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Pre-Chlorinated Pipe Bursting Offers Effect Water Main Rehab Option
6th In A Series From The IPBA
Editor’s Note: The International Pipe Bursting Association (IPBA), a division of NASSCO, is presenting a series of articles in Underground Construction that will provide the reader with a better understanding of the technology. Many myths and misconceptions exist regarding this proven rehabilitation method for replacing existing underground utilities.
Pipe bursting is a proven method for replacing underground pipelines and is the only method of pipeline rehabilitation and replacement other than open cut-excavation that can increase the size of an existing utility without trenching.
This article will discuss replacement of municipal potable water mains utilizing the pre-chlorinated pipe bursting method. This technique has been used for over 30 years in Europe and successfully installed over 100-million feet of new pipe, and has been used in North America for nearly 15 years. This article is written with the assumption that the reader will have a basic level of understanding of the pipe bursting process.
With any construction associated with a municipal water main, the expectation is that service cannot be disrupted for the general public for any extended period of time, which is normally about one work shift. With that said, it is common practice for any construction method to provide either temporary water service or a very limited amount of disruption to an area that is undergoing construction. The temporary water service installation is a cost to the project. Although minimal, disruption to public and private property does commonly occur, often there is some level of damage to existing driveways when they are crossed. Since connections must be made to existing water lines and cross areas that are landscaped and precious to property owners, these may incur damage as well. The cost associated with installation of the temporary water main is typically in the order of a few dollars per linear foot and as public funds are stretched, every dollar that can be invested in installing additional permanent infrastructure is a benefit worth exploring.
First let’s review the most common types of construction associated with water mains and differentiate between rehabilitation and replacement.
With water rehabilitation, the existing pipe is utilized as a host for the new product. The most common and widely accepted methods are sliplining, CIPP, and cement mortar lining (most common), all of which are trenchless methods which can reduce but not eliminate the need for some excavation.