The pressure vessel is generally speaking just a container that holds gases to allow ambient pressure.
During a long time, air tanks or pressure vessel has been dangerous unit to handle. In fact, there are government engineers who mostly design them for the highest safety factors. The dangerous factors lies in that the air and gas tanks easily can explode if not handled correctly. There is currently laws about tanks that says they can’t operate over a PSIg of 15.
Pressure vessels are generally used in a variety of situations and industries. Mainly for industrial or private operations with compressed air or how water storage tanks. Oil refineries and nuclear reactor vessels are also often mentioned.
Historically the pressure vessels started their use to lift heavy weights from the water. Today these tanks are very portable and can be used by any person. In fact you can actually build your own form of a air tank or pressure vessel 🙂
Here is an interesting video showing how to build portable air tanks from limited resources at home:
aircompressorportablenow 