estimating cubic feet of air in pipes

Uni R_2

You can put this in a spreadsheet.

Let's say cell B2 is the diameter in inches and B3 is the length in feet.

In B4 the formula to calculate the CF would be:

=((B2/2)*(B2/2))*3.14159*B3/144



Or as a quick and dirty Dia" x Dia" x Len' x .006

3" x 3" x 25' x .006 = 1.35cf

steam newbie

cubic feet of air in pipes?

Hi everyone. I'm the new super of a steam heated 157 unit building in Manhattan. Due to what I'm assuming was either ineptitude or lack of concern by former supers, I have a big heating mess on my hands. Thanks to Ken at Gorton's, I was directed to this site. My previous building did not have steam heat so I'm desperately trying to figure out this system before the Arctic blasts arrive. I've ordered a couple of the books (which have yet to arrive)and "Balancing Steam Systems" (the e-book... which has been incredibly helpful so far).

Anyway, my question: (and I'm sure the answer is so obvious it hurts) how do you figure out the cubic feet of air in the pipe that needs to be vented? I know it has to do with the size and length of the pipe (My mains are 3"). If I look at system drawing #1 from "Balancing Steam Systems" I see that 20 ft of 1 & 1/2 pipe = .28 but I don't know how one arrives at that. I'm sure there is a standard on the cf in any size pipe, but I don't know what it is.

I would appreciate any help I can get on this. Thanks!

steam newbie

thanks

Hey Uni R,

Thanks so much for the information. I truly appreciate the help.