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<br />. <br /> <br />e <br /> <br />2. For sanitary sewers larger than 39 inches in diameter, the Professional Engineer <br />of Record shall determine the appropriate grade utilizing a full pipe maximum <br />velocity of 4.5 fps and minimum velocity of2.0 fps. <br /> <br />J. Gravity sanitary sewers shall be lain in straight alignment with uniform grade between <br />manholes. Changes in grade without the use of manholes at the grade change shall not be <br />allowed. Deflection in sanitary sewer pipe runs shall never exceed manufacturer's <br />recommendation. The use of bends to achieve deflections in alignment are encouraged in <br />lieu of pipe deflections. All construction plans showing alignment change by use of <br />deflections are subject to review by the City Engineer. <br /> <br />K. Manholes <br /> <br />I. Type: Manholes shall be either precast concrete manholes in accordance with <br />standard details or the Professional 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 mil. or <br />thicker. Fiberglass manholes with precast, gasketed, concrete bottoms are <br />allowed outside paved areas where the manhole depth is designed to be 8 feet <br />deep or less. It shall be the responsibility of the Professional Engineer of <br />Record to ensure that the precast manholes conform to the latest ASTM <br />requirements. Manhole covers shall have the City of La Porte logo on them. <br />All manholes shall be installed with stainless steel or polyethylene manhole <br />inserts with 1/8 inch vents and strap handles. <br />2. Location: Manholes shall be placed at changes in alignment, changes in grade, <br />changes in size of sanitary sewers, at the intersection of sanitary sewers, junction <br />points, and either at street, alley, or easement intersections. <br /> <br />a. Sanitary sewers laid in public easements shall have a manhole in each <br />street right-of-way outside the paved section of the street crossed by the <br />sanitary sewer regardless of the manhole spacings mentioned in these <br />criteria. <br />b. The maximum distance between manholes shall be determined from the <br />following table for 6 inch to 39 inch pipe diameters. Spacings for <br />manholes on sewer mains with diameters larger than 39 inches shall be <br />recommended on an individual basis by the Professional Engineer of <br />Record subject to City of La Porte approval. <br /> <br />Table 4.2 <br />MAXIMUM DISTANCE BETWEEN <br />SANITARY SEWER MANHOLES <br /> <br />PIPE DIAMETER IN INCHES MANHOLE MAXIMUM SPACING IN FEET <br />6-15 400 <br />18-39 800 <br />>39 Per PE of Record subject to City of La Porte <br /> Approval <br /> <br />c. Place manholes at the dead-end of sewer mains and lateral sewers. A <br />clean out may be used with special permission and approval of the City <br />Engineer. <br />d. Manhole covers shall be cast iron, traffic bearing type ring and cover. <br />e. Criteria for Manhole Junctures <br /> <br />Sanitary Sewer Design Criteria Page 9 of] 1 <br />