1978-06-07 Septic System Design - Laserfiche WebLink

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E. Block or Sectional Tanks 1. Rectangular Blocks a. Rectangular blocks shall be laid on an approved bottom. Block shall be at least eight inches thick, constructed of a 4 000 psi core test concrete mix, and cured to a 28 -day strength before installation. b. Rectangular blocks shall be laid either with mortar joints or filled cores. c. There shall be at least two coats of 1/4 inch thick concrete plaster placed on the inside of the block tank. There shall be at least two hours elapsed time between coats. The plaster coat shall start at the bottom course and work up. 2. Circular Block Tanks a. Circular blocks shall be carefully placed oar an approved bottom. Circular blocks shall be at frost two inches thick and constructed of a 4,000 psi core test concrete mix, cured to a 28 -day strength before installation. b. There shall be at least two coats of 1/4 inch thick concrete plaster placed on the inside of the block tank. There shall be at least two hours elapsed time between Coats. The plaster- coat shall start at the bottom course and work up. 3. Sectional Tanks a. A sectional tank shall have an entire section cast as an integral unit. b. A sectional tank shall have two oc more sections and shall have at least one joint below the level of the outlet invert of the tank. c. Sectional tanks shall have an irtegrally cast bottom, or shall be laid on an approved bottom. d. The joint or joints shall be permanently sealed so as to be watertight. 4. Bottom: a. Any tank not having an integrally cast bottom shall not be installed when the water table is closer than twelve inches to the bottom of tht excavation. b. 1f the bottom is poured -in-place concrete, it shall be at least four inches thick and extend to at least four inches outside the tank wall. A concrete mix of at least one part cement, two parts washed sand and three parts washed rock shall be mixed before placement in the excavation.