Page 150 - Trenchless Technology Piping Installation and Inspection

116 Cha pte r T h ree

Parameter Cement-Mortar Epoxy Polyurea Polyurethane
Typical lining 4–8 mm for Minimum Minimum Minimum
thickness 4–12-in. pipe 1 mm typical 1 mm 1 mm typical
and 8–12 mm 2–4 mm typical 2–5 mm
for more than 2–5 mm
12-in. pipe
Curing time Minimum 24 h Minimum 16 h Minimum Minimum 2 h
before (can be less 1 h
disinfection for some
products)
VOC (lb/gal) 0.00 0.30 0.00 0.00
Application Centrifugal, Plural Plural Plural
method mechanical, component component component
pneumatic, spray spray spray
hand application
Curing Moist curing Maintain Not Not required
procedure or accelerated temperature required
curing
Structural No No Yes Yes
enhancement
Odor No odor Strong odor No odor Strong odor
generation during curing during curing
Bonding to Good Strong Extremely Weak
concrete strong

TABLE 3.10 Cement-Mortar, Epoxy, Polyurea, and Polyurethane Comparison
(Continued)

3.19 Ongoing Research on Liner and Pipe Interactions
The decision making process for determining a renewal strategy is
generally driven by a condition assessment of existing pipeline.
Internal and external corrosion and pit depth measurements made
on pipe samples, can provide predictions regarding the residual life
of pipe. The corrosion damage is normally concentrated in localized
“hotspots” rather than being universal damage. Failure of these
pipelines commences with the appearance of transverse fractures or
“back breaks” where soil and ground movement combined with
traffic loads and thermal movements cause tensile stresses to be
induced in the inherently brittle cast iron. Therefore, for structural
enhancement lining to be effective, it must survive the sudden energy
release imposed upon it when pipelines fail under this degree of