Resolutions-1997-021

2. For the same size pipe with a change in alignment of greater than 45 degrees, or junction of two pipes, a 0.2 feet drop is required. 3. For the same size pipe with a junction of three or more pipes, a 0.3 foot drop is required. 4. When a smaller sewer joins a larger one, the invert of the larger sewer shall be lowered sufficiently to match the 0.8 depth point of both sewers at the same elevation. C. Bedding: All precast manhole bases shall be placed on a minimum of 6 inches of crushed stone bedding. D. Materials 1. Joints: All joints will be confined O-ring gasket meeting ASTM C443. 2. No lift holes through the entire wall. 3. Mark Class and date of manufacture. 4. Inverts: Precast and cast-in-place inverts must provide a channel at least one-half the depth of the pipe and match the full cross-sectional area of the pipe. All junctions and changes in directions of inverts shall be smooth and rounded to the maximum extent possible to supplement flow through the manholes. 5. Diameter: The minimum diameter for manholes is 48 inches for pipe 24 inches in diameter and smaller, and 60 inches for pipe greater than 24 inches in diameter. Seventy two (72) inch diameter manholes may be required for pipes greater than 36 inches in diameter. Reducers may be used above the chamber section of 60 inches and 72 inch manholes. Precast T's may be used on pipes 48 inches and larger in diameter. 6. Castings shall be Neenah R-1670 non-rocking self-sealing or approved equal. E. Standard manholes, step details, and risers are the same as for sanitary sewers as shown in Figures 8.1, 8.2 and 8.3, except cretex chimney seals are not required. F. All manholes shall be marked with two metal fence posts to remain in place until landscaping is complete. In subdivisions, the posts shall remain in place until landscaping has been completed by the lot owner. G. Manholes in paving shall have an interior Cretex manhole chimney seal (or approved equal). H. Concrete spacer rings or metal shims shall be the only materials utilized to adjust manhole frame elevations. Grout must be used to bond and seal materials used for adjustment.