High Pressure System At Baltimore—Important Change in Hydrant Methods
Brief mention has heretofore been made in this journal of the high pressure system in Baltimore. Some details, however, in connection with this important work, especially relating to the hydrant used were not fully described. As this hydrant arrangement is a wide divergence from that existing in other plants of a similar kind, and being decidedly in the line of progress, further data concerning the installation will prove interesting. The hydrants are of a specially designed tlusli type, opening against the pressure, having 10-inch barrels, 28 square inches minimum waterway at valve opening and N-inch branch connection to the main; hydrant branches are inserted through a hole cut in the wall of the main pipe, and thoroughly welded to it, with a liberal fillet built on at the intersection of the two; branches are bent in the form of an off-set, to facilitate connection to the hydrant. Each hydrant was subjected to a hydrostatic test pressure of 000 pounds per square inch. Hydrants arc provided with sidewalk cover, upon removal of which there can be connected a special portable service head, which locks into position by a slight turn; heads have four 2%»inch outlets, each provided with a regulating valve, so designed as to also act as a shut-off valve; an outlet in the top of the head permits connecting a monitor nozzle directly thereto. The new portable hydrant head shown in the illustration, was designed and made by the Ross Valve Manufacturing Company, of Troy, X. Y., to meet the requirements of the Baltimore specifications, which include the following: The head, complete with cap not to weigh more than 110 pounds, and shall have five openings all fitted to receive Baltimore standard hose couplings. Four of the above openings to be fitted to receive 2½-inch hose couplings located on the side of the head, spac.d equally around same, and center of each of side openings to be about 10½ inches above street or sidewalk surface when head is in place. The fifth opening shall be fitted to receive ,’1-inch hose coupling and he located on top of head, and shall be used for the purpose of attaching a monitor nozzle, valve or hose and he closed by a cap. The head shall he fitted with suitable grab handles, which shall he so placed as to balance the head. The openings shall be numbered from one to five, and such numbers shall be placed in a conspicuous place and finished in white enamel. Kadi head shall also have a number commencing with Xo. 10, these latter numbers to be not less than 3 inches in height. The base of head shall be so constructed as to fit hydrants as installed for Baltimore high pressure fire service. A drop latch shall be provided to lock the head in place after same has been properly placed in hydrant. Base of head shall be fitted with a moulded rubber ring. The four side openings shall be fitted with combination operating and regulation valves, each capable of adjustment from shut-off as follows: 50 pounds, 75 pounds, 100 pounds. 125 pounds, 150 pounds, or the full pressure, if desired, up to 300 pounds. The pressures herein specified shall be marked clearly on valve bv notches so that the operator can use same as a guide in setting the regulating handles. Regulators must hold the pressure steadily and within 10 pounds of the set pressure, whether the play pipe is closed or open, and shall he provided with a locking device which will not permit the sotting of same to a greater pressure than 150 pounds, without unlocking; hut after same has been unlocked it can then be opened up to 300 pounds. When wide open under the maximum pressure, the valves shall not show a loss of head over 15 pounds. A suitable operating handle and pet cock shall be attached to each valve. The pet cock to be used for attaching a gage, one gage to be furnished with each head. To meet these specifications a light bronze casting was fitted with special Ross combination operating and regulating valves, controlling each of the four 2‘•.•-inch hose outlets. These are numbered 1, 2. 3 and 4, respectively. The operating handle is provided with a lever and catch which registers with notches in the cap of valve. These notches are graduated to indicate the pressure carried. An air cock on each opening is provided for a gage and the fireman in charge of the head at a fire has a gage he can attach at any time to test the pressure of any of the streams. When operating handle is turned full to the right, water is shut off: turning it to the left turns on the water, and to the pressure desired, by allowing the catch to drop in the proper notch. A lock is also provided to prevent pressure greater than 100 to 125 pounds being put on a line without first having orders from the chief in charge. When unlocked, and the handle turned full to the left, the full hydrant pressure of 300 to 350 pounds is obtained. The lock makes it perfectly safe to handle hose on ladders or inside of building, and also permits shut-off nozzles to be used on any 2V&-inch line. The 3-inch opening in top of head is designed to permit the use of a deluge or special spray nozzle. It also permits 3-inch lines to be connected and laid a considerable distance beyond the present high pressure mains, thus extending the high pressure fire zone. Xo regulation is attempted on this opening. Full hydrant pressure only would be used. This opening is ordinarily covered with screwed cap. Two grab handles are provided, one of which plainly shows in cut. One man can readily lift the head, and the cover having first been removed from the flush hydrant, he drops it in position. A latch shown on side of head holds it in place. The main hydrant valve is then opened. The connection to hydrant is 10 inches, and is made much quicker than the ordinary 2M-ineh hose connection can be attached to a hydrant. The heads are carried on the hose wagon or auto truck with the hose and other fire fighting apparatus. Only a few heads are required to equip the entire department. while the standpipes or flush hydrants to which they can be attached may be numbered up in the thousands. This head has fully met the most exacting tests, and Chief Emerich and his assistants arc unstinted in their expression of approval.
The Ross Valve Manufacturing Company is also making an independent combination of operating and regulating valve that can be attached to any high pressure type of hydrant. This valve protects the fireman and enables shut-off nozzles to be used on any high pressure line.
The total number of hydrants in the present Baltimore system is 220, the average linear spacing is 170 feet, and the area served by each, 42,700 square feet. Hydrants are located at street intersections between corner of building lines and curb corners, at alley intersections and alternating on opposite sides of the streets. Markers located on trolley feeder poles and other convenient points are being installed to indicate locations. This important and decidedly advantageous hydrant head opens up a new field in high pressure systems, and there cannot be any doubt that it will be adopted where future plants will be installed.