Calculation Parameters

ISO 10816 – Evaluation of machine vibration by measurements on non-rotating parts







RPM



Calculation Results

Machine Class:
—
Zone A (Good) – up to:
—
Zone B (Satisfactory) – up to:
—
Zone C (Acceptable) – up to:
—
Zone D (Unacceptable) – above:
—

Zone Condition Assessment:

Zone A: Vibration of new machines during commissioning
Zone B: Machines suitable for long-term operation without restrictions
Zone C: Machines unsuitable for long-term continuous operation. Repair planning required
Zone D: Vibration level capable of causing machine damage

How the Calculator Works

ISO 10816 Standard

Reference Standards:

  • ISO 10816-1: General guidelines
  • ISO 10816-3: Industrial machines
  • ISO 10816-6: Reciprocating machines
  • ISO 20816: New consolidated standard (replaces ISO 10816)

ISO 10816 establishes general conditions and methods for measuring and evaluating machine vibration by measurements on non-rotating parts. The standard defines four vibration condition zones:

  • Zone A – vibration of new machines
  • Zone B – acceptable for long-term operation
  • Zone C – acceptable for limited time
  • Zone D – vibration causing damage

Machine Classification

Machines are classified into four classes based on power and installation type:

  • Class I: Individual parts of machines connected to the operating machine (electric motors up to 15 kW)
  • Class II: Medium power machines (15-75 kW), up to 300 kW on special foundations
  • Class III: Large prime movers and other large machines with rotating masses on rigid foundations
  • Class IV: Large prime movers and other large machines on flexible foundations

Vibration Velocity Threshold Values

RMS vibration velocity threshold values for zone boundaries (mm/s):

Class A/B B/C C/D
I 0.71 1.8 4.5
II 1.12 2.8 7.1
III 1.8 4.5 11.2
IV 2.8 7.1 18

Measurement Recommendations

  • Measurements are taken in three mutually perpendicular directions
  • Measurement points are selected on or near bearing housings
  • RMS (root mean square) vibration velocity is used in the 10-1000 Hz range
  • The maximum measured value is used for evaluation

Notes

These threshold values are indicative. For specific equipment, manufacturer recommendations and operating history should be considered. For variable speed machines, evaluation is performed at nominal speed.

Usage Examples & Value Selection Guide

Example 1: Small Electric Motor

Scenario: Monitoring a 11 kW electric motor driving a pump

  • Machine Class: Class I (motors up to 15 kW)
  • Power: 11 kW
  • Speed: 2950 RPM
  • Foundation: Rigid (concrete base)
  • Measurement: Bearing housing
  • Result: Zone A: 0-0.71 mm/s, Zone B: 0.71-1.8 mm/s
  • Typical good condition: 0.5-1.0 mm/s
Example 2: Medium Power Compressor

Scenario: Centrifugal compressor with 55 kW motor

  • Machine Class: Class II (15-75 kW)
  • Power: 55 kW
  • Speed: 1480 RPM
  • Foundation: Rigid
  • Measurement: Bearing housing
  • Result: Zone A: 0-1.12 mm/s, Zone B: 1.12-2.8 mm/s
  • Action: If > 2.8 mm/s, plan maintenance
Example 3: Large Turbogenerator

Scenario: 50 MW turbogenerator on spring foundation

  • Machine Class: Class IV (large, flexible foundation)
  • Power: 50 MW (50000 kW)
  • Speed: 3000 RPM
  • Foundation: Flexible (spring supported)
  • Measurement: Bearing housing
  • Result: Zone A: 0-2.8 mm/s, Zone B: 2.8-7.1 mm/s
  • Note: Higher limits due to flexible mounting

How to Choose Values

Machine Class Selection
  • Class I:
    • Motors ≤ 15 kW
    • Small pumps, fans
    • Auxiliary equipment
  • Class II:
    • Motors 15-75 kW (standard)
    • Up to 300 kW on special foundations
    • Medium pumps, compressors
  • Class III:
    • Large machines > 300 kW
    • Rigid foundation (concrete)
    • Heavy rotating equipment
  • Class IV:
    • Large machines > 300 kW
    • Flexible foundation (springs, frames)
    • Turbines, large generators
Foundation Type
  • Rigid Foundation:
    • Concrete block or slab
    • Grout-filled steel frame
    • Natural frequency > 1.25 × operating frequency
  • Flexible Foundation:
    • Spring supports
    • Rubber mounts
    • Light steel structures
    • Natural frequency < operating frequency
Measurement Point Selection
  • Bearing Housing: Primary measurement location
  • Foundation: To check transmission/isolation
  • Structure: For overall building vibration
  • Best practice: Measure at all accessible bearings
Interpreting Results
  • Zone A (Good):
    • New or recently overhauled machines
    • No action required
    • Baseline for future comparison
  • Zone B (Satisfactory):
    • Normal operation
    • Continue regular monitoring
    • No immediate action
  • Zone C (Unsatisfactory):
    • Plan maintenance soon
    • Increase monitoring frequency
    • Investigate root cause
  • Zone D (Unacceptable):
    • Immediate action required
    • Risk of damage
    • Consider shutdown