CFM, PSI, and Pipe Diameter

Very good answer Tom and I especially like the part about wearing a belt and suspenders. It never hurts to be safe in these situations and sometimes allot can be on the line. I am assuming that the 2" lines are final runs to some sort of equipment and may be very short? In this case or in the case where one would use a short 2" feeder line from the compressor to the main 6" line I can see it but like you said that is a very large pressure drop if you have to run it in 2" pipe for very far. I think it would be allot better to use a 3" or 4" pipe instead of a 2" for many reasons. I would also think that any equipment that has this kind of capacity would have larger than 2" sized connections as well.

Well, to be exact, we already have two 2" lines that are very long. From each of these 2" lines, there is a 1" that feeds air to two or three mills/lathes. I am proposing to add one or two more 2" lines that will supply the scfm required for some air knives I am installing. From these two 2" lines, I will tap in with a 1" at several places that will feed into the air knives. My whole reasoning behind this question was to determine if our compressors would be able to handle all of this, and if the 6" can sustain the volume/pressure.

Thank you to all for our comments. Keep 'em coming!

Your 6" pipe is in good shape. Try a 3" line instead of 2" just one time. Like the Toby Keith song "That will put a big Texas smile on your face." and your compressor will breath easier too. Pressure drop in plumbing causes your compressor to work harder and use more electricity. The best part is that it is unnecessary.

Of course - I don't know why I didn't think about that. Thanks!