Cubic Feet Per Minute (CFM)- Why You Need to Understand Your Compressor?

Air Compressor Specifications

It takes more than just size and color when shopping for an air compressor. There’re a number of specifications as well as vital pieces of information to be considered prior to purchase.

Here’s a brief on the critical air compressor specifications to guide you through your spending.

Pressure

This is measured in Pounds Per Square Inch Gauge (PSIG) with most air tools requiring at least 90PSIG to operate.

Heavy-duty pneumatic applications may require more PSIG to function.

Horsepower

A compressor must have an engine. Horsepower is the amount of work that the engine can perform.

Many compressors in the market are overpowered making them inefficient. 4 Cubic Feet per Minute at 100PSIG for every unit of power is the recommended application.

Regulation

Regulation is necessary for units that don’t need to be operating at full capacity. Instead of manually starting and stopping the motor, a regulator automatically takes over the process.

The two main types of regulation are load/no-load control (when a given pressure is achieved) and modulation control (to draw less air).

Cooling features

These are essential features such as diaphragm cooling, heat exchangers, among others to prevent damage or failure during continuous operation.

Lubrication

Since most compressors have movable parts, lubrication is important to limit wear.

Motor type

Electric or gas-powered?

Most compressors use electricity or gas although alternative fuel applications are slowly being introduced to the trade.

If you are going for power and portability, gas-powered compressors are great.

Cubic Feet Per Minute (CFM)
If you are going for power and portability, gas-powered compressors are great.
Credit: woodmagazine.com

Tank size

The larger the tank, the longer you take without running the compressor motor.

Duty cycle

This is the percentage measure of the time it takes for a compressor to run before shut down. Heavy-duty compressors have a bigger percentage compared to other duties with 100% marked as the “ultimate duty”.

Mounting option

Compressors come in different shapes and sizes. The best configuration is the one that provides the necessary flexibility when mounted.

What Does CFM Stand for?

When choosing a compressor, the most critical detail to note is its CFM rating.

This is what determines the power capacity as well as the number and type of tools you’ll be able to operate at a given time.

Cubic Feet Per Minute is a unit of measurement that describes how much airflow a compressor can push in a minute.

It is important as it defines the suitability of an air compressor for a given application.

CFM Classification include:

  • Displaced CFM (DCFM): Calculates the bore, stroke, and rpm into a CFM figure. Doesn’t consider other variables
  • Standard CFM (SCFM): ISO standard measure of air flow (14.5 PSIA, 68 Degrees F, and 0% relative humidity)
  • Actual CFM (ACFM): Takes in effect all variables such as atmospheric pressure, temperature, humidity, friction, and heat dissipation and will give the true output

How To Choose An Air Compressor Basing On CFM?

It can be quite confusing when you head to the stores to shop for a compressor based on Cubic Feet Per Minute.

The volume of compressed air flow at a given time is effective as it will help you determine what’s best for your capacity.

The Standard CFM (SCFM) is specified by some brands meaning that it is supposed to deliver air at the speed of the particular Cubic Feet Per Minute.

It is also important to note that this may not be your case depending on where you are located. Location matters because air expands and contracts at different temperature and atmospheric pressure levels.

The higher the altitude the lesser the atmospheric pressure. This is why suction capacity will reduce and the same compressor will give lesser air affecting overall performance.

Each tool connected to a compressor will have its own CFM needs making it imperative to choose the ideal unit for your project.

Some tools such as sanders, pressure washers, and shears that require a continuous flow may require a higher Cubic Feet Per Minute.

Determining the right CFM in the large pool of pneumatic tools available in the market can be difficult for some people. Here’s a brief list to make it clear for you:

  • Carpentry tools require 0.3-just over 2CFM. Illustrations include brad and framing nailers
  • Mechanical tools such as ratchets, impact wrenches, and other tools in this category may require 2.5- 5CFM
  • Auto body tools require higher CFM
  • To avoid any future miscalculations and for a better understanding of the compressor based on CFM, two things are important, the CFM and the operating pressure.

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