Gents i read with great interest: It is my undertanding that air cylinders are not subject to pressure testing as they are under 1/2 litre capacity as already mentioned test pressure are at least 340 bar for a 200 bar fill
If you have ever charged a cylinder you will know that they get hot this is what is known as parelstatic heating and over a period of time can weaken large cylinders.
Large cyliders are subject to a 5 year test regardless of materials used for thier construction.
Steel cylinders have no life span and are good until the test station says othewise
Composite cylinders must be scrapped at year 15 regardless of condition
Oh one last thing please remember you get.
Air in cylinders
Soldiers in tanks
Milk in bottles
Sorry gents!!