ISO 10816 Series Overview
ISO 10816 is a multi-part standard covering vibration measurement and evaluation of non-rotating parts of machines. Key parts:
- ISO 10816-1: General guidelines — measurement locations, measuring quantities, and evaluation criteria framework
- ISO 10816-3: Industrial machines with nominal power above 15 kW and nominal speeds 120–15,000 RPM — the most widely applied part in industrial plants
- ISO 10816-7: Rotodynamic pumps — specific limits for centrifugal, mixed-flow, and axial pumps
- ISO 20816: Updated series (supersedes ISO 10816 in some parts) — same zone concept with revised limits
Machine Groups (ISO 10816-3)
ISO 10816-3 divides machines into four groups based on rated power and mounting:
| Group | Machine type | Power |
|---|---|---|
| Group 1 | Large rotating machines, directly coupled to rotating loads (turbines, compressors) | >300 kW, or 15 kW on special support |
| Group 2 | Medium-sized machines, generally electric motors and pumps | 15–300 kW |
| Group 3 | Pumps with multivane rotary impellers, installed on separate foundations | >15 kW |
| Group 4 | Pumps with multivane rotary impellers, installed on common foundations with driver | >15 kW |
Zone Limits — ISO 10816-3 (mm/s RMS velocity)
| Zone | Group 1 — Rigid | Group 1 — Flexible | Group 2 — Rigid | Group 2 — Flexible |
|---|---|---|---|---|
| A/B boundary | 2.3 | 3.5 | 2.3 | 3.5 |
| B/C boundary (Alert) | 4.5 | 7.1 | 4.5 | 7.1 |
| C/D boundary (Danger) | 7.1 | 11.2 | 7.1 | 11.2 |
"Rigid mounting" = machine bolted to a stiff concrete foundation. "Flexible mounting" = machine on anti-vibration mounts or flexible structures.
Zone Descriptions and Actions
| Zone | Description | Action |
|---|---|---|
| A | New or recently overhauled machine in excellent condition | No action — continue routine monitoring |
| B | Acceptable for unrestricted long-term operation | Monitor — investigate any upward trend |
| C | Not suitable for continued long-term operation — marginal condition | Alert — schedule inspection; increase monitoring frequency |
| D | Sufficiently severe to cause damage — operate at operator's risk | Stop machine or reduce load; immediate inspection required |
ISO 10816-7 — Pump Specific Limits
For centrifugal pumps in industrial use, ISO 10816-7 defines limits based on rated power and speed. Key values for pumps >15 kW at 600–3,600 RPM on rigid foundations:
| Zone | Pump class I (foundation-mounted) | Pump class II (integrated unit) |
|---|---|---|
| A/B boundary | 2.3 mm/s | 3.5 mm/s |
| B/C boundary | 4.5 mm/s | 7.1 mm/s |
| C/D boundary | 7.1 mm/s | 11.0 mm/s |
Applying the Standards
The ISO zone limits are useful as a starting point for condition monitoring alarm setting. However, for machines with known baseline data, statistical alarm methods (baseline + N standard deviations) are more sensitive and should be used in conjunction with ISO limits.
For acceptance testing of newly installed or overhauled machines: the machine should be in Zone A or low Zone B when measured under normal operating conditions. A machine leaving the factory or repair workshop in Zone C should be rejected and investigated before acceptance.