Eljen GSF A42 - 6 Above Grade Bed Design and Installation

2018 Indiana Design and Installation Manual 35 www.eljen.com
6.0 Above Grade Bed Design and Installation
6.0.1 ACCEPTABLE METHODS OF DISTRIBUTION: Gravity, dosed and pressure distribution are acceptable.
6.0.2 GENERAL CROSS SECTION
FIGURE 20: SUBSURFACE BED CROSS SECTION
SPECIFIED SAND
12" MIN - 19" MAX
OF COVER SOIL
MATERIAL
ORIGINAL GRADE
FINAL GRADE
1
3
12"
1
3
All above grade bed systems are required to have a minimum of:
 6 inches of Specified Sand at the edges of the GSF module.
 6 inches of Specified Sand at the beginning and end of each GSF Row.
 12 inches of Specified Sand directly below the GSF module.
 Minimum 12 inches of cover soil material above the 4-inch distribution pipe
6.0.4 VERTICAL SEPARATION TO SEASONAL HIGH WATER TABLE OR LIMITING LAYER: Refer to section
Rule 410 IAC 6-8.3 72.b.4 for above grade beds 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
Above Grade Bed (12” of sand under
GSF module)
Any 20” 20”
VSD measured from the existin
g
g
rade for the above
g
rade bed s
y
stem.
6.0.5 DISTRIBUTION BOX: Parallel distribution is preferred. Sequential distribution may be utilized for sloping
sites and must conform to 1.1.4. Distribution boxes are recommended to be 5 feet from the proximal end of each
soil absorption field row as per Rule 410 IAC 6-8.3 Section 75.i or ISDH Rule 410 6-10.1 Section 74. This may be
amended to shorter distance per the designer.
6.0.6 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 bed
systems.
6.0.7 ROWS REQUIRED: All bed systems shall have a minimum of two rows of modules.
6.0.8 ROW LENGTH: Rows 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).
6.0.9 EQUAL LENGTH: Rows must be of equal length in order to provide equal distribution.
6.0.10 DISPERSAL AREA: Dispersal area requirements are located in IAC 6-8.3 (58) or ISDH Rule 410 6-10.1
(62).