Liquid Fuel Storage
Liquid fuel storage failure
& how to prevent it
This article is the first in a
series on proper tank selection,
installation and maintenance
and is based on the National
Oilheat Research’s Advanced Fuel
Storage Tanks Gold Certification
course and manual authored by
John Levey, NORA, Director of
Education and John Donohue,
Special Projects Coordinator,
Fuel Merchants Association of NJ
and Donohue Associate, LLC
The course and manual are
available, at no charge at
Learning.NORAweb.org
A properly installed and maintained
storage tank is an
extremely safe and efficient
way to store power. A full 275-gallon
tank holds over 34 million
BTUs of potential heat in the fuel
itself. This is equivalent to more
than 11,000 kilowatts of electricity.
All this energy is at the customer's
ready disposal day and night.
This on-hand power contributes
to oilheat's deserved reputation
for comfort, cleanliness, safety and
efficiency.
However, it is critical the storage
tank be properly selected, installed
and maintained. Also, homeowners
must be aware that the tank
is their property and their responsibility.
Working with their fuel
provider, they can be confident of
many years of worry-free service.
Why do tanks fail?
Research shows that there are
four primary reasons tanks fail.
They are:
• Corrosion
• On-site damage
• Transportation damage
• Manufacturing defects
Corrosion
(Either internal or external)
Internal corrosion is the main
cause of above ground storage tank
(AST) failures. The presence of
water in the tank is a significant
contributor to internal corrosion.
Bacteria can live in the water as
it feeds on the fuel in the tank.
These bacteria produce biologically
active sludge that can accelerate
the rate of corrosion of the tank
and other components from the
inside. This is referred to microbial
induced corrosion. Results of recent
studies suggest the bacteria often
excrete substances that are acidic.
These substances can combine
with moisture and form compounds
that negatively affect fuel quality,
the steel tank bottom and system
components.
Keeping water out of ASTs will
help maintain fuel quality, reduce
the frequency of service issues
and help prevent corrosion related
component failures.
There are several simple things
that can be done to reduce the accumulation
of water in tanks:
• Drain water before installation.
Tanks can accumulate significant
amounts of
water during storage
and shipment even
when tapping plugs
are in place.
• Keep tanks full
during the summer
months. NORA’s
research has shown
that when ASTs are
left less full over the
off season, condensation
is increased.
Condensation can
generate about 1
quart of water in
tanks that are left
¼ full during the off
season.
• Install tanks inside whenever
possible. Outside ASTs accumulate
significantly more water
than inside tanks. As outside
tanks are warmed during the
day and then cooled at night,
they accumulate water from
condensation.
• Do not pump-over to new
tank. Pumping fuel from the
old tank into the new tank
also transfers existing water
and contaminants. It is best to
schedule non-emergency tank
replacements at a time when the
tank being replaced will be less
than ¼ full. This fuel needs to
be disposed of properly. When
larger volumes of fuel are present,
or the replacement is being
performed on an emergency basis,
the use of a temporary tank
on-site is advisable.
• Look for signs of water during
service calls and tuneups.
Inspect the filters, filter
canisters, pump strainers and
pump components for the presence
or evidence of water, such
as rust. Water in the fuel system
is evidence of water in the tank.
Tanks installed with direct fill
pipes, such as underground storage
Water is a primary contributor ot tank corrosion.
4 ICM/July/August 2020