Surface Safety Valve (SSV) or Shutdown Valve is a fail-safe gate valve which is used to quickly shut down the well upstream in the event of overpressure, failure, fire, a leakage in downstream equipment, or any other well emergency requiring an immediate shut-down. SSV can be driven by hydraulic actuator or pneumatic actuator depends on the pressure rating. The pneumatic actuator mainly comes in two types, Diaphragm Actuator and Piston Actuator.