Installation of a sewrage line

Installation of a sewrage line

The sewer pipe below the street (in a typical installation) connecting a house to the municipal branch or main sewer line is called a lateral one. This is generally a 4-inch pipe buried in a correctly prepared and sloped trench below the frost line. The slope is the most critical element of the work because it determines how well the gravity force drains the pipe. A new sewer lateral's basic installation process can be broken down into five major steps. The local code authority governs all installation information and must be approved by one or more inspections.

01

 Determine the Elevations

A sewer pipe installation's first major stage is to determine how far the pipe has to go and the elevation (depth) of each pipe end. The sewer pipe typically begins where the primary drain of the home exits the basis of the house for a housing installation. At a link called a tap, the line then slopes downhill to where it connects with the town branch or main. Laser level, GPS, or traditional surveying equipment can be used to measure and lay elevations.

02

 Calculate the Slope

For the initial calculations of the slope, the elevations and the length of the pipe run are used. Subtracting the elevation ending from the beginning elevation produces the complete elevation decrease. The slope is produced by dividing the fall by the complete run (length) of the tube.

For instance, if the pipe meets the main city at a depth of 6 feet and it starts at a depth of 4 feet at the house, the total drop is 2 feet. If the running of the pipe is 80 feet, the slope is: 2/80= 0.025 or 2.5%

For laterals (in most areas) the standard minimum slope is 2%, or 2 feet of drop per 100 feet of run. The actual slope may be somewhat steeper than this target, but it must meet the local code requirements. A slope that is too steep will cause the liquids to run faster than the solids, leading to clogs. A slope that is too shallow does not create enough velocity for proper drainage.

03

 Dig the Trench and Lay the Bedding

To avoid unnecessary soil disturbance, trenching for a lateral sewer must be performed thoroughly. To minimize settling, any disturbed soil must be carefully compacted. In most cases, making the trench as narrow as possible (to minimize soil disturbance) is best, but this requires accurate knowledge of where the pipe will end. There is sometimes a need for a wider trench.

The trench bottom must be smooth and compact, and the required slope must be followed. To provide constant support for the pipe, a bedding material, typically sand, is often placed in the trench. Also, sand is much easier to slope than soil, allowing the slope to be fine-tuned before installing the pipe.

04

 Install the Pipe

Sewer pipe is mounted one segment at a moment, typically from the smaller end of the tube to the greater altitude. Modern sewer pipe is produced of PVC and is either joined by gasket fittings or by solvent glue. The standard residential lines pipe size is 4 inches. Local code indicates the material and size needed for the tube. 

The bell (female) end of each segment of the pipe should be facing uphill in order to minimize modifications in the pipe joints. According to the city specifications, the pipe connects to the main city. At the end of the house, most codes require one or two cleanouts to allow easy access to the pipe for scoping or sewer auger cleaning.

05

 Backfill the Trench

The trench is backfilled to finish the project after the sewer lateral is fully mounted and passes final inspection. In order to safeguard the pipe and eliminate any voids around the pipe, the backfilling method often starts with a layer of sand. The trench is then filled with added layers of soil. Each layer of soil is compacted carefully to prevent future settling.

Installing a warning tape over the first layer of compacted soil is always a good idea — and often required. This alerts crews to the presence of the pipe in order to avoid accidental damage during any excavation in the area.