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. 

View 3 Products

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.

View 5 Products

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.

View 1 Products

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.

Do you have an idea for our #expertcorner? Let us know!

Useful links:

Book Your Compressor Service



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


Talk to the team today:  CONTACT US CONTACT US

Read more from our #expertcorner


Just like any other equipment, a compressed air installation also requires the necessary maintenance work during its entire lifespan. Even though maintenance costs are only about 5 to 10% of a machine's annual operating costs, failure to budget for maintenance can have potentially disastrous consequences. …


The air dyer is one of the most ignored cooler in the system. A dirty condenser will cause water in the lines, or worse it will cause complete dryer failure. …


Using nitrogen is not about fully replacing CO2, but it can reduce their consumption of CO2 by close to 70%. Using nitrogen is about sustainability. Creating your own nitrogen is easy and will reduce the use of a greenhouse gas, which is better for the environment. It will also save you money as early as month one adding that savings to your bottom line. …


A question that is occasionally asked by our customers to Ash Air is 'what is the cost of compressed air?'  This article looks at the product costs involved with compressed air, as well as minimising the energy cost of compressors and cost allocation. When looking at these factors, we need to realise what causes dropped efficiency of your compressor, leading to increased costs of compressed air. …


You may have great fall protection measures in place to keep employees safe when working at height, but what about their co-workers below? Dropped tools and other falling objects are a major hazard – and one that isn’t always fully addressed.  …


Providing a safe working environment for operators is essential, especially when using pneumatic tools and compressed air. If there is a failure in the air network and the hose is not adequately clamped, the resulting whiplash could be devastating. Failure to follow best practice can result in injuries, associated production downtime and decreased productivity. …


A common questions asked is why do I need an air dryer for my compressor? Typically, air compressors produce water, and although the water can be drained, there can still be aerosol and vapour droplets that are present. This is because water cannoet be compressed. Water can damage your compressor by corroding the valves, pipes and machinery controls, which will cost you time and money to resolve. In the long run, the cost of a new compressor is a small price to pay compared to the loss of production that could potentially arise due to water damage in your compressor.





…


Air compressors can fail for an assortment of different reasons: Normal wear and tear, lifespan and age of the unit, poor maintenance, power surge, install issues are just a few the come to mind. Check out this blog to find out our top 7 tips to ensure your compressor is looked after!  …


That cold, rainy, and in some places icey New Zealand winter is upon us, and with the following air compressor tips, your air system will be prepared with the preferred temperatures, despite the weather outside. Regardless of whether or not it actually snows or freezes up where you live, most winterisation service recommendations are also basic, solid maintenance procedures that will help extend the life and operational efficiencies of air compressors regardless of whether you live in Queenstown or Northland. …


If you're wondering what an air compressor actually is, you've come to the right place. Simply, air compressors convert power in to air that is pressurised which is then used to power air tools such as spray guns. Air compressors are used in a wide range of applications, so naturally if you want one that will be designed for spray painting your vehicle, you want a compressor specifically made for spray guns! This way your compressor will be able to provide the right amount of power to perform the job. …


Compressed air plays a fundamental role in industrial activities. Depending on the type of application, the energy cost of producing compressed air can be very high. Below are some tips to save on you compressor bill. …

Show More