Although similar in style to the octagonal gaskets, the BX Series can only be used with 6BX flanges and 16BX hubs. BX-Gaskets have been designed for higher-pressure ratings from 5,000 lbs. to 20,000 lbs. Pitch diameters on BX gaskets are slightly larger than the pitch diameter of the flange. This forces the gasket to initially seal on its outside angles and secondly seal with its inside angles as the flange is bolted down to respective torque settings.
The vent hole on the BX series through the gasket helps equalize pressures caught between the flange grooves. Gaskets that have been torqued initiating a metal-to- metal seal should be discarded and not reused.