DIN ISO 7919-4:2010-06

The standards of the DIN ISO 7919 series contain provisions for the evaluation of shaft vibration, the standards of the DIN ISO 10816 series contain provisions for the evaluation of housing vibration, when measured in situ in the radial direction, that is transversely to the shaft axis, at or next to the main bearings or in the axial direction on thrust bearings. Two criteria are provided for this purpose. One criterion considers the magnitude of the measured vibration; the second one considers changes in the magnitude of the vibration. In addition, different criteria are provided for transient operating conditions, such as run-up and coast-down. The evaluation procedures presented in these standards are based on broad-band measurements of - vibration under normal steady-state operating conditions; - vibration under other (non-steady-state) conditions, that is under transient operating conditions, including run-up or coast-down, initial loading and load changes; - changes in vibration which can occur during normal steady-state operation. The International Standards ISO 7919-2, ISO 7919-4, ISO 10816-1/Amendment 1, ISO 10816-2 and ISO 10816-4, which form the basis of this standard, have been prepared by Technical Committee ISO/TC 108 "Mechanical vibration, shock and condition monitoring", Subcommittee SC 2 "Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures", the secretariat of which is held by NALS. German collaboration has been performed through Working Committee NA 001-03-06-02 (NALS/VDI C 6.2) "Messung und Beurteilung von Maschinenschwingungen" ("Measurement and evaluation of machine vibration") of the Acoustics, Noise Control and Vibration Engineering Standards Committee (NALS). DIN ISO 7919-4 is applicable to heavy-duty gas turbine sets with fluid-film bearings, outputs greater than 3 MW and an operating speed range under load between 3 000 min ^-1 and 30 000 min ^-1 which drive a generator or are used as drive motors. This includes gas turbines coupled to other rotating machinery either directly or through a gearbox. DIN ISO 7919-4 does not apply to the following: a) aero-derivative gas turbines (including gas turbines with dynamic properties similar to those of aero-derivatives); b) gas turbines with outputs less than or equal to 3 MW (see DIN ISO 7919-3); c) gas turbine driven pumps (see DIN ISO 7919-3); d) coupled steam turbines and/or generators with outputs less than or equal to 50 MW (see DIN ISO 7919-3); e) coupled steam turbines and/or generators with outputs greater than 50 MW (see DIN ISO 7919-2); f) synchronizing clutches which couple the gas turbine to a steam turbine or generator (see DIN ISO 7919-2); g) coupled compressors (see DIN ISO 7919-3); h) rolling element bearing vibration; i) gearbox vibration. (DIN ISO 7919-2 is also applicable to machines which can be coupled to a gearbox, but does not address the evaluation of the vibration condition of those gears.). Compared with DIN ISO 7919-4:1997-08, the following significant changes have been made: - clarification that the standard applies only to gas turbine sets with fluid-film bearings, thus also a new title; - emphasis on the fact that acceptance criteria should always be agreed upon between the supplier and the purchaser prior to the installation of the gas turbine sets; - the inclusion of additional evaluation criteria for the vibration of coupled gas turbine sets during transient operation.