What is the difference between safety valve and relief valve of any pressure vessel or system?

Diff erence between safety valves & relief valves?

safety valves and relief valves are used in manufacturing and power plants. Widely used in hydraulic and pneumatic based plants.
safety valves are used for when pressure of the pumping agent increases more than designed value. By using this safety valves we can control the pressure of the pumping agent. Relief valves are used for relive the pressure of the fluid after completion of the operatins.