Calculating CFM to MPH

Published
<h3>Calculating CFM to MPH</h3>

The cubic feet per minute (CFM) of a gas describes its volumetric flow rate through a pipe or vent. The volumetric flow is a good measure of how much gas goes through the system, but it isn’t the clearest way of picturing how quickly it moves. To picture this speed, calculate the linear speed, which simply describes the linear distance that the gas travels in terms of miles per hour.

Step 1

Divide the flow rate in cubic feet per minute by the duct’s cross-sectional area. If, for instance, 2,000 cubic feet flow through a duct with a cross-sectional area of 4 square feet each minute: 2,000 / 4 = 500 feet per minute.



Step 2

Multiply this answer by 60, the number of minutes in an hour: 500 x 60 = 30,000 feet per hour.

Step 3

Divide the answer by 5,280, which is the number of feet in a mile: 30,000 / 5,280 = 5.68. This is the air’s speed in miles per hour.

Dave Pennells

By Dave Pennells

Dave Pennells, MS, has contributed his expertise as a career consultant and training specialist across various fields for over 15 years. At City University of Seattle, he offers personal career counseling and conducts workshops focused on practical job search techniques, resume creation, and interview skills. With a Master of Science in Counseling, Pennells specializes in career consulting, conducting career assessments, guiding career transitions, and providing outplacement services. Her professional experience spans multiple sectors, including banking, retail, airlines, non-profit organizations, and the aerospace industry. Additionally, since 2001, he has been actively involved with the Career Development Association of Australia.