Page 127 - Trenchless Technology Piping Installation and Inspection

CHAPTER 3

Spray-on Coatings and

Linings for Renewal of

Potable Water Pipe

Distributions

3.1 Introduction
Spray-on coatings and linings ∗ have been used to protect and renew
pipelines and other infrastructure (tanks, reservoirs, clarifiers, pri-
mary and secondary retention and treatment basins, pump stations,
diversion boxes, manholes, and other structures) for decades.
Shotcrete, an air-assisted spray-on lining method for cementitious
products, was developed at the beginning of the twentieth century
in Allentown, Pennsylvania, and became accepted as a construction
method in 1910. Today, high-tech polymer coatings and composite
lining methods are used to restore, protect, repair, and renew a wide
range of pipelines and concrete, masonry, and steel structures.
The principal objective of a coating or lining for potable water
pipe application is to apply a monolithic layer that inhibits further
deterioration. Type of deterioration is dependent upon pipeline infra-
structure under consideration. In water pipes, it is characterized by
tuberculation, scale buildup, and corrosion that can significantly
reduce flow capability and water quality (see Fig. 3.1). In sanitary
sewers, coatings and linings are effective at eliminating infiltration
while providing containment. In corrosive sanitary sewer environ-
ment, pipe crowns, pump stations, and manholes can lose an inch or
more of concrete in less than a year. Coatings and linings can mitigate

∗ The distinction between coatings and linings is not clear so the terms are used
interchangeably in practice.

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