Lateral Sewer Lining through CIPP
(Cured-in-Place Pipe)

Maintaining a Critical Connection A lateral sewer is the main sewer drain extending from a private home or building which typically connects to a main city sewer beneath a neighbourhood street. In recent years, CWW’s resident lateral sewer rehabilitation specialists have installed up to 10 km of lateral sewer lining CIPP, and completed several complex drain lining projects in the commercial and industrial sectors including restaurants and hospitals.

Compromising Factors The most common lateral sewer defects encountered are caused by the infiltration of roots, which can rapidly increase in size and form root balls that eventually block the sewer and lead to unpleasant odors, backups, and a series of related damages. Lateral liners are recommended for the rehabilitation of pipes that display defects such as roots, cracks, fractures, holes, open or offset joints, water infiltration, and (or) wear and deterioration from years of use.

Examination and Diagnosis The lateral lining process is typically complete within six hours. Initially, the pipe is inspected and cleaned in preparation for lining. Next, a high pressure jet, rotating blades or a flusher can be used to blast away roots and other debris. Laterals often vary in size from 3″ to 6″ and material changes are often present. Once the pipe is clean, the pipe diameter and length is examined and confirmed. CWW’s lateral liners are designed to seamlessly mould to the exact configuration of the pipe regardless of a potential change in the lateral pipe material or to the diameter of the section of pipe designated for rehabilitation. In addition, CWW deploys an additional quality check by verifying the potential presence of a hidden weeping tile connection. If it is determined that a weeping tile connection is present, a mini robotic cutter is used to reopen the connection after the liner installation has been completed.

Unobtrusive and Cost-Effective Methodology CWW employs two reliable and proven lateral lining techniques installed from the cleanout that is typically located in the basement of the home or building, with negligible disruption to the homeowner. The most common method: air inversion installation and hot water cure. The second: pull-in-place installation and hot water cure. When rehabilitation of a pipe is required in proximity to extensive landscaping, driveways, trees and shrubbery, CIPP is by far the preferred choice and the most effective means of lateral sewer lining, for so often the large proportion of rehabilitation costs are associated with extensive excavation inherent to conventional dig-and-replace methods.

Enhanced Performance Homeowners often wonder whether reducing a pipe’s diameter by installing a pipe within an existing pipe will affect the performance of their sewer line. Not only will a CIPP structural liner restore the structural integrity of the pipe, it will also improve the overall hydraulic characteristics of the pipe as a result of the smooth finish of the CIPP liner. Manning’s Equation* for hydraulic flow resistance demonstrates that flow characteristics are not only maintained through the installation of a CIPP liner; they are actually improved. CWW will also verify that the final diameter based on the required liner thickness calculations is never less than 95% of the original pipe diameter. Upon customer request, CWW will also provide results of tests performed on samples of the installed liner by an independent laboratory. In addition, part of CWW’s Quality Assurance Plan dictates that CWW’s liners are tested on a regular basis. Moreover, CWW CIPP liners continuously surpass the minimum design requirements of ASTMD638 for tensile strength and ASTMD790 for flexural strength through standard testing for all types all liners including sewer, drain, lateral, and culvert liners.

*The Manning formula, known also as the Gauckler–Manning formula, or Gauckler–Manning–Strickler formula in Europe, is an empirical formula for open channel flow, or free-surface flow driven by gravity. It was first presented by the French engineer Philippe Gauckler in 1867, and later re-developed by the Irish engineer Robert Manning in 1890. The discharge formula, Q = A V, can be used to manipulate Gauckler–Manning’s equation by substitution for V. Solving for Q then allows an estimate of the volumetric flow rate (discharge) without knowing the limiting or actual flow velocity.

The Gauckler–Manning formula is used to estimate flow in open channel situations where it is not practical to construct a weir or flume to measure flow with greater accuracy. The friction coefficients across weirs and orifices are less subjective than n along a natural (earthen, stone or vegetated) channel reach. Cross sectional area, as well as n’, will likely vary along a natural channel. Accordingly, more error is expected in predicting flow by assuming a Manning’s n, than by measuring flow across a constructed weirs, flumes or orifices.

The formula can be obtained by use of dimensional analysis. Recently this formula was derived theoretically using the phenomenological theory of turbulence.