This document is the Water Quality Unit Installation Guide. It describes backfill material, trench construction, risers and final cover.

ADS polyethylene products and a well-constructed backfill envelope work together to support soil and live loads. Although backfill has special significance in applications involving high loads, it is important to take reasonable precautions during any pipe installation. Correct installation will ensure long-term trouble-free service for all types of

pipe systems.

The recommendations detail how to correctly install Water Quality Units. Installation with proper backfill materials, compaction levels, and placement procedures are essential to achieve long term system performance.

The backfill materials must be a Class I material. Native soil meeting class II, III, or I VA, are NOT acceptable initial backfill materials. However, they may be used as final backfill once the initial backfill is placed and compacted. Class I materials shall be compacted to a minimum Standard Proctor Density of 95%. In regions where Class I backfill material may not be readily obtainable, flowable fill may be a suitable alternative. Where flowable fill is used, precaution must be taken to prevent flotation during installation.

The table shows the acceptable backfill material and compaction requirement values.

Trench construction is explained, including a table for size/depth/width dimensions and 2 details.

Backfill envelope construction for placing the unit and initial backfill is described. More information for connecting the bypass, backfill around the unit and bypass, final cover and riser extensions is included. Supporting details, charts and tables included.