DWR_2951354

• Title: WESTERN DAM ENGINEERING NEWSLETTER, VOLUME 4, ISSUE 1, MAY 2016
• Author/Source: AECOM
• Keywords: CIPP, EMBANKMENT, DAM, APPS, ENGINEER, SEEPAGE
• Document Type - Reference Library: Research, Thesis, Technical Publications
• Document Date: 5/31/2016
• Year: 2016
• Team/Office: Dam Safety

Western Dam Engineering
Technical Note

May 2016

10
Advantages of CIPP
The advantages of selecting the CIPP outlet conduit
rehabilitation method include:
CIPP is a trenchless pipeline rehabilitation
process
o The embankment does not need to be
excavated to install the CIPP.
o The CIPP is installed directly inside the
existing pipe.
No grout is needed of the annulus between the
CIPP liner and host pipe.
o With proper installation, the CIPP
lining fits tight against the existing
pipeline and should not require grout
for a watertight seal.
Typically no joints are required and installation
is rapid
o The CIPP is installed in one continuous
process, extending from one end of
the pipe to the other; and does not
require joints.
o Long lengths can be installed quickly,
but proper curing is required before
recommissioning the pipeline.
o After curing is complete, the ends of
the CIPP liner are cut flush with the
ends of the existing pipe and treated
to create a seal. End treatments can
consist of mechanical seals, grinding
the ends of the CIPP smooth, and using
epoxy.
o No thermal or contraction joints are
required because CIPP is installed in
one continuous piece.
The CIPP lining decreases the interior diameter
of the pipeline, but the smooth interior surface
of the CIPP lining usually improves the
roughness coefficient, resulting in increased
flow capacity in some cases.
Noncircular pipes can be rehabilitated with
CIPP.
The CIPP lining is capable of accommodating
bends, minor changes in cross section, and
other slight shape variations in the pipeline.
The cost of CIPP can be competitive with other
rehabilitation methods for longer lengths of
pipe (e.g. several hundred feet), but may not
be cost-effective for shorter lengths of pipe
due to higher installation costs.
Design Considerations
The American Society for Testing and Materials (ASTM)
Standards F1216, F1743 and F2019 provide design
standards for CIPP. Manufacturers also provide
guidelines for designing their individual CIPP products.
Most manufacturers specialize in certain CIPP systems,
thus ensure the proper CIPP system is selected and
understood independent from the manufacturer.
Thickness of the CIPP lining depends on the diameter
of the existing pipe, the type of CIPP resin system,
discharge requirements, condition of the existing
pipeline, and loading. Liner thickness typically ranges
from about one half inch for smaller pipes to over 2
inches for larger pipes under external loads. CIPP
typically has up to a 50-year design life and can be
used to rehabilitate pipes ranging in diameter from 4
to 108 inches with insertion lengths of up to 3,000
feet. One limiting factor is weight restrictions for
transporting the liner from the manufacturer to the
jobsite, as it must be transported in one piece.
CIPP can rehabilitate aging pipes that range from
partially to fully deteriorated, as the liner provides
improved structural integrity. A fully deteriorated pipe
has lost most of its structural capacity and thus the
liner needs to provide structural support for the pipe,
as well as a water tight seal. The liner thickness can be
designed and fabricated to meet the necessary
structural criteria for most applications. A partially
deteriorated pipe may have sufficient structural
capacity to support soil and surcharge loads and the
primary function of the liner is to create a water tight
seal and slow further deterioration. However,
regardless of the degree of deterioration of most host
pipe materials, the CIPP should be designed assuming
the host pipe provides no support. This more robust
design of a self-supporting CIPP improves the longevity
of the rehabilitated pipe for a small incremental cost.