If you’re not familiar with the pipeline industry, pipe specifications can seem like a difficult task to understand. Here’s our easy guide to understanding pipe specifications.
The first thing to grasp is that all pipe is to be made of a long hole surrounded by metal or plastic centred around the hole. All pipe should be hollow throughout the entire length; do not use holes of different length to the pipe. The inside diameter of all pipe must not exceed the outside diameter otherwise the hole will be on the outside. All pipe should be supplied with nothing in the hole, so that water, steam, etc. can be put inside at a later date.
It’s particularly important that all pipe is supplied without rust – this can be more readily applied at the job site. Some vendors are now able to supply pre-rusted pipes, if these are available in your local area, it can save you a lot of time at the job site.
Determining Pipe Lengths
All pipe over 500ft in length should have the words “LONG PIPE” clearly painted on each side and end so that the contractor knows it is a long pipe. Also, pipe over 2 miles in length must have the words “LONG PIPE” painted in the middle to ensure the contractor does not have to walk the entire length of the pipe.
Additionally, all pipe over 6ft in diameter must have the words “LARGE PIPE” painted on it, so the contractor doesn’t mistake it for small pipe.
Another thing to take into consideration is that when you are ordering 90- or 30-degree elbows, be sure to specify left-hand or right-hand, otherwise you will end up going the wrong way. It is also vital to specify to your vendor whether you want level, uphill or downhill pipe. If you use downhill pipes for going uphill the water will flow the wrong way. All couplings should have either right-hand or left-hand threads, but do not mix the threads, otherwise as the coupling is being screwed on one pipe, it is being unscrewed from the other.
All pipes shorter than 1/8 (3mm) are very uneconomical in use requiring many joints. These are generally known as washers. It is also important to remember that the joints in pipes for piping water should be water-tight. Those in pipes for compressed air, however, need only to be air-tight.
Lengths of pipes may be welded or soldered together, but this method is not recommended for concrete or earthenware pipes.