Eljen GSF A42 - Page 9

2018 Indiana Design and Installation Manual 9 www.eljen.com
2.0 Subsurface Trench and Single Lateral Bed Design and Installation
2.0.4 VERTICAL SEPARATION TO SEASONAL HIGH-WATER TABLE OR LIMITING LAYER: Refer to section
Rule 410 IAC 6-8.3 70.b.5 for subsurface absorption systems or ISDH Rule 410 6-10.1 (61).
V
ertical Separation Distance
(
VSD
)
System Type Daily Design Flow
Limiting
La
y
er
Seasonal High
Water Table
Subsurface Trench and Single Lateral
Bed System
>450
30”
24”
<450 24”
Pressure Distribution Any 24” 24”
VSD measured from the bottom of the excavated trench or bed for the subsurface s
y
stem.
2.0.5 DISTRIBUTION BOX: Parallel distribution is preferred. Sequential distribution may be utilized for sloping
sites and must conform to 1.1.4. Distribution boxes are required to be 5 feet from the proximal end of each soil
absorption field trench.
2.0.6 PARALLEL DISTRIBUTION: Parallel distribution is the preferred method of application to a gravity or pump
to gravity system. It encourages equal flows to each of the lines in the system. It is recommended for most trench
systems.
2.0.7 TRENCH LENGTH: Trenches will have a maximum of 100 ft in length unless pressure distribution is used per
410 IAC 6-8.3 (74) (r) or ISDH Rule 410 6-10.1 (82) (r).
2.0.8 EQUAL LENGTH: Trenches must be of equal length in order to provide equal distribution.
2.0.9 SPACING GUIDANCE BETWEEN TRENCHES AND SINGLE LATERAL BED ROWS: Ensure trenches are
of equal length throughout the system. If using the B43 in a single lateral bed system, ensure there is center to
center distance of 10 feet and 7.5 feet center to center distance for the A42 in a trench.
2.0.10 DISPERSAL AREA: Dispersal area requirements are located in IAC 6-8.3 (58) or ISDH Rule 410 6-10.1
(62).
2.0.11 MINIMUM SLOPE REQUIREMENTS: Maintain a 3:1 slope or gentler for all slopes off the application area.
2.0.12 SUBSURFACE DRAINS: If subsurface drains are utilized they must remain 10 feet from the edge of the
system sand perimeter.