14.00 2 Section X-X NOMINAL DIAME THICKNESS CLASS e m TER NUM- AP- inches STANDARD SPECIFICATIONS FOR HYDRANTS AND VALVES* SPECIFICATIONS FOR HYDRANTS 1. Size Classification. The size of hydrant shall be designated by the nominal diameter of the valve opening, which must be at least 4 inches for hydrants having two 24-inch hose nozzles; 5 inches for hydrants having three 24-inch nozzles; and 6 inches for hydrants having four 24-inch nozzles; and shall be classed as one-way, two-way, three-way or four-way, etc., according to the number of 24-inch hose outlets for which they are designed. Area of water-ways. The net area of the hydrant at the smallest part, when the valve is wide open, must not be less than 120 per cent that of the valve opening. Bell ends or flange ends. All hydrants must be fitted with bell ends to fit standard cast-iron pipe, or if flanged they must be fitted with flanges of the standard dimensions corresponding to the pressure under which they are to be used; connecting pipe or flange from main to hydrant in no case to be less in diameter than the valve opening. (The standards referred to are those adopted or that may be adopted by this Association.) 2. General design Type. Hydrants may be of compression or gate type. - Change in diameter. Any change in diameter of the water passage through the hydrant must have easy curve, and all outlets must have rounded corners of good radius. Water hammer. Hydrants must be so designed, particularly as regards the pitch of the thread of the operating stem, that, when properly operated a water hammer will not be caused which will give an increased pressure to exceed the working pressure, when such pressure is over 60 pounds, nor increase the pressure more than 60 pounds when operated under less working pressure than 60 pounds. Broken hydrant. Valves when shut must remain reasonably tight when upper portion of barrel is broken off. Friction loss. With a 5-foot hydrant discharging 250 gallons per minute, through each 24-inch outlet, the total friction loss of the hydrant must not exceed 2 pounds for two-way, 3 pounds for three-way, and 4 pounds for fourway hydrants. Strapping. When requested, hydrants must be fitted with 2 lugs, so that the leaded joint under ground can be strapped. Flange joints above ground. When hydrant barrel is made in two sections, the upper flange connection must be at least 2 inches above the ground line. Adopted by the American Water Works Association, June 24, 1913. Revised, June 9, 1916. 3. Material Hydrant body. The hydrant body must be made of cast iron. Cast iron. All castings shall be made from a superior quality of iron, remelted in cupola or air furnace, tough and even grain, and shall possess a tensile strength of 22,000 pounds per square inch. The casting must be clean and perfect, without blow or sand holes, or defects of any kind. No plugging or stopping of holes will be allowed. Specimen bars. 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 2200 pounds, and show a deflection of not less than 0.35 of an inch, before breaking; or, if preferred, tensile bars shall be made which shall show a breaking point of not less than 22,000 pounds per square inch. Bars must be cast as nearly as possible to the dimensions without finishing, but corrections may be made by the engineer for variations in width and thickness, and the corrected result must conform to the above requirements. Wrought iron. All wrought iron shall be of the best quality of refined iron of a tensile strength of at least 45,000 pounds per square inch. Composition metals. All composition or other non-corrodible metals used to be of the best quality, to have a tensile strength of not less than 32,000 pounds per square inch, with a 5 per cent reduction of area at breaking point. 4. Hose nipples and valves Hose nipples. Hose nipples must be of bronze or suitable non-corrodible metal, either threaded with a fine thread into the hydrants and securely pinned in place, or carefully locked and caulked in place. Hose threads. Hose threads on all hydrants to be installed in any given community must of necessity be interchangeable with those already in service, but, where practicable, threads should conform to the National Standard. 5. Hydrant seat and gate Seat. The seat must be made of bronze or suitable non-corrodible metal, securely fastened in place. Valve. The valve must be faced with a yielding material, such as rubber or leather, except that, if of the gate type, a bronze ring may be used. The valve must be designed so that it can be easily removed for repairs without digging up the hydrant. 6. Drip valve Drip. A positively operating non-corrodible drip valve must be provided and arranged so as to properly drain the hydrant when the main valve is closed. The seat for the waste valve, which must be fastened in the hydrant securely, must be made of non-corrodible material. All other parts of the drip mechanism must be so designed as to be easily removed without digging up the hydrant. |