There are several different materials available to consider, black pipe, copper, PVC, rubber hose, etc. Each material has its strengths and weaknesses.
Black pipe typically comes in 20', 10' and nipple lengths. Consider purchasing from a local plumbing supply house. They typically they carry a better quality of pipe than the local home supply store.
A draw back of black pipe is water and rust. Really, there is only some much that one can do to dry the air. Unfortunately a percentage water does travel in the air stream and will be deposited on the inside of the line. Over time the inside of the line will rust. The question is how long it will take until the rust weakness the wall. Usually a compressor tank will rust out sooner than the air piping.
Tip: Install a tee on the pipe before it transitions to a horizontal run. Have the leg of the tee pointing down. Cap off the end or put a full flow ball valve on the end of the nipple. It will serve a couple of purposes. First, it will help trap debris in the line before it jams your air tools. Second, it will act as a water drain.
Black pipe takes some time and effort to install. It will be necessary to cut and thread the pipe. This will require either having determined before hand, and having the material cut and threaded at the store. Or, rent a pipe threader, manual or powered. Side note, growing up I have cut threads on black and galvanized pipe that was being run for the natural gas lines in a new home (teenage summer job). Cutting threads with a manual tool is not that hard to do; however, power threaders are nice.
Copper is a nice material to use for air distribution system. It is easier to install than black pipe. It does not rust. It will handle the pressure a home air compressor puts out. If the copper tubing fails it will fatigue and bulge out instead of bursting with shrapnel.
Type L and K copper pipe is acceptable for compressed air applications. Type M is NOT. Type M is usually used in residential homes for the fresh water supply lines. The pressure that a copper pipe can handle is dependant on the temperature and the size of the pipe - for more information, see Table 6, Publication 28E, of the CCBDA. The joints are usually rated for less pressure than the pipe.
PVC pipe is very attractive for the home wood worker. It is low cost, easy to install and does not rust. Here is the big problem with it. If / when the pipe ruptures it will send sharp shards of plastic flying and can injure a person. The last thing that you want to have happen is the pipe to fail when your child is in the wood shop with dad. Check out this OSHA bulletin for more information.
I have seen home wood shops that string rubber air hoses along the walls of the shop. The draw back to this solution is that cutting the air hose is not an option since special tools are needed to crimp a fitting on the end. So, what to do? Well just coil up the excess tubing and all is well. Well.... Not really, for each bend in the air line adds turbulence and increases the static air pressure in the line. Thus there will be a significant drop in air pressure at the tool end of the hose compared to the setting on the air compressor's regulator.
