By The Metric Maven
In a recent episode of Modern Marvels Essentials, on The History Channel, the subject was Freight Trains. Modern train braking systems, which use a combination of air brakes and dynamic brakes, are described. On long downhill grades, the electric motors, which are used to move the train, are used in reverse as electrical generators. This provides mechanical resistance, and slows down the train. This is called dynamic braking. The operator of the train then is shown on screen and states:
“I’m in full dynamic brakes. I’m demanding 35 kilopounds from my motors.”
A modern flat panel computer screen is shown, mounted in the cab of the train engine. A small yellow rectangular indicator is then shown with this title: Effort klb, and the number -34 inside of the indicator box. Kilopounds!? WHAT ON EARTH! A metric prefix kilo with the non-metric unit of pound (force). The unit is described as effort?–not force! It seems as though the engineering designers of the train anthropomorphized their creation! Perhaps too many Thomas the Tank Engine reruns? Kilopound “Effort” is simply an American proxy, mongrel retread unit, with an attached human metaphor, created out of thin air. Its use should embarrass American engineers with its absurdity.
A Kilopound?—What will we create next?—the peter for pint-liter?
I was convinced that a unit this ridiculous had to be an aberration, and was created in a single instance of industrial foolishness.
When I next had breakfast with Sven, I related the strange unit and before I could finish my sentence Sven asked with slight surprise and levity:
“Haven’t you heard of a kip?”
My mind screeched to a halt, the walls began to close in on me, and time ceased for a microsecond.
“A what?” I blurted.
“A kip, a kilopound?”
No, in fact, I had not. Sven asserted the “unit” was not uncommon in the US.
I stated with incredulity: “Metric prefixes with non-SI units?—that’s just wrong. It’s twisted.”
Sven told me to look on Wikipedia for Kips, he suspected there would be an entry. There is, and reading it only distressed me further.
A kip is a non-SI unit of force. It equals 1,000 pounds-force, used primarily by American architects and engineers to measure engineering loads. Although uncommon, it is occasionally also considered a unit of mass, equal to 1,000 pounds, i.e. one half of a short ton. One use is as a unit of deadweight to compute shipping charges.
1 kip = 4448.2216 Newtons (N) = 4.4482216 kilonewtons (kN)
The name comes from combining the words “kilo” and “pound”; it is occasionally called a kilopound. Its symbol is kip, or less frequently, klb. When it is necessary to clearly distinguish it as a unit of force rather than mass, it is sometimes called the kip-force (symbol kipf or klbf). Note that the symbol kp usually stands for a different unit of force, the kilopond or kilogram-force.
The kip is also the name of obsolete units of measure in England and Malaysia.
When I checked the reference, I found out that the kip has alternative definitions, making it a retread unit:
In England, at least as early as the 16th – 17th centuries, a unit of count for skins, 30 for lamb and 50 for goat. Also spelled kippe, kyppe, and kipp.
In Malaysia, ? – 19th century, a unit of mass primarily used for tin, about 9.19 kilograms. link to a chart showing relationships between units of mass in Malacca Said to be equal to 37½ Dutch troy pound, but that is difficult to understand, as it is much closer to 37½ marks trooisch.
Dutch troy pound?—marks trooisch? A kilogram-force?—called a kilopond? Who could confuse that with a kilopound?
Wikipedia made matters worse for my blood pressure by also telling me:
There are also reports of engineers using base-ten SI prefixes in combination with Imperial or US customary units, for example the kiloyard (914.4 m). The kip or kilopound is regularly used in structural engineering. Similarly, the kilofoot is quite common in US telecommunication engineering, as significant distances in cable route planning are usually given in thousands of feet. Instruments like optical time-domain reflectometers usually have an option to display results in kilofeet
Humans seem to relish creating new units, and apparently are most interested in doing so when they have no idea how to use commonly accepted ones—you know—SI.
When I operated an offset printing press years ago I went to a technical lecture on how to understand all the interrelated parameters of this printing method. One needs to mix fountain water of a printing press with a small amount of acidic chemical, generally just called fountain solution. It is then best practice to measure the
PH pH of the solution and make certain it’s within an accepted range. If the PH pH varies, and the acidity becomes too large, it can damage the printing plate. As I recall, the amount of fountain solution was about 50 mL to a liter of tap water.
The technical lecturer then related that he was called into a printing company to investigate problems with plate wear and printing quality. He asked the pressman how much fountain solution he puts into a liter of tap water.
The man replied “two glugs.”
Yes, he was taking the bottle of fountain solution, turning the bottle over and counting two glug sounds. He had created a new proxy unit, where sound would be used to measure liquid volume.
I’m sure a lot of American engineers might laugh at this story, but apparently they don’t seem to realize that creating kilopounds, kiloyards, kilofeet is not far from determining the dynamic breaking in kilopounds needed for a set of railroad tanker cars with 500 kiloglugs of water in each.
Unfortunately, it has been my experience that many American engineers see nothing wrong with feral and mongrel units, and have tried to justify them, rather than “giving in to metric.” One may not judge a book by its cover, but I’ve often had a hard time not judging engineers from Engineers according to their preference for metric or not. It’s long past time that American Engineering, Mechanical, Electrical, Chemical, Civil, Nuclear and so on, demand and embrace metric in the US. Unfortunately US engineers may be desensitized to these scientific absurdities because they grew up in the perennial Barley Corn Hillbillies zeitgeist. When one is surrounded by a world measured with imperial and a science classroom where metric is taught in isolation, it’s tough not to be inculcated. However, this is no excuse. In Engineering the simplest way to solve a problem is often the best and most robust. Engineers are taught to express formulas produced from mathematical derivations in the simplest form possible. Why should measurements be any different? Everything you need to express engineering quantities, in the simplest manner possible, is provided by the metric system. One possible way to determine the difference between Engineers and engineers is that the former use kilonewtons (kN) and the later use kilopounds or kips. The feedback I’ve received from well known engineers (and scientists) which I have approached about endorsing metric, has been tepid or non-existent. It seems very much like a “foolish consistency” to me.
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