| name | vibration-acceptance-criteria |
| description | Vibration acceptance criteria — ISO 10816/20816 machinery severity zones, velocity RMS limits, bearing acceleration envelope, process plant piping vibration (Energy Institute), hand-arm vibration HAV. |
| metadata | {"priority":7,"promptSignals":{"phrases":["vibration acceptance criteria","vibration limits","ISO 10816","ISO 20816","machinery vibration","bearing vibration","piping vibration"],"minScore":3}} |
Vibration Acceptance Criteria — Complete Skill
ISO 10816 / ISO 20816 — Machinery Vibration
ISO 10816: measurement on non-rotating parts (bearing housing); RMS velocity in mm/s
ISO 20816: updated replacement for ISO 10816; same philosophy
Zone Classification
Zone A: newly commissioned equipment; should always operate here
Zone B: acceptable for long-term operation; no restrictions
Zone C: borderline; cause for investigation; likely short-term only
Zone D: dangerous; can cause damage to machine; shutdown risk
Part-Specific Limits
ISO 10816-3 (industrial machines 15 kW–50 MW, rigid mounting):
| Velocity V_rms [mm/s] | Zone | Class I | Class II | Class III | Class IV |
|---|
| A/B | 2.3 / 4.5 | 4.5 / 7.1 | 7.1 / 11.2 | 11.2 / 18 | |
Class I: < 15 kW, up to 15 kW
Class II: 15–75 kW, medium machines up to 300 kW on special foundation
Class III: large machines 75–300 kW rigid
Class IV: large machines on soft mount
ISO 10816-1 (large rotating machinery 300 kW+):
Zone A/B/C/D boundary velocities [mm/s]:
- Class I (small): 0.7/1.8/4.5/11.2
- Class II (medium): 1.12/2.8/7.1/18
- Class III (large rigid): 1.8/4.5/11.2/28
- Class IV (large flexible): 2.8/7.1/18/45
ISO 10816-6 (reciprocating machines — compressors, engines):
Zone limits higher due to inherent unbalance; up to 28 mm/s (Zone B/C boundary)
ISO 10816-7 (rotodynamic pumps):
Zone A: < 1.4 mm/s (pumps on special foundations, highly reliable applications)
Zone B: < 2.8 mm/s
Zone C: < 4.5 mm/s
Zone D: > 4.5 mm/s
Measurement Requirements
Frequency range: 10–1000 Hz (standard); 2–1000 Hz for slow machines
Measurement location: on bearing housing, perpendicular to shaft, horizontal and vertical
Metric: true RMS velocity in band 10–1000 Hz
Bearing-Specific Criteria
High-Frequency Envelope (HFE/SEE/PeakVue)
Vibration at very high frequencies (2–50 kHz) correlates with early bearing defect severity
Methods:
- SEE (Spectral Emitted Energy): Emerson/CSI
- PeakVue: Emerson trademark; capture spike energy
- HFE: generic term
Acceleration envelope [g-peak]:
Good: < 0.5 g; Alert: 0.5–2 g; Alarm: 2–5 g; Danger: > 5 g (rough guidance; machine-specific)
Bearing defect frequencies:
BPFO (ball pass frequency outer race): N/2 × (1 - d_b cosα/D_p) × RPM/60
BPFI (inner race): N/2 × (1 + d_b cosα/D_p) × RPM/60
BSF (ball spin): D_p/(2d_b) × (1 - (d_b cosα/D_p)²) × RPM/60
FTF (fundamental train frequency): 1/2 × (1 - d_b cosα/D_p) × RPM/60
d_b = ball diameter; D_p = pitch diameter; α = contact angle; N = number of balls
Overall Bearing Vibration (G_rms)
Enveloped acceleration severity:
Good: < 0.015 g_rms; Acceptable: 0.015–0.06; Alert: 0.06–0.25; Danger: > 0.25
(Based on ISO 10816 overall A_rms converted to g; very approximate)
Process Plant Piping Vibration (Energy Institute GL-M1)
Energy Institute Guidelines for Avoidance of Vibration-Induced Fatigue in Process Pipework:
Assessment zones:
Zone A (Green): No significant concern; no action
Zone B (Green): Generally acceptable; check special conditions
Zone C (Amber): Assessment required; may need support changes
Zone D (Red): Immediate action; risk of fatigue failure
Measurement metric: vibration velocity [mm/s_rms] at nominated frequencies
Simplified screening thresholds (EI GL M1 Table 1):
For pipework (straight runs, no significant stress concentration):
Zone A/B: < 12 mm/s_rms; Zone C: 12–45 mm/s_rms; Zone D: > 45 mm/s_rms
Stress concentration effect: fittings (elbows, tees) require lower limits
Screened for each fitting category (Category A–D per fitting type)
Piping vibration causes:
Acoustic resonance from pulsating flows (compressor, pump discharge)
Flow-induced turbulence (high-velocity gas)
Mechanical excitation from rotating machinery
Check: f_natural_pipe ≠ n × f_excitation (resonance avoidance)
Hand-Arm Vibration (HAV) — ISO 5349 / EU Directive 2002/44/EC
Exposure action value (EAV): A(8) = 2.5 m/s² (frequency-weighted; 8-hr daily exposure)
Exposure limit value (ELV): A(8) = 5.0 m/s² (must not exceed)
Frequency-weighted RMS acceleration:
a_hw = √(a_hwx² + a_hwy² + a_hwz²) [m/s²]
Daily exposure A(8):
A(8) = a_hw × √(T/8) [T = daily exposure time in hours]
Time to reach EAV at given a_hw:
T_EAV = (2.5/a_hw)² × 8 [hours]
Power tools typical a_hw:
Grinder: 5–10 m/s²; Hammer drill: 8–20 m/s²; Impact wrench: 3–8 m/s²; Sander: 2–5 m/s²
Health risk: Hand-Arm Vibration Syndrome (HAVS) — "white finger" (Raynaud's phenomenon)
Risk increases with years of exposure and daily dose
Whole-Body Vibration (WBV) — ISO 2631 / EU Directive 2002/44/EC
EAV: A(8) = 0.5 m/s² (vertical); ELV = 1.15 m/s²
Frequency weighting: W_k (vertical, z-axis); W_d (horizontal, x, y)
Vehicles: forklift, agricultural machinery, construction equipment
Health risk: low back pain from chronic WBV
Structural Building Vibration — ISO 10137 / BS 6472
Vertical floor vibration perception:
Threshold: ≈ 0.005 m/s² below 8 Hz; rising to 0.05 m/s² at 80 Hz
OS-RMS90 criterion: occupant-weighted time-averaged; limit = 0.1 m/s² for office floors
Gym floors: higher limits; 0.5–1.0 m/s²
Hospital operating theater: very strict; < 0.02 m/s²
Condition Monitoring (ISO 13373)
ISO 13373-1: vibration monitoring; measurement requirements
ISO 13373-2: analysis and trend monitoring
Alert setpoints: typically Zone A/B boundary (e.g., 2.8 mm/s for ISO 10816-3 Class II)
Alarm setpoint: Zone B/C boundary (7.1 mm/s)
Danger setpoint: Zone C/D boundary (18 mm/s)
Trending: rate of change more important than absolute value for gradual degradation
Output
Provide: vibration velocity V_rms [mm/s] measured, zone classification (A/B/C/D) per applicable ISO 10816/20816 part, bearing defect frequency list [Hz], HFE level [g_peak], piping vibration assessment zone per EI GL M1, HAV daily exposure A(8) [m/s²] vs. EAV/ELV, recommended action (none/monitor/investigate/immediate shutdown), alarm and danger setpoints for condition monitoring system.
