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BSTIM1fATING TfiE CUS'I'OMER'S PEAK DEMAND 33 <br />plumbing problems occur duc to expansion or ather causes in existing structures. <br />Continuous-Demand Use <br />Watcr use by equipment requiring continuous ilows, some hospital tixtures, and <br />plant proccsses must be added to ihe irrigution and domestic demand. The estimator <br />must rcly on the engineer, architecl, plumbing contractor, or manuiacturer of the <br />equipment ro ubtain this flow data. Conti,�uous•waler-use equipment often results in <br />high bills and low pressures when lhe customer is negligent in proper maintenance. <br />Procedure for Fstimating Customer Demand <br />l. Determine: <br />Iksign pressure at nieter outlet. <br />Type of customcr to be served. <br />Number and type of fixtures. <br />?. Ucicrmine the combined fixture value: <br />Multiply the approximatc fixture values in Table 4.3 times the number of cach <br />type of fixture lo obtain lhe combined value. <br />3. From fig. 4.4 0: 4.5, detcrmine thc proUaUle customer pcak watcr demand in <br />US gpm at 35-psi pressurc available al thc meter oullet. <br />4. If �he utility's design picssure at lhe mcler ouUet is greatcr than 35 psi, :+djust <br />the �robable n���: noN� at 35 psi to the utility's design pressures by multiplying <br />by llie appropriatc factor from Tablc 4:? (scc p. 29). <br />Yc:ik water demand at 35 psi x jactur = adjusted demand <br />5. Irrigation demand: <br />Detenninc: Arca of irrigable lurf. Type of irriyition. Squares (of 100 sy ft) x <br />Squares (of 100 sy ft) x sprinklcr capacity = 6p;n demand <br />TABL� �}A <br />Sprinklcr Capacitics <br />'I'yp; ul Spnnklcr 1'rccipil;itiun Ralc Dcmand per Squ.in: (100 u� ft) <br />in.�hr gp�n <br />Spray hcads 1 L04 <br />Rotary 1/4 0.2G <br />Snap vah•cs I /4 0.2G <br />I( huse and sprinklcrs arc to bc used, then multiply thc number of sprinklcrs th;d it <br />is practical to use by Ihe sprinkler demand sho�vn in Table 4.1 (sce p. 2G). For <br />dischargc througl� watcr hosc wi�h 3/4-in. huusc piping and 3/4-in. hosc bib with opcn <br />disch:irgc scc Tablc 4.5. <br />6. Total customer pcak demand can nu�v Ue detennined by add:ng the following: <br />Uomestic [� mand <br />Irrigation Demand <br />Con�inu��us LoaJ ToWI Demand <br />Summ�ry <br />Thc a��,,:��,a ������5 �r r��;. a.a and a.5 arc identificd for ccrtain typcs of customers <br />as Iis1eJ un cach curve; however, the cngineer ���ill find that the customcr's piping and <br />