Document 9J1KMk5k5yo9nB3w8JDQY32ge

746 CHAPTER 55 1959 Guide "U. S. Patent 1395,730. "U. 8. Patent 2/153,024. "U. S. Patent 1303387. "A. A. Berk: Treating steam chemically to reduce return line corrosion (Industry and Power, November 1947, p. 79). . "Testa in The Detroit Edison Co. (Unpublished). **J. J. McNeil: Rubber linings and raatinga (Corrosion and Material Protection, Marcb-April 1947). , "L v- Schaefer: Protection of steel bins from corrosion (rotoer Plant Engineering, Vol. 26, 1922, p. 632). "E. R. Walters: Some Notes on Corrosion of Cast-Iron Sectional Boilers (The Institution of Heating and Ventilating Engineers, preprint, 1944). ^ Seep. 67 of Reference 2. "K. H. Logan and M. Romanoff: Soil corrosion studies, 1941 (National Bureau of Standards Journal of Research. Vol. 33 1944, p. 145). ' L. P. Sudrabin: Cathodic protection of steel equipment submerged in water (.Water.Conference Proceedings, Engineers' Society of Western Pennsylvania, 1944).' *D. W. Haering: A discussion. (See p. 66 of Reference 14.) T, S. Carswell and H. L. Morrill: Cydohexylamine and dicyclohexylaraine (Industrial and Engineering Chemistry. Vol 29. 1937. p. 1247). aDrmkmg Water Standards, etc. (Public Health Reports, Vol. 58. No. 3. Reprint No. 2440, January 15, 1943). R. M. Palmer: Discussion (Heating and Ventilating Oc tober 1953). " Official Plumbing Code of the City of Detroit, Article V. Private Communication from H. S. Jordan, AWWA. CHAPTER 56 WATER SERVICES Sizing Cold Wafer Supply Piping, Procedure for Sizing Cold Wafer Systems, Cooling Wafer Piping, Estimating Heating Load and Storage Capacity, Methods of Heating Water, Direct-Fired, Electric, and Indirect Water Heaters, Computing Heat Transfer Surface, Hot Wafer Supply Piping, Control of Service Water Temperature, Safety Devices, Solar Water Heaters, Domestic Hof Water by Heat Pump PROPER design of the water distributing system in a types of fixtures, and the average pressure necessary to give building is necessary in order that the various fixtures this rate of flow. The pressure necessarily varies with fixture may function properly. The amount of either hot or colddesign, a much greater pressure being necessary with some water used in any building is variable, depending on the type fixtures to give the same rate of fiow as in others. In general, of structure, usage, occupancy, and time of day. It is neces- the lower the quality of the faueet the greater will be the sary to provide piping, water heating, and storage facilities pressure required. of sufficient capacity to meet the peak demand without In estimating the load, the rate of flow is frequently com wasteful excess in either piping or equivalent cost. puted in fixture units. One fixture tout is equivalent to 7.5 SIZING COLD WATER SUPPLY PIPING gal per min. Table 2 gives the demand weights in terms of fixture units for different plumbing fixtures under several One of the important items that must be determined before any part of the water-piping system can be sized, is the probable rate of fiow in any particular reach of piping. The rate of flow in the service line, risers, and main branches, however, will rarely be equal to the sum of the rates of flow of all connected fixtures. In fact, the probability that every fixture in a large group will be in use at the same time is so remote that it would be very poor engineering practice to design the piping to take care of such simultaneous flow. The demand load in building water supply systems cannot be determined exactly and is not readily standardized. The two main problems to be considered are: (1) the satisfactory^ supply of water for a given fixture, and (2) the number of fixtures which may be assumed to be in use at the same time. The minimum flow that will be satisfactory to the con sumer depends greatly on the consumer, his standard of liv ing, his professional needs, size of family, garden require ments, and similar factors. Depending on these factors, the per capita water consumption for domestic use usually varies conditions of service, and Fig. I gives the estimated demand in gallons per minute corresponding to any total number of fixture umts. Fig. 2 shows an enlargement of Fig. 1 for a range up to 250 fixture units. The estimated demand load for fixtures used intermittently on any supply pipe will be obtained by multiplying the num ber of each kind of fixture supplied through that pipe by its weight from Table 2, adding the products, and then referring to the appropriate curve of Figs. 1 or 2 to find the demand corresponding to the total fixture units. In using this method it should be noted that the demand for fixture or supply out lets other than those listed in the table of fixture units is not yet included in the estimate. The demands for outlets (such as hose connections, air-conditioning apparatus, etc.) which are likely to impose continuous demand during times of heavy use of the weighted fixtures, should be estimated sepa rately and added to the demand for fixtures used intermit tently, in order to estimate the total demand. So far, the information presented makes possible the de- between 20 and 80 gal per day. Experience indicates that the type of dwelling also has considerable influence on the water consumption. In apartment houses the per capita daily water consump Table 1.... Proper Flow and Pressure Required During Flow for Different Fixtures tion is generally higher than in single-family houses. This is due to the use of a central metering system which is not con ducive to the saving of water, and to the long hot water lines Ftxfcrre Row Prwttww* Row gpa which cause high heat losses and an increase in the wasting of the cooled water. In designing water supply systems for apartment houses, a daily per capita water consumption of 50 gal may be considered a safe design figure. Ordinary basin faucet................................. Self-closing basin faucet............... .......... Sink faucet--$6 in......................................... Sink faucet--% in......................................... 8 12 10 5 3.0 2.5 4.5 4.5 Although a considerable number of housing projects have Bathtub faucet.............................................. 5 6.0 been developed throughout the United States, conclusive Laundry tub cock--% in...................... 5 5.0 water consumption data have not yet been gathered. Never theless, it seems that the daily per capita water consumption Ball-cock for closet...................................... 15 3.0 in housing projects falls in between the consumption in apart ment houses and that in single dwellings at the same geo graphical location. In general, a daily per capita water con Flush valve for closet................................. Flush valve for urinal................................. Garden hose, 50 ft, and sill cock............ 10-20 15 30 15-40* 15.0 5.0 sumption of 40 gal can be used as a safe design figure for housing projects. Table 1 gives the rate of flow desirable for many common * Flow pnseure a the piceeuie hi the pipe et the entnflce to the particular fixture considered. b Wide ruse due to venation in deeicn end type o( fluah-valv* doeeta. . 747 .