U.S. Federal Pipe Regulations 55 Code of Federal Regulations (CFR) 1229

§1229.1. All pipe is to consist of a long hole surrounded by metal or plastic.

§1229.2. All pipe is to be hollow throughout the entire length. Do not use holes of different length than the pipe.

§1229.3. The I.D. (inside diameter) of all pipe must not exceed the O.D. (outside diameter); otherwise the hole will be on the outside of the pipe where it does not belong instead of on the inside the pipe where it belongs.

§1229.7 All pipe is to be supplied with nothing in the hole so that water, steam, or other stuff can be put inside at a later date.

§1229.4. All pipe should be supplied without rust. Rust can be more readily applied at the job site. N.B. Some vendors are now able to supply pre-rusted pipe. If available in your area, this pre-rusted pipe is recommended; it will save time on the job site.

§1229.5. All pipe over 500 ft (153m) in length should have the words "long pipe" clearly painted on each end so builders will know it is a long pipe.

§1229.12. Pipe over 2 miles (3.2 km) in length must have the words "very long pipe" painted in the middle so builders will not have to walk the entire length of the pipe to determine whether or not it is a long pipe or a very long pipe.

§1235.11. All pipe over 6 inches (152 mm) in diameter must have the words "large pipe" painted on it so builders will not mistake it for small pipe.

§1229.10. Flanges must be used on all pipe. Flanges must have holes for bolts that are separate from the big hole in the middle of the pipe.

§1229.9. When ordering 90-degree, 45-degree, or 30-degree elbows, be sure to specify whether the elbows are to be right-handed or left-handed elbows; otherwise your pipe will end up going the wrong way.

§1229.8. Be sure to specify to your vendor whether you want level, uphill, or downhill pipe. This will avoid problems once the pipe becomes operational. For example, if you use downhill pipe for going uphill, the water will flow the wrong way.

§1229.6. All couplings should have either right-hand or left-hand thread, but do not mix the threads; otherwise, as the coupling is being screwed on one pipe, it is unscrewed from the other.