"There are many types of formula which is self generated by BHEL , AND CROSBY but during hauling or setting of the presure in safety valve it doesn't provide any accurate value but I have a great formula to find out mean seat area which is used by professionals "
(((OD - ID)÷2)^2)×π/4
WHERE :-
OD = OUTER DIA OF SEAT
ID = INNER DIA OF SEAT