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<br />I <br />I <br />I <br />I <br />;1 <br />:1 <br />'I <br />I <br />'I <br />-- <br /> <br /> <br />I <br />11 <br />II <br />.. <br /> <br />~ <br />'I <br /> <br />'. <br /> <br />'I <br /> <br />. ' <br /> <br />I <br />L. <br />~ <br /> <br />'I <br /> <br />. <br /> <br /> <br />tl <br />~ <br /> <br />t <br /> <br />where: <br /> <br />6= central angle of bend, degrees <br /> <br />4. Manhole Losses, hm <br />(a) No sudden enlargement or contraction: <br /> <br />hm = 0.05 <br /> <br />V2 <br />2g <br /> <br />(b) Terminal manhole: <br /> <br />V2 <br />h =- <br />m 2g <br /> <br />5. <br /> <br />Junction Losses, hj: <br /> <br /> <br />~~ 2 _ (~:3~ (~~2) <br /> <br />(CDS e) <br /> <br />h. <br />J <br /> <br />V22 <br />= 2g - <br /> <br />where: <br /> <br />V2 = downstream velocity <br /> <br />VI = upstream velocity <br /> <br />A3 = cross-sectional area of lateral pipe <br /> <br />A2.= cross-sectional area of main line <br />V3 = velocity of flow in lateral pipe <br /> <br />e = angle of intersection; (measured between lateral <br />and mainline upstream of junction) <br /> <br />The EGL and HGL should be plotted on the profile of the <br />storm sewer to check for design errors and wrong assumptions. <br />This data will then be used to size the storm inlet laterals <br />as discussed in Section IV-E. <br /> <br />Basic criteria for structural design of storm sewers shall <br />be an HS-20 loading. Maximum manhole spacing shall be as shown <br />in Table IV-4. Values of Manning's On" to be used for storm <br />sewer analysis are shown in Table IV-5. <br /> <br />Table IV-4 <br /> <br />MANHOLE SPACING <br /> <br />Pipe Size <br /> <br />Maximum Manhole Spacing <br /> <br />18" (minimum) - 36" <br />36" - 60" <br />60" and larger <br /> <br />400 feet <br />500 feet <br />750 feet <br /> <br />45 <br />