. psia 3 3 .2 5 47.04 psia Stage Two 47.04 psia 3 3 .2 5 15 0. 528 psia Stage Three 15 0. 528 psia 3 3 .2 5 4 81. 689 psia Stage Four 4 81. 689 psia 3 3 .2 5 15 41. 407 psia. between 1, 750 and 3,600 RPM and have capacity ratings above 12 ,000 cfm (cubic feet per minute) on the inlet volume and discharge pressures between 3 and 20 ...