What does a psi matter anyway?

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities and you. In this blog we’ll look at why a PSI or two matters.

What does a psi matter anyway?

Underinflated footballs created a viral controversy before Super Bowl 2015.  Measurements of air pressure of 10.5 pounds per square inch (psi) instead of the minimum 12.5 were the issue. Rather than just talk about the issue (a.k.a. Deflategate), engineers performed calculations and more. One company conducted experiments as well.

In its testing, HeadSmart Labs found that on average, footballs dropped 1.07 psi from temperature change in a 75°F room to a 50°F room. Exposing the football to water resulted in an additional 0.75 psi pressure drop. With the combined effects, the footballs’ pressure decreased by an average of 1.82 psi to a max of 1.95 psi.

Richard P. Binzel, professor of planetary science at MIT, calculated that a 5 to 10% drop in temperature could create a drop of 0.5 to 1.5 psi, in a football’s air pressure. Equally important, he noted that the accuracy of the meters used to measure the footballs is unknown.

The bottom line for this or any critical pressure measurement is that for accurate measurements, especially at lower pressures, temperature changes are among the operating environment aspects that should be taken into account and accurate meters need to be used.


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-Dan DeFalco, Marketing Manager, All Sensors Corporation ([email protected]m)