Going with the Flow:
A Sampling of
Water Tank Maintenance
Painting Programs
Program managers and engineering personnel describe the
development and budgeting of formal maintenance painting
programs for their water tanks, and they explain how the
programs support capital preservation, efficient asset
management, and cost efficiency.
by Lori R. Huffman, JPCL
A
lthough only a minority of public
water utilities have adopted formal
painting programs apart from or at
least equal to their programs for routine
structural maintenance, many utilities do
recognize the benefits of regular maintenance painting. Among the benefits are
capital preservation, efficient asset management, and cost efficiency.
According to Jack Hoffbuhr, the executive director of the American Water Works
Association, most medium and large water
authorities have maintenance programs that
include the inspection and application of
protective coatings in addition to structural
maintenance and sanitation. Maintenance is
a “pay me now or pay me later” proposition, he says, and later payments equate to
costly tank replacement and inconvenienced customers. Despite the importance
of maintenance painting, however, figures
on the cost of coating water tanks are hard
to come by. In fact, AWWA’s Water Industry
Database, which is based on information
from the 4,000 member utilities, does not
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Journal of Protective Coatings & Linings
break out painting costs from its figures on
average operations and maintenance expenditures for its members.
The importance of stand-alone programs has, however, been recognized by
some cities and water authorities, both
public and private. This article will discuss
4 maintenance painting programs, the budgeting process within them, and critical aspects of program development.
Programs Surveyed
East Bay MUD’s Program
Nears Thirteenth Year
The East Bay Municipal Utility District
(EBMUD; Oakland, CA) developed a maintenance painting program in 1985 for its 64
steel water storage and distribution reservoirs,
says Ron Bianchetti, program manager. The
agency’s 73 concrete reservoirs and 24 opencut reservoirs also fall under this program.
The program ties together the work of
engineering, maintenance, and operations
Copyright ©1997, Technology Publishing Company
Maintaining Water Tanks
personnel so that structural maintenance
and water quality improvements can be accomplished along with coating removal and
application during available construction
periods. Bianchetti explains that other noncoatings-related maintenance upgrades
have been integrated into EBMUD’s coating
program because the coatings program represents the largest portion of work undertaken for the agency. Grouping structural,
safety, and coating improvements also
helps to maximize the value of maintenance funding, he says.
The program addresses maintenance
needs by working on 3 to 4 tanks over
every 14-month cycle. Bianchetti notes that
by 2001, the agency will wind down its
high priority projects and move toward an
ongoing, preventive maintenance program.
Two to 3 tanks per year will be scheduled
for rehabilitation/coating improvements
under the ongoing program. The agency
will also perform diver inspections of 5-10
tanks per year to evaluate the performance
of the new epoxy coating systems, which
are expected to last for 30 years.
EBMUD’s program developed through
careful consideration of the tank inventory
and its condition. First, EBMUD reviewed
its maintenance records for each tank to
determine when their interiors and exteriors had last been painted.
In 1993, the District initially identified
candidate tanks painted during or before
1981 as requiring the most maintenance.
Copyright ©1997, Technology Publishing Company
Each of
these tanks
was then inspected by
divers to assess the
amount of
corrosion in
the roof and
shell areas,
the overall
condition of
the coating
system, the
remaining
wall thickness, the
amount and
depth of pitting, and the
type of coating in the tank interior. They
also sampled coatings for any hazardous
components (such as lead). A combination
of the historical records of tank maintenance and the divers’ reports and photographic documentation was then used to
start ranking the tanks.
Maintenance and operations personnel collaborated to further rank each tank
based on its importance to the overall
water distribution system and the District’s
ability to take the tank out of service. This
ranking system considers risk assessment of
each of the candidate tanks to evaluate the
condition scenarios if maintenance is de-
Figs. 1 and 2
(far left and left) At East Bay Municipal
Utility District,
maintenance
coating work on
tank interiors is
usually done under
contract while
coating work on
tank exteriors
(Fig. 3, bottom)
is generally
performed by
in-house maintenance
crews.
Figures 1-3
courtesy of EBMUD
MAY 1997
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Maintaining Water Tanks
Figs. 4 and 5 In the City of Houston,
60 percent of a
project’s budget is
typically allotted to
coating operations
while the other
40 percent is spent
on mechanical
improvements.
Figures 4-7
courtesy of the
Houston Department
of Public Works
and Engineering
layed a number of years. The District then
develops a detailed outage plan, giving a
higher ranking to tanks that can be taken
out of service easily because of lower water
demands or the presence of sufficient additional capacity in the area. The District has
typically given water tanks that are critical
to area demands and emergency water supplies a lower ranking until proper outage
plans are developed.
Project specifications for the interiors
and exteriors of steel tanks are based on a
general specification developed by
EBMUD. This specification establishes parameters for surface cleanliness, use of approved coatings, methods of application,
dehumidification, and tank temperatures,
among other considerations. Tight specifications pay off, says Bianchetti, because if
and when problems arise on projects, it is
easy to go back to the specification and determine whether it has been followed.
General specification requirements include an SSPC-SP 5 (White Metal) surface
preparation, two- to four-mil (50- to 100micrometer) surface profile, and a singlecoat 100 percent solids epoxy system that
has approval from NSF and the District for
tank interiors. The system is specified at a
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Journal of Protective Coatings & Linings
16-mil (410-micrometer) minimum dry film
thickness (dft) and a 30-mil (760-micrometer) maximum dft. The District’s typical exterior coating system includes an epoxy
primer and a urethane topcoat. It is also
evaluating acrylic urethanes for use on tank
exteriors to possibly replace the epoxy/urethane system presently used.
Proper lead paint removal plays an
important role in the District’s maintenance
program. Existing tank coatings are routinely sampled by the District to determine
their lead content, says Bianchetti. Bid documents also include a line item for the cost
of hazardous waste disposal based on an
estimated quantity. In accordance with the
Occupational Safety and Health Administration’s rule on lead exposure in construction
work, contractors must provide a health
and safety program developed by an industrial hygienist. Under the federal Resource
Conservation and Recovery Act, contractors
also must have a hazardous material removal and disposal plan.
EBMUD does not pre-approve contractors who bid on maintenance painting
projects, beyond requiring specific experience with coating tank interiors, says
Bianchetti. Unlike some water authorities,
the District does not require bidding contractors to be certified by SSPC’s Painting
Contractor Certification Program. Bianchetti
explains that although contractor certifications are a good basis for narrowing the
field of contractors, he would prefer to see
a painter certification system. “These are
the guys holding the paint guns and applying the coatings,” he says. For now, the
District feels comfortable with the group of
contractors that typically bid on water
reservoir projects.
Coatings work is inspected by the
District’s NACE-certified inspectors, who remain on site to verify humidity and temperature conditions, adherence to the specification, and integrity of the interior coating
system through holiday testing.
Copyright ©1997, Technology Publishing Company
Maintaining Water Tanks
The program also has a provision for
follow-up warranty inspections after 1 year.
Divers inspect the tanks using video and
still photography. The warranty requires
less than 1 percent rusting after the first
year. If the tank passes, it goes into a fiveyear cycle for diver inspection.
Bianchetti notes that the maintenance
painting program is geared primarily toward protecting tank interiors, due to the
specialized work requirements of interior
coating application. The age of the existing
exterior coating and its condition is noted
when a tank is inspected, but exterior
work is typically scheduled by the District’s
maintenance division and performed by
the District’s maintenance crews. Maintained on an ongoing basis, exteriors are
less of a problem than tank interiors,
says Bianchetti.
The EBMUD program extends from
ranking to budgeting maintenance. The
District first considers the tanks on its priority list, the historical maintenance costs,
and the size of the reservoirs to be coated.
Armed with this information, the District
shapes the budget to fit its needs. According to Bianchetti, the District has made a
commitment to maintain its infrastructure as
well as to control costs. The District has initiated a successful cost control system that
tracks equipment purchases, labor hours,
contractor invoices, and other sources of
charges on each project. With these cost
controls, maintenance project costs have
been within 90 to 95 percent of budget estimates, Bianchetti says.
Bianchetti estimates that EBMUD’s
annual maintenance budget for tank interiors averages $2.2 million per year for steel
reservoirs. Eighty percent of this amount
is spent on painting; 20 percent goes toward structural, maintenance, and operational upgrades, he says. Broken down
even further, coating costs average about
$8 per sq ft ($86 per sq m) for general
coating removal and repainting. Lead paint
Copyright ©1997, Technology Publishing Company
Fig. 6 - The City of
Houston prefers total
removal of lead-based
coatings, but it
occasionally calls
for overcoating on
tank exteriors.
removal jobs are more expensive—approximately $10 per sq ft ($108 per sq m),
Bianchetti says.
He attributes the increased cost to
waste handling, containment, air monitoring, and disposal costs. Lead paint has
been found in only a few tank interiors that
the District has repainted. (Most of the lead
paint has been found on the exteriors.)
When the program moves into the
preventive cycle in 2001, the annual budget
for ongoing tank maintenance should drop
by at least one-half million dollars per year,
Bianchetti predicts. The District will continue to perform maintenance painting and
improvement work on 2-3 tanks every year
and continue diver inspection of the tanks
on a regular basis.
Newport News Has Preventive
Maintenance Program
The City of Newport News, VA, has taken a
proactive stance on maintenance painting
for the last 2 decades, says the City’s Chief
Engineer, Bryan Bradish. The city started its
program by addressing only appearance.
Now, the program includes appearance,
structural integrity, and water quality. The
city’s inventory of tanks includes 7 elevated
steel tanks, 2 steel ground tanks, and 3
concrete tanks.
All the tanks are in good condition because they have been in a preventive maintenance cycle for some time, Bradish says.
The tanks are inspected by a professional
engineer on a five-year cycle to assess
structural integrity and coatings. The appearance is constantly checked by the public, and water quality is monitored as part of
routine distribution system sampling.
MAY 1997
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Maintaining Water Tanks
Fig. 7 - The City of
Houston’s program
calls for a three-coat
epoxy-urethane system
for tank exteriors.
Newport News divides its maintenance painting between contractors and inhouse maintenance crews. Tank maintenance is left to independent contractors,
while exposed pipe maintenance is conducted by employees, says Bradish. Like
many authorities, the city awards contracts
to the lowest qualified bidder. And, although it does not have a roster of prequalified contractors, the city requires contractors to have experience in painting tanks
and expertise in rigging. Bradish has found
in the past few years that the increasing
need for containment during lead paint removal on tank jobs has naturally weeded
out unqualified contractors.
The presence of lead on its water
tanks is a concern for the city. Bradish
notes that lead paint removal has effectively doubled the cost of maintenance painting projects, due mostly to additional moneys spent on containment.
Eastern Municipal Draws on
In-House Expertise
Chuck Daniel, senior engineering inspector
for the Eastern Municipal Water District
(Hemet, CA), has administered a formal
tank maintenance program for the last 15
years. The plan features annual condition
inspections on its 89 water tanks, which
have capacities ranging from 250,000 to 7.3
million gallons.
The maintenance program utilizes
boiler-plate specifications for new construction and maintenance projects, which can
be altered with addendums for site-specific
considerations, says Daniel. The authority
uses epoxy systems on tank interiors. Typically, it follows manufacturers’ recommen-
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dations for cleanliness, but it usually specifies an SSPC-SP 10, Near White finish.
The authority uses its own inspectors,
except in extreme cases, when it hires
third-party consultants. In-house crews perform touch-up work and minor maintenance. Jobs over $25,000 are awarded to
low-bid contractors, says Daniel. Typical
contracts are worth $100,000 or less, and
they include two-year warranties.
The presence of lead-based coatings
on tanks has influenced the methods by
which they are maintained. If exterior
coatings are in good condition, they are
pressure washed (minimum 125 psi [862
kPa]) to remove contaminants and then
overcoated; however, interior lead-based
coatings are always completely removed,
contained, and replaced, says Daniel. Overcoating exteriors is also preferred to total
removal when a small tank is to be replaced soon.
The budget for Eastern Municipal’s
maintenance program is predicated on the
number of tanks to be painted each year.
For 1997, says Daniel, the authority has
slated 3 tanks for recoating.
Houston’s Program Enters Tenth Year
In 1987, the City of Houston, TX, determined that, due to its growth rate and the
deterioration of its infrastructure, its maintenance forces could not keep up with the
extensive maintenance needs of its water
storage system’s 200 tanks, says Walter Harris, project manager. The maintenance
crews were too busy “stamping out brush
fires” generated by citations of non-conformance from the Texas Department of
Health to perform substantive, long-range
preventive maintenance, he says.
Thus, Houston embarked on a program to allot funds for systematic coating
inspection and maintenance and to budget
long-range capital improvements. The program slates 10 to 15 tanks per year for
maintenance and has an annual budget of
Copyright ©1997, Technology Publishing Company
Maintaining Water Tanks
approximately $6 million, including consultant and inspection costs. Sixty percent of a
project’s budget is typically allotted to coating operations, while the other 40 percent
is spent on mechanical improvements, says
Harris. To date, the city has completely removed and replaced coatings on 90 tanks,
almost half of Houston’s inventory.
According to Harris, the city’s water
operations division knows the most about
the general condition of its tanks. The program, therefore, relies on this division to
recommend the inspection of specific tanks
in the system. During inspection, the tanks
are assessed for their compliance to current
AWWA standards, Texas Department of
Health standards, and OSHA safety standards, says Harris.
The city hires a consulting firm to
perform condition surveys, says Harris. The
city schedules outages of approximately 1
week per tank for a thorough cleaning and
possible test blasting to examine the substrate and perform metallurgical, safety,
and coating inspections. The consultant inspects interior and exterior coatings, performs ultrasonic thickness testing on the
steel, and assesses the overall condition of
the tanks.
Based on these data, the consultant
estimates the cost of bringing the tanks into
compliance with standards and regulations
and prepares a report comparing rehabilitation and reconstruction estimates. The
maintenance program does not rule out
tank reconstruction. If repair costs are too
high, scrapping an old tank and replacing it
with a new one is sometimes more cost-effective, Harris says.
The engineering reports are reviewed
with its operations division; a scope of
work is defined; and the consultant is directed to prepare the bid documents. Typically, says Harris, each contract is under
approximately $2 million. The consulting
firm is also responsible for project management, scheduling, and inspection.
Copyright ©1997, Technology Publishing Company
At least half of Houston’s tanks have
lead-based paint on the exterior or interior,
says Harris. These aged coatings have lead
contents of anywhere from a few parts per
million to approximately 25 percent by
weight of the coatings, he says. Houston
prefers total removal to overcoating, says
Harris, but it occasionally performs overcoating of tank exteriors.
Before launching the maintenance
program, Houston left the specification of
surface preparation and coatings application to coating suppliers and contractors.
Since 1987, however, the city’s specification
for coating work has increased from 3
pages to a 30-page performance specification, he says. The program specifies the use
of 3 coats of a two-part epoxy on tank interiors and a three-coat system of epoxy and
urethane for tank exteriors. Harris notes
that to maintain product warranties, the city
generally follows the coatings manufacturers’ recommendations for surface preparation and application, unless more stringent
requirements are warranted.
As a municipal agency, Houston must
accept the “qualified” low bid on its projects, says Harris. The city, therefore, requires bidding contractors to have applied
similar protective coatings to a minimum
number of storage tanks over a certain time
span. The contractors are also required to
document this experience with a list of
tanks completed and references to confirm
the work. His projects receive bids mostly
from local contractors, because it is difficult
for out-of-state contractors to compete on
the basis of low bids, Harris says.
The consulting firm keeps track of
square footage costs from job to job, says
Harris. On average, regular tank coating
and lining jobs run from $3.50 to $4.50 per
sq ft ($38 to $49 per sq m), depending on
the size of the tank and the complexity of
the work to be done. Lead paint removal
jobs on tank interiors and exteriors average
$5.00 to $7.00 per sq ft ($54 to $75 per sq
MAY 1997
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Maintaining Water Tanks
m), with more severe corrosion and higher
percentages of lead influencing costs, he
says. Square footage costs increase to between $6.50 and $8.50 ($70 and $90 per sq
m) when worker exposure monitoring and
hazardous waste disposal are included.
With five- to seven-year maintenance
touch-up cycles, the program endeavors to
make its maintenance systems last for 20
years, says Harris. Maintained tanks receive
follow-up inspections every 2 years. Harris
says that coating failures will almost always
occur within the first year of service.
Although Houston’s program has settled into smooth operation, it is not immune to occasional jolts from unexpected
maintenance needs. For instance, he says,
smaller water systems annexed by the city
put a strain on the program, because they
often require emergency repairs to bring
them to an acceptable operating condition.
gram bids work to a consultant on contracts that typically last 11⁄2 to 2 years, says
Harris. The city can extend the contract if it
is satisfied with the consultant’s work.
Consultants Can Help Keep
Programs Running
One benefit of routine maintenance painting is its ability to prolong the useful life of
water tanks, Bianchetti says. EBMUD’s
tanks were built with a design life of 50
years. “If we had done nothing [to maintain
the tanks], the reservoirs wouldn’t make it.
By spending money on a periodic basis,
the District can get the 50 years.” In fact, he
says, the District expects to see an additional 50 years of available service life for the
maintained tanks. The interior 100 percent
solids epoxy system has an anticipated performance of 30 years, so the District figures
that it can rehabilitate tanks many times before having to replace them, he says. With
such benefits, “it doesn’t make sense to let
things go,” says Bianchetti.
Daniel says the benefit of a maintenance painting program is clear: a water
authority can either perform yearly touchup on its tanks or spend millions to replace
neglected structures. Touch-up repairs, he
says, can take only hours; total recoating
jobs can last for weeks.
Consultants can be important contributors
to the development and implementation of
a maintenance painting program. However,
says Bianchetti, input from consultants is
not always necessary if personnel with the
water authorities are knowledgeable about
developing and implementing programs for
coatings. End users who are uncomfortable
about writing specifications or performing
inspections should turn to consultants for
help. Ultimately, however, in-house knowledge is better than outside administration,
says Bianchetti.
Bradish, whose maintenance program
was developed in cooperation with a consulting firm, believes that input from engineering consultants is crucial to effective
specifications. “A painting company can
help you with coating specifications but
can’t address structural concerns,” he says.
Houston’s maintenance painting pro-
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Journal of Protective Coatings & Linings
The Pay-Off of Preventive
Maintenance
Bianchetti’s program has labored to develop benefit-to-cost ratios on maintenance
painting versus reconstruction, based on information gathered over the length of its
program. For a typical 1.5-million-gallon
(5.7-million-liter) water reservoir, the benefit-to-cost ratio of maintenance painting
(versus replacement cost over a typical 50year design life) is 4 to 1, he says.
The Benefits of a
Formalized Program
Copyright ©1997, Technology Publishing Company
Maintaining Water Tanks
When asked how the maintenance
painting program has benefited Houston’s
water operations, Harris points to the results of Texas Department of Health inspections. Ten years ago, these inspections generated pages-long lists of violations of the
Rules and Regulations for Public Water Systems required by the
Texas Natural Resources
Conservation Commission, Water Utilities Division. Now, violations
have decreased dramatically. In fact, in 1996,
the City of Houston received the prestigious
“Superior Water” rating
classification by the
Texas Department of
Health, due in part to the accomplishments
of the water tank maintenance program,
says Harris.
An additional benefit of successful
maintenance painting programs is their effect on customers. Planned maintenance
improves the public’s perception of its
water service, says Bradish. “Tanks are our
billboards,” he says.
inventory should be the first step toward
launching a program, says Bianchetti. Tank
owners should keep in mind the available
historical data on maintenance, so that they
can better define what needs to be done.
• Develop a log of each tank’s maintenance history, says Daniel. Eastern Municipal has researched its
records and, in some
cases, analyzed coatings
to determine their
generic type. The logs
go back approximately
30 years, Daniel says,
and serve as a road
map for the authority
when planning its maintenance itinerary.
• Consider using divers
to inspect tanks and gather visual documentation of deterioration, Bianchetti says.
In some cases, tanks critical to water supplies cannot be taken out of service for dry
inspections.
• Develop a system to rank tanks for maintenance, to estimate costs and to establish
annual expenditures for capital programs,
says Bianchetti.
• Good specifications are critical, says
Bianchetti. If an owner doesn’t have the expertise to write coating specifications, it
should contract the job to consultants.
• Implement warranty inspections to verify
that work has been done correctly. Problems don’t show up immediately, says
Bianchetti.
• Owners must not become complacent
about the condition of their tanks, says
Bradish. Without regular tank inspection
and touch-up as necessary, the program
rapidly becomes a problem.
• Know when maintenance is not enough.
Some tanks may be so deteriorated that replacement is cheaper, says Bianchetti.
• “The cost of maintaining tanks is expensive, but it doesn’t compare to the cost of
losing customers’ trust,” says Bradish. JPCL
“Tanks are our
billboards,” says
Newport News’s
Bradish.
Lessons Learned:
Critical Components
The owners’ representatives interviewed
gave pointers for initiating and running
successful maintenance painting programs.
• Maintenance programs benefit from community support, says Bradish. As the largest
structure in many neighborhoods, a water
tank is a visible reminder of the water authority’s stance on quality control. The
community should understand that the authority is painting the tanks not just to improve their appearance but also to prolong
their service lives, thus saving the community money.
• A condition analysis of each tank in the
Copyright ©1997, Technology Publishing Company
MAY 1997
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