FPM to CFM

[Unregistered]

I need to measure the amount of cfm in a 24" pipe, I can calculate the FPM but how can I convert to CFM.

[Robert Fogt]

You need to multiply the feet per minute times the cross-sectional area of the pipe.

Make sure all units are the same base unit.

feet/minute * square feet = cubic feet/minute

The formula for the area of a circle is Pi*radius², with radius being 1/2 the diameter.

Is the 24" the inside diameter? If so then:
3.14 * (1 foot * 1 foot) = 3.14 square feet

FPM * 3.14 square feet = CFM

[dr_rupa]

I need to know 500 FPM = how much CFM

[Robert Fogt]

That depends on the cross-sectional area of the pipe. (or river or whatever it is)

feet/minute (FPM) * square feet = cubic feet/minute (CFM)

[mflanagan]

How do you calculate the cross sectional?

[Robert Fogt]

The formula for the cross-sectional area of a pipe is:

Area = Pi * radius2

[britt44]

I need to find out how many cfms i need to in a 1000 square foot space with 12 foot ceilings

[Unregistered]

you will need
1200 cfm

[Unregistered]

you will need
1200 cfm
According to ASHRAE you will need to know what the space is used for and or how many people are going to be in it (if in the usa). most office spaces require 20cfm/person of outdoor air alone! and then whatever u need for cooling, usually .5cfm/sq ft. you should call a hvac contractor as i've been out of the business for about 5 years and dont have the latest figures, but that's what it was when i was designing systems, good luck!

[Unregistered]

how do you calculate the cross sectional?

1000fpm how mach cfm

[SAJID]

i want to know if a package unit ac has 800 cfm how i know that what is its fpm