Definition(s)
Surface Safety Valve
Safety device that is located in the production bore of the well tubing above the wellhead (platform well), or at the point of subsea well production embarkation onto a platform, and that will automatically close upon loss of hydraulic pressure.
Source: API SPEC 17F, Specification for Subsea Production Control Systems, Second Edition, December 2006 (Reaffirmed April 2011). Global Standards