How to Buy Pipe
HOW TO BUY (or how not to buy) PIPE FOR FENCING???
More and more lately, I have been getting calls from people pricing materials for
the fencing of corrals, arenas, working pens etc. with a lot of confusion going
on. They want to make sure they are comparing apples to apples and, from the sound
of it, there are a lot of apples and oranges out there. I get a lot of questions
about gauges, schedules (relating to wall thickness) and about used vs. new vs.
reject vs. secondary vs. surplus. Questions like: what is the difference between
schedule 30 and schedule 40? How come as a "schedule" gets bigger, the pipe gets
thicker, but as a "gauge" gets bigger, the pipe gets thinner? Is used pipe OK to
use? What's the difference between "new" pipe, "new reject" pipe" and "new secondary"
Well, these are good questions and not all of us are blessed (or cursed) with 29
years in the pipe and steel business. Furthermore, with the wildly fluctuating steel
prices these days, and the fact that steel is still by far the best way to fence
livestock, it is very important to understand what you are buying. It is also very
important not to waste money by over killing your needs. So when I was asked to
write this article, I was happy to do it. Maybe it will save me a few hours on the
telephone. So let's break it down.
NEW VS USED
Used pipe is subject to decay from the inside out.
Used pipe is next to impossible to keep painted
Used pipe is subject to pitting, internally and externally.
The quality of used rods in recent years has declined, making them subject to sag.
When using used pipe, you never know where the corrosion will break out.
Let me tell you up front, I'm biased and I don't have a lot of good things to say
about used pipe. Now I'm not saying all used pipe is a bad buy, I'm just saying
that MOST used pipe is a bad buy. Let me count the ways. First of all, the used
oilfield pipe available for the fence market is pipe that is deemed no longer fit
to be used in the oil patch. With the high oil prices and the pipe shortages, believe
me, they (the oil operators) are wearing it out before they sell it off as structural.
Here's what happens: Let's talk about salt water and oil production. Most of the
existing wells in Oklahoma, Kansas and Texas are classified as stripper wells. These
are wells that produce a lot of fluid on a daily basis but take it from my oil patch
pipe days; the oil operators consider themselves lucky if they get a 10% "cut" in
their production. This means that if the well produces 10 barrels of oil a day,
it also produces 90 barrels of SALTWATER per day. Do I need to explain the effects
of saltwater on steel? Don't think so! Furthermore, periodically, acid is dumped
down the wells to help the flow of fluids into the well bore. Hmmm, That can't be
good on the pipe. I think you're getting it.
Last but not least, let's just touch on rod wear, the most destructive effect on
oilfield pipe. Bet you thought the hole that is drilled to make an oil well goes
straight down...right? Wrong!----- That is what I thought when I first started selling
oil country tubulars in the early 80's. Well, let me tell you, oil and gas wells
are spiral! Without going into the dynamics of drilling into rock several thousand
feet, you're just going to have to take my word for it.
What were we talking about? Oh yeah. Rod wear. Inside the oilfield pipe, which a
lot of folks call drill stem, are the sucker rods. Now very quickly, a brief lesson
on oil production and artificial lift. The pumping unit sits on the surface. Attached
to the horse head on the pumping unit is the bridle. Attached to the bridle is the
polish rod. Attached to the polish rod are the sucker rods. Wayyyyy down the hole
is the rod pump. Well, to pump this fluid (saltwater & oil) out of the hole, the
horse head, the polish rod, the sucker rods and the pump have to go up & down, 60
minutes per hour, 24 hours per day, 365 days per year. OK, stop and think. All these
rods, going down all this pipe, IN A SPIRAL HOLE, are rubbing against something
and that something is YOUR USED PIPE. By the way, did I mention that sucker rods
are harder than the hubs of H E double hockey sticks? Getting my drift on rod wear?
To spell it out, these super hard rods, rubbing constantly against YOUR pipe, causes
some very thin spots inside the pipe. Thus pipe that was nice and thick when it
was new, has salt-water corrosion, acid corrosion and very thin spots due to "rod
wear". Does this sound like pipe that will last a lifetime? Don't think so. How
does an oil operator determine their pipe is no longer fit to re-use in their well?
Usually there are 3 ways. The first is the easiest. They know their pipe has holes
in it because their well is leaking down the backside or will not hold pressure,
so they pull it out and get rid of it (hopefully not in your fence). The second
way is by pulling the pipe out of the well and hydro-testing it. Here a service
called "pipe testers" fill each individual piece of pipe with water then pressure
up on it to see if it will hold the pressure or "pop". This is where the splits
we have all seen come from. Is all pipe without splits OK? Not necessarily. The
third way to test is by electronic-magnetic inspection (known as an EMI). Here each
piece of pipe is run through a high tech inspection unit that determines if there
are thin places in the pipe.
There are four grades of EMI'd pipe. Most generally they use these specs: White
band - Means pipe has a maximum of 12% body wall loss (this is new specs according
to the API, we will cover this later). Yellow band - Means the pipe has a maximum
of 15 % body wall loss. Blue band - Means the body wall loss is somewhere between
16 & 30%. Finally, Red band - Means the pipe has a body wall loss of over 30%. This
is the pipe usually that is turned over for structural use. All the white, yellow
& blue are reused in oil wells. Does that mean you should stay away from pipe with
red bands painted on it? Well, probably yes, but many times the inspection companies
simply do not paint the red band so you don't really know.
Now not all oil field tubing is like this. How can you tell? If you can look 30
feet down a 2" or 2 ½" hole and see the internal condition of the pipe, you don't
need it any way. You're too busy flying around in a red cape and jumping tall buildings
in a single bound. Seriously, however, if you know the pipe came from a flowing
gas well (they don't use rods or produce salt-water) it is probably all right. Trouble
is, unless you buy it right at the wellhead, it is hard to know. Enough bashing
of used pipe. Let's move on.
Pipe that has not been subject to corrosion will last a lifetime or more. My place
was built in 1957 and a couple of years ago we tore out some of the fence to expand
the lot. New pipe posts that had been set in concrete 45 years previous were pulled
out of the ground. We busted off the concrete at the bottom of each post and they
were all reusable. New pipe is definitely the safest way to go in building your
fence but there are different types of new pipe. New is new and if your pipe vendor
is honest and knowledgeable, he can help you determine what is best for you.
Since there are no guidelines for identifying the specifications for fencing pipe
and everybody makes up their own definitions, I'm going to tell you what ours is;
Good: Good pipe in our book is normally a dead length (vs. random lengths), has
no holes, no un-welded seams and is straight. Secondary or Seconds: Secondary pipe
per our interpretation is like good pipe but is probably random length or has some
minor cosmetic flaw. Reject: Reject pipe is kind of a catchall term where the pipe
could have one or more separate defects. Some of those are un-welded seams, windows
(where small samples of the pipe were cut out for testing), bows and varying wall
thicknesses. Since every mill has their own criteria for what they reject, the quality
will vary from mill to mill.
All of this pipe is usable if it meets your needs. Keep this in mind. Seconds and
reject are usually a good buy for fencing pipe (if you know what you are getting)
but it is the hardest to find. You and I are hoping the mills screw up and produce
a lot of reject while they are doing their best not to. That's why our supplier
is always looking for alternatives, which brings up another good point. Don't be
stuck on the most popular pipe sizes. They are highest in demand and lowest in supply.
You can usually make a good buy if a slightly oddball size is available. What does
it matter if it will do the job? I sincerely doubt your neighbor will be out there
with a tape measure to make sure you used a 2 3/8" instead of a 2 ¼" or 2 ½". So
ask your pipe vendor if any off sizes are available.
APPLES TO ORANGES?
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 who 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
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.