ISO 20816 defines how machine vibration is measured and evaluated — not as a single pass/fail number, but as a framework of severity zones specific to the machine's class and mounting. Vibration is often the earliest observable sign that something mechanical is changing inside a rotating machine, well before a bearing or shaft failure becomes audible or catastrophic. This page explains when and why SRT applies this framework, most often as a mechanical-condition counterpart to the electrical evaluation IEEE 43 provides.
ISO 20816 exists so that "how much vibration is too much" has a defensible answer instead of an intuitive guess. Different machine classes (a small motor versus a large industrial turbine, for example) tolerate very different absolute vibration levels — this standard's framework accounts for that, rather than applying one universal threshold to every machine.
In SRT's practice, this framework is applied when establishing a baseline vibration signature at commissioning, when investigating a reported noise or vibration complaint, during periodic reliability-focused condition monitoring, and — most relevant to recovery work — when verifying that a repaired or recovered machine's mechanical condition has actually returned to an acceptable range rather than just "running."
Reuses the Engineering Context component, extended with Typical Equipment and Industrial Applications.
Applicable Machine Types
Typical Equipment
Any rotating machine mounted on bearings is potentially in scope; in SRT's engagements this is applied most often to motors and their directly coupled driven equipment (pumps, fans, gearboxes) where bearing condition is a central recovery question.
Industrial Applications
Assessment starts with identifying the correct machine class and mounting type, since the evaluation framework this standard provides is class-specific — applying the wrong class's criteria to a machine produces a misleading judgment regardless of how carefully the measurement itself was taken.
Inspection includes selecting appropriate measurement points (typically at bearing housings), verifying sensor mounting is rigid and consistent between readings, and recording machine operating conditions (load, speed) alongside the vibration reading itself, since vibration severity can vary with operating point.
After bearing replacement, shaft alignment correction, or balancing work during recovery, a post-work vibration reading verifies the mechanical repair actually achieved its goal — much as an IR/PI re-test verifies an electrical repair. A motor that "sounds fine" but hasn't been measured against its class's evaluation zone has not been mechanically verified, only assumed acceptable.
The signature feature of this page.
Ask how ISO 20816 applies to your specific machine's vibration.
SRT's own edit history of this reference page — not ISO 20816's own revision history.
| Rev | Date | Change |
|---|---|---|
| 0 | 2026-09-13 | First issue — Release 1 |
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