Design Data 5: Multiple Pipe Installations - Trench Condition
A multiple pipe installation is the placement of two or more pipelines in a single trench or embankment condition. This installation procedure is most commonly used where restrictive cover requirements preclude the use of a single pipe of larger diameter, where an assembly of pipes is used to create a buried stormwater storage system, or where a storm and sanitary sewer are installed in the same trench at different elevations.