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Calculation Parameters

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

Metric System Imperial System

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

📘 Complete Guide: Vibration Velocity Calculator

🎯 What This Calculator Does

This calculator determines permissible vibration velocity levels for industrial equipment according to the international standard ISO 10816. It's a fundamental tool for diagnosing the technical condition of rotating machinery and predicting potential failures before they occur.

🌍 Understanding ISO 10816 Standard

ISO 10816 is the international standard that establishes rules for evaluating machine vibration by measurements on non-rotating parts (bearing housings, foundations). The standard divides all equipment into 4 classes based on power and installation type, with defined permissible vibration levels for each class.

Vibration Zones Explained:

Zone A (Green): New machine vibration - equipment in excellent condition
Zone B (Yellow): Acceptable for long-term operation - equipment in good condition
Zone C (Orange): Acceptable for short-term only - maintenance planning required
Zone D (Red): Unacceptable vibration - risk of equipment damage

Note: Since 2016, ISO 10816 is being replaced by ISO 20816, but the principles remain the same.

💼 Real-World Applications

Typical Scenarios:

1️⃣ New Equipment Acceptance

After pump installation, vibration is checked. Value should be in Zone A. If higher - installation or balancing problems exist.

2️⃣ Scheduled Diagnostics

Monthly vibration measurements on motors. Trend growth warns of developing faults. Allows planned repairs before failure.

3️⃣ Troubleshooting

Fan became noisy. Measured vibration - Zone C. Cause: bearing wear or rotor unbalance.

4️⃣ Post-Repair Evaluation

After bearing replacement, vibration is checked. Should return to Zone A or B. If not - repair done incorrectly.

📊 Practical Example: Pump Station

Situation:

Centrifugal pump, 55 kW, 1480 RPM
ISO 10816 Class II
Measured vibration: 4.5 mm/s (Zone C)

Action: Urgent diagnostics revealed impeller unbalance Result: After balancing, vibration reduced to 1.8 mm/s (Zone B) ✓

📖 Technical Glossary

Vibration Velocity (RMS)

Speed of oscillatory motion at a point on machine housing. Measured in mm/s. Root Mean Square value in 10-1000 Hz range.

Machine Class

Equipment category by power and installation type:

Class I: Small machines up to 15 kW
Class II: Medium machines 15-75 kW (up to 300 kW on special foundations)
Class III: Large machines on rigid foundations
Class IV: Large machines on flexible foundations

Rigid Foundation

Foundation whose natural frequency > 1.25 × rotation frequency. Practically doesn't vibrate.

Flexible Foundation

Foundation on spring mounts or light frame. Natural frequency < rotation frequency.

Measurement Point

Location of vibration sensor placement. Usually - bearing housing, as close to the bearing as possible.

Vibration Trend

Change in vibration level over time. More important than absolute value - shows defect development.

⚠️ Important Notes

This calculator provides orientation values based on ISO 10816
For critical equipment, detailed engineering analysis is required
Always consider vibration trends, not just single measurements
Local standards may have stricter requirements

🎓 Pro Tips

Measure in three directions: vertical, horizontal, axial
Take measurements at the same points for trend analysis
Record operating conditions (load, temperature, speed)
Use quality sensors and certified instruments
Compare with baseline measurements from commissioning

Permissible Vibration Velocity Calculator – ISO 10816 | Vibromera.eu

Published by admin on October 20, 2025 December 9, 2025

Permissible Vibration Velocity Calculator