Considers the effects of internal pressure in the determination of the shell course thicknesses. By default, TANK follows API-650 in computing the required shell course thicknesses (by One- Foot, Variable Point, or the Appendix A methods). However, you may need to account for internal pressure by increasing the fluid head.
If you select this check box, the methodology of Section F.7.1 is implemented for all three thickness computation methods, increasing the Operating Liquid Level by (P/12G).