What’s CFM Mean? | Spal Electric Cooling Fans

Playing to the Fanbase

One of the most common questions Spal hears from customers is “What is the CFM rating?” of a particular fan. Much like my whereabouts in high school, this is a tricky question. That’s because with the CFM rating it’s vital to understand how CFM ratings are determined as well as how much CFM an application actually requires. Spal CFM ratings are based on tests using their ISO certified airflow chamber and the data is not subjective. But, generally speaking, CFM ratings should be looked at subjectively. There is no universally accepted standard method of measure when it comes to determining CFM ratings.

“Think of it like wheel horsepower. Different Dynamometers (dyno’s) will give different wheel horse power ratings. Sometimes there is a ‘correction factor’ from one dyno manufacturer to another. This is the same situation, where measuring on a machine with different certifications could give different data,” said Thom Balistrieri, Director of Aftermarket Sales for Spal USA.

Spal provides tabular airflow data to its customers. This tabular data allows customers to see how the fans perform across the entire static pressure range. That’s critical information when selecting the correct fan for the job, and often the most misunderstood aspect of fan selection. “When customers don’t consider the static pressure drop of the radiator it’s easy to get a fan that is underpowered for the task,” added Balistreri.

Don’t be fooled by false CFM ratings. One way to determine if CFM ratings make sense is to look at the current draw of the fan. The current draw (amps) the fan draws are proportional to overall fan performance. Motor current draw is directly related to motor torque and the amount of pressure the fan can generate to overcome the restriction of the radiator. Put simply: Increased amperage typically equates to increased airflow.