I am trying to determine the actuator torque required for my metal seated, eccentric (meaning offset) butterfly damper. I am using formulae from Appendix A of AWWA C504-87, titled "Suggested Method for Calculating Torques Required to Operate Rubber-Seated Butterfly Valves".The formula for SEATING TORQUE: Ts = Cs D^2;where Cs is the SEATING COEFFICIENT, D is the valve diameter in feet.If I were to use the SEATING COEFFICIENT of METAL SEATING it should allow me to use the formulae to size the torque of my damper (despite the method being for rubber seated valves). My sealing system is 316SST on 316SST, but I do not know the seating coefficient or where I might find it.The formula for DYNAMIC TORQUE: Td = Ct D^3 ?P;where Ct is the DYNAMIC TORQUE COEFFICIENT, D is the valve diameter in feet, ?P is the pressure drop across the valve in PSI.The DYNAMIC TORQUE COEFFICIENT varies as the DISC OPENING ANGLE varies from 0