007154-EC-03 rev01-Buried PipeCALCULATION OF TIME FOR WATER IN BURIED PIPE TO REACH GROUND TEMPERATURETemperature StabilizationConductivity of pipe (k)26BTU/(hr Ft deg F)(k= Thermal Conductivity of pipe from Ref Kent's Mechanical Engineer's Handbook 12th Edition, pg 3-14)Length of pipe (L) Ft6300FtTemp of water inside pipe (t1)82deg F82.182.282.382.482.582.682.782.882.9Ground Temp outside of pipe (t2)83deg F838383838383838383Spec heat of water1BTU/lb deg FPipeline Outside Dia (OD - in)26in.Pipeline Wall thickness (Wt - in)0.438in.Outer radius of pipe (ft)1.0833333333Ft1.0831.0831.0831.0831.0831.0831.0831.0831.083Inner radius of pipe (ft)1.047Ft1.0471.0471.0471.0471.0471.0471.0471.0471.047lbs of water1353412lbsBTU to raise one deg1353412.2BTU/deg FArea A outside42861sq ftArea A inside41417sq ftTheta=t1-t21deg F0.90.80.70.60.50.40.30.20.1h on outside18.6BTU/hr sq ft deg F17.716.715.614.413.211.810.28.35.9h on inside18.5BTU/hr sq ft deg F17.516.615.514.413.111.810.28.35.9(h= Heat transfer coefficient Above from Kent's Mechanical Handbook 12th edition, Pg 3-18U9.28.78.27.77.16.55.85.14.12.9Heat transfer rate3.9E+05BTU/hr3.7E+053.5E+053.2E+053.0E+052.7E+052.5E+052.1E+051.7E+051.2E+05(U= initial Heat Transfer Rate - Above from Intro to Fluid Mechanics, Parker Diggsand Blick, equation 13-12)Time per degree (hr)3.5063.73.94.24.54.95.56.37.810.9Time per degree (sec)12620sec132941407815033162171774119808228372792039400Total Time (sec)198949secondsTotal Time (hrs)55.3hoursTotal Time (days)2.30days

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