(a) Footing drains around the foundation shall be a minimum four (4) inches in diameter, installed on the outside of the footings and shall be properly surrounded with granular filter material. The granular filter material shall be well graded from fine to coarse to prevent washing of fines from the surrounding soils into the drains while at the same time maintaining adequate permeability for the flow of water into the drains.
(b) The grain size requirements for satisfactory filter materials are defined by the following formula:
D15 (Filter 4 D 15 (Filter
D85 (of Protected Soil D 15 (of Protected Soil
Where D15 (Filter) = 15% size of filter material from graduation curve
D15 (of Protected Soils) = 15% size of protected soil from gradation curve
D85 (of Protected Soil) = 85% size of protected soil from gradation curve
In order to assure adequate permeability of the filter material, the minimum D15 size of filter material shall be equal to the #60 sieve size (.0098).
The maximum permissible opening between tiles shall be no more than 1/2 the D85 size of the filter material.
(c) The drains shall be connected to a gravity system discharging into the Village sewer system, or shall be discharged into a sump pit in the basement of the building, with a sump pump and float valve to discharge the water either into the flood plain or into the Village storm sewers if and when permitted by Village ordinances.
(d) Under floor drains shall be a minimum four (4) inches in diameter and there shall be a minimum of ten (10) feet of drain for every one hundred (100) square feet of floor area. The drains shall be properly surrounded with a minimum of six (6) inches of granular filter material as defined above for the footing drains. In addition, a minimum of four (4) inches of approved granular material shall be placed beneath the slab and shall connect to the under drains to facilitate seepage to the drain tile.
(M.C. 1963, § 22.904; Ord. No. 0-64-29; renumbered Ord. 0-77-60, 9-19-77)