Underground Infrastructure - August 2023 - 22

Center for Underground
Infrastructure Research & Education
Classifi cation, Certifi cation Requirements
for Polymeric Spray-Applied Pipe Lining
for Gravity, Pressure Pipes
Kawalpreet Kaur | Research assistant, CUIRE, Department of Civil Engineering, University of Texas at Arlington
Sanaz Ghalambor | Researcher, polymer engineer, Nukote Coating Systems International, LLC
Mohammad Najafi | Ph.D., P.E., F.ASCE, professor/director, CUIRE, Department of Civil Engineering, UTA
Diego R. Calderón | P.E., M.ASCE, Research Assistants, CUIRE, Department of Civil Engineering, UTA
Pipe deterioration is a complex process,
involving a combination of aging, chemical
and environmental factors.
Th e trenchless technology renewal
method of spray-applied pipe lining
(SAPL) is one of the most cost-eff ective
and sustainable methods, with minimum
ground disturbance. Th is method
TABLE 1 - Main Characteristics of SAPL
Method
Diameter
Range (in.)
Spray-applied
pipe lining
3-180
Source: Najafi and Gokhale 2022
Maximum
Installation (ft)
1,000
Liner Material
Epoxy, polyurea,
polyurethane, cementitious
Applications
Gravity and pressure
pipelines
provides an eff ective solution for improving
the deteriorated condition of
culverts and pipelines to enhance their
design life (TABLE 1).
In addition, SAPL provides a monolithic
layer that prevents further deterioration
of pipes (Najafi , 2022). Th e materials
used for SAPL fall within two broad
categories: cementitious and polymeric.
Cementitious products are categorized
as rigid, and polymeric materials - including
polyurea, polyurethane, and epoxy
- are categorized as fl exible.
Th e polymeric liner has a thermoset
material characteristic. TABLE 1 depicts
the main characteristics of SAPL.
Polymeric SAPL is a new application
to structurally renew deteriorated
gravity and pressure pipelines and can
be applied to a wide range of concrete,
masonry, corrugated metal, and steel
pipelines. Furthermore, polymeric lining
is approved for water mains by the
National Sanitation Foundation (NSF)
(Najafi , 2022).
FIGURE 1. SAPL manual application (left) and SAPL robotic application (right)
22 AUGUST 2023 | UndergroundInfrastructure.com
SAPL can be applied manually or
with robotic application, depending on
the pipe diameter and space constraints.
FIGURE 1, below, shows manual and robotic
application of the SAPL liner.
SAPL has material characteristics
that can be applied for corrosion protection
and/or to increase the load bearing
capacity of the host pipe. Th e potential

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Underground Infrastructure - August 2023

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