Inching Up To Use of Metric System in U.S.

Inching Up To Use of Metric System in U.S.

NEWS ITEM: Chief Doe today accepted delivery of a new truck to boost the complement of apparatus in this city. The new truck comes equipped with a 2-kiloliter booster tank and 152 meters of 4-centimeter hose and a 2-centimeter nozzle. It also has 366 meters of 6-centimeter hose and 3-centimeter nozzles. There is an assortment of ladders from 3-meter portable ladders to a 31-meter snorkel, which will enable firemen to reach the 10th floor of most buildings. The truck weighs 9072 kilograms fully equipped and is 7 meters long.

The foregoing is probably a report on some foreign fire department, right? Wrong! Such reports will be commonplace in the next decade as the process of metrication progresses. Metrication may be defined as the gradual conversion of our customary system of weights and measures, known as the foot-pound-second system, to the more orderly metric system known as the meter-gram-second system.

The United States alone of all large industrial nations does not use the metric system. England is now in the process of converting.

Since the founding of our nation, the system based on the British Imperial Arrangement has been accepted as the customary one, although the two differ in some aspects. Because of long use and the fact that most legislation implied it, we have considered the customary plan as the only legal system.

The truth is, however, that only the metric system has been legally authorized as a method of weights and measures. The Congress in 1866 passed legislation making the metric system legal. Since that time we have used both systems with almost equal sanction. Customary units are in everyday common use. Metric units are used in science, medicine and the photo industry.

Since 1971, more and more pressure is being brought on Congress for legislation leading to a metrication program. In that year Commerce Secretary Maurice H. Stans recommended a gradual changeover in 10 years. When completed, the program would make the United States a predominantly metric country, with a secondary foot-pound-second system, which would be phased out completely over a longer period.

Some Comparisons


A little longer than a yard (about 1.1 yard)


A little larger than a quart (about 1.06 quarts)


About 1/28 ounce

(a dime weighs about 2 grams)


A little heavier than 2 pounds (about 2.2 pounds)


For fine measurements.

About diameter of paper dip wire


About 3/8 inch

(about 2 1/2 centimeters in inch)


About 5/8 mile (35 m.p.h. would approximate 55 kilometers per hour)

Metric ton:

A little heavier than our ton (about 2205 pounds)

Many bills have been put before Congress without success so far. As late as May 1974, the United States House of Representatives defeated just such a bill.

Delay in converting is costing this nation much money. We lose $10 billion to $25 billion every year, according to estimates by Senator Claiborne Pell (D-R.I.) because of the difficulty in fitting our system into the world metric system. But, the change is inevitable. The sooner we start to think metric, the easier it will be when the metric revolution takes over.

The metric system was first suggested about 1670, at the time when scientific thought was blooming. However, it was not until 1790 that the system received its greatest impetus. The French Academy, led by the eminent mathematicians Legrange and Laplace, submitted a report to the French National Assembly recommending the change from the system then in use.

The basis of the new system was the meter. It was then defined as one ten-millionth of the distance from the Equator to the Pole, and is now slightly different. It is the length between two lines on a platinum bar held in the vaults at the International Bureau of Weights and Measures near Paris. The original French Metric System has now been incorporated into a broader and more precise system known as the Systeme International d’Unites, or simply, the International System.

Difficulties in our system

Our present system is a jumble of odd-sounding and difficult-to-handle units, even in simple calculations. For example, we know that 1 foot is equal to 12 inches. But a yard is 3 feet, and a mile is 5280 feet or 1760 yards. We all know the difficulty in memorizing all these equivalents that have no common base for comparison.

To make matters worse, these common units are based on a very unscientific scheme. Thus, the inch was originally the width of a man’s thumb. The yard was the distance from the nose to the outstretched hand. History relates that it was King John of England who set the measurement for the yard. As we consider more weights and measures in our system, we are overwhelmed with the inconsistencies and the lack of a common relationship between units. We also find such archaic names as rods, furlongs, gills, hands, acres, links, chains, grains, pecks, drams, hundredweights.

Then again, 1 pint liquid measure is not the same as 1 pint dry measure. One ounce troy weight is not the same as 1 ounce avoirdupois. And a barrel can be anything from 31 to 42 gallons, not counting the “standard” 55-gallon drum barrel.

Our familiar temperature scale continues these inconsistencies. It was originally based on the temperature at which water froze when placed in a snow bank near the home of the German scientist Fahrenheit. He set that point at 32 degrees, the boiling point of water as 212 degrees, and divided the distance between them into 180 even parts. Thus the zero point became meaningless. In the Celsius system, the boiling point of water is 100 and freezing is zero.

Contrasted to this hodge-podge of units, the metric system consists of a few units placed in a simple and accurate relationship. Units become larger or smaller in multiples of 10. Thus the basic unit is the meter (about 1.1 yards). The unit of capacity is the liter (about 1.6 quarts). The unit of weight is the gram (about 1/28 ounce).

A set of prefixes is used to increase or decrease the basic units. Even the prefixes make sense, because their names indicate how many times it increases or decreases the basic units, and always in units of 10 as follows:

Milli: one thousandth (0.001)

Centi: one hundredth (0.01)

Deci: one tenth (0.1)

Deka: 10 times (10)

Hecto: 100 times (100)

Kilo: 1000 times (1000)

So, if you want to express a measurement of 1/1000 meter, we use the term millimeter. If we wish to say something weighs 1000 times a gram, we use the term kilogram. The kilogram has in fact replaced the gram as a basic unit of weight. It is an easier unit to handle than the smaller gram.

Another beautiful feature of the metric system is that it eliminates fractions in computations. This will come as a blessing to those of us who labored over such things as adding 7/8ths and 3/4ths, or subtracting 5/8ths and 5/16ths. This process is long and involved—changing to common denominators, adding or subtracting the numerators, reducing the fractions to lowest terms. How much easier it will be to simply work with decimal fractions, adding .875 and .750, or subtracting .188 from .625.

We are more at ease working with decimal fractions than common fractions, mostly because of our decimal money system. One of the greatest accomplishments of our founding fathers was the adoption of the monetary system based on the numeral 10.

Using the system

Let us suppose that we must know the weight of water used in fighting a fire, which is now collected in a layer 6 inches deep on a factory floor 40 feet long by 30 feet wide.

In the customary system we must first change all dimensions to inches. We multiply 40 by 12, which gives 480. We also multiply 30 by 12, or 360. Both are multiplied by the depth: 480 X 360 X 6 = 1,036,800. This is then divided by 1728 to convert to cubic feet, or 600. Finally, this is multiplied

by 62.5 (the weight of a cubic foot of water) for a weight of 37,500 pounds.

In using the metric system, only two steps are necessary. Multiply width by length by depth, or 12.19 X 9.14 X 0.15 = 16.71 meters.

Because a cubic meter of water weighs 1000 kilograms, all we need do now is multiply cubic meters by 1000, or simply shift the decimal point three spaces to the right. This gives us 16,710kilograms as the weight of water.

Of course, when we are converted to metric system, dimensions will mostly be whole numbers, making calculations so much easier.

Metrication today

Although metrication is not apparent at this time, many farsighted inindividuals and companies have taken the first step and are on the pathway leading to full adoption of the logical system.

Such large companies as Seven-Up will offer their product in liters and half liters, as well as in pints and quarts, starting in 1975. The Sun Oil Company is conducting pilot programs in Willow Grove, Pa., and Ft. Lauderdale, Fla., selling gasoline in liters as well as gallons.

Huntsville, Ala., was the first city to post highway speeds in miles per hour as well as kilometers per hour in this country. Other cities are following this practice. The Heinz Company is now showing metric and customary units on its products. For example, their ketchup bottle shows the net weight as 14 ounces and also as 397 grams. Other food companies are following suit.

The National Aeronautics and Space Administration uses only metric units, as does the entire pharmaceutical industry. Fever thermometers for home use have been available in Celsius or Fahrenheit scales for years.

The Lima, Ohio, plant of the Ford Motor Company, manufacturing the Pinto and Mustang II, has designed the first American plant using metric units. Following this lead, General Motors has announced its intention to go metric. Others are showing increased interest.


This is a very encouraging sign, because it was the auto industry which most vehemently opposed the metric system in the past, although some parts such as spark plugs were always measured in metric units.

The photo industry has always used metric measurements in their products, adding U.S. units only when the products were manufactured for exclusive sale in this country.

Others such as IBM, Caterpillar Tractor Company, Brown and Sharpe and Starret have used a dual system and are moving toward complete metrication.

Tool makers have been turning out metric tools at an ever-increasing rate. Store counters now display metric size wrenches, tapes, rules, drills, taps, dies, socket sets.

Almost all bicycles and motorcycles use metric parts.

Some newspapers have started to list daily temperatures in both Celsius and Fahrenheit degrees.

A generous supply of conversion charts, graphs, rules and aids is finding its way into stores and shops. Government agencies, as well as schools and many companies, are preparing helpful material on metrication.

Athletic events such as the Olympic trials in this country are measured in metric units.

Inexorably, relentlessly, the stream of metrication moves on. It will become a flood and finally a tidal wave, sweeping away at our inefficient, clumsy system of weights and measures, replacing it with the orderly, efficient, easy-to-use international system.

During the period of transition it will be necessary to convert back and forth between the two systems. After metrication is completed, there will no longer be a need for such manipulations.

Listed in table 1 are approximate conversion factors for common units. These are only for quick figuring. More accurate factors are in table 2.

Conversion of temperatures is a bit more involved. To change degrees Celsius to degrees Fahrenheit, multiply Celsius degrees by 1.8, then add 32. Conversely, to change Fahrenheit to Celsius, first subtract 32 from Fahrenheit degrees, then divide by 1.8.

Conversions listed are for normal day-today use. The more advanced conversions needed to change hydraulic and fire fighting computations into metric terms are, of course, more difficult. The writer has deliberately refrained from discussing this for two reasons:

First, this paper is offered as a brief report on impending changes and as a stimulus to further study. The serious fire fighter student will seek to increase his knowledge of the metric system in his own way. There is enough material available to make such a person skilled in the use of metrics. All that is needed is the desire to learn and the awareness that metrication is underway.

The second reason is that the writer plans to cover fire fighting computations at a later date in considerable detail. In the meantime, one will find numerous references to metric calculations in this journal and others in the fire service.

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