A security system for a pneumatic accumulator, the pneumatic accumulator being connectable with a pump and with a pneumatic apparatus by, respectively, a first and second connecting duct is described. The security system has a) a pneumatic bladder for containing high pressure gas, and b) flow distribution means connected with the first and second connecting ducts to the pneumatic accumulator and the pneumatic bladder, the flow distribution means being able to pass from a first operating position to a second operating position, in which the flow distribution means connects the first and second connecting ducts with the pneumatic bladder (40) pneumatic plant is also described.