What is the pressure for instrument air design?
Instrument Air Design Pressure
The typical instrument air (IA) design pressure in industrial applications is usually within the range of:
- Normal Operating Pressure: 6 to 8 bar (87 to 116 psi)
- Design Pressure: 8 to 10 bar (116 to 145 psi)
- Minimum Pressure Requirement: 5.5 bar (80 psi) (to ensure proper operation of instruments)
Why is 6–8 Bar Common?
- Most industrial control valves, actuators, and pneumatic devices are designed to operate efficiently within this range.
- Too low a pressure can cause malfunction or sluggish response.
- Too high a pressure can cause excessive wear, leaks, or damage to instruments.
- Most air compressors in industrial plants are rated to supply air at 8–10 bar, ensuring adequate supply even with pressure drops.
- Pressure losses are introduced via pipes, fittings, and filters. A larger design pressure guarantees sufficient leeway to consistently maintain the minimal operating pressure needed.
Important Things to Think About for the Instrument Air Design Quality Standard
- Instrument air needs to be clean, dry, and oil-free, according to ISO 8573-1 Class 1.4.1.
- Dryness: To avoid moisture-related problems, maintain a dew point of -40°C (-40°F) or lower.
- Filtration: Oil and particles are removed using a 0.01-micron filter.