State of Technology Report for Force Main Rehabilitation, Final ...

Hi-Build Polyurethane
3M (E. Wood)
One of the pioneers in the development of epoxy and polyurethane liners was E. Wood Ltd., a UK
company. They were acquired by 3M in 2008. E. Wood has developed a hi-build polyurethane liner,
which can be considered a semi-structural liner (i.e., one capable of bridging over holes in the host pipe).
This product was called Copon Hycote 169HB, but has been renamed Skotchkote for distribution in the
US. The product has DWI approval in the UK for use in a potable water system.
Copon Hycote underwent trials at Yorkshire Water and South West Water in 2004 and 2005, respectively
and was commercialized in 2005. Well over 200 km of water pipe have been lined to date. The smallest
diameter has been 4 inches (100 mm) and the largest 20 inches (500 mm). Bristol Water, a UK water
company with a poor burst history and water quality, is lining pipe with a 1.5 mm thickness where water
quality is dubious and 3 mm in areas prone to breaks. Since undertaking this program, Bristol Water has
not experienced a single break.
Tests have been carried out at Bradford University on 4 inches (100 mm) diameter pipes with 0.4 inches
(10 mm) and 1 inch (25 mm) gaps. The liner failed in the pipe with the 0.4 inches (10 mm) gap at 1,015
psi (70 bar) and 391 psi (27 bar) in the pipe with the 1 inch (25 mm) gap. The thickness of the liner
applied was not reported.
It is envisioned that this new emerging material could also be utilized in a sewer force main, providing the
inner surface can be sufficiently cleaned to allow proper adhesion. So far, this has not been demonstrated.
3.4.2.5 Polyurea Spray-On Linings
Standard Polyurea
A new family of polymer spray-on linings, based on the use of polyurea, is finding rapid acceptance for
lining manholes, wetwells, and other structures exposed to corrosive environments. One of the principal
benefits of the use of polyurea is a very fast cure, with gel times in 5 to 40 seconds and 80% cure in just 5
minutes. Structures can be put back into service 30 minutes after the application of the polyurea. Full
cure is achieved in 24 hours. The other primary benefit is the ability to spray apply a thickness from 0.25
to 2 inches (6 to 50 mm). The thick liner means this spray-on lining system also has the ability to be used
as a semi-structural or even a structural liner.
Innovative Painting and Waterproofing, Inc.
Innovative Painting and Waterproofing has developed a robotic delivery system that allows the spray
application of polyurea to pipes as small as 6 inches (150 mm) in diameter. These materials are not yet
NSF 61 listed, but could be used in a sewer force mains where that requirement does not pertain. The
bond strength to concrete on flat work is reported to be 350 to 800 psi (24 to 55 bar) and on sand blasted
white metal over 2,000 psi (138 bar).
PolySpray
Hunting Specialized Products produces three lines of polyurea spray-on linings, which range from
flexible to stiff, based on the flexural modulus of elasticity. Table 3-3 identifies the physical properties
for Hunting’s polyurea. The Flexible HE800 is tantamount to rubber with 800% elongation. For design
purposes (e.g., ASTM F1216), Hunting reports that the long-term (50 year) flexural creep modulus would
be 50% of the values listed in Table 3-3. In the case of the Fully Structural FS250 material, the flexural
modulus is comparable to some CIPP products.
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