ISO 10816 Vibration Severity — Zone Classification Calculator
ISO 10816 — Mechanical vibration — Evaluation of machine vibration by measurements on non-rotating parts
ISO 10816 is the international standard for evaluating the mechanical condition of rotating machinery from vibration measurements taken on the non-rotating parts — bearing housings, machine frames, and pedestals. Part 1 (ISO 10816-1:1995) establishes the general framework: broad-band RMS vibration velocity (mm/s) is measured and compared against class-specific zone boundaries (Zones A through D) to judge whether a machine is in new condition, acceptable for long-term operation, due for maintenance, or must be shut down immediately. Subsequent parts extend the classification to specific machine families (pumps, compressors, steam and gas turbines, wind turbines, and more).
The standard is the first check every condition-monitoring programme applies to rotating equipment: a vibration velocity reading above Zone C is an unambiguous shut-down criterion regardless of machine type. MechanixCalc implements the ISO 10816-1 zone classification engine directly: enter the measured RMS velocity and select the machine class, and the calculator assigns the zone, converts velocity to peak displacement, and flags the alarm or danger level. The same tool provides the full suite of supporting vibration calculations — natural frequency, resonance, isolation design, DVA tuning, Campbell diagram, and shock response spectrum — all in a single PDF-reportable session.
Calculators that implement ISO 10816
What ISO 10816 covers
- Broad-band RMS vibration velocity (mm/s) as the single primary measurement quantity on non-rotating parts
- Four machine classes by size and mounting: Class I (small, ≤15 kW), Class II (medium, 15–75 kW or up to 300 kW on rigid mounts), Class III (large, rigid foundations), Class IV (large, flexible or soft foundations)
- Four severity zones per class — Zone A (new-machine quality), Zone B (acceptable for unrestricted long-term operation), Zone C (alarm — use only for short periods, arrange correction), Zone D (danger — risk of machine damage, shut down immediately)
- Class-specific zone boundaries from 0.71 mm/s RMS (Class I, Zone A/B limit) up to 18.0 mm/s RMS (Class IV, Zone C/D limit)
- Conversion between broad-band RMS velocity and peak displacement at the rotational frequency for single-frequency estimates
- Part 2 through Part 8 extend the framework to specific machine families (large land-based steam turbines, coupled industrial machines, hydraulic machines, compressors, gas turbines, reciprocating machines, and wind turbines)
Parts of the standard
- ISO 10816-1General guidelines (non-rotating parts measurement framework, Classes I–IV, Zones A–D)
- ISO 10816-2Land-based steam turbines and generators over 50 MW
- ISO 10816-3Industrial machines with nominal power above 15 kW and nominal speeds 120–15 000 rpm
- ISO 10816-5Machine sets in hydraulic power generating and pumping plants
- ISO 10816-6Reciprocating machines with power ratings above 100 kW
- ISO 10816-7Rotodynamic pumps for industrial applications
- ISO 10816-21Horizontal axis wind turbines with gearbox
Governing formulas
v_RMS [mm/s] → Zone A / B / C / D (class-dependent boundaries)where v_RMS = broad-band RMS vibration velocity measured on a non-rotating part (mm/s). Zone boundaries by class — Class I: A/B = 0.71, B/C = 1.8, C/D = 4.5 mm/s; Class II: 1.12, 2.8, 7.1 mm/s; Class III: 1.8, 4.5, 11.2 mm/s; Class IV: 2.8, 7.1, 18.0 mm/s. Values from ISO 10816-1:1995 Table 1.
x_peak = v_RMS · √2 / (2π · f_rot) [mm]where x_peak = peak vibratory displacement at the rotational frequency (mm); v_RMS = measured RMS velocity (mm/s); f_rot = shaft rotational frequency (Hz). Note: this estimate assumes the vibration is dominated by the 1× component; multi-frequency broad-band measurements require spectrum analysis.
Frequently asked questions
What is ISO 10816 used for?
ISO 10816 is used to assess the mechanical condition of rotating machinery from vibration measurements taken on the non-rotating structure — bearing housings and machine frames. It compares the measured broad-band RMS velocity (mm/s) against class-specific thresholds to place the machine in one of four zones: Zone A (new-machine quality), Zone B (acceptable long-term), Zone C (alarm — schedule maintenance), or Zone D (danger — shut down immediately). It is the standard reference for condition monitoring and acceptance testing of rotating equipment worldwide.
What are the ISO 10816 machine classes and zone limits?
ISO 10816-1 defines four classes by machine size and mounting: Class I covers small machines up to about 15 kW; Class II covers medium machines (typically 15–75 kW or up to 300 kW on rigid mounts); Class III covers large rigid-mounted machines; Class IV covers large flexibly mounted machines. The Zone A/B boundaries are 0.71, 1.12, 1.8, and 2.8 mm/s RMS for Classes I through IV respectively; Zone C/D danger limits are 4.5, 7.1, 11.2, and 18.0 mm/s RMS. Enter your measured velocity and class into the MechanixCalc vibration calculator to get the zone instantly.
Does ISO 10816 measure displacement, velocity, or acceleration?
ISO 10816-1 uses broad-band RMS vibration velocity (mm/s) as the primary measurement parameter. Velocity is preferred because it correlates well with vibration severity across the mid-frequency range typical of rotating machinery (10–1 000 Hz). The standard also provides guidance on converting velocity to peak displacement or to acceleration when required, but the zone boundaries are defined exclusively in mm/s RMS.
How does ISO 10816 relate to ISO 20816?
ISO 20816 is the successor series to ISO 10816. ISO 20816-1 (2016) replaces ISO 10816-1 as the general framework document and introduces a consistent five-part structure across all machine families. The zone boundary values and the underlying measurement philosophy are essentially unchanged — the same four-zone classification applies — but ISO 20816 consolidates the part numbering, clarifies the frequency range, and adds guidance on shaft-relative vibration (complementing measurement on non-rotating parts). MechanixCalc implements the ISO 10816-1:1995 boundaries, which remain the dominant reference in industry practice.
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