Questions ans Answers
NOTE—Readers are invited to send in questions, will be answered in the order received. Names are omitted from questions unless otherwise specified
Liability for Fire Damage
To the Editor:
I am trying to locate some court decisions on suits involving the city as the defendant and a property owner as the plaintiff. We had a fire in a five-room frame dwelling. Fire had broken out through the shingle-roof over one room when the first company arrived. A 2 1/2inch line was placed from the hydrant about 100 feet distant. This line was siamesed into two 1 1/2-inch leader lines. The hydrant was found dry, and the 2 1/2inch line was connected to another line 300 feet distant.
During the time the hose was being connected, two one-inch booster lines were holding the fire. Due to this delay (which has been times as three minutes and fortyfive seconds) the property owner is suing the Fire Department for negligence. The plaintiff did not carry any insurance on the building or contents.
A. C. D.
Answer: This question was submitted to Leo T. Parker, attorney-at-law, for his opinion. He wrote as follows:
“As a general rule a municipality is not liable for its failure to supply water with which to extinguish fires.
“In other words, neither a municipality nor a water company is an insurer that consumers shall be furnished with water supply adequate to meet the demands and requirements of consumers at all times.
“One of the latest higher Court cases on this subject is Atlas Finishing Co. vs. Hackensack Water Co., 163 Atl. 20, in which it was shown that a state law provides:
“‘Nor shall any public utility as herein defined provide or maintain any service that is unsafe, improper or inadequate.’
“If, however, the failure to supply pressure is because the city is using the water or pumping equipment as rental or other source of profit, then the city may be liable. Of course, a valid state law may provide that the city would be liable.
“One day a fire started in a factory which was supplied with efficient hose and other fire fighting equipment. However, the pressure of the water was insufficient to enable the factory employees to extinguish the fire with the result that the buildings were totalling destroyed with other valuable property stored therein.
“The owner of the factory filed suit against the water company to recover damages alleging that it was the implied duty of a private water company engaged in furnishing water for industrial and domestic purposes to supply water at sufficient pressure to enable users to effectively utilize the water for fire protection. After considering all phases of the law the higher Court held the water company liable, and said:
“‘No one person had a right superior to another to demand that he should be supplied, and the legal duty is imposed upon the company to furnish it equally to the extent that its system was capable of doing it.’
“Also in the late case of Peoples vs. South Carolina Power Co., 164 S. E. 605, it was shown that a water company and a city entered into a contract by the terms of which the water company agreed to supply water to the citizens of the municipality at a specified rate. A clause in the contract provided that the water company agreed to supply water for the purpose of extinguishing fires, but it was not clearly stipulated that the water company would be liable for its failure to do so.
One day a building caught fire and the municipal firemen were unable to extinguish the conflagration for the reason that the water company had failed to have sufficient steam in the boiler to furnish sufficient water pressure. The Court held the property owner not entitled to recover. And in Mahe vs. City of Winston-Salem, 130 S. E. 169, the owner of property brought suit against a city to recover damages for the alleged negligence of the latter’s employees in permitting curbstones and rocks to collect around a fire plug or hydrant, for a period of about six or eight months, thus preventing the flow of water resulting in destruction of his house by fire. The Court refused to hold the city liable.”
Small Line Calculations
To the Editor:
Would you kindly solve the following problem? A booster pump is pumping through 200 feet of 1 1/2inch rubber lined hose, to which is attached a Y with two 100 foot lengths of 3/4–inch chemical hose with ⅜ tips. What is the friction loss, the pressure at the tips, and the discharge in g.p.m.? The pressure at the pump is 100 lbs.
C. R. P.
Answer: In brief, the method of solving the problem is to first reduce the entire layout of 1 1/2-inch and ¾-inch hose to a single line of 2 1/2-inch hose; combine the two nozzles into one nozzle of equal size, and then solve for the nozzle pressure. The pressure so found will be the pressure at each of the 3/8-inch nozzles. Discharge from each nozzle or from the combined nozzle may be found by the following formula:
Discharge = 30 x d x d x √p.
The factor for changing 1 1/2-inch hose to 2 1/2-inch is 0.074.
The factor for changing ¾-inch hose to 2 1/2-inch hose is 0.0029.
To combine the two ⅜-inch nozzles into a single nozzle, square each of the nozzles, add the squares and abstract the square root of the sum. This is done as follows:
For the first nozzle, 3/8 x ⅜ = 9/64.
For the 2nd nozzle, ⅜ x ⅜ = 9/64.
Add these two together, and we get 18/64, which reduces down to 9/32.
The square root of 9/32 is 3/5.66 or 0.53 inches, which is the diameter of the combined nozzle.
Reducing the hose layout to a single line of 2 1/2-inch hose, we proceed as follows:
200 / .074 = 2,700 feet of 2 1/2-inch hose, which is the equivalent of the 200 feet of 1 1/2-inch hose.
100 / .0029 = 34,500 feet of 2 1/2-inch hose, which is the equivalent of the 100 feet of ¾-inch hose. Each of the ¾inch lines is equivalent to the same, each being 100 feet long.
Then we combine the two 2 1/2-inch branch lines so found by dividing 34,500 / 3.6, giving us 9,580 feet of 2 1/2-inch hose, the equivalent of the two 100 foot lines of ¾-inch hose combined.
Hence we have a new layout representing a single line of 2 1/2-inch hose with a length of 2,700 + 9,580 or 12,280 feet long. This line is equipped with a nozzle of .53-inch diameter and the engine pressure 100 pounds.
Now solve for nozzle pressure:
N.P. = E.P. / (1.1 + KL).
K for 2 1/2-inch hose and .53-inch nozzle is found by multiplying .53 by itself three times and dividing by 10, or .53 x .53 x .53 x .53 / 10, giving us 0.0079.
L, the number of 50 foot lengths of 2 1/2-inch hose in the line is 12,280 / 50 or 245.6.
N.P. = 100 / (1.1 + .0079 x 245.6)
= 100 / (1.1 + 1.94)
= 100 / 3.04 = 32.9 pounds nozzle pressure.
Discharge = 30 x d x d x √p, where d is the nozzle diameter in inches and p, the nozzle pressure in pounds per square inch. _
Discharge = 30 x .53 x .53 x √32.9
= 48.5 gallons per minute approximately tor the combined nozzle, or 24.25 gallons per minute for each of the two 3/8-inch tips.
The friction loss between the engine and the combined nozzle, or the engine and either of the 3/8-inch nozzles, is equal to 100—32.9 or 67.1 pounds.