V - Vibration, mechanical analysis.
Reference for the ISA 5.1 first letter V.
What V means on a P&ID.
First slot V means vibration. Second slot V means valve. The combination VV-101 would translate to 'vibration valve' which makes no physical sense, so the convention disambiguates itself in practice. Critical rotating equipment usually carries a packaged machinery protection system, Bently Nevada or equivalent that interfaces with the BPCS as one block. The V tags inside that block don't always show up on the main P&ID.
Also stands for.
- Modifier. Valve, when used as a second letter, e.g. FV, PV
Common second letters.
| Tag | Meaning |
|---|---|
| VT | Transmitter, VT. Vibration transmitter |
| VE | Sensor, primary element, VE. Vibration probe, e.g. A proximity or acceleration sensor |
| VAH | Alarm high, VAH. High vibration alarm |
| VSHH | Switch high-high, VSHH. SIS trip on high vibration |
Example tags.
| Tag | Meaning |
|---|---|
| VT-101 | Vibration transmitter, often on a compressor or pump bearing |
| VE-101 | Vibration probe, the proximity or acceleration sensor on the bearing housing |
| VSHH-105 | Vibration switch high-high, SIS trip on machinery protection |
Typical placement.
On rotating equipment, compressors, pumps, gearboxes where bearing health, shaft vibration, or housing vibration drive predictive maintenance and shutdown logic.
Common questions
What does the ISA 5.1 first letter V stand for?
In ISA 5.1, the first letter V stands for Vibration, mechanical analysis. It can also stand for Modifier. Valve, when used as a second letter, e.g. FV, PV.
How is letter V typically used on a P&ID?
On rotating equipment, compressors, pumps, gearboxes where bearing health, shaft vibration, or housing vibration drive predictive maintenance and shutdown logic.
What second letters commonly follow V in ISA 5.1 tags?
Common combinations include VT (Transmitter, VT. Vibration transmitter), VE (Sensor, primary element, VE. Vibration probe, e.g. A proximity or acceleration sensor), VAH (Alarm high, VAH. High vibration alarm), VSHH (Switch high-high, VSHH. SIS trip on high vibration).
What are example ISA 5.1 tags starting with V?
VT-101 (Vibration transmitter, often on a compressor or pump bearing); VE-101 (Vibration probe, the proximity or acceleration sensor on the bearing housing); VSHH-105 (Vibration switch high-high, SIS trip on machinery protection).
Run it on your drawings.
Upload a P&ID set and see every tag read in the convention the drawing already uses.