ISO 7919-2:2009 establishes provisions for applying evaluation criteria for the severity of in-situ, broad-band shaft vibration measured radial (i.e. transverse) to the shaft axis at, or close to, the main bearings. These are in terms of:

- vibration under normal steady-state operating conditions;

- vibration during other (non-steady-state) conditions when transient changes are taking place, including run up or run down, initial loading and load changes;

- changes in vibration which can occur during normal steady-state operation.

ISO 7919-2:2009 is applicable to land-based steam turbines and generators with power outputs greater than 50 MW and a normal operating speed of 1 500 r/min, 1800 r/min, 3 000 r/min or 3 600 r/min.