Free Engineering Tool
Permissible Vibration Velocity (ISO 10816)
Look up permissible vibration velocity limits per ISO 10816 / ISO 20816. Select machine class, enter measured velocity to get zone evaluation A/B/C/D.
Results
| Zone | Velocity Range | Meaning |
|---|
Vibration Velocity RMS
The vibration velocity RMS value is related to peak velocity by:
- vRMS — root mean square vibration velocity (mm/s)
- vpeak — peak vibration velocity (mm/s)
ISO 10816 evaluates machine vibration severity based on broadband vRMS (typically 10–1000 Hz). Machines are classified into four groups, and each group has four evaluation zones (A, B, C, D).
ISO 10816 Zone Boundaries — All Classes
| Zone | Class I (≤15 kW) | Class II (15–75 kW) | Class III (rigid, >75 kW) | Class IV (flexible, turbo) |
|---|---|---|---|---|
| A (New) | ≤ 0.71 | ≤ 1.12 | ≤ 1.8 | ≤ 2.8 |
| B (Acceptable) | 0.71 – 1.8 | 1.12 – 2.8 | 1.8 – 4.5 | 2.8 – 7.1 |
| C (Tolerable) | 1.8 – 4.5 | 2.8 – 7.1 | 4.5 – 11.2 | 7.1 – 18 |
| D (Damaging) | > 4.5 | > 7.1 | > 11.2 | > 18 |
All values in mm/s RMS.
Practical Example
Given: Measured vibration velocity = 3.2 mm/s RMS
Class II boundaries: A ≤ 1.12, B ≤ 2.8, C ≤ 7.1, D > 7.1
3.2 mm/s exceeds B boundary (2.8) but is below C boundary (7.1)
Result: Zone C — Tolerable for limited periods only. Plan corrective action.
Vibration velocity is the speed at which a vibrating surface moves back and forth, measured in mm/s RMS (root mean square). It is the most widely used parameter for evaluating machine condition because it correlates well with vibration energy and the risk of mechanical damage.
ISO 10816 and ISO 20816 define permissible velocity limits organized by machine class and evaluation zone.
ISO 20816 is the modern replacement for ISO 10816. The zone boundaries and machine classes are essentially the same for housing (non-rotating parts) vibration evaluation.
ISO 20816 adds shaft vibration requirements and updated measurement practices. For broadband velocity RMS evaluation on machine housings — the most common industrial use — the classic ISO 10816 limits still apply.
Vibration velocity is measured with an accelerometer or velocity sensor mounted on the machine bearing housing. The sensor signal is processed by a vibration analyzer to produce a broadband RMS velocity value in mm/s.
Measurements should be taken in three directions: horizontal, vertical, and axial. The highest reading is used for zone evaluation. The standard frequency range is typically 10–1000 Hz.
Zone C: Vibration is tolerable only for limited periods — plan corrective action soon.
Zone D: Vibration is severe enough to cause damage — stop the machine immediately if possible and investigate the root cause.
Common corrective actions include: dynamic re-balancing, shaft alignment correction, bearing replacement, looseness repair, or addressing structural resonance.
For most industrial machines, a piezoelectric accelerometer with integrated electronics (IEPE/ICP type) is the standard choice — the acceleration signal is electronically integrated to velocity.
For low-frequency applications below 10 Hz, electrodynamic velocity sensors may be preferred. Ensure the sensor frequency range covers at least 10–1000 Hz per ISO 10816.
The procedures described on this page were developed and field-tested by the Vibromera team using the Balanset-1A, a portable dual-channel balancer and vibration analyzer for on-site rotor balancing.
Professional field balancing instruments with built-in ISO 10816 zone evaluation. Measure, analyze, and balance on-site. Used in 50+ countries.
Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
