Importance of ISO-8573 Air Purity Measurement

EXAIR Accessories

ISO-18573 is a standard that classifies contaminants in compressed air which helps to define purity classes for your compressed air system. This ISO standard is international and effectively a guideline to base your site standards and measurement procedures. Although ISO-18573 helps define the class of air within your system there is no legislation in place for absolute compliance. Some industries may have regulatory targets for compliance and this is why understanding ISO-18573 is helpful in understanding compressed air purity.

There are four (4) general categories that need to be removed or lowered when classifying your compressed air system:

  1. Particulate from pipe scale, wear particles, atmospheric dirt…
  2. Moisture from condensation, vapor, aerosol…
  3. Oil from liquid, vapor, aerosol…
  4. Microorganisms

The international standard ISO8573-1:2010 is a compressed air specification that considers these contaminants by providing a range of purity classes for particulate, water and oil. It does not include class for microorganisms.

When discussing “Clean Air” and the purity everyone involved must use a common standard when discussing clean dry air. ISO 8573-1 Purity Classes will standardize your goals making it easier to accomplish and monitor.

EXAIR has filter separators (5 micron) that come in a variety of sizes along with oil removal filters (3 micron) that are used with our products. EXAIR Intelligent Compressed Air Products are used in just about every industry worldwide using different purity levels. If you have questions please contact any Application Engineer here at EXAIR.

Eric Kuhnash
Application Engineer
Twitter: @EXAIR_EK

Compressed Air System Equipment

Compressed air is a valuable utility and understanding what makes up a solid system is very important. Most all manufacturing facilities have a demand for compressed air, so today we’ll discuss how when managed well, and with the proper equipment, how valuable this utility can be.

The equipment begins with the compressor. Specifying which compressor is best for you is genuinely specific to your needs, and many times even your geography. How many “users” of the air, the distance the air has to travel, how many and how sharp of turns need to be made are all specific to your building and setup. Drastic temperature changes, night and day, and many times summer to winter, can effect the compressor as well. Here is a list of things to consider when purchasing or upgrading the compressor itself:

  1. What is the actual air requirement? (SCFM) – as a rule of thumb – every 1 HP = 4 SCFM
  2. How many shifts, and do these shifts vary in air consumption?
  3. Average and Maximum Flow requirements
  4. What about leaks?
  5. What about the future?
  6. What is the highest pressure needed and why?
  7. How far away form the source are the users?
  8. Would a receiver tank/intermittent storage in the loop benefit your situation?

Compressor: Once you fully have a grasp of your demand, you can now move on to the compressor. There are 5 main types of compressors. One of the most common is the single-stage lubricant injected rotary screw compressor. This compressor is also offered in 2 stage. The other 3 types are a) 2-stage double acting reciprocating compressor b) Lubricant free screw compressor and c) Centrifugal 3-stage compressor. Each of these compressors have their own unique characteristics, benefits and faults. We highly recommend getting a local Air compressor company or professional involved to ensure the correct type and size.

Dirty Inlet Filter: Once the compressor is specified, you will need to ensure you have the best solution for dirty, ambient air being pulled into the compressor. The air coming out, begins with the air coming in, so this filter needs careful consideration based upon your individual ambient conditions. We’ve all heard the saying “garbage in – garbage out”… This filter should be checked, washed or changed often.

Receiver tank: The compressor(s) feed into a receiver tank. Many times this is call the Control Receiver, or the wet tank or cooling tank. Receiver tanks take in the air from the compressor and hold it under pressure for future use. These tanks reduce the cycles on the compressor, and prevents excessive loading and unloading in the system. These are not used on every system, but should be.

Dryer: Regardless of where you are in the world, all atmospheric air has some amount of vapor which will begin to condense into water when the air is cooled to the saturation point (This saturation point is better known as the dew point). The amount of moisture in the air depends on the temperature and relative humidity. As a rule of thumb, the moisture in the air will double for every 20°F increase in temperature. Your dryer should be able to dry the air to a dew point that is at least 18°F below the lowest temperature at the use point of the air. The size and amount of dryers is completely dependent on your companies needs.

Coalescent filter: Right after the dryer, it is recommended to put this type of filter to remove any other condensate, oils, or lubricants from the compressor. Unwanted oil in in the system can effect the machines and tools being used with the air.

Once your pipes have been laid to your point of use areas be it a machine or tools, you will want to have another filter at the point of use. Regardless of the age of your system, piping corrosion will happen leading to particulate in your air lines. You will want to filter this out prior to the final use of the air. The style and size of these filters should be determined at the point of use for the air. If your end use utilizes an EXAIR product – we recommend using our Automatic Filter Separators.

As the final step prior to use, it is recommended to have a pressure regulator and gauge on the line. Over time, every system will deplete air with small leaks, added users, or dirty filters. The most common cause of failure with EXAIR products, is actually lack of the appropriate air at the point of use.

Please keep in mind that this is a fairly simplistic explanation of a common Compressed Air System. Some systems have multiple receiving tanks, refrigerant coolers, dryers, and many different types of filters. The main goal is having enough clean, dry air to ensure that machines and tools function at peak performance.

Thank you for stopping by,

Brian Wages
Application Engineer
EXAIR Corporation
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Find It, Tag It, Fix It: Addressing Parasitic Draw

Leeks, and not the compressed air kind!

Leaks, and not the kind you see on a cooking show, are never good. Before you comment, yes I know the vegetable is spelled leek, that’s just the strength of my dad jokes. The point of this post is actually discussing leaks, mainly of the compressed air variety. All leaks cost. I recently found a leak within my home which was accounting for around a 20% increase in my water bill. Sad to say that it took a few months to locate, and solve the issue. Over the years, I’ve seen many facilities deal with common leak problems like being unable to leave their compressed air pipes energized over night because the parasitic draw will drain the entire system. That’s a problem!

Burst pipes and leaks are ALWAYS costly!

If the leaks are present when nothing is being utilized, then that means parasitic draw is happening on the system. This is when energy that is being converted into compressed air isn’t used but instead, leaking out to atmospheric conditions. These parasitic draws are not always easy to locate, so over the years I’ve had to help a few customers address this problem. One in particular stands out, so I am going to share how we honed in on the leak and ultimately gave them days without a shutdown.

The conversation all started with a customer asking about how our Digital Flowmeters work, and if they could be used to determine which production line is using the most air, and more importantly why their production line shuts down for low air pressure. After I explained how we would select their infeed pipe size as well as size a meter that would fit each machine infeed, we got to talking about the shut down sequence.

The approach they took to solving the issue was to first capture the flowrate of the entire system and then to evaluate the flowrates of each segment of their plant. From there, we would install flowmeters on the higher usage sectors, and drill down to each machine for the finite analysis. They could then go through all the other production lines and generate a full facility consumption profile. To start, they found one packaging line that was using a considerably higher volume of air throughout their first shift than any other line and than any other shift.

Once they started breaking down the high demand production line they found one leg of the production line which had a spike in usage at the same time every day. The trick was they couldn’t find a machine with high usage, that is until they traced all of the piping and found a filter bag house on the roof that had been added to the line at some point. This wasn’t documented and had a piece of pipe that had failed causing an open dump during the cleaning cycle every day at 2:30 in the afternoon.

This was all made possible by setting up multiple flowmeters with wireless capabilities so they could document and compare the usages between machines and production lines ultimately giving them a considerable amount of production time back into the day by fixing a broken pipe that caused daily shutdowns.

If you would like to discuss how to layout a compressed air monitoring system in your facility or the best way to track down the cause of some leaks and high compressed air demand, contact an Application Engineer.

Brian Farno
Application Engineer

1 – Leeks on shelf – Jeffery Martin, CC0, via Wikimedia Commons – retrieved from –

Henri Coanda and his Effect on Compressed Air

Henri defined the Coanda Effect – the tendency of a jet of fluid emerging from an orifice to follow an adjacent flat or curved surface and to entrain fluid from the surroundings so that a region of lower pressure develops.

Compressed air flows through the inlet (1) to the Full Flow (left) or Standard (right) Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.

Henri-Marie Coanda (1885-1972) discovered the Coanda Effect in1930. He observed that a stream of air (fluid) emerging from a nozzle tends to follow a nearby curved surface, if the curvature of the surface or angle the surface makes with the stream is not too sharp. For example, if a stream of fluid is flowing along a solid surface which is curved slightly from the stream, the fluid will tend to follow the surface.

A number EXAIR products are designed to utilize the Coanda Effect and aid their performance. In some products, the Coanda Effect aids to create an amplification area where additional ambient air is drawn into the total airflow to increase total volume of air upon a target. This creates a more efficient and effective product. Also, since not as much compressed air is required, the noise levels decrease for products like EXAIR’s air knives, air nozzles, air jets and air amplifiers. EXAIR has been successful with positive impact for compressed air energy savings and noise reductions helping us meet or exceed OSHA Standard 29 CFR-1910.95 9(a) Maximum Allowable Noise Exposure.

Please contact EXAIR with regards to our Intelligent Compressed Air Products. We can help you with your next cooling, blow-off, drying or any compressed air needs.

Eric Kuhnash
Application Engineer
Twitter: @EXAIR_EK

1- Spoon Coanda image-