Compression Fittings are used in variety of places, pretty much anywhere you are connecting either water line or air, gas pneumatic type lines. They are great at creating a seal. They give you a good solid connection. Pressure Brass fitting can take is 400 psi. Nominal working pressure is 200 psi. -65˚ to +250˚F. It is critical to avoid over-tightening the nut or else the integrity of the compression fitting will be compromised by the excessive force. If the nut is over tightened the ferrule will deform improperly causing the joint to fail. Indeed, over tightening is the most common cause of leaks in compression fittings.
Brass Compression Rings