Richard Ferguson wrote:
A variation on that theme is to measure the time required to increase
the pressure of the tank by 15 psi (14.7psi is atmospheric pressure at
sea level.)

Let me try a sample calculation.

25 gallon tank x 0.1337 cuft/gal = 3.34 cubic feet

If it takes 30 seconds to increase the tank pressure 15 psi, it would
take one minute to increase the tank pressure 30 psi (disregarding
efficiencies). 30 seconds is half a minute.

3.34 cubic feet / 0.5 minute = 6.68 CFM

Richard

Thanks, that is very straightforward. So if I measure the time from
60psi to 75psi and plug that in I should get a conservative value of
true CFM for 60psi ?