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Friction values "n" used in Manning's formula to size pipes <br />may not be less than 0.013, unless approved by the City <br />Engineer. Pipes should not be installed on slopes steeper <br />than that which results in flow velocities in excess of 10 <br />feet per second, except where unavoidable. <br /> <br />Sanitary sewer system hydraulic calculations normally need <br />not be presented for City review. They may be requested by <br />the City Engineer in the event of unusual circumstances. <br /> <br />Sanitary sewer pipes shall be sized to flow full or at less <br />than full. They may not be designed to flow with a "head". <br />They must be sized at a minimum to handle the volume of flow <br />of sewage capacity purchased by the developer from the City <br />for the project. <br /> <br />3. Sampling Manholes: Shall be generally constructed <br />onsite over the sewer lateral on projects containing: <br /> <br /> 1. Industrial buildings. <br /> 2. Restaurants. <br /> 3. Office buildings where specific tenant/user is not <br /> known at the time of site construction. <br /> <br />It is the developer/owner's option to construct the manhole <br />according to City Standard Drawing PRIV-4, a metering <br />manhole, or according to City Standard Drawing PRIV-5 (a <br />sampling manhole). The smaller manhole as shown in Drawing <br />Priv-5 is not able to accomodate flow volume measuring <br />equipment. Therefore, the actual volume of sewage discharge <br />from the building cannot be measured directly. For sewage <br />volume amounts, the City must use the domestic water volume <br />as measured by the domestic water meter. This may result in <br />slightly higher than real sewage volume. <br /> <br />The manholes must be constructed at locations onsite where <br />access to them is not likely to be blocked by parked <br />vehicles. Preferable locations are in drive aisles. They <br />should be located in paved areas whenever possible. <br /> <br />Where more than one building is to be constructed on a <br />single lot, and the multiple buildings share one sewer <br />lateral, it is permissible to construct only one sampling <br />manhole at the junction of the laterals to the buildings. <br />However, should the buildings ever become owned by different <br />entities, additional sampling manholes must be constructed <br />over the portions of the sanitary laterals leading to each <br />building. <br /> <br /> 15 <br /> <br /> <br />