Instrument Air Quality Standard Testing

The quality standard for instrument air is ANSI/ISA-S7.0.01-1996. The American National Standards Institute’s (ANSI) Instrument Society of America (ISA) recognizes the importance of clean dry air (CDA) and the role it plays in running pneumatic controllers and pneumatic instruments. Instrument air that is not clean and dry can have devastating affects on the instruments it controls resulting in system inaccuracies or failures.

ANSI/ISA-S7.0.01-1996 addresses 4 elements of instrument air quality; dew point, particle size, lubricant (aka oil) and contaminants. The compression process dramatically increases condensation and contaminants in the air once it is compressed. Learn more about Compressor Contamination here. Compressed gas contaminants while possibly harmless prior to compression, can have devastating results once they have been compressed. The instrument air quality standard lists the following items to help monitor these elements of concern: Monitored alarms or per shift monitoring for dew point control and filters for particle control. Automatic oilers are discouraged due to the potential for fire and scrubbers or absorbers are suggestions provided, and proper intake placement is suggested for corrosive and gas contaminants. Particulate contaminants can be introduced by any number of sources including the intake or the compressor itself. Desiccant dryers while very helpful and necessary, create particle dust that is often overlooked. Particulate contaminants can clog and corrode orifices in the system. So, how do you determine if you need to make any of these adjustments or determine if your proactive measures are working? It is simple — conduct regular instrument air quality standard testing.

Instrument Compressed Air & Gas Testing Specifications

Trace Analytics, LLC can test to a wide variety of specifications. Some example specs commonly used in Instrument Air Quality are shown below:

ANSI / ISA—S7.0.01-1996

Particles Water Lubricant Content
By Particle Size (N)
maximum number of particles per m3
Vapor Pressure Dewpoint
>40 microns °C °F ppm
NONE < 4 < 39 ≤ 1
A maximum 40 micron particle size in the instrument air system is acceptable for the majority of pnuematic devices. Pneumatic devices that require less than 40 micron particle size shall have additional filtration. Pressure dew point at the dryer outlet shall be at least 10°C (18°F) below the minimum temperature to which any part of the instrument air system is exposed. It shall not exceed 4°C (39°F) at line pressure. Should be as close to zero as possible, and under no circumstance shall it exceed 1 ppm.
(N) At the optical microscope magnification used to determine compliance, the entire filter is scanned with 5 µm being the minimum particle size determined. If no particles are detected, a <5 µm value is entered.
For Nuclear industry - INPO requirements include ensuring that air testing and sampling methods are performed in accordance with the most current ISO-8573 for solid particle content (particulates), humidity (dew point), oil aerosol content, and oil vapor and organic solvent content. Contact Trace for details.
Air & Gas Specifications referenced above may be viewed and/or purchased from: ANSI - American National Standards Institute

Use the AirCheck Kit™ Model K901 With NPT Adapter for testing to ANSI/ISA-S7.0.01-1996.

Some clients are demanding a more stringent air quality specification for their instrument air. ISO 8573-1 can provide a wider variety of Purity Classes to meet their needs. Use the AirCheck Kit™ K8573NB or K8573NX to sample for these more stringent air quality standards.

Established in 1989, Trace Analytics is an A2LA Accredited Laboratory offering instrument air quality standard testing. Our easy-to-use AirCheck Kits™ give you the opportunity to easily obtain compressed air or gas samples. Submitting them for analysis to our state-of-the art facility is even easier. If you prefer, we can locate an independent service distributor to come and take the compressed air samples for you.

To learn more about our A2LA accredited laboratory, analytical techniques and facility visit the About the Lab section of our website. To receive a quote or begin your instrument air quality monitoring program Contact Us for more information.

Other Process Air Industries We Serve:

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