TABLE OF CONTENTS Water treatment plant operators and engineering staff should be aware of the appearance of the interior of the distribution piping and how their water quality is affecting the materials in their system. Physical inspection is a very useful inspection tool to a utility, and it can also be done routinely at a very low cost. Both macroscopic (human eye) and microscopic observations of scale on the inside of the pipe are valuable tools for diagnosing the type and extent of corrosion. Macroscopic studies can be used to determine the amount of tuberculation and pitting and the number of crevices. The sample should also be examined also for the presence of foreign materials and for corrosion at joints. A record of historical observations of pipes in different parts of a distribution system and exposed to different water treatments over time could yield insights into slow corrosion or passivation reactions.
Utility personnel should try to obtain pipe sections from the distribution or customer plumbing systems whenever possible, such as when old lines and equipment are replaced. If a scale is not found in the pipe, an examination of the pipe wall can yield valuable information about the type and extent of corrosion and corrosion product formation (such as tubercles), though it may not indicate the most probable cause. Pipe sections of small diameter may be conveniently examined by sawing them lengthwise.
Examination under a microscope can yield even more information, such as...
