What Compressor Size do I Need?

One of the biggest challenges is to correctly size your new air compressor. Similarly to everything else, new compressors available on the market are more efficient and employ better technology, therefore you have to understand the application and usage to size the machine correctly. Choosing the wrong air compressor for your facility can lead to problems with production and or increased costs due to wasted energy.

What amount of pressure do I need?

Understanding the flow and pressure requirements for your facility is key when choosing an air compressor. Pressure and flow are two very common terms used when discussing compressed air systems.

Pressure can be measured in pounds per square inch (psi), or bar (metric measure of pressure). To think of this in simpler terms, pressure refers to the amount of force needed to perform certain amount of work at any given point in time. A simple example of pressure and how it works, is to imagine moving a wooden block across a table. In the illustration below, it shows that using 75 psi of compressed air is not enough force to move the block, but 100 psi of pressure has the ability to move the wooden block the desired distance.

The air compressor has to provide enough pressure to perform a given task (in this case it was to move a wooden block). Per illustration below, if 100 psi is required to move the block, anything less than that will not accomplish the task. It is important to understand what pressure is needed in order to size the compressor properly, otherwise you will be faced with problems, similar to illustration below where lower pressure was not able to move the wooden block, or perform the job.

What is the right air flow for my compressor?

Flow, also referred to as Free Air Delivery (FAD) can be measured in cubic feet per minute (cfm), liters per second (l/s) or cubic meters per hour (m3/h) depending on your geographical location. In simpler terms, flow is the ability of the compressor to continue performing a task within an acceptable time frame. The amount of flow required is determined by the length of time needed to complete a given task. Let us consider the wooden block example to explain this further.

To move a wooden block a certain distance every hour will require less flow and can be achieved with a smaller compressor and a storage tank. The compressor will cycle on and off and refill the storage tank for the next time the wooden block is required to move. However, if the wooden block has to be moved constantly within a given time frame, a larger flow of air (or CFM) with continuous flow will be needed, thus requiring a larger compressor. If the flow is insufficient, the process will require frequent breaks while the compressor builds up pressure in the reserve tank, therefore indicating that the compressor might be undersized.

Ultimately, when you are looking to supply enough compressed air for a given application, it is important to consider the amount of compressed air flow (CFM) needed at a specific pressure (PSI) required for the process to work properly.

One of the ways to find out the total flow needed is to contact the manufacturer of the equipment that uses compressed air and request data sheets with desired information. However, the best way to measure accurate flow, is to perform a β€œcompressed air audit”, which can be done by a compressed air sales professional. It is important to keep in mind that rotary compressors tend to put out more flow per kW or HP than piston.

To summarize, pressure (PSI) is determined by the job you are performing, while flow (CFM) will require the understanding of how frequently the job has to be done, or how many jobs you are performing at the same time. It is important to understand that under sizing a compressor will result in pressure drops and inability to complete a task, while oversizing the unit can lead to future mechanical problems and potential failure of the compressor. If you are unsure on how to size your new compressor for existing or new application, always contact a compressed air sales professional for an audit.

Do you have an idea for our #expertcorner?Β 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?'Β  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.Β  …


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.





…

Show More