# Piping size for plumbing compressed air over a distance

Published Categorized as Compressed Air Plumbing

I have two buildings that are about 300 feet apart. I am trying to figure out what size pipe, and compressor would be needed to span this distance. Or if this is unreasonable distance.

In each building it will have some piping for it, but no more than 50′ in on, and 10′ in the other of additional piping.

Thanks.

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Piping Distance

Your question opens up a lot of other questions that need to be addressed first.

The only reason you would need to adjust the compressor size for plumbing over a long distance is to allow greater pressure from the compressor to overcome the pressure drop that will occur as compressed air travels through the air mains. There’s quite a bit of information on this site about pressure drop. Check the site map or use a search box to find it. Figure out what your pressure drop will be, and you can then, if it’s enough to be an issue, up-size your compressor HP to provide the additional pressure needed.

You don’t indicate what it is that the compressor is supplying. You need to get demand information for the various air appliances you are planning to use to make sure you get a compressor big enough to handle that flow requirement.That’s first! See sizing the compressor on this site for more info.

The overall distance you are planning to plumb air isn’t at all unreasonable. Some plants have miles of air mains in their buildings.

One other point. In the north folks have to contend with freezing outdoor temperatures part of the year so if the compressed air contains a lot of moisture, once it exits a warm building into a cold outside air main, the water in the air will freeze and create problems. That being the case, air that’s being plumbed through walls to the outside in cold temperatures must be very dry to overcome condensation and freezing in the lines.

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Thanks for the input Bill, I found a calculator online to calculate the pressure drop. I have a .28 PSI drop max with 1″ pipe, 320 feet needing 15CFM which is more than needed. Mostly the building far away would be for car tools, and a few minor things. The building where the compressor is would have the bigger stuff.

Now this will be placed in the mountains, so my next question is how would I avoid having water issues? I could burry most of the pipe in the ground, and place insulation around it. With that said, should I have a water filter at the beging of the longest run?

Thanks.

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Air coming out of the compressor will be warm/hot and full of moisture and water vapor.

That water will travel the air line and the moisture will condense as the air cools in the run.

If the pipe hits freezing temperatures, the water will freeze and ultimately could block the air line.

Read the pages about water, and removing water from the lines on this site as it explains how to go about it, and what to do when the lines exit warm to cold and then back to warm.

Good luck. Let us know how it turned out, with a photo or two if you would.