The biggest confusion my customers have is in regard to wall thickness. The wall thickness on pipe makes all the difference in the world. Most importantly it determines the price per foot, but it also determines what job the pipe will perform. We will get into that in a minute. It has come to our attention that the use of "schedules" is probably the most abused term in the structural pipe business. Here you are, calling around, trying to compare apples to apples and you happen to ask, "What is the wall thickness on that 2 3/8" schedule 40?" and the pipe dealer you're talking to says, "I don't know"??!!.
I actually had one guy tell me that he called a pipe dealer for prices, a gal answered the phone and gave him prices on 2 3/8" schedule 30 and on schedule 40. When he asked her what the difference was she said she did not know but that she would ask her supervisor. When she came back on the phone, her answer was, "Well, schedule 30 is a little less than 1/8" and schedule 40 is a little more."
How does that make you feel? Let's talk about this just for little bit. There are three main organizations that maintain standards and specifications for pipe. The American National Standards Institute (ANSI), the America Society for Testing Materials (ASTM) and the American Petroleum Institute (API). The ASTM and ANSI cover most structural pipe while the API covers oil field pipe. Now there is a multitude of specs that these organizations maintain that don't pertain to us so all I'm going to talk about is wall thickness. As a general rule, the tolerances for pipe body wall are plus -0-, minus 12%. For example; the specified wall thickness on schedule 40 with a 2 3/8" OD (2" nominal) is .154 inches (which means 154 thousands). Per the tolerance, the thickness of the pipe can be no more than .154 inches but it can be as little as .1355 inches (this is the minus 12%).
The problem is this. Since all scrap is bought by the mills by the pound, all the mills sell the dealers by the pound which in turn sell it by the foot to you, it behooves them to buy the pipe as thin as possible. Since .1355 wall weighs less per foot than .154, you may not be getting as good a deal as you thought if you buy it from a dealer at the lower end of the tolerance versus a dealer with pipe at the higher end of the tolerance.
THAT'S why it is important to know the wall thickness of the pipe you are being quoted. Worst yet, I know for a fact a lot of pipe has been sold that is under tolerance. In our example, if one dealer is selling .130" wall and calling it schedule 40 and the other dealer is selling pipe with a .140" wall at a higher price (which he should be), then first dealer is either cheating or just ignorant. This is a big problem and nobody can fix it. So what do you do? If your pipe dealer does not know the wall thickness, how can you tell?
I think using schedules in fence pipe is a lost cause. Besides, what you really want to know is this: Will the pipe you're buying going to do the job you want it to do?. And just as important, don't spend more money than you need to. If a thinner wall will do the job, why spend more on thicker pipe? It is all going to look the same when it is welded up. Here is what we have done to make it easier to buy the pipe you need. We classify pipe by it's "Strength Rating", STR for short and give you a wall thickness range for each STR and pipe size. We also list the recommended uses for each STR. Have I lost you? It's really simple as I think you will see. Listed below are the STR's and recommended usage for 2 3/8" OD pipe. By the way "OD" stands for the "Outside Diameter"
2 3/8"OD STR 30 Wall thickness range - .063 to .074
Suitable for constructing light to medium duty gates and portable panels. Also may be used for rail material in very low pressure areas of your fence or just for decorative fence with no livestock. Too light for posts
2 3/8" OD STR 40 Wall thickness range - .076 to .089
Suitable for gates. OK for top rail and rails in low pressure fence (such as horse fencing). May be used in low pressure cattle fence if vertical stays are installed between posts. Too light for posts.
2 3/8"OD STR 50 Wall thickness range - .091 to .112
A little heavy for gates. Too heavy for portable panels. Can be used for top rails in a lot of applications if the top rail is set over five feet tall, especially horse fence. OK for lower rails in medium pressure areas like large pens. OK for post in very low or no pressure areas. Too light for corral posts.
2 3/8"OD STR 60 Wall thickness range - .113 to .122
Too heavy for gates & portable panels. Makes good top rail in livestock pens with top rail set over five feet, especially for horses. OK for lower rails in all pens and straight alleys. OK for posts in large pens or perimeter fencing, low to medium pressure. Too light for posts in heavy crowding areas.
2 3/8"OD STR 70 Wall thickness range - .123 to .129
Suitable for top rail in cattle pens with a recommended setting at five feet or more. OK for lower rails in medium pressure areas such as smaller pens. OK for posts in large pens and perimeters with medium pressure. Too light for posts in heavy crowding areas.
2 3/8"OD STR 80 Wall thickness range - .130 to .136
Suitable for top rail and lower rails in all applications. OK for posts in large pens, perimeters and small pens. Too light for posts in heavy crowding areas.
2 3/8"OD STR 90 Wall thickness range - .140 to .154
Suitable for top rails and lower rails all applications, including the heaviest crowding areas. May be used for posts in the heavy crowding areas if reinforced with extra posts in the corners.
2 3/8"OD STR 100 Wall thickness range - .190 to .218
Over kill for top rail and lower rails. Don't waste your money (for rails). Excellent for posts in the heaviest of crowding areas. Use these as posts as an alternative to 2 7/8" for a lot less money.
Well, I could tell you a lot more but I'm tired of typing and sharing all my wonderful knowledge for free. Just kidding on the sharing knowledge part, but the two finger "hunt and peck" typing is the truth. It is, however, a lot easier for me to talk. And I love to talk about pipe, steel , horses and cattle. There's other folks that like to talk, so if I'm already on the phone, bend their ears. Hope this helps ya!
Bob Studebaker and all the folks at GoBob Pipe.
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