[KenWittlief]

if you follow the 'can I use it' flowchart - when you get to pneumatics, the only thing you ARE allowed to use is standard cylinders from the approved supplier.

compressed air can be very dangerous. PVC pipes could go off like a pipe bomb if over pressurized, or if a fitting came off it would be like a bullet.

you are not allowed to make anything yourself that uses compressed air.