Eljen GSF A42 - 2 Subsurface Trench and Single Lateral Bed Design and Installation

2018 Indiana Design and Installation Manual 8 www.eljen.com
2.0 Subsurface Trench and Single Lateral Bed Design and Installation
2.0.1 ACCEPTABLE METHODS OF DISTRIBUTION: Gravity, dosed and pressure distribution are acceptable.
2.0.2 MINIMUM DEPTH FROM ORIGINAL GRADE FOR SUBSURFACE SYSTEMS: The minimum depth for
subsurface systems is 10 inches from original grade to the sand/soil interface for the system.
2.0.3 GENERAL CROSS SECTIONS
FIGURE 3: SUBSURFACE A42 TRENCH CROSS SECTION
SPECIFIED SAND
GEOTEXTILE FABRIC
FINAL GRADE
13"
36"
6"24"6"
6"
7"
MIN 12" OF
COVER SOIL
MATERIAL
MAXIMUM
TRENCH
DEPTH 36"
FIGURE 4: SUBSURFACE B43 SINGLE LATERAL BED CROSS SECTION
SPECIFIED SAND
GEOTEXTILE FABRIC
FINAL GRADE
13"
48"
6"36"6"
6"
7"
MIN 12" OF
COVER SOIL
MATERIAL
MAXIMUM
TRENCH
DEPTH 36"
All subsurface trenches and single lateral beds are required to have:
 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.
 Minimum 6 inches of Specified Sand directly below the GSF module.
 Minimum 12 inches of cover soil material above the 4-inch distribution pipe.
 Maximum trench or single lateral bed depth from final grade is 36 inches.