Azbil Corporation No. SS2-EGV100-0001 - 3 - Allowable differential pressure (Air-to-close and Air-to-open) Note) 1) Positioner is necessary. 2) If a pneumatic backup system is used as a provision against air supply failures, base valve selection on either the normal supply air pressure or the set point of the backup system pressure (the trip pressure), whichever is lower. 3) Take care that the maximum allowable differential pressure does not exceed the highest working pressure in ANSI B16.34-1981 4) Take care that the inlet pressure (P1) does not exceed the allowable differential pressure for a closed valve. Table 2 Pressure rating of ANSI Class 1500 Pressure rating Actuator Supply pressure kPa {kgf/cm2} kPa {kgf/cm2} by rated Cv values 5 10 16 25 35 50 70 ANSI 1500 DAP560 490 {5.0} 26000 {265} 26000 {265} 20100 {205} 12700 {130} DAP1000 490 {5.0} 26000 {265} 21600 {220} 15200 {155} 11300 {115} DAP1500 490 {5.0} 26000 {265} 23500 {240} 16700 {170} 11300 {115} Table 3 Pressure rating of ANSI Class 2500 Pressure rating Actuator Supply pressure kPa {kgf/cm2} kPa {kgf/cm2} by rated Cv values 2.5 6.3 10 16 25 35 50 ANSI 2500 DAP560 490 {5.0} 42700 {435} 42700 {435} 32400 {330} 20100 {205} 12700 {130} DAP1000 490 {5.0} 42700 {435} 34300 {350} 21600 {220} 15200 {155} 11300 {115} DAP1500 490 {5.0} 42700 {435} 33300 {340} 23500 {240} 16700 {170} 5 6