Glossary
Controls and ancillaries
Instrument air and plant air
Also known as instrument air, plant air, utility air.
Instrument air and plant air are the two grades of industrial compressed air distributed in process plants:
| Attribute | Instrument air | Plant air |
|---|---|---|
| Quality | Filtered, dried, oil-removed | Filtered only |
| Pressure | Typically 6–7 bar | 4–10 bar |
| Use cases | Controls, pneumatic instruments, precision devices | Pneumatic tools, general utility, sonic horns |
| Cost premium | 20–30% over plant air | baseline |
Sonic-horn supply
Industrial sonic horns can use either grade. Plant air is acceptable for most service; instrument air or dried plant air (see air drying) extends diaphragm life by removing the water vapour that would otherwise condense inside the horn.
Related terms
Related terms
- Compressed air (industrial)Compressed air at 4–7 bar from plant or instrument-air systems drives industrial sonic horns. Consumption typically 8–14 Nm³/min during a firing burst.
- Compressed-air filtration and dryingFiltering particulate and drying moisture from compressed air extends sonic-horn diaphragm life by preventing internal corrosion and abrasion.
- Air receiver and surge tankAn air receiver buffers the pulse demand of sonic horns from the upstream compressor. Correct sizing prevents SPL drop-off during multi-horn firing cycles.