QUESTIONS AND ANSWERS

QUESTIONS AND ANSWERS

B.Sc., M.E., Technical Editor

“He that questioneth much shall learn MUCH”-BACON

NOTE—Readers of FIRE AND WATER ENGINEERING are invited to send in questions, which will be answered in the order in which they are received. Names are omitted from questions unless otherwise specified.

Purpose of the Churn Valve

To the Editor:

What is the purpose of a churn valve on a motor pumping engine? This may be a simple question to you, but possibly others have too been asked what its function is and have been “stumped” for an answer.

Yours truly,

Camden, N. J., March 27, 1920. H. T.

Answer: A churn valve is for the purpose of causing the circulation from discharge to suction side of main pump, and has to be operated by hand. The automatic relief valve has the same kind of communication to and from the main pump as the churn valve.

Placing Water Tower at Fire

To the Editor:

Will you kindly answer in your Questions and Answers page the following: You are in charge of a water tower and ordered to place it in position, so that the stream from the same will reach in 22 feet on the ninth floor. Show by arithmetic how far away from building it is necessary to place the tower?

Respectfully yours,

Brooklyn, N. Y., March 10, 1920. W. M. J.

Answer: Refer to sketch herewith. The ninth floor will, be 108 feet above street level, allowing 12 feet per floor. Allow further two feet for height of window sill. The stream from tower must then pass over the top of sill which is 110 feet above street level. The water tower extends to 65 feet, so that the stream must raise 110 minus 65 feet, or 45 feet higher still. Assume the stream travels in a straight line and strikes the ceiling 22 feet in as required. Two similar triangles may thus be formed, the first, ABC and the second, CDE. BC is to DE as AB is to CD, or 10 is to 45 as 22 is to CD. If this is expressed in ratio form, we have 10:45 = 22: CD. From the arithmetic rule that the product of the extremes is equal to the product of the means, we get 10 X CD = 45 X 22. CD, or the distance at which the tower must be placed from the building, solves out to be 99 feet. This is the theoretical distance based on a straight line stream travel, which is not possible. The actual distance may be taken as three-quarters of 99, or 75 feet, approximately.

Raising Hose on Fire Escape

To the Editor:

What is the proper way to run a line of hose up a fire escape, where it has to be raised, for instance, eight stories? Thanking you for this information, I am Respectfully yours,

Newark, N. J., March 31, 1920. F. W.

Answer: Give the order to stretch the line on the same side of the street that the engine is located, or on a second or greater alarm, to the front of the building. Pull sufficient hose from the wagon, have a truck company raise a 25-foot ladder; send two men up ahead with rope and nozzle; have line pulled up on the outside of fire escape, then let men with hose work their way up, and the balance of the men remain on the fire escapes lightening up on the line. Have them put pipe straps at two or three different points to take the strain off of the line. After this, the pipe and nozzles may be put on and water ordered.

Frequent Fires in Tobacco Dryers

To the Editor:

I once heard a remark by an insurance man that tobacco dryers have a larger percentage of fires than almost any other line of industry. Having during my boyhood days had considerable to do with the raising of tobacco, I am inclined to doubt the statement. If you could give me any enlightening information on this topic through your journal, your kindness will be much appreciated. Very truly yours,

Richmond, Va., April 8, 1920. D. M. D.

Answer: In recent years there have been numerous fires in tobacco dryers, but it can hardly be said that these establishments hold the record for the number of fires. The introduction of patent drying apparatus, which began about thirteen years ago, had a lot to do with the increase in the number of fires. Before that time drying was done in inert air in enclosed spaces or rooms highly heated by steam. Attending this method were many deplorable conditions. The advantages of the patented forced blast heating over the old method were first recommended to the tobacco industry by a prominent insurance company in 1898, and after drying machines were introduced an official of another insurance company said: “With the introduction of artificial dryers we have a hazard in tobacco factories and warehouses fully equal to that of the average lumber dry kiln. What companies need to do is to watch the new hazard known as the patent dryer.” It may be safely asserted that there is nothing specially hazardous in drying tobacco as far as the leaf and the machines are concerned. The great cause is matches. Particularly in drying scrap tobacco is there an ever-present and positive match hazard. Scrap tobacco comprises the sweepings and trash of sales warehouses, prizeries and factories, and, besides matches, often contain rags, paper, etc. The sulphur match being ignitible at a very low temperature will readily ignite in most any machine, especially if slightly rubbed on the apron. Parlor matches are ignitible at a little higher temperature.

As to the number of fires in dryers, a member of the South-Eastern Underwriters Association interviewed sixtythree owners of tobacco drying machines (through his agents) and out of this number only twelve had any experience with fires, and seven of them claimed that the only fires they knew of had occurred when scrap was being dried.

Exit Regulations in Moving Picture Theatres

To the Editor:

What are the ordinance regulations in New York City relative to exits in moving picture houses, or are the requirements the same as for sweatshops? Thanking you, I am, Yours very truly,

New York, N. Y., April 10, 1920. S. A.

Answer: Portions of the New York City Code of Ordinances relating to exits in moving picture houses are as follows: Over every exit there must be painted on the inside in letters not less than six inches high, the word “Exit” in legible type, and one red light or illuminated sign must be placed inside over each exit, and illuminated while the audience is present. Obstructions to exits are prohibited. All exit doors and doors leading to fire-escapes in all motion picture theatres and open-air motion picture theatres must be unlocked when the theatres are open to the public. All passageways and exits to the street required by law or ordinance must be kept free and clear, and shall be used for no other purpose than for entrance and exit to and from the theatre. No aisle, passageway or space in the rear of the seats in such a theatre shall be obstructed by any camp stool, chair, sofa or settee, nor shall any person be permitted to stand or sit therein.

Decisions Relative to Stream Pollution

To the Editor:

Could you refer me to any instance where a court has decided against pollution of a stream passing through private property, or give me the name of a party who might be able to secure such information for me. I have in mind the pollution of a stream by a glucose works, said pollution creating a bod odor from the stream. Any aid you may be able to give me in this matter will be highly appreciated.

Very truly yours,

New York, N. Y., April 9, 1920. T. M.

Answer: Suits involving this question are of quite frequent occurrence. One of such suits, and which seems to be of the specific kind you have in mind, was that of the Weston Paper Co. vs. Pope, Indiana, (57 N. E. 719). Defendant was engaged in the manufacture of straw-board, and the waste from its mill was discharged into a stream flowing through plaintiff’s farm. This waste polluted the water, making it unfit for use, and caused obnoxious odors on plaintiff’s premises, so that their value was lessened, and great inconvenience caused plaintiffs and their families. The business was conducted skillfully, without negligence or malice. Held, that defendant had no right to pollute the stream, and was liable for the damage sustained; also, held that the defendant should be restrained by injunction from further pollution of the stream. The fact that defendant had spent large sums of money in the construction of its plant, and conducts its plant in a careful manner, without malice, is no defense in an action for damages for polluting a stream by discharging obnoxious waste matter into it to the injury of other riparian owners. The fact that the sewage of a city is emptied into a stream is no defense in an action against a manufacturing company for damages for polluting the stream by discharging the waste matter from its factory into it, and thereby injuring other riparian owners below it on the course of the stream. Damages are not restricted to mere depreciation of property, but may properly be allowed for the inconvenience and discomfort thereby caused.

As to party who could give additional data on pollution decisions, the correspondent is referred to the secretaries of the New England Water Works Association and the American Water Works Association.

Vaporization of Oils

To the Editor:

I wish you would answer or explain the following in your Questions and Answers department: Do oils require heat to vaporize? If so, then why is it that gasoline will evaporate (vaporize) at even zero weather?

Very truly yours,

Brooklyn, N. Y., April 7, 1920. T. W.

Answer: Yes, oils do require heat to become vaporized, but not necessarily high temperatures. Evaporization is a cooling process, and when an oil evaporates it absorbs heat from the surrounding materials, lowering their temperature. Temperature determines the rate of evaporation. To put it in other words, oils vaporize by the application of heat. The temperature at which vaporization takes place varies roughly according to their density; Some of the heavier oils used for lubricants will not give off a vapor until they have been heated to about 600 degrees Fahrenheit. Ether, on evaporating, absorbs so much heat from surrounding bodies and so readily, that their temperature may be lowered below freezing point.

Cock Lofts

To the Editor:

In the New York Fire College Course which is now appearing in your journal, you described the hazardous arrangement of cock lofts. Does not New York City, which poses as possessing the most efficient and best organized fire prevention and fire fighting organization in the country, prohibit the construction of these dangerous fire passages?

Respectfully yours,

Peekskill, N. Y., April 7, 1920. C. T.

Answer: Yes, the construction of such lofts is prohibited. The present New York City building code demands that in rows of two or more frame buildings their sidewalls shall be filled with some fireproofing material, 4-inches thick from the basement to the bottoms of the roof boards. Buildings already having cock lofts have not been ordered to fire-stop them.

Reserve Pumping Engines in Fire Department

To the Editor:

What percentage of engines in a fire department should be held as reserve? As an example, if the department had 40 pumping engines, how many of these should be considered as reserve? Thanking you for an answer in an early issue of your journal, I am Your very truly,

Pittsburgh, Pa., March 31, 1920. W. M.

Answer: About 1 per cent, or one in eight, of pumping engines should be considered as reserve. If a department had 40 pumpers, five of these should be in the reserve.

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