ISO 20816-3:2022

This document specifies the general requirements for evaluating the vibration of various coupled industrial machine types with a power above 15 kW and operating speeds between 120 r/min and 30 000 r/min when measurements are made in-situ. Guidelines for applying evaluation criteria are provided for measurements taken on non-rotating and rotating parts under normal operating conditions. The guidelines are presented in terms of both steady running vibration values and in terms of changes to vibration magnitude, which can occur in these steady values. The numerical values presented are intended to serve as guidelines based on worldwide machine experience, but shall be applied with due regard to specific machine features which can cause these values to be inappropriate. In general, the condition of a machine is assessed by consideration of both the shaft vibration and the associated structural vibration, as well as specific frequency components, which do not always relate to the broadband severity values presented. The machine types covered by this document include: a) steam turbines and generators with outputs less than or equal to 40 MW (see Note 1 and Note 2); b) steam turbines and generators with outputs greater than 40 MW which normally operate at speeds other than 1 500 r/min, 1 800 r/min, 3 000 r/min or 3 600 r/min (although generators seldom fall into this category) (see Note 1); c) rotary compressors; d) industrial gas turbines with outputs less than or equal to 3 MW (see Note 2); e) turbofans; f) electric motors of any type, if the coupling is flexible. When a motor is rigidly coupled to a machine type covered by any other part of ISO20816, the motor may be assessed either against that other part or against ISO 20816-3; g) rolls and mills; h) conveyors; i) variable speed couplings; and j) blowers or fans (see Note 3). NOTE 1 Land based steam turbines, gas turbines and generators of greater than 40 MW capacity, which run at 1 500 r/min, 1 800 r/min, 3 000 r/min or 3 600 r/min are covered by the requirements of ISO 20816-2. Generators in hydro-electric plants are covered by ISO 20816-5. NOTE 2 Gas turbines of power greater than 3 MW are covered by ISO 20816-4. NOTE 3 The vibration criteria presented in this document are generally only applicable to fans with power ratings greater than 300 kW or fans which are not flexibly supported. As and when circumstances permit, recommendations for other types of fans, including those of lightweight sheet-metal construction, will be prepared. Until these recommendations are available, classifications can be agreed between the manufacturer and the customer; using results of previous operational experience (see also ISO 14694). Machinery including a geared stage can fall under the scope of this document. For performing acceptance tests of gearboxes please refer to ISO 20816-9. The following types of industrial machine are not covered by this document: k) land-based gas turbines, steam turbines and generators with power outputs greater than 40 MW and speeds of 1 500 r/min, 1 800 r/min, 3 000 r/min or 3 600 r/min (see ISO20816‑2); l) gas turbine sets with power outputs greater than 3 MW (see ISO20816‑4); m) machine sets in hydraulic power generating and pumping plants (see ISO20816‑5); n) reciprocating machines and machines solidly coupled to reciprocating machines (see ISO10816‑6); o) rotordynamic pumps and any integrated or solidly coupled electric motors where the impeller is mounted directly on the motor shaft or is rigidly attached to it (see ISO10816‑7); p) reciprocating compressor systems (see ISO 20816-8); q) rotary positive displacement compressors (e. g. screw compressors); r) submerged motor-pumps; and s) wind turbines (see ISO10816‑21). The requirements of this document apply to in-situ broad-band vibration measurements taken on the shafts, bearings, bearing pedestals, or housings of machines under steady-state operating conditions within their nominal operating speed range. The requirements relate to both acceptance testing and operational monitoring. The evaluation criteria included in this document can be applied to both continuous and non-continuous monitoring situations. The requirements of this document cover machines which can have gears or rolling element bearings, but do not address the diagnostic evaluation of the condition of those gears or bearings. The requirements in this document are applicable only for the vibration produced by the machine set itself and not for vibration that is transmitted to the machine set from external sources.