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P <br /> formula, for trench and bed systems, shall not be less than "5". <br /> <br /> 3. Long Term Acceptance Rates (LTAR): <br /> <br /> The minimum absorption azea A in squaze feet may also be computed as a <br /> function of the design flow (~ and the Long Term Acceptance Rate (LTAR) <br />® <br />I according to the formula: <br /> <br /> <br /> ~~ <br />~ <br />( <br /> .. <br /> ' <br /> LTAR <br />s for Wastewater for soil Absorption Systems <br /> <br /> Percolation hate 'I'voical Soil Maximum Loadioa <br /> (Minutes/Inch) Textures Rate <br />i (gaUsq. ft./day) <br />r _ <br />~' <5** Gravel** Not Suitable <br />L 1-5 Coazse to Medium Sand 1.30 <br />~ 6-10 Fine Sand to Loamy Sand 1.20 <br /> I 1-20 Sandy Loam to Loam .72 <br />L 21-30 Loam 50 <br />~ 311}0 Loam to Silty Loam* 40 <br /> 41-60 Clay Loam to Clay* .30 <br /> Over 60** Silty Clay Loam/Silty Clay 20 <br /> <br />{ * Soils without highly expansive clays <br /> ** Design by Registered Professional Engineer required <br />r <br /> Note: Perwlation rates faster than five (5) minutes per inch require a Professional <br />~ Engineer design as per Section 3.06.B.8 <br /> <br />L E. Allowable Absorption Area Reductions and Increases: <br />~ <br />I~ 1. Adjustment for Deep Gravel: <br /> The length of an absorption trench or seepage bed may be calculated by <br /> <br />~ allowances for the sidewall area of additional depth of gravel in excess of six <br />' (6) inches below the bottom of the distribution pipe according to the following <br />~ formula: 1- W-t~~ <br />~di~5+~~ l~ty+~t = w <br />~. ~t 2t~.a <br />r Where: L =length required prior to adjustment <br /> W =width of trench in feet <br /> d =depth of gravel below distribution pipe in feet. <br />L! <br />~ <br />~i 39 <br /> <br />