The Unistrut line of metal framing products has a lot to offer when it comes to pipe and conduit clamps, many of which are designed to be used in conjunction with their popular 1-5/8” metal channels, utilizing tabs that slide inside the channel track for a versatile, easily adjustable system.

Unistrut’s robust line of pipe and conduit clamps includes: pipe clamps for rigid steel conduit and thin wall conduit (EMT), one and two-hole pipe straps, universal pipe clamps, adjustable pipe clamps, u-bolts, cushioned pipe clamps, and more for a wide range of applications.
The world of pipe and conduit can be a scary place for someone who doesn’t live there full time; it’s fraught with many strange terms and abbreviations that can honestly be quite intimidating: nominal, schedule, IPS, EMT, O.D. – what does it all mean?

Let’s start with schedule, since this is where a lot of the problem with measuring comes from: the pipe schedule is the thickness of the pipe wall, and since there are so many different types of materials and material thicknesses used in making pipe and conduit this measurement is not constant.


Now how do we measure the size of the pipe? Depending on the thickness of the pipe material (or pipe schedule) there can be a fairly great difference between the measurement on the inside of the pipe (inside diameter, or I.D.) and the measurement on the outside of the pipe (outside diameter, or O.D.). Which measurement do we use? And what happens when the contents of the pipe cause these measurements to fluctuate? Some gases and liquids can cause the pipe to expand or contract especially during temperature and pressure changes. How do we measure then? Oh boy…

Outside diameter (O.D.), which is a commonly used pipe measurement, is an actual physical measurement of the pipe and remains constant no matter what the pipe schedule is or what material it’s made out of, where as the inside diameter of a pipe, with say a 2” O.D., is variable depending on the pipe’s schedule.

There is another measurement that is commonly used to measure pipe: nominal pipe size. What the heck is that? It’s really a nod to the fact that there are two measurements associated with each pipe: inner and outer. Nominal pipe size is not an actual measurement; it is a relative measurement that typically falls somewhere between the actual inner and outer dimensions of the pipe. For instance, a 2-1/2” nominal pipe may have an O.D. of 2-7/8” and an I.D. of 2.47”. Nominal pipe size is the standard used in North America for pipes that are subject to high and low pressures and temperatures.

There are many other terms and abbreviations you may come across when navigating the confusing world of pipe and conduit clamps, depending on what type of pipe or conduit you’re using and what type of application it’s for: plumbing, electrical, mechanical, etc. – we won’t get into those now, except to say that Unistrut’s General Engineering Catalog houses a very comprehensive – and very handy – set of reference data that you can use to cross-reference nominal and O.D. pipe sizes depending on what type of pipe or conduit you’re working with.

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