This part of ISO 10816 gives specific guidance for assessing the severity of vibration measured on the bearing housings or pedestals of gas turbine driven sets.

The vibration criteria provided in this part of ISO 10816 apply to heavy-duty gas turbine sets. Aircraft derivative gas turbines (including gas turbines with dynamic properties similar to those of aircraft derivatives) are excluded from this part of ISO 10816. Large differences exist between these two turbine types in, for example, casing flexibility, bearing design, rotor to stator weight ratio and mounting structure. It is therefore necessary to establish separate criteria for these two turbine types.

This part of ISO 10816 is applicable only to heavy-duty gas turbines used in electrical and mechanical drive applications covering the power range above 3 MW and a speed range under load between 3 000 r/min and 20 000 r/min. This includes gas turbines directly coupled to other prime movers such as steam turbines, but the evaluation of the steam turbine vibration is not dealt with in this part of ISO 10816 (see the following exclusion list). It also includes any driven equipment not included in the exclusion list below.

The following are excluded from this part of ISO 10816:

• gas turbines with power outputs less than or equal 3 MW (see ISO 10816-3);
• gas turbine driven pumps (see ISO 10816-3);
• coupled steam turbines and generators with outputs less than or equal 50 MW (see ISO 10816-3);
• coupled steam turbines and generators with outputs greater than 50 MW (see ISO 10816-2);
• coupled compressors (see ISO 10816-3);
• gearbox vibration (see below).

The criteria of this part of ISO 10816 are applicable to the vibration measured on the bearing housings or pedestals of gas turbines and driven equipment using fluid-film bearings. They assume that the measurements are in-situ broad-band values taken under normal steady-state operating conditions. This part of ISO 10816 encompasses machines which may have gears or rolling element bearings but does not address the evaluation of the condition of those gears or bearings.