What a Water Supply Engineer Can do in the Fire Department.
DETROIT, as far as my knowledge goes, is the only city in the United States where the Fire Department is charged with the duty of providing a water supply for fire extinguishing purposes, or, more properly speaking, the hydrants and reservoirs from which water is obtained for the use of the engines. The various municipal departments are controlled by the commissions, and it is due to the doubtful phraseology of the acts creating the Fire and Water Commissions that the fire department took charge of the hydrants and reservoirs nearly twenty years since.
Detroit was settled upwards of two hundred years ago, in 1701, and its water works were first intended for distribution only. The first mains were two-inch tamarack logs, succeeded later by three-inch iron pipe and with these primitive conduits connections for hydrants were first made, and long after pipes of greater diameter had superseded the earlier mains the original connections remained to remind us of how little water we required for fire purposes during the ancient regime and the first triumphs achieved by the Fire Department were :
1. The taking out of all three inch connections.
2. The removal of all hydrants with two and a half inch openings.
3. The drainage of all hydrants so they would not freeze in winter.
The abandonment of 3-inch connections was attended with much labor and patient research Some of the earlier water worts officials seemed to have been inveterate foes to records and statistical data, and it was generally necessary to dig down and ascertain what was feeding a hydrant when a short supply at a fire led us to inquire as to the cause.
1 think that one of every kind of hydrant that had been manufactured, from that of Bartholomew up to the very latest, had been planted in our streets in order that our experience in this regard might be of benefit to the future. There were gate and compression hydrants. Few wete good and many were poor. What was considered the best, a compression hydrant, with a frost jacket, was selected and the other relegated to the scrap heap. And it is worthy of remark here to state, that during the years that have sped it has been a ceaseless struggle to retain this uniformity in hydrants, and while it has not been altogether successful, it has been the means of making the system as near perfect as possible. In the early days very little attention was paid to the matter of drainage for hydrants, its importance not being fully appreciated. Now, of 3,000 hydrants, less than five per cent, are not drained to the sewer, and they only because there are no sewers to drain them into.
If water works engineers would resolve not to have a “dead end in their system of distribution, the supply for lire service would be greatly enhanced thereby. Detroit, 1 am sorry to say, has too many “dead ends.” A hydrant is of no use at the end of a water main, but 1 have utilizer.! them by adopting a plan of placing reservoirs there. For this purpose we use a tub having a capacity of 7.000 gallons. We run a feed pipe from the main into the tub anil place a valve at end of the pipe. The engine, having 7,000 gallons of water to start with, is able to care for the majority of fires. The reservoir is of paramount importance in all cities as affording storage for water that can be used in case of fire. In the event of a break in the mains or the freezing of pipes in extreme weather the reservoir is always available. Should it ever be necessary to call in help from neighboring cities it is frequently found that connection cannot be made with hydrants because of the lack of a uniform thread, but the reservoir can always be relied upon.
Down town we use larger sized reservoirs, some of them being sewer shaped, with a holding capacity of 20,000 gallons. Incur five hundred reservoirs we have nearly 4.000,000 gallons of water stored. Some of our larger reservoirs have two valves, or one very large valve, and are capable of feeding two or three of the largest engines.
Hydrants are constantly examined by inspectors, who open the valve and allow the water to run through short lengths of hose into the sewer. This serves to flush the pipe and get rid of tbedead water, which is very apt to cause the boiler of tlte engine to foam. By this inspection the induction and waste valves are found to be performing their functions, and the parts are oiled and left in condition for instant service. I11 Detroit a fire hydrant is considered sacred, and street sprinklers, sewer diggers and others who have occasion to use water in the streets are obliged to get their supply elsewhere. To those who know how easy it is for a hydrant to get out of order in the hands of a person inexperienced in its use, the utility of stringent regulations for the protection of the hydrant will be appreciated.
The old adage that there are tricks in all trades applies to the fire department, and I found early in my career that it was the fashionable thing when an engine had a short supply at a fire to lay it to a lack of water. There are few propositions which cannot be demonstrated either by logic or mathematics, and when the conditions were favorable to a bountiful supply, I could only solve the problem on the basis of a fire engine out of order, lienee, I was invariably skeptical when confronted withja condition which I could only persuade myself was a theory. Finally I proposed to the master mechanic of the department that we place a combination gauge on the inlet of the engine. If the machine ran away from her water a vacuum pressure would be recorded: otherwise the hydraulic pressure would be shown while the engine was working. The scheme was eminently successful, and we have had no complaints about poor water that could not be substantiated since.
Take the matter of poor water at fires, for instance; I will cite two for the purpose of showing what may happen in water supply engineering. In April, 1893, a fire occurred in one of the buildings forming a part of the plant of a large brewing company in Detroit. The fire was quite ugly at the outset, and the officer in command promptly sent in a third alarm. When I arrived on the ground three engineers, whose engines were located on Jefferson avenue, in which was a 42inch supply main with a 6-inch distributing main alongside, complained of poor water, and proved it by recording a vacum pressure on their combination gauges. It did not need the gauge, however, to fell the story, as by standing next the hydrant I could hear the suction. I could only think of a broken gate somewhere on the line, but when my friend, the engineer of the water works, got my interrogatory and set about investigating, he developed one of the most serious minor defects in our system. It appears to have been the practice heretofore to lay large and small supply mains through districts they were intended to supply without connecting them to cross lines. I11 this case the engines actually pumped dry a section covering 10,368 square feet, and the investigation revealed that while the 42 inch and 6-inch mains were laid parallel, they were only connected at points 5,100 feet apart, and that the district north was supplied entirely from this 6-inch main, and all hydrants were connected with it.
In March, 1894, a lire occurred on Michigan Avenue and the following is the water supply record, as submitted to the Engineer of the Water Works:
“Engine No. 3 took suction at the N. W. corner of Sixth Street and Michigan Avenue.
Water Pressure on engine when No. 8 was working, . 44
Pressure on combination gauge at same time,. o
Pressure on engine when at rest . . 30
Eeet of hose (3 inch) worked through. 350
Lines of hose. 1
Size of nozzle 1/2 inches
Engine No. 8 took suction at the S. W. cornerof Baker Street and Michigan Avenue.
Water pressure on engine when No. 3 was working. . . So Pressure on combination gauge at same time, vacuum 15 in.
Pressure on engine when at rest. 27
Feet of hose (2)^inch) worked through. 500
No of lines 2, length 200 feet and 300 feet.
Size of nozzle on 200 feet, inches, on 300 feet, 1 )4 inches.
No. 3 shut down first. No. 8 had both nozzles open about ten minutes. Hydrant did not properly supply both lines and the 1)4 inch nozzle was shut ofT. The water pressure on engine then jumped up to 170 pounds, with ten pounds on the combination gauge at the same time. The supply in this case was an 8-inch main, the hydrant being on four-inch mains, one just north and the other just south of the eight-inch. An in. vestigation revealed that the following conditions existed:
The gate on the north side of Michigan Avenue was closed so that engine No. 3 was pumping out of a 4-inch pipe, having a feed from but one way and that from a 3-inch pipe. This was in a section which has been built up a great many years and the pipeage is as old as the locality. liven had not the gate been closed the pipeage was not sufficient to feed the large engines as was shown in the case of No. S. With one i^-inch stream they were all right, but when they came to add a 1 J^-inch stream they were lost.
Here was a positive demonstration that a 4-inch hydrant on a four-inch main was of no use when big streams were required. To return to the combination gauge on the inlet of the engine: If I go to a tire and see a feeble little stream that we should only expect to escape from the pipe of a lawn hose I follow the line back to see where it comes from. If the gauge shows any pressure, I ask the engineer to ‘‘let her out’ and see how much the pressure can be run down. If running at his maximum speed the pressure is still maintained, I know the water supply is not to blame for that little stream, the trouble is with the engine. If, on the other hand, the gauge runs down to a vacuum pressure I begin my work to locate the trouble. The first thing, of course, conceding that the hydrant is equal to the occasion, is to look for broken and shut off gates and locate the feeders to this particular main. Former superintendents of construction, as I have shown, had a bad habit of running cross lines without connecting them and this omission is the frequent cause of a poor supply for fire extinguishing purposes. Wehavein use 6-inch, 4 J^-inch and 4-inch hydrants and 1 find in practice that the difference between the hydrostatic and hydraulic pressures is in the case of the 4-inch hydrants 35 per cent, and with the 4 j^-inch, 2b per cent. I his test was made with an ordinary engine, capacity 500 gallons a minute working through a length of 2 j4-inch hose with a 1 J/fj-inch nozzle, the static head being seventeen pounds. For each additional length of hose deduct two per cent. The evolution of the modern fire engine with its pumping capacity of i,200gallons per minute, the introduction of three-inch hose and inch nozzle held by the “iron man”, as the firemen term the hoseholder, has given the fire service the opportunity of throwing big streams of water, solid streams that do not break until they reach the fire, and which leave a black mark where they strike. Rut they have shattered the idols of water supply engineers who have clung to the four-inch hydrant as being plenty large enough Some things come to us when we least expect them, with stunning force and when we recover from the blow, we wonder we were not hit sooner, for clinging to the idiotic notions that what we could do in the eighties could be done in the nineties. Yesterday is no relation of to-morrow. 1 well remember we had a fire a few years ago in one of our finest residence districts. The fire was in a church edifice, in process of construction, and it burned so fiercely that a second alarm was sent in. Up to that time I had held tenaciously to the idea that a hydrant at every corner was sufficient, but on this occasion I learned that it was not, some engines having to stretch a thousand feet of hose. I could not shield myself behind the belief that no one ever thought a second alarm would be sent in from that district. It had been, and what had occurred might be repeated any day or night. The answer to this problem was: more hydrants are needed, and plant them in the centre of the block as well as on the corners. So it was with the four-inch hydrant, which might be expected to serve the large engines. They would not doit, and the only recourse was to take them out. In reaching this conclusion I made some experiments, the results of which are herewith given.
* Paper read at the Hoslon Convention of the New Ragland Water Works Association by James K. Tryou, of Detroit,