use a torque wrench, well-lubricated fasteners, and hardened flat washers to ensure correct initial loading.
• All bolts should be tightened in one-third increments, according to proper bolting patterns.
• Make a final check pass at the target torque value moving consecutively from bolt to bolt.
• Retorque 12 to 24 hours after initial installation, whenever possible. All applicable safety standards including lockout/tagout procedures should be observed.
• Never use liquid or metallic based anti-stick or lubricating compounds on the gaskets. Premature failure could occur as a result.
  

Figure1