Definition(s)
Subsurface Safety Valve (SSSV)
Device whose design function is to prevent uncontrolled well flow when closed. NOTE SSSVs can be installed and retrieved by wireline or pump-down methods (wireline retrievable) or be an integral part of the tubing string (tubing-retrievable).
Source: API SPEC 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition, October 2005 (Reaffirmed June 2012). Global Standards
Subsurface Safety Valve (SSSV)
device installed in a well below the wellhead with the design function to prevent uncontrolled well flow
when actuated
Note 1 to entry: These devices can be installed and retrieved by wireline (Wireline retrievable) and/or pump
down methods (TFL-Thru Flow Line) or be integral part of the tubing string (Tubing retrievable).
Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global Standards