As seen on another site

[Plumbus]

Why is pipe 21' long?

[Killertoiletspider]

I was told, and I have no idea if it is true, that it dates back to when they first started building high rises, the difference between the decks was nine feet, with six in thick floors, so a 21' length could go two floors and still have enough to work with on both ends.

Back in the late forties through the early seventies you could buy steel pipe in what they called random lengths, which was anything from ten to nineteen feet, they were what was left after the extruder was done and the 21' lengths had been cut.

[myakka]

I was told it was to accommodate the usable inside length of a railroad boxcar (42')
Mike

[NHMaster3015]

wouldn't it be a ***** to load it into the box car? Usually it's shipped on open cars or trucks.

[BHD]

at one time a lot was 18 foot lenghts, most I get now is 21 foot,

[Australian Plumber Josh]

fits in a shipping container.

[BHD]

I don't have any proof of this but my guess is that it has some thing to do with the manufacturing process and the length of Skelps that original were produced, and the machinery to join them in the welding process.

and the lengths (standards)I believe have been around longer than shipping containers,

[aero1]

dam# good question, i have nothing to add oh yea wait uh 21 feet?:rolling-eyes2:

[APHCO]

always thought it had some thing to do with the weight of the pipe, but somehow that doesn't make sense as the different sizes would have different weights

and while we are on the subject, why was copper only in 20 foot (not 21 foot) lengths?? Ten footers are just a recent development.

[stokefire7]

it falls under the heading single random length P. E. 18'-25',T & C 18'-22'

[gear junkie]

In 1824 a new way to manufactor steel pipe was made which involved rolling dies to stretch the metal to the desired length. The 1st and last 6" of the pipe were not truly round as that was the section the rollers grabbed onto. Think of snipe in a planer. So to get a useable, true 20' length required the ends to be cut off. Another 35 years had passed when they could get a useable 21' length but rather than produce 20' section, manufactors stuck with tradition and continued to produce 21' sections.




























:killingme::killingme::killingme:Oh I had you guys going. You really believed me on this one. hahahahahahaha

[PLUMBER RICK]

actually ben, this is pretty much the story that i heard many years back.

rick.

[toolaholic]

Funny, whenever I get 2x4s at the plumbing supply house there always 21 Ft. looong!

[SlimTim]

Really, Gear, I thought someone living in Virginia would know this one.

In the mid 18th century, the early Virginia code required that the outhouse be 7 paces from the well. Before Thomas Jefferson built Monticello he rigged a trough from the well to the privy so Sally wouldn't have to tote a bucket of water for him to clean himself (He had rigged up a resevoir over the seat with a long tube that snaked down and pointed right at the "spot of evacuation" as he put it. It had a little sliding block of wood that he could move to start the flow of water, thus the rudiments of the first bidet were born. I think he called it the BB-1).

Well, anyway, when the plumbing inspector in his tall pointy hat, (this is where the phrase "pinhead" first came into use, as in 'frickin pinhead', or Jefferson's favorite, 'imbecilic pinhead"), came out to make sure the well and the "john" (another Jefferson euphemism to honor John Adams) were properly spaced he encountered Jefferson's trough. After a few remarks about backflow and cross-connection he put an evergreen branch on the device (ancestor to our green sticker) and hurried back to his office where he drew up plans and stole Jefferson's idea (the one about the trough not the bidet which he considered lunacy).

Since his paces were exactly 3 ft. he put that in the specs and somehow it has survived to this day.

That's my story and I'm stickin' with it.
(Apologies to TJ, JA, SH, and all the pinhead inspectors)

[Bob D.]

Found this online:
http://www.madehow.com/Volume-5/Steel-Pipe.html

It gives a brief history of pipe manufacturing, but it doesn't address how the ~21 ft length came about.

[Plumbus]

From http://www.answers.com/topic/steel-pipe



An early notable method for producing metal tubes quickly and inexpensively was patented by James Russell in 1824. In his method, tubes were created by joining together opposite edges of a flat iron strip. The metal was first heated until it was malleable (http://www.answers.com/topic/malleable). Using a drop hammer, the edges folded together and welded. The pipe was finished by passing it through a groove and rolling mill.
Russell's method was not used long because in the next year, Comelius Whitehouse developed a better method for making metal tubes. This process, called the butt-weld process is the basis for our current pipe-making procedures. In his method, thin sheets of iron were heated and drawn through a cone-shaped opening. As the metal went through the opening, its edges curled up and created a pipe shape. The two ends were welded together to finish the pipe. The first manufacturing plant to use this process in the United States was opened in 1832 in Philadelphia.
Gradually, improvements were made in the Whitehouse (http://www.answers.com/topic/whitehouse-band) method. One of the most important innovations was introduced by John Moon in 1911. He suggested the continuous process method in which a manufacturing plant could produce pipe in an unending (http://www.answers.com/topic/unending) stream. He built machinery for this specific purpose and many pipe manufacturing facilities adopted it.
While the welded tube processes were being developed, a need for seamless metal pipes arouse (http://www.answers.com/topic/arouse). Seamless pipes are those which do not have a welded seam (http://www.answers.com/topic/seam). They were first made by drilling a hole through the center of a solid cylinder. This method was developed during the late 1800s. These types of pipes were perfect for bicycle frames because they have thin walls, are lightweight but are strong. In 1895, the first plant to produce seamless tubes was built. As bicycle manufacturing gave way to auto manufacturing, seamless tubes were still needed for gasoline and oil lines. This demand was made even greater as larger oil deposits were found.
As early as 1840, ironworkers could already produce seamless tubes. In one method, a hole was drilled through a solid metal, round billet (http://www.answers.com/topic/billet). The billet was then heated and drawn through a series of dies which elongated it to form a pipe. This method was inefficient (http://www.answers.com/topic/inefficient) because it was difficult to drill the hole in the center. This resulted in an uneven (http://www.answers.com/topic/uneven) pipe with one side being thicker (http://www.answers.com/topic/thick) than the other. In 1888, an improved method was awarded a patent. In this process the solid billed was cast around a fireproof (http://www.answers.com/topic/fireproof) brick core. When it was cooled, the brick was removed leaving a hole in the middle. Since then new roller techniques have replaced these methods.

[NHMaster3015]

Yes............... but why 21' ?

[toolaholic]

Why NOT ??????????????

[stokefire7]

hope this helps

[NHMaster3015]

Nope, too small, can't read it. Does it splain why Lucey?

[gear junkie]

I can see it just fine. No explanation, just a humorous explanation of pipe installation. Worth the read.

[Bob D.]

"From http://www.answers.com/topic/steel-pipe (http://www.answers.com/topic/steel-pipe)"

That is practically word-for-word the same history as the URL I gave. I wonder which site copied the other?

At any rate it does not talk about how the 21 foot length came about. I have a query out to someone who
may know though. He was around when the made the _first_ pipe I think :)

[Australian Plumber Josh]

This is what the experts say:-

Dear Joshua,
Thank you for your enquiry. The 6 metre length is the equivalent of the original 20 foot length. Perhaps you are too young to remember what a "foot" is. This length was deemed to be the optimum for a single person to handle and also be transported on the top of a van/ute without unacceptable bending of the tube. Thus, manufacturing processes were designed to yield the most number of 20'/6m lengths with the minimum amount of scrap. Also, distributors/plumbing stores designed stock racks to accommodate tubes of the "standard" length.I trust that this response has satisfied your need.

Kind regards, JOHN WILLIAMSON

Technical Officer
Copper Development Centre Australia Limited
Email: williamson@1earth.net
Mobile phone: 0402044898
Phone (H): 61 2 42616861

[HVAC HAWK]

it is so when you drop one end of the pipe and it gets all bent up you cut that off and you still have your 20' leg :eek:

[NHMaster3015]

Funny enough, there was a show on the history channel just last week and they we're showing the manufacturing process for steel pipe. The machines put out 21' lengths.