What is compressed air humidity?

Air, water vapour and condensation

Air usually has a certain level of humidity, meaning it contains a certain amount of moisture, water vapour or condensate. The amount of vapour air is able to absorb depends on the temperature of the air. The higher the temperature of the air, the more water vapour it absorbs or holds.

The maximum amount at any given temperature is called the relative humidity. When relative humidity reaches 100%, the air is no longer able to absorb any more water vapour. This is known as a saturation point or a dew point. It’s the point at which condensation begins to form. 

Compressed air and condensation

The higher the temperature of air going into an air compressor, the more water vapour in the air and, as such, the more condensation that will be produced. If the ambient air temperature is 20°C, there will be about 17.30 g/m3 of moisture in the air. At 35°C, this more than doubles to 39.63 g/m3.

When the air is compressed the temperature initially rises, even as the volume of air – what we just saw as m3 â€“ reduces.

The air will also eventually cool. And as it cools, the amount of moisture in the air won’t change. Instead, because the compressed air has less volume, it will be unable to hold as much water vapour or condensate, resulting in condensation. 

How much condensation depends on the temperature and pressure of the compressed air. At a pressure of 800 kPa, the compressed air has only 1/8 the volume it previously had. This means it will only be able to hold 1/8 of the condensate. The rest turns into condensation as soon as temperatures begin to drop.

This means condensation needs to be removed from compressed air before the temperature drops, which usually happens when the air is discharged from the air compressor. For this reason, a condensation or adsorption dryer is used to eliminate condensation.

Avoiding condensation in compressed air

What else will help to reduce condensation? Keep the temperature of your intake air as low as possible. This is particularly important in the summer months, or if you’re working in a particularly warm or humid environment. 

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Refrigerated Air Dryers

Ash Air has a range of quality cycling and non-cycling Pneumatech refrigerated dryers for your air compressors.Our non-cycling Pneumatech refrigerated dryers offer a reliable and economic solution for removing moisture from your compressed air system. These refrigerated dryers for air compressors are easy to install, offer energy savings, prevent pressure losses, are equipped with rotary compressors and R410A refrigerant, and have improved connectivity features.

The Ash Air collection of very dependable cycling Pneumatech refrigerated dryers offer easy-to-use controllers, are easy to install with low maintenance needs, and are energy efficient with zero-loss drains.

We also supply a range of superior performance refrigerated dryers for air compressors with variable speed technology that matches energy consumption to the actual compressed air demand, have stable pressure dew points, and are available with both air-cooled and water-cooled condensers.

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Desiccant Air Dryers

Our innovative desiccant dryers give customers efficient protection against the presence of any humidity in the air, which often is the source of pipe corrosion and decreased efficiency of equipment and tools.

The Ash Air range of advanced technology 360-1080 m3/hr and 1188-10800 m3/hr adsorption air dryers are for customers who have a focus on energy efficiency and low operating costs, while maintaining the highest standards in air purity. Our Pneumatech blower purge air dryers use heated blower purge air to remove moisture from the desiccant material, which means no purge loss during regeneration.

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Breathing Air Dryers

Here at Ash Air, we offer BA 15-310 HE Breathing Air Purifiers. The Pneumatech solution for Industrial Breathing Air applications, build to exceed standards. The Breathing Air Dryer range assures safe working environment in a wide range of applications. Built to exceed standards, Breathing Air Dryers provide certified breathing air, even in situations with polluted intake air to ensure personnel safety at all times.

The Pneumatech solution for Industrial Breathing Air applications, build to exceed standards. The Breathing Air Dryer range assures safe working environment in a wide range of applications. Built to exceed standards, Breathing Air Dryers provide certified breathing air, even in situations with polluted intake air to ensure personnel safety at all times.

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Who we are and how Ash Air can help your business!

Ash Air has been around in New Zealand since 1979, and we’ve grown into a nationwide company with international support and a reputation for quality and reliability.We look after all things compressed air for your business!

  • Reciprocating, Screw, air compressors
  • Vacuum pumps
  • Nitrogen
  • An extensive line of air treatment components

Ash Air's range of Chicago Pneumatic, Alup, Pneumatech, and Quincy compressors are used extensively around the world in industries ranging from oil and gas to food, automotive and farming, and we bring you these world class compressors here in the land of the long white cloud.Our technicians are compressed air equipment experts and are dedicated to addressing customer needs. Supported by a 13 locations nationwide, Ash Air offers one of the widest selections of compressed air equipment and parts available today in New Zealand.

Reliability and Efficiency

With Ash Air compressors, you can count on reliability and high performance for even the most demanding applications. We focus our efforts on the following:

  • Increasing uptime
  • Reducing unexpected repairs
  • Reducing energy consumption
  • Improving the cleanliness of compressed air


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