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The pump should be placed as near to the source of supply as possible, especially when operating with a suction lift.
In order to keep the suction line full of water, a foot valve should always be installed on the end of the suction pipe.
General Practice The general practice is best represented by use of belt driven pumps with internal combustion engine using oil for fuel. Depending upon the cost of fuel as compared to cost of power, the internal combustion fuel oil engine or electric motor is preferable as power unit. Transmission other than belting has not been generally used by Railways. Silent chain drive appears to have an advantage in compactness of units and low transmission losses, but is largely offset by excessive first cost for the smaller installations. The use of indirect connected centrifugal pump usually arises from the necessity of putting the pump within reasonable suction lift of supply and keeping the prime mover, particularly, electric motors above possible extreme floods.
C. R. KNOWLES, Chairman; R. C. BARDWELL, Sub-Committee.
During the past year the Committee has given careful consideration to the adoption of standard specifications covering cast iron water pipe and special castings, and standard specifications for hydrants and valves. The conclusion reached was that the standard specifications of the American Water Works Association were complete in every detail and so well established that practically all cast iron pipe specials, valves and hydrants now used by railroads were furnished under these specifications. Therefore, upon the recommendation of the Standardization Committee, the Board of Direction instructed the Committee to present these specifications to the Association for approval.
Tables of sizes, classification, and illustrations may be obtained in pamphlet form from the Secretary of the American Water Works Association, 153 West 71st Street, New York City.
The specifications follow:
STANDARDS FOR CAST IRON WATER PIPE (Adopted by the American Water Works Association May 12, 1908. Reprinted by
permission.) STANDARDS FOR HYDRANTS AND VALVES (Adopted by the American Water Works Association June 24, 1912. Revised June 9,
1916. Reprinted by permission.)
STANDARD SPECIFICATIONS FOR CAST IRON PIPE AND
Description of Pipes.
Section 1. The pipes shall be made with hub and spigot joints and shall accurately conform to the dimensions given in Tables Nos. 1 and 2. They shall be straight and shall be true circles in section, with their inner and outer surfaces concentric, and shall be of the specified dimensions in outside diameter. They shall be at least 12 ft. in length, exclusive of socket.
Pipes with thickness and weight intermediate between the classes in Table No. 2 shall be made of the same outside diameter as the next heavier class. Pipes with thickness and weight less than shown by Table No. 2 shall be made of the same outside diameter as the Class A pipe; and pipes with thickness and weight more than shown by Table No. 2 shall be made of the same outside diameter as the Class D pipe.
All pipes having the same outside diameter shall have the same inside diameter at both ends. The inside diameter of the lighter pipes of each standard outside diameter shall be gradually increased for a distance of about 6 inches from each of the pipe so as to obtain the required standard thickness and weight for each size and class of pipe.
For pipes of each size from 4-inch to 24-inch inclusive, there shall be two standards of outside diameter, and for pipes from 30-inch to 60-inch inclusive, there shall be four standards of outside diameter, as shown by Table No. 1.
For pipes 4-inch to 12-inch inclusive, one class of special castings shall be furnished, made from Class D pattern. Those having spigot ends shall have outside diameters of spigot ends midway between the two standards of outside diameter as shown by Table No. 1, and shall be tapered back for a distance of 6 inches.
For pipes from 14-inch to 24-inch inclusive, two classes of special castings shall be furnished; Class B special castings with Classes A and B pipe, and Class D special castings with Classes C and D pipes; the former shall have cast on them the letters "AB" and the latter “CD.” For pipes 30-inch to 60-inch inclusive, four classes of special castings shall be furnished, one for each class of pipe, and shall have cast on them the letter of the class to which they belong. Allowable Variation in Diameter of Pipes and Sockets.
Section 2. Especial care shall be taken to have the sockets of the required size. The sockets and spigots will be tested by circular gauges, and no pipe will be received which is defective in joint-room from any cause.
The diameters of the sockets and the outside diameters of the spigot ends of the pipes shall not vary from the standard dimensions by more than .06 of an inch for pipes 16 inches or less in diameter; .08 of an inch for 18-inch, 20-inch and 24-inch pipes; .10 of an inch for 30-inch, 36-inch and 42-inch pipes; .12 of an inch for 48-inch, and .15 of an inch for 54-inch and 60-inch pipes. Allowable Variation in Thickness.
Section 3. For pipes whose standard thickness is less than 1 inch, the thickness of metal in the body of the pipe shall not be more than .08 of an inch less than the standard thickness, and for pipes whose standard thickness is 1 inch or more, the variation shall not exceed .10 of an inch, except that for spaces not exceeding 8 inches in length in any direction, variations from the standard thickness of .02 of an inch in excess of the allowance above given shall be permitted. For special castings of standard patterns a variation of 50 per cent greater than allowed for straight pipes shall be permitted. Defective Spigots May Be Cut.
Defective spigot ends on pipes 12 inches or diameter may be cut off in a lathe and a half-round wrought-iron band shrunk into a groove cut in the end of the pipe. Not more than 12 per cent of the total number of accepted pipes of each size shall be cut and
banded, and no pipe shall be banded which is less than 11 feet in length, exclusive of the socket.
In case the length of a pipe differs from 12 feet, the standard weight of the pipe given in Table No. 2 shall be modified in accordance therewith. Special Castings.
Section 5. All special castings shall be made in accordance with the cuts and the dimensions given in the tables forming a part of these specifications.
The diameters of the sockets and the external diameters of the spigot ends of the special castings shall not vary from the standard dimensions by more than .12 of an inch for castings 16 inches or less in diameter; .15 of an inch for 18-inch, 20-inch and 24-inch ; .20 of an inch for 30-inch, 36-inch and 42-inch and .24 of an inch for 48-inch, 54-inch and 60-inch. These variations apply only to special castings made from standard patterns.
The flanges on all manhole castings and manhole covers shall be faced true and smooth, and drilled to receive bolts of the sizes given in the tables. The manufacturer shall furnish and deliver all bolts for bolting on the manhole covers, the bolts to be of the sizes shown on plans and made of the best quality of mild steel, with hexagonal heads and nuts and sound, well-fitting threads. Marking.
Section 6. Every pipe and special casting shall have distinctly cast upon it the initials of the maker's name. When cast especially to order, cach pipe larger than 4-inch may also have cast upon it figures showing the year in which it was cast and a number signifying the order in point of time in which it was cast, the figures denoting the year being above and the number below, thus:
etc., also any initials, not exceeding four, which may be required by the purchaser. The letters and figures shall be cast on the outside and shall not be less than 2 inches in length and 18 of an inch in relief for pipes 8 inches in diameter and larger. For smaller sizes of pipes the letters may be 1 inch in length. The weight and the class letter shall be conspicuously painted in white in the inside of each pipe and special casting after the coating has become hard. Allowable Percentage of Variation in Weight.
Section 7. No pipe shall be accepted the weight of which shall be less than the standard weight by more than 5 per cent for pipes, 16 inches or less in diameter, and 4 per cent for pipes more than 16 inches in diameter, and no excess above the standard weight of more than the given percentage for the several sizes shall be paid for. The total weight to be paid for shall not exceed for each size and class of pipe received the sum of the standard weights of the same number of pieces of the given size and class by more than 2 per cent.
No special casting shall be accepted the weight of which shall be less than the standard weight by more than 10 per cent for pipes 12 inches or less in diameter, and 8 per cent for larger sizes, except that curves, Y-pieces and breeches pipe may be 12 per cent below the standard weight, and no excess above the standard weight of more than the above percentages for the several sizes will be paid for. These variations apply only to castings made from the standard patterns. Quality of Iron.
Section 8. All pipes and special castings shall be made of cast iron of good quality, and of such character as shall make the metal of the castings strong, tough and of even grain, and soft enough to satisfactorily admit of drilling and cutting. The metal shall be made without any admixture of cinder iron or other inferior metal, and shall be remelted in a cupola or air furnace.
The contractor shall have the right to make and break three bars from each heat or run of metal, and the test shall be based upon the average results of the three bars. Should the dimensions of the three bars differ from those given below, a proper allowance therefor shall be made in the results of the tests. Tests of Material.
Section 9. Specimen bars of the metal used, each being 26 inches long by 2 inches wide and 1 inch thick, shall be made without charge as often as the engineer may direct, and in default of definite instructions the contractor shall make and test at least one bar from each heat or run of metal. The bars when placed flatwise upon supports 24 inches apart, and loaded in the center, shall support a load of 2,000 lb. and show a deflection of not less than .30 of an inch efore breaking; or, if preferred, tensile bars shall be made which will show a breaking point of not less than 20,000 lb. per square inch. Casting of Pipe.
Section 10. The straight pipes shall be cast in dry sand molds in a vertical position. Pipes 16 inches or less in diameter shall be cast with the hub end down.
The pipes shall not be stripped or taken from the pit while showing color of heat, but shall be left in the flasks for a sufficient length of time to prevent unequal contraction by subsequent exposure. Quality of Castings.
Section 11. The pipes and special castings shall be smooth, free from scales, lumps, blisters, sand holes and defects of every nature which unfit them for the use for which they are intended. No plugging or filling will be allowed.