How to choose pneumatic actuators

we know that, do a set of continuous water supply system, are generally use of pneumatic actuators, after all in the water supply system, environment are basically very wet, if we use a electric actuator, humid environment will make its internal components from corrosion and burned, it will cause flooding fault, and serious explosion may occur. So we have a better choice is to pneumatic actuators. The pneumatic actuator and how should choose? The choice of pneumatic actuator is to see what is our demand, need it for what we do. If we want to be in power after the actuator remains in situ, can choose double acting pneumatic actuator, if equipped with a gas tank, also should use double acting pneumatic actuator, because after the power is still double acting actuators can complete one cycle control. Power on the other hand, if there is a need to reset pneumatic actuators, should choose single acting spring return pneumatic actuators.