
2018 Indiana Design and Installation Manual
32
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5.1 Elevated Sand Mound Design Example
VERIFY MINIMUM REQUIREMENT MET:
TABLE 7: MINIMUM ELEVATED SAND MOUND BASAL AREA REQUIRED
Notes:
The Minimum Basal Areas have been adjusted to reflect a 33% reduction in absorption field area.
Any jetted bath tub with a capacity greater than 125 gallons will be treated as an extra bedroom for the system sizing requirements per Rule
410 IAC 6-8.3.
Using the Table 7, determine required basal area
Minimum required basal area
1608 ft
2
Determine the Minimum Distribution Cell Size: Daily Design Flow ÷ 1.2 gpd/ft
2
600 gpd ÷ 1.2 gpd/ft
2
500 ft
2
Determine minimum downslope area needed: Minimum required basal area – minimum distribution cell size
1608 ft
2
- 500 ft
2
1108 ft
2
Determine if Design meets required downslope.
B (Distribution Cell Length) x G
125 ft x 12.2 ft
1525 ft
2
Since 1525 ft
2
is greater than 1108 ft
2
, the design meets the minimum basal area requirements.
Make sure to consult Rule 410 IAC 6-8.3-80 or ISDH Rule 410 6-10.1 Section 87, Design of Basal Area. In this
example, the sand extension from the distribution cell meets the minimum requirements. Final Dimensions of the
system are on the following page.
DESIGN REQUIREMENT:
410 IAC 6-8.3-80 and ISDH Rule 410 6-10.1 Section 87 state use the greater result:
(for this section, the Distribution Cell Width is equivalent to the Aggregate Bed Width referred to in section 80)
a) Minimum basal area sand width = minimum basal area (from Table 8) ÷ length of bed (B)
1608 ft
2
÷ 125 ft = 12.86 ft
b) For slopes, less than or equal to 0.5%:
Eljen application area width + 14 ft
c) For slopes, greater than 0.5%:
Eljen application area width + 9 ft
4 ft + 9 ft = 13 ft
Actual basal area width is A + G. 4 ft + 12.2 = 16.9 ft
From section 6-8.3-80 it was determined the system required a minimum of 13 ft of Eljen application area width
and downslope basal width. The design is more (Actual basal area width = 16.9 ft) and G (Distance from edge of
distribution cell to down slope edge of system) shall not be increased.
3
4
5
1.2
252
335
419
6
6
0.75
402
536
670
8
7
0.6
503
670
838
9
8
0.5
603
804
1005
11
9
0.25
1206
1608
2010
13
11
Soil
Loading
Rate
(gpd/sf)
Minimum Basal Area Required
(Square Feet)
Bedrooms per House
A42
Modules per
Room
B43
Modules per
Room