Subsea Isolation Valve
valve which closes within a defined time limit derived from the risk assessment in order to reduce
consequences of pipeline/riser leak or rupture
Note 1 to entry: The SSIV can be an actuated valve (e.g. remotely controlled subsea valve) or a non-activated valve
(subsea check valve). An activated valve is normally designed as fail safe (i.e. closes and remains closed on all
failures external to the valve and actuator themselves).
Note 2 to entry: Where the flexible risers are connected directly to the subsea wellhead, the master and wing
valve may be considered to represent the SSIV function.
[SOURCE: ISO 14723]
Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global Standards