It's really easy to pick up a low cost air compressor at the local store anymore. But, how do you get the air from the compressor to your application? Folks that are plumbing up compressed air lines for their garages or workshops at home, as well as the professional plant person, have a variety of options with which to do connect the various air-lines available to them.

Usually the air compressor will come with a rudimentary kit which will include a PVC (Polyvinyl Chloride) or RVC (Rubber Vinyl Chloride) air hose. If not, these kits are available as accessories.

Rather than having a clutter of air hose running across the floor (a trip hazard) consider emulating the factory installation. Have the discharge air line from the compressor run up to the ceiling in the garage or workshop, and then install "drop lines" down to the various locations on the bench where compressed air might be used.

The discharge from the compressor should have, at the very least, a compressed air filter where the air exits the receiver / tank, and the smaller home-compressors will often have a regulator there as well. Compressing air causes water problems, and you can read more about this in my article in this E-zine entitled "Why does water run out my compressed air lines...". The regulator is necessary too, and you can read about this in an article titled "Why use a compressed air regulator" also on this site.

Commercial installations of compressed air will have a large general purpose compressed air filter at the compressor discharge, and then a filter, regulator and sometimes an in-line lubricator (oiler) at each of the points where the compressed air is to be used, to help deal with compressor generated water.

The regulator will provide the ability to control the pressure of the air to that particular application. You might want 90 PSI of air to run a grinder at one drop line, but farther along the bench you might only want 12 PSI for an air brush paint set up. Individual regulators give you this capability. If you are installing a regulator at each drop location, remove the regulator at the compressor to ensure you have full pressure and flow to the air main overhead and the drop lines.

On your work bench, at the bottom of each drop line, you can install a coupler. A coupler is a device into which you can insert a connector. The coupler will be "checked", meaning that compressed air is trapped at that point until a connector is inserted into the coupler which opens the "check" and allows air to flow.

Compressed air can then be supplied to the air tool or whatever you wish to drive with compressed air via an air-line extension cord. You can purchase ready made or you can make your own. They are lengths of air hose or tube with a connector at one end and a coupler at the other. The air tool will have a connector in it's air port. When ready to supply compressed air to your tool, you simply insert your air-line extension cord connector into the drop line coupler, and the other end, which will be a coupler, has the air tool connector inserted into it.

Connectors and couplers are not all the same. Different manufacturers have differing styles and they are not usually interchangeable. When you first start purchasing couplers and connectors for your air line, make a note of the brand first purchased, and purchase the same brand as your needs continue.

I remember the difference between a coupler and a connector by making a mental image of a "cup" into which I insert the connector. The "cup" is the coupler.

If it were me installing an "air main" and drop legs down to my workbench in my garage, I would use soldered copper pipe. Copper pipe won't rust, and there are more than sufficient adapters available to convert from the soldered (sweated) copper to a thread.

If opting for an overhead main, know that the longer the supply line to the application, the more pressure loss there will be. Each elbow and every turn creates a loss in available pressure at your application, so make the air main as large as practical. How big? Why not 3"' copper pipe at the ceiling and 3/4" copper drop lines for the home workshop?

Remember that PVC or RVC air hose size is measure on the I.D. A 1/2" air hose will have a 1/2" I.D., regardless of the O.D. of the line. Different air line manufacturers will have hose with different wall thickness, so the outer diameters will vary.

To connect PVC or RVC air hose together, you can use the aforementioned couplers and connectors. Usually the coupler and connector has a "barbed" male protrusion, though other styles are certainly available. Make sure the "barb" size of the coupler / connector corresponds with the internal diameter of your air hose. A gear clamp (do yourself a favour and purchase stainless steel clamps over carbon steel. A few pennies more, but much longer life) is installed on the hose first, and then the barb is inserted into the I.D. of the hose. After insertion of the "barb" the gear clamp is brought up the air hose, over the area where the "barb" is inserted, and tightened firmly. Using a small wrench to tighten the clamp is preferable over a slotted screw-driver which have a tendency to distort the nut.

There are a variety of other fittings available to join air hose. "Barb" to "barb" connectors, "barbed" elbows, "barbed" T's, and so on.

Source:   connector hose,  stainless steel hose

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