What Is SCFM on an Air Compressor? SCFM Rating Guide

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SCFM is a critical measurement of airflow volume in air compressors. SCFM, along with CFM and PSI, are acronyms that you should know in order to understand air compressors and ensure you select the right air compressor. This article will provide you with all the relevant information to understand what SCFM is.

Table of Contents

What is SCFM?

SCFM stands for Standard Cubic Feet per Minute and is a measurement of the flow rate of air under standard pressure and temperature conditions. In other words, the SCFM rating of any air compressor is the cubic feet of air that an air compressor can deliver minute by minute while under standard conditions.

There are many standard conditions for pressure, temperature, and even standard relative humidity, so while choosing standard conditions, care must be taken. The SCFM values are calculated after expanding the air up to a standard pressure of around 14.7 PSI.

The accepted standards of temperature and pressure are 68 degrees Fahrenheit and 36 percent humidity at sea level. But, it’s important to know that various industries and organizations have varying opinions on the values that should be used.

Pressure varies inversely with SCFM, so if your PSI is 90, your SCFM will be lower than if your PSI is 50. Lowering your pressure is one method for increasing your air compressor CFM.

The alternative measurement to SCFM is CFM, cubic feet per minute, or ACFM, actual cubic feet per minute. This is the pure flow rate of gas independent of standard pressure or temperature conditions. For more information on the differences between SCFM vs CFM visit our guide here!

Why Is SCFM Important for Air Compressors?

It is crucial to understand and respect your air compressor’s SCFM rating and the rate of airflow you can deliver to your pneumatic tools when you’re deciding which air compressor to purchase.

Knowledge of your air compressor’s SCFM will tell you if you have the right air compressor for the size of the project you wish to complete with your air compressor. If your air compressor is unable to push enough air, this will mean that your applications will not work optimally. On the other end of things, one that pushes more air than you need will cause you to waste money and energy.

It’s said that by calculating how much pressure you need for your applications, you can verify you are working with the right air compressor by finding out its SCFM. An air compressor with 10 horsepower or more should generate around 3 or 4 cubic feet of air per minute at 90 PSI.

Frequently Asked Questions

Are CFM and SCFM the same thing?

No, CFM and SCFM are different in that they use different values in their calculations. CFM (cubic feet per minute) is typically calculated at 90 PSI while SCFM (standard cubic feet per minute) is calculated with standardized pressure and temperature. For more information visit our guide to SCFM vs CFM!

How much SCFM do I need?

To gauge the minimum compressor SCFM rating you need, it is best to examine the SCFM requirements of all the tools you intend to power. You should then multiply the highest tool rating by 1.5 to get the minimum compressor SCFM for your projects. This allows you to have a little bit of leeway, which is important as the actual SCFM varies during the compressor’s operation.

What is the difference between CFM SCFM and ACFM?

CFM is the cubic flow rate of air per minute that an air compressor can deliver, while SCFM is the standard cubic feet per minute of an air compressor at standard conditions. ACFM is the actual cubic feet per minute of the compressor’s flow rate, taking into consideration environmental conditions (standard conditions + ambient temperature, saturation pressure, humidity).

How many CFM air compressor do I need?

The amount of CFM you need for your air compressor typically depends on the tools you plan to power. Most air tools will only require 5 CFM or less, while bigger tools may require up to 10 CFM or more. It’s generally recommended to have a compressor that can provide 1.5 times more CFM than your largest tool to provide you with some leeway.

If you have any questions about air compressor SCFM ratings, please leave a comment below, then someone will be able to help you!

By Ashley Pearce

As a passionate manufacturing and mechanical engineer, I've had my fair share of run ins with air compressors and compressed air systems. With over a decade of experience in the industry, I have both a fresh perspective and time-served hands and mind to help you with your compressor problems (along with our able community!)

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