Water utilities often do not know the specific cause of external corrosion observed on their water mains, and consequently, the chosen preventative measure may not work effectively. Historically, these choices are based on data from other industries (e.g., gas and oil) and may not be suitable for the water industry. Corrosion of metallic pipes can be caused by a variety of mechanisms, each of which requires a different solution. Determining which corrosion mechanism is at work is not a simple matter, because the resulting pipe damage looks similar for all of them. The failure to properly identify corrosion sources may produce prevention systems that are ineffective or do not last. For example, it is not effective to install an anode bag on a main that has a bacteriological corrosion problem. Similarly, an anode bag installed to reduce corrosion caused by a stray impressed current would be quickly used up and would provide only short-term protection. Much recent research on corrosion has focused on internal corrosion, primarily related to water-quality issues, such as lead and copper control and red water. This project will examine external corrosion, which affects the structural integrity of the pipe and makes it vulnerable to leaks and breakage. After identifying the causes of external corrosion, the study will find economical solutions for each type of corrosion and verify them through field trials.

This manual of water supply practices explains the causes and prevention of external pipe corrosion. Third Edition.

The basics are explained along with how to institute a corrosion control program. This book explains how to evaluate the potential for damage by studying soil content, pipe material, and other variables. Includes information on installing and protecting distribution system pipe.

This manual of water supply practices explains the causes and prevention of external pipe corrosion.

Ductile iron pipe (DIP) was introduced about 50 years ago as a more economical and better-performing product for water transmission and distribution. As with iron or steel pipes, DIP is subject to corrosion, the rate of which depends on the environment in which the pipe is placed. Corrosion mitigation protocols are employed to slow the corrosion process to an acceptable rate for the application. When to use corrosion mitigation systems, and which system, depends on the corrosivity of the soils in which the pipeline is buried. The Bureau of Reclamation's specification for DIP in highly corrosive soil has been contested by some as an overly stringent requirement, necessitating the pipe to be modified from its as-manufactured state and thereby adding unnecessary cost to a pipeline system. This book evaluates the specifications in question and presents findings and recommendations. Specifically, the authoring committee answers the following questions: Does polyethylene encasement with cathodic protection work on ductile iron pipe installed in highly corrosive soils? Will polyethylene encasement and cathodic protection reliably provide a minimum service life of 50 years? What possible alternative corrosion mitigation methods for DIP would provide a service life of 50 years?