Simple Coiled Line
The most simple, basic air lines are flexible tubes. Coiled line is often used for garages or big shops. Coiled hoses stretch incredibly long distances. When you're not using them, they slink back and out of sight. They're lightweight and affordable. Some shops prefer them because of accessibility and the fact that they can be replaced easily with little cost. Purchase several individual lines of coiled hoses. They come in lengths ranging from a few feet to more than 50 feet long. The ends snap together to plumb a line that reaches anywhere in almost any shop. Hang one from the rafters. Run one along a wall. Install a "T" fixture and run separate lines from an overhead line.
Plastic PVC pipe is the choice for many shops. Look for PVC pipe that's rated at 125 psi or more. Compressors rarely exceed that much pressure, and if they do, they have a safety valve that blows off long before they reach it. The most common PVC pipe used for an air line is 1 1/4 inch in diameter. Install sections of pipe together, using PVC glue and fittings for any configuration of plumbing. Choose elbows ranging from 15 degrees to 90 degrees. Other fittings include "T" shapes for tapping into main lines, 5/8-inch galvanized metal fittings for attaching coiled hoses or any other type of fitting to install drain lines or tools.
Smart air-line plumbing almost always ascends vertically from the air compressor. No matter what type of line you decide upon, it's a good idea to run the line straight upward into the rafters or even attached to the ceiling. Run a horizontal main line from the ceiling line to all points of the shop, branching it off where needed at each workstation or bench. Drop coiled lines downward from the main line for each individual worker or station. This is the most common plumbing configuration for shops. If the ceiling is too high or inaccessible, run the main line along the floor or wall where it's out of the way. Attach the coiled lines to it. If the shop is under construction, drill and place the main line inside the wall as if it were wiring. If you choose to place it in the wall, use PVC or galvanized metal pipe for longevity.
Air compressors generate moisture. It's essential that drains are installed at the lowest point on the main line. If you're using nothing but coiled lines, drain them occasionally by blowing air through them. Steam or mist will come out if there's moisture in the line. When the mist stops, the line is clean. For fixed lines such as PVC, install a vertical line dropping downward from the main line at the lowest point of the line. Install a drain outlet on the end. Water or moisture will gather at the low point where you installed the drain. Open the valve regularly to purge the water or moisture from the line before using it. Water has a detrimental effect on tools. Prolong the life of your equipment by always installing a drain.