Dirk, in class you gave an example on a safety valve with a 10% blowdown, from that we could figure out at what pressure the seat would close the valve. My question is on the size of the cirucurlar disk under the spring. I know how to find the area of the circle, but how does that relate to the example you gave us in class? Example: the safety valve is set at 10 lbs and the safety valve has a 3 inch disc. Area of the disk is approximately 7 sq inches. Do we multiply that by the set pressure of the safety valve to give us the total force needed to open the valve? - kind of confused on this example. Any help is welcome. Matt