The Metric System and Fire Prevention

The Metric System and Fire Prevention

THE World Trade Club, the American Metric Association and other metric promoters, who at present are pushing their campaign for the adoption of the Metric System to the exclusion of the English System now in daily use with us, are directing their main appeal to the “people”—to the average man and woman, rather than to the Industries, the Manufacturers, etc. whose interests would be vitally affected by the change.

Their propaganda is in the nature of special pleading, as a lawyer will plead his case before a jury, magnifying the strong points, minimizing the weak, distorting the facts and drawing conclusions which often are utterly misleading. In fact they practice upon the credulity and ignorance of the people, who, are not in a position to become informed on the subject.

Like all idealists they exude a certain infectious enthusiasm and confidence which carries conviction to the unthinking. All this is helping to create a public sentiment in favor of the metric system, a sentiment which has already found its reaction in Congress.

In the face of this growing sentiment, manipulated by the metric party for their own ends, it becomes necessary to discuss this subject in the light of the consequences which we all would have to bear, should such a change be forced upon us.

The average citizen does not have the slightest conception of what the practical application of the compulsory adoption of the metric system would mean to him personally or to Industry. And to a greater or lesser extent this is true also of the artisan, the mechanic and even the steam and fire engineer.

To treat this subject fully is beyond the limits of this article, therefore such phases only will be mentioned as fall under the scope of this publication,

The FIRE ENGINEER, and are of interest to its readers. But even under this limitation all angles cannot be explored, the object of this article being mainly to stimulate interest in so important a change, affecting as it does

Construction of Fire fighting apparatus Handling “ “ “ “

Rules for Fire prevention Insurance

Let us take up the first subject. Here it is at once evident that the tools the fire engineer of today works with are more or less complicated mechanical apparatus. Starting with a simple two-wheeled hose-cart on through the line of implements we find chemical extinguishers, chemical engines, steam fire engines, gasoline fire engines, hook and ladder trucks, watertowers, etc. either horse-drawn or gasoline propelled. These machines, and such they are, have been brought to a high degree of perfection in smoothness of running, output, efficiency and staying qualities.

The production of these machines is conditioned on other machines on which are produced the parts and details composing them. The accuracy with which such parts are manufactured guarantees their fitting together and so producing the products we are familiar with.

In the building of machinery the use of measurements of length enters largely. Naturally it is of importance that the workman be supplied with a system at once handy and convenient in order to facilitate his work and insure the accuracy needed. The English system gives us the foot and the inch with its subdivisions down to 1/1000th of an inch, which latter unit is used in precision work as a “limit” of accuracy and which the workman handles as readily as the inch itself by means of his micrometer caliper.

On this system we have built our method of “Interchangeability of parts” which in turn has enabled us to make such strides in “Standardization.” Standard hose couplings, hydrant fittings, standard screw threads have thus become possible. Any part of the present day fire fighting machines, should it be broken or need repair, can quickly be replaced by a spare part sliding easily and gracefully into its place. A 3/4 inch nut for instance made in the West will fit a 3/4 inch bolt made in the East and a wrench made anywhere will fit the nut, yet we take this as a matter of course.

Now we are asked to use as our unit of length the meter.

There is no unit in the metric system equivalent to the foot. The meter will not take its place because it is too large, nor will the decimeter because it is too small. With the inch the same holds true, here the decimeter is too large, the centimeter too small. Again this is true when, for precision work, we try to use 1/10th millimeter and 1/100th millimeter. The “handiness” and “convenience” of our measuring tool has disappeared and what have we gained in its place? Nothing whatever for the millions of artisans and mechanics who actually use measuring tools, but we have enabled the “scientists” to facilitate somewhat his calculation on paper. The seriousness of such a change, however, lies on our thus throwing overboard all standards, standards which it has taken years to establish, which have cut down costs and produced uniformity. Diversity, confusion and disorder will follow as a consequence.

The FIRE ENGINEER CALCULATOR

To standardize on the metric system is a far more difficult matter than to standardize on the English system. To go into the tehnical reasons for this here would lead us too far. It suffices to point to the fact that in metric countries on metric built machines screw threads often are used made to the English system. About 80% of all screw products produced in the world today are on the English system. The English “inch” is well known in France, Germany and Italy.

The English speaking nations are the great industrial nations, they produce the bulk of manufactured articles. One example will illustrate this. The United States turns into finished goods over 70% of the world’s crude rubber production. The metric advocates ask that this great majority accommodate itself to the small metric minority. Reason would suggest that the reverse be done.

The Fire Engineer is concerned with water pressure. If the hydrant pressure is not sufficient he raises it with his engine in order to throw the stream of water the required height or distance. Once his engine is coupled to the hydrant his pressure gage will tell him what to do.

In the text of this article appears a cut showing the front and back side of a handy “Calculator” by means of which, provided we know the size of nozzle in inches and the water pressure in pounds per square inch, we at once can determine the flow of water in gallons per minute, and the friction loss in pounds of pressure per 100 feet of hose, also the friction loss due to an L or T connection. The effective reach of fire streams in height and distance is also given for different size nozzles expressed in feet.

From this it is apparent that the pressure gage is an important instrument. To learn something about the metric system let us consider how this instrument would have to be modified to conform to metric requirements.

We have expressed the pressures in pounds per square inch, now we will have to express them in kilograms per square centimeter.

1 lb. = .4536 kg. 1 sq. inch = 6.4516 sq. cm. 1 lb. per sq. inch = .4536/6.4516 — .07031 kg. per. sq. cm.

Equivalent readings therefore on the gage now in use and the metric gage compare as follows:

Instead of gallons we shall use liters and instead of feet, meters. We have:

1 gallon=3.7853 liters 1 liter= .2642 gallons

1 foot= .3048 meters 1 meter=3.2808 feet

The nozzles in use are now made to the following sizes, for which the metric equivalents are given in millimeters.

To what metric dimensions these nozzles would be changed it is hard to say. We must remember that the area of a circle varies as the square of its radius, therefore a small change in the diameter makes quite a difference in the area. New standards will have to be agreed upon and anbody can see that this is not as simple a matter as our metric friends would want us to believe.—Examples of this kind confront us on all sides, should we try to adopt the metric system.

To prevent fires as much as possible, to make them more accessible if they should occur, elaborate rules and regulations have been framed for the guidance of builders, contractors, electricians, etc. by the Fire Prevention Boards and the Underwriters. The carrying out of such requirements is entrusted to building inspectors trained to many technical details.

In looking through the Underwriters Specifications one at once is made aware of the definite use of units of length, weight and volume.—Minimum sizes of doors are given in feet and inches, thicknesses of walls in inches, stresses in pounds per square inch for all kinds of materials, floor loads in pounds per square feet, capacities of fire pumps in gallons per minute at prescribed pressures in pounds per square inch, etc. ect.—In fact the study of these rules is almost an engineering education in itself.

On the other hand the building trade deals largely in standardized materials. Structural steel shapes such as angles, channels, I beams, etc. are rolled to accepted sizes. An 11 inch steel 1 beam is not obtainable, but a 16 or 12 inch beam is. The lumber dealer furnishes joists, studding, beams, planks, etc. in even foot lengths such as 10, 12, 14, 16, 18, etc. feet long. Bricks are standard. Besides such standards do not stand by themselves, they are inter-related.

To give up such standards would make it impossible to follow the rules evolved for the general safety and would create a confusion which generations could only partially alleviate.

Such a confusion aside from making the calling of the men who fight fires more hazardous, would make itself felt in many other ways. The Insurance Companies, for instance, confronted with a breakdown of carefully considered restrictions would be obliged, as a matter of self interest, to increase the rates of insurance. This added burden is naturally passed on with the added risks to the ultimate consumer, the average citizen.

Therefore if the average citizen thinks he wants the metric system, circumstances will conspire to make him pay the bill in many unexpected ways.

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