Subsea Isolation Valve

Definition(s)


Subsea Isolation Valve

SSIV

SIV

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