An Example of Benefits of Water Main Cleaning
Capacity of Mains Greatly Increased by Process—Some Results Obtained—How Large Consumer Benefited—The Methods Employed
THE importance to a city and its water works that its mains are kept in a serviceable and efficient condition can hardly be over-estimated. The following article tells how one water company accomplished the task of cleaning its distribution system satisfactorily, so as to render proper service to the city which it supplies:
In order that you may appreciate the value of the work we have accomplished in water main cleaning in New Albany, I would first like to give a brief history of the city, its environs and the water plant. New Albany. Ind., is a city situated on the Ohio River just below the Falls and on account of its location has a considerable river frontage. It is bounded on the west by hills, on the south by the Ohio River and on the east and north by open rolling country. The city itself, is rather flat. Due to the advantage of being located on the river, the city in its growth has extended in an eastward direction making it long and narrow.
In 1875, when the original water plant was erected advantage was taken of the hills in the western section of the city, which provided a gravity system of water supply.
The pumping station is located near the banks of the Ohio River from which the supply is taken. It is pumped from this point to a series of natural sedimentation basins on the hill west of the city, a suburb called Silver Hills.
Company Installs Modern Filtration Plant
Our company some few years ago installed a modern filtration plant adjacent to the sedimentation basins which have a daily reserve capacity of approximately 26,000,000 gallons. As stated previously the water is pumped first into the open basins then through the filtration plant by gravity into the clear well, then by gravity through a series of distribution mains to the city supply.
The natural pressure obtained is from seventy to eighty pounds. One of the greatest problems that confronted our company was the fact that a great percentage of our daily demand is required in the eastern section of the city, which is admirably adapted as a manufacturing locality. Being in the opposite end of the city from our plant considerable loss in pressure and volume was experienced through friction in transmission.
In 1875 when the plant was first installed filtration was not thought of and the only means of purification was aeration in the reservoirs and as much natural sedimentation as could be obtained. This as the city grew and the demand for water increased, became less and less until at certain periods of high turbidity in the Ohio River, water with considerable sediment was delivered into the distribution system. This along with the natural incrustation, which takes place through long usage of water through pipes, increased the friction losses and decreased the delivery to such a point that in cases of unusual demand in various sections of the. city and especially in case of fire, the supply became inadequate.
Heavy Incrustation Necessitates Investigation
This necessitated our making some investigations, as to whether our demand had increased to such a point that great expenditures would have to be made in additional main feeder lines, or whether it had been brought about to a great extent by the corrosion that had collected in the lines in the forty-eight years they had been in service.
In making my explanation of these conditions, I do not want to leave the impression with you that the distribution system in the city of New Albany, laid out in 1875, had all the necessary provisions made to take care of the 1923 or 1924 delivery. We did find out, however, through tests and experiments that the older portion of our distribution system was very badly corroded and that some increased efficiency could be obtained by a series of main cleaning operations.
Decide Upon Main Cleaning Operations
This work was begun on a large scale in 1922, but only in our smaller distribution mains in the outlying districts of the city where the effects of low pressure were so noticeable. Owing to our rather high general pressure carried throughout the gravity distribution system of the city, quite a few manufacturers have found it greatly to their advantage to provide themselves with automatic sprinkler systems. A good many were able to obtain decidedly lower insurance rates with one source supply sprinkler system depending upon the water company to supply this, which was accepted by the insurance companies and the state inspection bureaus.
This, in some eases, placed us in a rather embarrassing position since all manufacturers desiring sprinkler systems connected to our supply, felt that they should enjoy the same privilege as others who had obtained approved single source connections from us, and insisted that they be furnished the same service in their locality and thereby prevent their having to spend considerable sums of money on the installation and maintenance of a secondary supply.
Of course, we did not feel obligated in all cases to fulfill the manufacturer’s wish, as some concerns located their plants in such isolated districts that our distribution mains were unable to take care of the excessive demand. However, the policy of our company has always been to he as fair as possible, commensurate with the returns obtained therefrom.
Incidentally I would like to mention in this connection that the requirements of the inspection bureaus and insurance companies, in order to protect themselves against losses are many times not only an injustice but an imposition to the water company furnishing service.
How a Large Factory Benefited
I want to mention one particular case where this year’s cleaning operation materially benefited one of our large factory consumers. The Pickrcl Veneer Company was anxious to install a sprinkler system, but wanted it on the one source supply. The inspection bureau came to New Albany, made their tests and reported back that our supply was insufficient. My company at that time was very doubtful regarding the results obtained from main cleaning but I persuaded them to let me try the idea in this particular section.
Today we have a six-inch sprinkling connection with the Pickrel Veneer Company’s plants and one that has been accepted by the inspection bureau and the insurance company entirely due to the results obtained by main cleaning work.
While the static pressure was not materially changed the volume delivered was increased by about forty per cent. and yet when we proposed to this particular manufacturer that we use this method in furnishing him with adequate service, he would not accept it and stated further that he did not like to see us waste our money in this manner, but we have today in our files a letter from him commending us upon the results we obtained and the benefit we were able to give his plant.
“We have found by our experience in main cleaning that we have so increased the efficiency of the system that outside of some cross connecting mains which we are installing from year to year, we have been able to postpone a great expenditure on new distribution lines indefinitely.”
A Hazardous Job Undertaken
The results we obtained in our program for 1922 were so satisfactory that we increased our program for 1922 and undertook, what we considered a very hazardous job, in order to increase the service to our consumer. I previously mentioned the fact that our main distributing arteries from our reservoirs on Silver Hills were a portion of the original plant, and these were badly in need of being brought back to their original capacity. One of these mains, sixteen inches in diameter is the nucleus of the eastern supply of the city and by taking it out of service would not only cut the pressure more than half, but what was more serious, it would reduce the volume by approximately sixty per cent.
There being three lines, two, twelve inches and one sixteen, to he cleaned, we chose the smaller ones first in order to increase their efficiency as much as possible before trying the sixteen-inch leading to the factory district. In pipes of this size where the pressure is sufficient the cleaning machine is pushed through by the water and as long as there is no obstruction such as valves partly closed, valve stems hanging, lead from a poorly poured joint or a sharp right angle bend, one may feel sure that the machine will bring the pipe within 98 per cent. of its original capacity in a very few minutes.
Two 12-Inch Lines Cleaned
These two twelve-inch lines pass under two creeks and through a tunnel approximately 200 feet long where we realized it would be a very serious matter if the cleaner became obstructed. We were very fortunate however to get the cleaner through this portion of the line but when we reached the city and under the first block of brick pavement we encountered our first obstruction.
Incidentally, following up a cleaner that is being pushed through by the pressure of the water is very interesting. Under ordinary circumstances it can readily be followed with an aquaphone placed against the ground just above the point where the pipe line is located. In some cases, however, this method fails and it is necessary to determine the location by opening fire hydrants or various valves along the line to ascertain by the flow of water the approximate location thereof.
The First Obstruction Met and Overcome
At our first obstruction it was necessary for us to tear up the street, break the pipe where we found the cleaner had become caught on lead from a joint that had been poorly yarned before pouring. In fact when we got it out and weighed it, it was equal to a full pig of lead or one hundred pounds. After this, however, it took but a short time to finish the twelve-inch sections as we encountered no more serious trouble.
The first section of twelve-inch main cleaned in one shot was 2,200 feet; the second was 2,700 feet and the third was 465 feet, which completed the work of the twelve-inch lines into the distribution system of the city. Our next task was to undertake the cleaning of the sixteen-inch line from the reservoirs to Vincennes and Elm Streets in the eastern section of the city, a distance of a little over two miles.
Two Right Angle Turns
In this length there were two right angle turns. Not knowing whether these turns had been made with 90 degree bends or two 45’s, it was necessary for us to determine this so as not to run any chances. In fact it was necessary for us to eliminate all the possibilities of danger that we could anticipate, in order that this line could be taken out of service and placed back again within the shortest possible time.
We had hoped to begin the first thing in the morning and have the line back in service by noon time. Before we began, however, every manufacturing concern affected, and in fact every large water consumer was notified by a personal letter, telling them of our intentions, and what we hoped to accomplish by our work, and suggested that while this work was in progress that particular diligence be given the subject of fires.
Fire Department Co-operates
A good many of the manufacturers helped us to the extent of stationing a man at their plants during this period, whose duty would be to locate fires in their incipiency, if such should occur. We also asked the help of the fire department in realizing fully the deficiency that would occur in the water supply and wherever possible to use chemicals. Then we determined if all the valves leading to and from this line were in good operating condition, and found them all satisfactory. We were then prepared to insert the cleaner in the outlet from the basin on Silver Hills ready for its journey through the city.
The next morning our work began and the first trouble we encountered was the breaking of one of the stems in the valves of our sixteen-inch main at the base of the hill. This delayed our work about a half a day, during which time the pressure in the city had been greatly decreased. With the help of one of the pumping engines of the fire department in taking the water from the ditch while repairs were being made we overcame this trouble.
Cleaner Travels Two Miles in 40 Minutes
We were again ready in the afternoon to make the shot and to our surprise and satisfaction the cleaner traveled the entire distance of over two miles in about forty minutes and brought with it tons of refuse from the pipe. In fact aside from that which was washed into the sewer in the surrounding locality, two five ton truck loads of reddish-brown substance resembling iron oxide, were removed from the street. The pipe was examined as soon as the water was pumped out to determine the efficiency of the cleaning, and found to be practically in its original condition, even the tar coating on the pipe was perfect. All replacements were immediately made and the same evening about five o’clock the valves on the line were opened and observations made on the various test gages that had been placed through the city.
Static Pressure Increased from 9 to 10 lbs.
It was gratifying to find that the static pressure in all sections affected by this line was increased from nine to ten pounds, and with various flow tests made within the next few days an increase in delivery of from thirty to forty-five per cent, was found. This completed the major portion of our work. In addition we cleaned one half mile of ten inch and several miles of six and eight inch with equally good results.
We have found by our experience that we have so increased the efficiency of the system that outside of some cross connecting mains which we are installing from year to year, we have been able to postpone a great expenditure on new distribution lines indefinitely.
Use All Own Men Except Superintendent
We have signed another contract with the main cleaning company for our 1924 cleaning program, in which we expect to clean from six to eight miles more of our mains. We use our own organization for this work with the exception of a superintendent, who is furnished by the main cleaning company along with the equipment. The average cost to us. including all sizes, has been approximately twenty-two cents per foot.
In conclusion. I have found in our experience of main cleaning that we not only accomplished the purpose of increasing the efficiency of the mains but it is also an excellent way of detecting leakage, defective valve, closed or partially closed valves, sizes of lines and where they begin and end, and various intersecting conditions on which our records on the older distribution system were vague.
(Excerpts from paper read before the annual convention of the Indiana Sanitary and Water Supply Association.)