Air Compressor CFM Guide
Air Compressors are common in the home and workplace. You can use them for various purposes, including inflating tires, filling gas cylinders, removing paint from cars, and undertaking DIY projects. Brought to you by Best of Machinery, there are so many effective ways to use an air compressor that we thought you should know more about them!
What is an Air Compressor?
An Air Compressor is a motorized tank of high-impact air. They’re usually portable, so you can take them on the job for a range of tasks.
These tools blast a high volume of air in a concentrated place. You control the air pressure with a gauge. High pressured air is very abrasive; if it can take the paint off a car, think how easily it could take the skin off your hand! Lowering the pressure of the air means you can use it for multiple purposes.
The ideal pressure is 30 PSI, though avoid letting the air make contact with your skin! It’s possible to target the compressed air onto specific areas, thanks to a pinpointed nozzle available in different shapes and sizes. In addition, many models of air compressors come with accessory kits. This way, you can choose the right tool for the job.
What does CFM Stand for in Relation to an Air Compressor?
When purchasing an air compressor, you’re sure to come across term CFM. It might seem complicated, but actually, you’ll be pleased to know that it’s not! Simply put, CFM stands for ‘cubic foot per minute.’ This measurement refers to the amount of air being pushed down the hose and through the nozzle.
The bigger the number, the more air is pushed through the compressor. The higher the air pressure, the greater the speed expelled from the compressor, and the more powerful the blast.
How to Determine the Correct CFM
When looking for an air compressor, it’s important to know the specific CFM you need. This will help you complete jobs properly, keep your air compressor from being damaged, and ensure your safety while working. You must be sure that any tools you use alongside it are compatible with the compressor so that it can work to the best of its ability,
Here are a few popular examples to consider:
- If you want to use an air sander, you’ll need an air compressor of up to 10CFM and 100 to 120 PSI.
- If you want to use an air nailer, you’ll need an air compressor with a CFM between 2 to 5 that offers a PSI of 70 to 90.
Calculating the Real CFM of your Air Compressor
The CFM of an air compressor is rarely represented accurately by manufacturers. This can sometimes be problematic for users. The best thing to do is to test the CFM of the air compressor yourself. This may seem complex, but don’t worry – it’s super straightforward. You’ll do a much more accurate and safe job if you know exactly how much air you’re using and the rate at which you’re doing so.
- What is the air compressor volume? This measurement is in gallons and is always marked clearly on the tank itself.
- Divide the air compressor volume by 7.48 so that you can determine the specific amount of gallons in a singular cubic foot.
- Now release the remaining air from your air compressor.
- Start to refill the air compressor. Record precisely how long it takes for the tank to reach full capacity. You must pay close attention to the gauge on your air compressor.
- Make a note of the PSIG at two different intervals, ideally as soon as you turn the air compressor on and as soon as you turn it off (when the tank has reached its capacity.)
- Next, subtract the second PSIG reading from the first.
E.g., If you turned the air compressor on at 80 PSIG and off at 105 PSIG, the difference is 25 PSIG.
- Divide the difference between the two PSIG recordings by 14.7. This will decipher the pressure added when the tank was refilled. This is referred to in units of atmospheric pressure.
- Using the notes you’ve made from previous steps, take the tank volume and times it by the atmospheric pressure. You’ll end up with a number that refers to the number of pumps it took for your specific air compressor to fill its tank.
- You then need to convert the number to minutes. Finally, take the number and divide it by the seconds it took for this process to occur. Having done this, times the number by 60, and you’ll have successfully worked out the correct CFM of your air compressor.