DISTRIBUTION SYSTEM

DISTRIBUTION SYSTEM

The Vital Section of the Water Works—Great Activity in Extensions and Additions to ComeDevelopments in Accessories

IT is no exaggeration to say that the vital section of the water works department of a city or town is the distribution system. No matter how well constructed the primary water supply of a municipality is— no matter how admirably situated and ample its reservoirs are, or how perfect a filtration and purification system it may have, if the distribution system be defective and not well planned and laid out, the whole water works will be the sufferer, and will be nullified, as far as efficiency is concerned. Let us see just what is included in the distribution system. In the first place there is the feeder line, leading from the reservoir, from the sedimentation basins or filters. This may be of wood stave, cast iron, steel or cement. Then there are the street mains of varying sizes, according to the necessity of their service, ranging from 4-inch sizes up to 16-inch, and even larger, generally of cast iron, but sometimes of wood or other materials. At various points in the system there must be installed valves of different kinds, including pressureregulating and shut-off service connections, where the pipes supplying private residences and business houses branch off from the street mains, and lastly the hydrants for the use of the fire department, and in some instances special connections for the street cleaning department.

The proper regulation and maintenance of this system of pipes that gridiron the streets of the smallest village, and of course are much more complicated in the case of a town or city of greater size, is of the utmost importance, and requires the expert attention of the superintendent of the water department and his assistants. Not only must the pipe be kept clean and unobstructed, but leaks that develop must be located before damage is done and water and coal wasted in useless pumpage. If the pipe is old and worn out or defective, it must be located without undue disturbance of the street surface, and replaced as rapidly as possible. New systems and additions must be placed as sections of the city open up, and all this must be done with as little disturbance of the ordinary water supply as possible.

The use of cast iron pipe as a medium for carrying water is of considerable antiquity, the first record of its use being in a pipe line laid by order of Louis XIV, from the reservoirs of Picardy, France, to those of Montbauron, the whole supplying the city and parks of Versailles. This pipe, varying in size from 13 to 20-inch, was laid in 1685—234 years ago, and a great part of it is said to be still in use, and apparently good for many years to come, illustrating the long life of cast iron pipe. In this country the first pipe to be constructed of this matcri. I was imported from England, and was laid in Philadelphia in 1817, bell and spigot joints being used to join the lengths. Considerable of this pipe is still in use and serviceable.

Standard specifications for cast iron pipe were adopted by the New England Water Works Association in 1902, and by the American Water Works Association in 1908. The latter, a proposed revision of which has been prepared by a committee appointed for the purpose (see Fire and Water Engineering, Vol. LXIV, page 344, are very extensively used throughout the country.

For mains of 12-inch and over wood stave pipe is sometimes used, and there are a number of installations of this type that have been in use for years. Concrete and reinforced concrete pipe are used in some sections, also, for water conveyance.

Steel pipe of large diameter is quite often used, though not as extensively as that of cast iron. A notable example of the use of steel riveted pipe is in the case of the Catskill System, of the New York City water supply, where inverted siphons of riveted steel are used to cross several valleys, the diameters being 9 and 11 feet, and the plates 7/16 to 3/4 inch thick. Another instance of the use of riveted steel pipes is the Los Angeles, Cal., aqueduct.

There is no doubt that in the coming months of 1919 there is going to develop in the distribution systems of the country a vast amount of activity. Never before in the history of water supply have the prospects for enlargement and extension been so bright as at this time, Many factors have entered into this result. The anticipated declaration of peace, the return of the soldiers and sailors and the necessity of providing work for them, the resumption of delayed improvement, all are moving toward the same end, the pushing of public works of all kinds, and undoubtedly one of the first to be taken up will be the extension of the distribution system. One reason for this will be the opening up of new sections of cities and the spreading out of towns, necessitating the laying of new mains and service connections. This, combined with the replacement of old pipe that undoubtedly will take place in unusual amount, owing to long cessation and delay in this kind of work, will not only tax the manufacturers of pipe, valves and accessories, to their utmost capacity, but even beyond it.

Accessories for Distribution System

Accessories employed in the distribution system of a water works plant are large in number and variety. Valves alone in a single system may vary from one, six feet in diameter, to the small curb cock of less than an inch waterway.

The use of valves on the larger mains in the distribution system in increasing numbers is one of the developments of the past two or three years, and is a direct result of the underwriters’ efforts to have water systems render more efficient and reliable fire protection. The modern idea of an efficient distribution system is one in which any section can be completely cut out when a break occurs therein. This is best accomplished by use of valves in liberal number, a practice which promises to become quite general during the present year. Another practice of a particularly valuable nature which is also coming more into use daily is the placing of valves on laterals at each hydrant. In such an installation it is easy matter to shut off the water should a hydrant, with hydrant valve working against the main pressure, become broken, and likewise it facilitates repairs. The modern idea of getting at a break is to first isolate it by closing valves and then replace the broken section rather than shutting down the entire system until the repair is made.

The adoption by the Underwriters of a standard code for rating cities and towns with regard to their fire protection and which places particular emphasis on the importance of liberal distribution of fire hydrants, has proved a permanent incentive for increase in this line. Those in authority in various cities are beginning to realize that proper hydrant protection is no longer a moral obligation but instead a good business proposition. Money spent in proper hydrant protection is likely to eventually pay for itself many times through bringing a better insurance rating to a city or town and the lower insurance rates which follow improvement in rating. There is certain to be a pronounced movement for better hydrant equipment throughout the entire country and it can only be second to the increase in use of valves, which accompany each hydrant installation as well as head each branch line. There seems to be no trend toward any particular type of hydrant, but instead, a movement toward a much extended use of all. New water main installations during the current year will likely find hydrants spaced much nearer together to meet the insurance interests’ recommendations.

Some years ago when the percentage of services metered in municipal water plants began to creep up there developed a necessity for quick meter installation, repair and testing service. The ordinary plumbing and contracting establishment, not being in a position to render this service in a satisfactory manner, it fell to the cities to provide shops for their meters and install a force sufficient to take care of installations, repairs and tests. So successful was this departure that repair organizations expanded and assumed jurisdiction over hydrants, valves and service appliances. They did not stop here but their development has been such that they now include laying mains and doing those lines of work formerly done by private contracting and plumbing concerns. All this has tended to shape the modern works system into a more independent and self-contained unit, and more uniform and satisfactory installation and repair work throughout can be looked for.

An example of the development in this direction is found in the use of air compressors for calking water mains. Three or four years ago the number of such compressors for distribution system work in water works could be counted on the fingers of one hand. At present nearly every large water department has either purchased or is planning purchase of one or more. The adoption of such labor-saving devices can be expected in increasing numbers.

The importance of this trend of affairs to the manufacturers of water works tools is evident. Instead of furnishing distribution accessories to the city and tools with which to install them to private contractors, the manufacturers can now find their market for both right in the water department. This movement is not yet fully developed. It is only well under way. Although the shortage of labor on the market forced many water plants to use their regular forces on installations and repairs formerly let to private concerns there are a large number who have not yet discovered the advantages and economy of doing their own work. These will, however, eventually fall in line.

Like the New York Telephone Company, many large water departments discouraged new service connections during the past year, and where urgently needed were only able to make them after lengthy delays. This difficulty was the direct result of labor shortage. But each suspended service connection represents just one more to be made when conditions for extensions reach a point where they are satisfactory for such work ; and such service connections are likely to receive attention before main extensions. There is a very busy period ahead for water works in this small work just as soon as weather conditions permit of them on a large, and the same time economical scale. There is likely to lie no radical change in the near future in corporation cocks or service pipes but outside installations of meters will doubtless become more and more popular. There has always been and always will be that opposition on the part of consumers to have meter readers enter cellars to secure meter readings, and the water departments have also found a great deal of the readers’ time is lost by finding no one at home and having to retrace a part of their scheduled routes to get readings on other days. One of the factors which adds to the impetus toward outside meter installations is the development of satisfactory meter boxes. During the past few years meter boxes have been developed that have shown themselves to be frostproof and quite troubleproof, and their cost of installation is easily offset by the saving in time of the readers and in making meter repair and testing work more convenient generally. Curb cocks, as well as curb boxes, will continue as heretofore, and installations thereof will keep pace closely with new services installed.

With the use of steel water pipe and steel tanks in water works came the need of some form of protection against rust or corrosion, for with the comparative thin metal used in both these structures it does not take much corrosion to produce a large percentage reduction in the plate thickness. Protection of steel towers and tanks is a much simpler matter than protection of steel mains, for in the latter case unusual care must be exercised in order that the coating is not injured or rubbed off in process of laying. Water departments realize that a little extra money spent on giving water towers and tanks -an additional coat of paint occasionally is a good investment, and pays for itself many times in eliminating repairs. The water works field is proving itself not only a growing field for steel protective paints and coatings, but also a permanent market for these products.

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