Sizing in Imitation Bamboo (Bamfaux) is not easy. Well, it is easy to sell, but not so easy to buy. You want to buy the right size, and not re-buy it when it arrives, simply because it is the wrong size. It would have been so much easier if the size it was named, were the actual size, but no, it isn’t. Nothing could be further from the truth.
PVC pipes, and their fittings, are not the only commodity with this silly naming convention. Take metal piping for instance; both the round rod and the square rod, are not the same size as what it is called/named.
They, in this case the “historical” they, the ‘experts’: ‘They’ decided to standardize things, to supposedly make it easier for us, to make everything the same. At the time (in the past), we must have had many different sizes, but why ‘they’ chose these strange, final, sizes, only ‘they’ know. No one seems to know why only these specific sizes are so important. Except for the fact that, today, these are the sizes everyone uses and everyone makes.
All this preamble to say, I am going to make things a little easier for you, or at least try to.
First, we must choose whether the outer diameter, as opposed to the inner diameter, is the important measurement. It is this measurement that is most exact, whereas the other figure, well, that depends on the thickness of the pipe, whether it is PVC or metal, and, the tools the manufacturer uses to produce the final product. It might even pertain to other products, but all I am interested in, right now, is the PVC.
If these pipes are meant to overlap other pipes of the same type, then the outer diameter is the most important number. It must be exact, so that overlapping can be accomplished with minimal complications. Then the bell, or the section that overlaps, will be enlarged correctly to maintain the thickness of the pipe, while keeping the inside of this small section exact enough to cater to the outer dimension of the original pipe.
Allow me re-phrase that. If the outer diameter of pipe number one is supposed to be half an inch, then the inner diameter of pipe number two (the overlapping area, or bell, or coupling) must also be half an inch otherwise the overlap will not fit. Then, whatever the inner diameter of the pipe is (apart from this small overlapping, or contact, area), will be determined by the thickness of the material, and, because it is not regulated, it will vary. This will depend on the manufacturer and the different methods of achieving this measurement, or maybe some other, unknown, reason. It is not important.
Both metal and PVC have the same measurements and the same naming convention. Whatever it is named, the actual measurement is larger, but generally, not as large as the next size, well, mostly in the larger sizes. When we take a look at the smaller sizes, they vary enormously. Some of these actual measurements should have been named one, or more, sizes up.
The best way to know what the ‘actual versus named’ dimension is, is to have a chart that tells you. Find one, if possible, that gives you both the inner and outer diameter of the type of material you want to use. Put this table near to the telephone, so that you know what to order. Then, find the desired measurement on the table and work backwards and order the correct size for your project.
Or, send me an email, and I will return it with a spreadsheet table that gives you a range of what you might want, and then suggests the correct pipe to order. It works backwards from normal tables and charts. I hope it helps.
Written by Judeline Meintjes. Copyright 2016