A gasket is only as good as its compression, so proper bolt torquing is essential to provide consistent sealing.
If your gasket is under-compressed it will be prone to leaks (and for users of glass-lined equipment that can often equate to leakage of a highly corrosive product!). Under compression also creates risk of entrapment areas between the gasket and flange, which are not only dangerous, but they make cleaning difficult. On the flip side, over compression produces high stresses on the gasket material, clamps, and flanges which can lead to damage or premature failure.
By controlling the torque applied to the gasket clamps, you can achieve correct compression during initial installation. The correct torque setting depends on the gasket material. Generally after the final torque is reached a re-torque should be done after the first heat cycle or 24 hrs. For more detailed procedures, instructions, and recommendations on bolting torques for our AFII gaskets, consult Section V of our Glass-Lined Equipment Maintenance Manual.