Compressor Sizing

Compressor-sizing is not that complex. Yet many folks buy their air compressor without due regard as to how big an air compressor they are really going to need to run their air tools, or compressed air using equipment.

For compressor sizing, all you have to do is figure out how much air you're going to need for all of your home workshop or in-plant operations, and figure out that demand for now and for the foreseeable future.

You need to find out the compressed air requirement for all the air tools, all the blow guns, all the air cylinders, all the air operated diaphragm pumps, all the everything that is in your plant or workshop that uses (or has the potential to use) compressed air.

Nothing to it, right? To start off, here's a bit of a video on the subject.

Compressor Size Matters

There is lots of additional information about compressor sizing on this page, and the comment form at the bottom of the page invites you to ask a question about compressor sizing, or make a suggestion to help others.

Simpler Blocks Of Info When first venturing into the air compressor-sizing arena, folks tend to be more than a bit intimidated. There's such a vast array of compressors, of types, of capacities, with a veritable feast of accessories; it's easy to become confused!

And, though there are many manufacturers of compressors world-wide, all are focused on selling their own products, which may impart a certain bias to the information that's available from them about their compressor-sizing, you think?

Here is help in compressor sizing. I'm going to break what may seem to be overwhelming information down into simpler blocks.

What's The Air For?

Have you determined what you'll be using compressed air for? In order to correctly size your compressor, you really must do some homework towards figuring out the volume of compressed air you will require. Here are some ideas that will help you on your way.

The "ideas" link you may have just visited took you to a short list of some in-plant compressed air applications to help you determine which of those you are or are planning to have, equipment that will be consuming your compressed air.

Total Or Periodic Demand

If it is necessary in your plans to run all of those compressed air using appliances at the same time, and for long periods of time, then you are going to require a much bigger compressor than if they are used intermittently and sporadically.

If your compressor is for continuous air use then start making a list of everything in your plant that uses air, and leave a space beside each to note the expected CFM demand for each. Better yet, use a spreadsheet so that the air consumption numbers can be set up to give you a running total of the air you'll need.

Know that compressed air consumption of tools varies depending on the size of the air tool, it's speed, and the efficiency of that air tool. You need to get the specific compressed air demand for that air tool from the manual or the manufacturer.

You may find the chart below handy in approximating the CFM requirements of an assortment of standard air tools, though your air tool consumption of compressed air, depending on their size and design, may vary.

Air Tool Consumption

Air tool consumption changes based on variables. Grinders will have changes in consumption due to grinding wheel size, and rotary sanders will have their consumption change due to the pad size. Even the same tool from two manufacturers will have different air consumption rates.

Consider "factoring in" the highest air consumption figures you find for the tools you expect to use. You may oversize your air compressor capacity by doing so, but under sizing the compressor you purchase may bring greater long term costs to your plant.

Other Air Use

Air tools are only one of many applications in a plant that consume air. It's necessary to give consideration to all of the ways that you will consume air in your plant and applications.

Often it is air operated automated production machinery that consumes far more air than air tools.

Air operated production equipment with valves, air cylinders and other air actuators is often run for 2 or 3 shifts per day, with uptime measured in weeks. Each piece of equipment may have dozens of air actuators / cylinders operating at high speed.