Air Compressor CFM Guide

Last updated: November 13, 2020
Published 3:13 am

Introduction

Air compressors are popular tools commonly used at home and on construction sites. They are multi-functional tools used for different purposes including inflating tires and powering pneumatic tools. As a contractor, DIY enthusiast or home owner, you must have used an air compressor a number of times. An air compressor works by pressurizing the air around it in a tank. It sucks up the air around it, stores it in a tank at a very high pressure, and then forces it out through a small outlet. The air compressor can be used for both heavy-duty and small-scale projects and can also power many different pneumatic tools at the same time. Cubic Feet per Minute (CFM) is one of the most important requirements when using pneumatic tools with an air compressor. In this article, we’ll discuss the meaning of CFM and how it can be determined.

How Do Air Compressors Work

Air compressors are powered by electric or gas motors and feature a tank. Once the machine is switched on, it sucks up the air in its surrounding into the tank which is usually made of steel. A large volume of air is forced into the tank, increasing the pressure inside the tank. When the pressure reaches a limit called the “cut-out” limit, the compressor shuts off and stops forcing air into the tank. This pressurized air remains in the tank until it needs to be used. Pneumatic tools are powered by kinetic energy expelled from the air compressor. When the air outlet is open, the air rushes out of the compressor, reducing the pressure in the tank.

Your hands should be as far away from the compressed air as possible because it is dangerous and may peel your skin. Using an air compressor is very easy and efficient because it features narrow nozzles making it easy to get the air in the needed areas. Air compressors are powered by different sources; the most common types of air compressors are those powered by gas, diesel or electricity. Some large-scale industries use air compressors with engines and hydraulic ports.

Another feature that helps air compressors function properly is the pump. Air compressor pumps are of two types; oil-injected pump and oil-less pump. The oil-injected requires a lot of oiling when performing maintenance checks, while the oil-less has better quality but is expensive and noisy. Air compressors should be maintained often so it can work properly; ensure to inspect for leaks, check the differential pressure and monitor the air compressor fitting. Check Air Compressor Maintenance Guide

For more on air compressors, see

Air Compressor Piping Diagrams and Tips

How to Use An Air Compressor?

Air Compressor Sizing Guide

What Is CFM In Relation To Air Compressor

CFM (Cubic Feet per Minute) is a term used when dealing with air compressors and pneumatic tools. It is used to measure the speed of air sucked into and forced out of the air compressor. It measures the flow rate of air pushed out of the air compressor into an object. To explain it better, it is a measure of the amount air forced through the air compressor’s nozzle at a particular time. For instance, if an air compressor has 5 CFM, it can push out 5 cubic feet meter of air in one minute. The CFM rating of an air compressor can often be measured by the size of the tank, cylinders, and the operating speed of the pump.

Pneumatic tools also have CFM ratings that need to be achieved for them to function properly. It represents the amount of air needed to operate the tool. If your pneumatic tool has a CFM rating of 5 CFM, it means it requires 5 cubic feet meter of air in one minute to operate correctly. The CFM rating can be adjusted to meet the requirements of the tools you are using it with. There are two common methods used to increase the CFM of your air compressor. See How to Increase CFM on Air Compressor?

Determining the Correct CFM

Determining the CFM rating required for a task is the most important step when using an air compressor. The CFM determines how much air can be pushed out of the air compressor, and you won’t be able to work without it. If the air compressor is being used with an air tool, the tool’s CFM requirements will give you an idea of the compressor’s rating. Air compressors have to be compatible with the tool being used for that project so it can function correctly. Below are some factors used to determine the CFM needed.

Using Multiple Pneumatic Tools

One of the advantages of using an air compressor is that it can be used with multiple tools. You can have two or more people working on the same project and using the same air compressor. Using multiple will require more power from the air compressor. Add up the CFM requirements for each tool to get an idea of the required CFM for that project.

How You Use the Tools

The method of operating your pneumatic tool can also be used to determine the CFM you need. There are two ways to use your tool; you either use it continuously by holding the trigger while you work or intermittently. If you use your pneumatic tools continuously for a long time, you’ll need an air compressor with a 100% duty cycle. Less power is required if you use the tool intermittently.

Some pneumatic tools have a standard CFM requirement. A pneumatic sander works well with air compressors that work at 10CFM and 100 to 120 PSI, and air compressors with CFM between 2 and 5 work perfectly with pneumatic nailers.

Conclusion

Air compressors are multi-functional tools that can be measured by PSI, pounds per square inch or CFM, cubic foot per minute. Air compressors release a volume of forced air that is measured in CFM. The higher the CFM number of your air compressor, the more air it can push out, and the more power it generates to run your tools. Air compressors with high CFM can be used for heavy-duty industrial work, while those with smaller CFM are used for simpler tasks. It is important to understand what CFM is before buying an air compressor because it’ll give you an idea of the type you need to purchase.