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<br />." <br /> <br />-;:-. <br /> <br />.~1~1 ~, <br />,:' 1 <br /> <br />. <br /> <br />. <br /> <br />Table 4.1 <br />MINIMUM GRADES FOR SANITARY SEWERS <br /> <br />, PIPE SIZE MINIMUM GRADE (PERCENT) <br />6 0,50 <br />8 0.33 <br />10 0.25 <br />12 0.20 <br />15 0.15 <br />18 0.11 <br />21 0.09 <br />24 0.08 <br />27 0.06 <br />30 0.055 <br />33 0.05 <br />36 0.045 <br />39 0.04 <br /> <br />2. <br /> <br />For sewers larger than. 39 inches' in diameter, the Professional. Engineer of <br />records shall determine the appropriate. grade utilizing a full' pipe maximum <br />velocity of 4.~ fps and minimum velocity of2.0 fps. . <br /> <br />). ' Gravity sewers shall be lain m straight alignment with uniform grade betWeen manholes. <br />Deviations from,uniform grade without manholes shall not be allowed. <br /> <br />K. Manholes <br /> <br />~ <br />,I <br />-' <br /> <br />1. <br /> <br />Type: Manholes shall be either precast concrete manholes in accordance with <br />standard details or the Profession~l Engineer of record may submit a cast~in- <br />place manhole design for review and approval by the City. All concrete <br />manholes shall be coated with a coal tar epoxy to a thickness of 10 mI. or' <br />approved equal Fiberglass manholes with precast, gasketed, concrete bottoms <br />are allowed outside paved areas where the manhole depth is designed to be 8 <br />feet deep or less. It shall be the respoIll!ibility of the Professiol)al Engineer of <br />record to ensure that the Precast manholes conform to the latest ASTM <br />requirements. Manhole covers shall be 24 inches in diameter and have the City <br />of La ~orte logo 'on them. All manholes shal~ be installed with a ,stainless steel <br />or p~lyethylene manhole inserts with 1/8 inch vents and strap handles. , <br />Location: Manholes shall be placed at changes in alignment, changes in grade, <br />thanges in size Of sewers, at the intersection ,of sewers, junction points, at the <br />end of all sewers, and either at street, ~lley, or easement intersections., <br /> <br />2. <br /> <br />a. , Se~;ers laid in easements shall have a manhole in each,street or alley <br />crossed by the sewer. <br />b. The maximum distance between manholes shall be determined from the <br />following table for 8 inch to 39 inch pipe diameters. Spacings for <br />manholes on mains with diameters larger than 39 iriches shall be <br />determined on an individual basis by the Professional Engineer of <br />record. <br /> <br />Sanitary S~wer Design Criteria Page 8 of 10 <br />