407860-EU-EN v2.7 3/14
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Appendix A: Machinery Classification
When evaluating machinery and equipment it is useful to know their classification range and group
type. There are four machine groups and classification ranges recognized internationally (ISO 2372
and VDI 2056). The limits for vibration severity (mm/s) are shown in the Tables below:
GROUP K – Small Machinery up to 15KW (for example, production motors)
Testing Status
Vibration Severity (mm/s)
Good
0 to 0.71
Acceptable
0.72 to 1.80
Permissible
1.81 to 4.5
Dangerous
Greater than 4.5
GROUP M – Medium-sized Machinery up to 75KW (for example, electrical motors without
special foundations)
Testing Status
Vibration Severity (mm/s)
Good
0.00 to 1.12
Acceptable
1.13 to 2.80
Permissible
2.81 to 7.10
Dangerous
Greater than 7.10
GROUP G – Large Machinery on Heavy Foundations
Testing Status
Vibration Severity (mm/s)
Good
0.00 to 1.80
Acceptable
1.81 to 4.50
Permissible
4.51 to 11.20
Dangerous
Greater than 11.20
GROUP T – Large Turbo Machinery on Special Foundations
Testing Status
Vibration Severity (mm/s)
Good
0 to 2.80
Acceptable
2.81 to 7.10
Permissible
7.11 to 18.00
Dangerous
Greater than 18.00