POWER July 2010 - 16

New Coating System Extends
Life of Cooling Tower
American Electric Power's (AEP's) Cardinal
Power Plant Unit 3 cooling tower in Brilliant,
Ohio, was coated and lined in the
spring of 2008 by a team of coatings professionals
that included the plant's project
and coatings engineering staff, SherwinWilliams
(coatings supplier), Cannon Sline
Industrial (contractor), and OTB Technologies
(third-party inspector). The team
completed the project in just 11 weeks
through damp springtime conditions in
the Ohio River Valley (Figure 1).
The team formulated a fast-track coatings
system and application process to
extend the service life of the tower while
reducing cost-prohibitive downtime. The
schedule also included time for pressure
washing the 457-foot-tall tower's concrete
interior of more than 30 years' worth of
dirt and biological growth.
Key among the contractor's challenges,
according to Cannon Sline President Mark
Chuplis, was the job's overall rigging and
staging. " Envision an hourglass, " he said.
" You're pushed into the side at the top and
drift away from the substrate at the bottom.
You can't make a mistake at over 400
feet in the air; you don't live to repeat it.
Everything we did had a professional engineer's
stamp on it. And it's not a job for the
faint of heart. Our union-trained painters
really helped make this job a reality. "
Another concern was the ability to
spray coating material from the base of
the tower to a vertical length of 500 feet.
" No one had ever pushed this type of material
that distance straight up in the air
before, " Chuplis said. " We actually tested
coatings through 500 feet of spray hose in
the specification process to make sure it
would work properly. "
Complicated Coating System
AEP's project and engineering staff, along
with Cannon Sline, contacted several coatings
companies to determine the optimum interior
lining system and exterior coating system for
the tower. Sherwin-Williams was selected
based on its recommendation of using an interior
lining system that would provide fast
return to service and long-lasting protection.
The selected lining system utilizes a primer
and surfacing material that are 100% solids
and a finish material that is 78% solids.
The lining system proposed by SherwinWilliams
focused on these key compo16
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POWER
| July 2010
nents: products that would provide fast
return to service while providing low permeability,
chemical resistance at elevated
temperatures, and long-lasting protection
to the interior.
Once the primer was applied to seal the
concrete, surfacing material was hand-troweled
over the entire interior surface-more
than 250,000 square feet. This was required
because the tower's interior had never been
coated, and its condition could not be determined
until it had been cleaned and the
sides completely pressure washed (Figure 2).
After pressure washing, workers found
that the interior was much rougher than
expected, with pitting of 2 to 3 inches in
1. Cooling tower refurbishment. The AEP Cardinal Power Plant Unit 3's 457-foot-tall
concrete cooling tower was refurbished in the spring of 2008. The 11-week project began with
the tower's first pressure washing in 30 years, was followed by surface repairs, and was topped
off with a fresh coat of primer and paint. Courtesy: Sherwin-Williams Co.
2. Much manual labor required. After pressure washing, an inspection of the surface
found 2- to 3-inch pitting that required repairs. The entire 250,000-square-foot surface of the
interior was hand troweled with concrete filler to produce a like-new-condition surface before
the two epoxy surface coatings were applied. Courtesy: Sherwin-Williams Co.

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POWER July 2010

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