5. Convert the desired tonnage per hour (tph) to be conveyed to the equivalent in cubic feet per hour (ft3/hr). (ex. 1000 tph x 2000 / 60 = 33333 ft3/hr) 6. Convert the desired capacity in cubic feet per hour to the equivalent capacity at a belt speed of 100 fpm. (ex. Capacity (eqiuv) = 33333 x (100 /