ISO 10816-3: Vibration Limits for Industrial Machines
The practical standard providing specific RMS velocity limits and evaluation zones for pumps, motors, fans, compressors, and other industrial machines rated 15 kW and above.
Vibromera implements these zone limits in the Balanset-1A portable balancer, which classifies measured vibration into zones A to D on site, before and after balancing.
Portable balancer & Vibration analyzer Balanset-1A
Balanset-1A is a portable, USB-powered vibration analyzer and balancer for one- and two-plane balancing of rotors in their own bearings. The Full Kit includes the interface unit, two vibration sensors, optical laser tachometer, reflective tape, Windows balancing software on a USB drive, magnetic stand, digital scale and transport case. Requires a compatible Windows computer with a free USB port; computer …
Vibration sensor
Vibration sensor for Balanset balancing devices, based on the ADXL335 accelerometer. Supplied with a 5 m cable as standard for measuring vibration during rotor balancing and analysis. A 10 m cable option is available.
Optical Sensor (Laser Tachometer)
Optical laser sensor for Balanset balancing devices, based on the modified HS2234 tachometer. Measures rotational speed without contact using a reflective mark on the rotor. Supplied with a 5 m cable as standard; a 10 m cable option is available.
Balanset-4
Balanset-4 is a four-channel vibration analyzer and balancing system for correction in one to four planes. Designed for cardan shafts and rotors supported on four bearings, it can also serve as the measuring system for a balancing machine. The kit includes four vibration sensors, an optical laser tachometer, USB interface, software, magnetic stand, scale and transport case.
Magnetic Stand Insize-60-kgf
Adjustable magnetic stand for positioning the laser RPM sensor in Balanset balancing kits. The switchable magnetic base provides up to 60 kgf of holding force on suitable ferromagnetic surfaces. Adjustable arms and joints help align the sensor with the reflective mark on the rotor.
Reflective tape
Silver self-adhesive reflective tape for the optical laser tachometer in Balanset balancing kits. Apply a small piece to the rotor to provide a reflective reference mark for rotational speed measurement. Supplied as a 1 m length for multiple setups.
Dynamic balancer “Balanset-1A” OEM
Balanset-1A OEM is the core measuring kit for one- and two-plane rotor balancing and vibration analysis. It includes the USB interface unit, two vibration sensors, optical laser tachometer, reflective tape and Windows balancing software on a USB drive. Compared with the Full Kit, the magnetic stand, digital scale and transport case are not included. Requires a compatible Windows computer with …
Quick Reference: Vibration Severity Limits
Historical reference: ISO 10816-3:2009, now withdrawn. Group/support limits below are cross-checked against Beckhoff’s implementation guidance. See ISO’s edition and replacement record and the current ISO 20816-3 guide.
Measure broadband RMS velocity (mm/s) on the bearing housing. Classify your machine, then find your zone below.
Evaluation Criteria — RMS Velocity (mm/s)
ISO 10816-3 zone boundary values for industrial machines
| Machine Group | Zone A / B | Zone B / C | Zone C / D |
|---|---|---|---|
| Group 1 — rigid Large, rigid foundation, >300 kW | 2.3 | 4.5 | 7.1 |
| Group 2 — rigid ★ Medium, rigid foundation, 15–300 kW | 1.4 | 2.8 | 4.5 |
| Group 1 — flexible Large, flexible foundation, >300 kW | 3.5 | 7.1 | 11.0 |
| Group 2 — flexible Medium, flexible foundation, 15–300 kW | 2.3 | 4.5 | 7.1 |
Newly commissioned machines. Typical of new or recently overhauled equipment in excellent condition.
Acceptable for unrestricted long-term operation. Most well-maintained machines operate here.
Not suitable for continuous operation. Investigate root cause and plan corrective maintenance.
Vibration in this zone can cause damage. Investigate promptly and follow the machine-specific operating and shutdown instructions.
Imperial Units — RMS Velocity (in/s)
Equivalent values for regions using imperial measurement system (1 mm/s ≈ 0.03937 in/s)
| Machine Group | Zone A / B | Zone B / C | Zone C / D |
|---|---|---|---|
| Group 1 — rigid | 0.091 | 0.177 | 0.280 |
| Group 2 — rigid ★ | 0.055 | 0.110 | 0.177 |
| Group 1 — flexible | 0.138 | 0.280 | 0.433 |
| Group 2 — flexible | 0.091 | 0.177 | 0.280 |
⚡ Vibration Zone Calculator
Enter your machine parameters and measured vibration to instantly determine the ISO 10816-3 zone
Visual Comparison of Zone Boundaries
The proportional width of each zone shows how limits expand for flexibly mounted and larger machines.
What is ISO 10816-3?
ISO 10816-3 is one of the most widely referenced industrial vibration standards in the world. Published by the International Organization for Standardization, it provides specific numerical limits for vibration severity on common rotating industrial machines. It serves as the direct, practical application of the general framework established in ISO 10816-1: while Part 1 explains the general principles of how to measure and evaluate machine vibration, Part 3 gives you the actual numbers—the RMS velocity values in mm/s—that define whether a machine's vibration is acceptable or dangerous.
ISO 10816-3:2009 uses four evaluation zones, A–D. The machine groups shown here are Group 1 (large) and Group 2 (medium); each has separate limits for rigid and flexible supports. Support flexibility does not create a new machine group.
ISO 10816-3:2009 was withdrawn in 2022 and revised by ISO 20816-3:2022. This page explains the older edition for existing specifications. For a new assessment, confirm the applicable current standard and the machine supplier’s requirements; do not assume the editions are interchangeable.
Scope and Applicability
ISO 10816-3 applies to a broad range of industrial rotating machinery. Understanding whether your equipment falls within the scope of this standard is essential before applying the zone boundary values.
Machines Covered
This summary of ISO 10816-3:2009 concerns covered industrial machines above 15 kW operating from 120 to 15,000 r/min, measured in situ on non-rotating parts. Examples include suitable electric motors, fans and compressors. Rotodynamic pumps have dedicated guidance in ISO 10816-7; choose the applicable machine-specific part before applying a chart.
Machines Excluded
Machines covered by another machine-specific standard need that standard’s scope and criteria. Examples include rotodynamic pumps (ISO 10816-7), reciprocating machines (ISO 10816-6), and machine tools (ISO 10816-8). Check the applicable edition and its exclusions for turbines, hydraulic machinery and other specialised equipment.
Power Range
Applies to machines rated above 15 kW. Equipment below this threshold typically has different vibration characteristics and is evaluated using manufacturer specifications or other criteria.
Speed Range
Valid for operating speeds of 120 to 15,000 RPM. This covers the vast majority of industrial rotating equipment from slow gear-driven machinery to high-speed turbomachinery.
Measurement Location
All measurements must be taken on non-rotating parts: bearing housings, pedestals, or structural parts that directly respond to rotor dynamic forces.
Measurement Parameter
Broadband RMS velocity in mm/s is the primary evaluation parameter. This single number captures the overall vibration severity across a wide frequency range (typically 10–1000 Hz).
Machine Classification: Two Groups and Two Support Types
Select the machine group from power and, for electrical machines, shaft height. Group 1 covers large machines; Group 2 covers medium machines. Then determine support rigidity separately for each measurement direction. The four rows below are group/support combinations, not four numbered machine groups.
| Group | Power | Foundation | Typical Machines | Key Characteristic |
|---|---|---|---|---|
| 1 | > 300 kW, or electrical shaft height > 315 mm | Rigid | Covered large motors, fans and compressors | Group 1, rigid-support limits |
| 2 ★ | 15–300 kW, or electrical shaft height 160–315 mm | Rigid | Covered medium motors, fans and compressors | Group 2, rigid-support limits |
| 1 | > 300 kW, or electrical shaft height > 315 mm | Flexible | Covered large machines with flexible supports | Group 1, flexible-support limits |
| 2 | 15–300 kW, or electrical shaft height 160–315 mm | Flexible | Covered medium machines with flexible supports | Group 2, flexible-support limits |
How to Determine Foundation Type
Support rigidity is determined by dynamics, not by the material or mass of the foundation alone. The support is rigid in a measurement direction when the lowest natural frequency of the combined machine/support system is at least 25% above the principal excitation frequency, usually running speed. Otherwise it is flexible in that direction.
The same installation can be rigid in one direction and flexible in another. Rubber or spring mounts, a concrete pad, or a steel frame do not by themselves establish the classification. Use measured or calculated natural frequencies and the relevant operating excitation.
When support behaviour is unknown, establish it by a suitable modal, impact or run-up/coast-down assessment before selecting limits. A foundation-to-housing amplitude ratio, felt vibration, or a foundation mass ratio is not a substitute for the frequency criterion.
Guidance on Practical Application
ISO 10816-3 distinguishes between two fundamentally different use cases: evaluating the condition of new or repaired machines (acceptance testing), and monitoring machines already in service (operational monitoring). Each use case has its own methodology and criteria.
Acceptance Testing of New/Repaired Equipment
Acceptance limits should be agreed between the supplier and customer with a stated standard edition, machine group, support condition and operating conditions. The zone descriptions are guidance for condition assessment; they are not automatic contractual acceptance criteria or a universal shutdown rule.
Operational Monitoring of In-Service Equipment
For machines already in service, evaluate both the absolute vibration level and its change from the established baseline. Zones A and B normally permit continued operation; Zone C calls for remedial action because long-term operation is generally unsuitable. Zone D indicates vibration that can cause damage. Follow machine-specific operating and shutdown instructions, and investigate the cause rather than treating the zone as a diagnosis.
Trend-based assessment is equally important. A sudden increase in vibration — even if the reading remains within Zone B — is a significant change that warrants investigation. A machine that has been running at 1.0 mm/s for years and suddenly jumps to 2.2 mm/s is still in Zone B for Group 2, but the change of 1.2 mm/s represents a developing fault that will continue to worsen. The standard recommends establishing baselines for each machine and tracking changes over time, not just checking against absolute limits.
Measurement Procedures
The standard specifies that vibration measurements should be taken at each accessible bearing location in three orthogonal directions: horizontal (perpendicular to the shaft axis), vertical, and axial (parallel to the shaft axis). The highest reading from any direction at any bearing is used for the overall machine evaluation. This "worst case" approach ensures that directional vibration patterns (such as misalignment that primarily manifests in the axial direction) are not overlooked.
| Direction | Abbreviation | Common Defects Detected |
|---|---|---|
| Horizontal (perpendicular to shaft) | H | Unbalance, looseness, bearing wear |
| Vertical | V | Unbalance, structural resonance |
| Axial (parallel to shaft) | A | Misalignment, bent shaft, thrust bearing faults |
ISO 10816-3 is a broadband screening tool. It tells you that a problem exists (by placing the machine in Zone C or D), but it does not tell you what the problem is. To diagnose the specific fault — whether it is unbalance, misalignment, bearing damage, or something else — you need frequency spectrum analysis using a vibration analyzer or portable balancing system.
Practical Examples
Step-by-step evaluations using ISO 10816-3 zone criteria.
Machine: Electric motor rated 75 kW, within the applicable standard scope
Foundation: Concrete pad; support verified dynamically as rigid in the measurement direction
Classification: Group 2 (15–300 kW, rigid foundation)
Measured vibration: 3.5 mm/s RMS on the motor drive-end bearing housing, horizontal direction
Group 2 boundaries: A/B = 1.4 mm/s · B/C = 2.8 mm/s · C/D = 4.5 mm/s
3.5 mm/s falls between the B/C boundary (2.8) and C/D boundary (4.5). This machine is not suitable for continuous long-term operation. Schedule a vibration analysis to identify the root cause — common faults at this level include unbalance, misalignment, or early bearing deterioration.
Machine: Centrifugal fan, 500 kW motor, 1480 RPM
Foundation: Steel frame on spring isolators; support verified dynamically as flexible in the measurement direction
Classification: Group 1 (>300 kW, flexible support)
Measured vibration: 2.0 mm/s RMS (highest reading, axial on drive-end bearing)
Group 1, flexible-support boundaries: A/B = 3.5 mm/s · B/C = 7.1 mm/s · C/D = 11.0 mm/s
2.0 mm/s is below the A/B boundary of 3.5 mm/s for Group 1 with flexible support. The example is in Zone A. This zone assessment alone does not establish acceptance or prove an absence of faults; also apply the agreed acceptance criteria and trend information.
Machine: Electric motor, 45 kW, driving a small blower
Foundation: Rubber mounts; support verified dynamically as flexible in the measurement direction
Classification: Group 2 (15–300 kW, flexible support)
Baseline vibration: 3.0 mm/s RMS (established 6 months ago)
Current vibration: 6.8 mm/s RMS
Group 2, flexible-support boundaries: A/B = 2.3 mm/s · B/C = 4.5 mm/s · C/D = 7.1 mm/s
6.8 mm/s lies between 4.5 and 7.1 mm/s, so this Group 2 machine with flexible support is in Zone C. The increase from 3.0 mm/s also warrants investigation. Plan corrective action using the machine-specific operating instructions, vibration spectrum and trend.
Key Concepts and Best Practices
Actionable Limits
The zone boundaries support condition assessment of machines within the applicable scope. Set acceptance limits and operating alarms from the specified edition, manufacturer guidance, operating baseline and contract; the table is not a universal pass/fail certificate.
Foundation Matters
Apply the correct combination of machine group and support type. A reading can fall in different zones for Group 1 and Group 2, and for rigid and flexible supports. The zone alone does not identify the fault or determine a universal shutdown instruction.
Trend Over Threshold
Experienced practitioners know that the trend is often more important than the absolute value. A machine running steadily at 2.5 mm/s is a lower priority than one that jumped from 1.0 to 2.5 mm/s in two weeks — even though both read the same number today.
Screening, Not Diagnosis
This standard is a broadband screening tool. It identifies that a problem exists but not what the problem is. For root cause diagnosis, use spectral analysis, time waveform analysis, and phase measurements with a vibration analyzer.
Setting Alarm Levels for Monitoring Systems
When configuring alarm levels on continuous or periodic vibration monitoring systems, the zone boundaries from ISO 10816-3 provide a natural framework. A common industrial practice is to set the "Alert" (or "Warning") alarm at the Zone B/C boundary and the "Danger" (or "Trip") alarm at the Zone C/D boundary. Some practitioners set a lower "Caution" level at the Zone A/B boundary to flag early changes. For machines with established baselines, additional change-based alarms (e.g., "alarm if vibration increases by more than 25% from baseline") provide earlier detection of developing faults than absolute threshold alarms alone.
Relationship to Other Standards
ISO 10816-3 is part of a comprehensive family of vibration evaluation standards. ISO 10816-1 provides the general principles. ISO 10816-7 covers rotodynamic pumps specifically. ISO 7919 addresses shaft vibration (measured on the rotating parts with proximity probes) rather than bearing housing vibration, and is primarily used for machines with fluid-film bearings such as turbines. The successor standard ISO 20816-3 (2022) harmonizes the housing vibration approach of 10816 with the shaft vibration approach of 7919 into a single unified framework. Understanding where ISO 10816-3 fits within this family is important for selecting the correct standard for each specific machine and measurement type.
Frequently Asked Questions
For a covered Group 2 electric motor with rigid support, the A/B, B/C and C/D boundaries are 1.4, 2.8 and 4.5 mm/s RMS. With flexible support they are 2.3, 4.5 and 7.1 mm/s. Confirm the scope, support dynamics, operating conditions and applicable edition before using these values.
Classify support dynamically in each direction: a rigid support has a lowest machine/support natural frequency at least 25% above the main excitation frequency. Otherwise treat it as flexible in that direction. Construction material and the presence of isolation mounts are not sufficient on their own.
Yes. ISO 10816-3:2009 was withdrawn on 5 October 2022 and revised by ISO 20816-3:2022. An existing contract may cite the older edition, but new work should establish the applicable current standard and supplier requirements.
ISO 10816-3 does not formally apply to machines below 15 kW. However, in practice many technicians use the Group 2 limits as a rough guideline for smaller equipment. For critical small machines, it is better to establish a baseline vibration level after installation and commissioning, then monitor for changes relative to that baseline rather than applying absolute limits from this standard.
Official ISO Standard
For the complete official standard with full measurement procedures and comprehensive guidance, visit: ISO 10816-3 on ISO Store
The information presented above is a summary for educational purposes. For the full official standard, please purchase the complete document from ISO.
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