Fills that are flush to the ground, fills with missing caps,
broken tank gauges and vials are among the common
causes of water entry. These situations should be
corrected to ensure a watertight seal.
tanks (USTs) or ASTs installed
outdoors, can usually be checked
for water using a tank gauge stick
with water indicator paste. When
checking for water the burner
should be off. Water finding paste
should be applied to the bottom
several inches of the tank gauge
stick, adjacent to the side with the
measurement increments. Whenever
possible, a non-folding gauge
stick should be used. Fully insert
the gauge stick into the lowest part
of the tank until it touches the bottom.
Leave the stick at the bottom
for about 30 seconds. The paste
changes color to the height of any
accumulated water.
With USTs, water accumulates
due to mechanical failure of
components such as fill caps, fill
cap gaskets and vent caps. Less
seldom, a broken or corroded fill or
vent pipe may provide a means of
surface water to enter.
Checking basement tanks for the
presence of water is less straightforward.
In some cases,
the tank is not pitched
towards the bottom fitting
and in other cases this
fitting was plugged at the
time of installation. Tanktop
component removal
to facilitate tank gauging
should only be undertaken
when evidence exists that
water may be present
(excess water in the filter,
rust in pump cover or filter
canister, etc.). Removal of
tank top fittings requires
those fittings be properly
sealed after the gauging
is complete to assure the
tanks integrity.
When water is detected,
every effort should be
made to remove it or at
least reduce the level.
However, just removing
the water is not the full
solution. Anytime water is
identified in a tank, it is
important to inspect the
entire tank system, identify
how the water got in
and advise the customer of
recommended repairs.
External Corrosion is
the main cause of failure
of unprotected USTs. It occurs
when the moisture and oxygen
along with other elements in the
soil lead to corrosion of the tank.
ASTs are also subject to external
corrosion due to contact with walls,
structures, soil, organic matter,
etc. Manufacturers' instructions
provide valuable information
regarding tank placement and
recommended maintenance.
On-site Damage
On-site damage is easily prevented
when proper handling, installation
and maintenance procedures are
followed.
Some manufacturers suggest
that damage during delivery and
installation may be a greater cause
of tank failure than corrosion.
To prevent the occurrence of onsite
damage, tanks should be:
• installed in full compliance
with manufacturer instructions
and NFPA practices
• properly secured & supported
• protected from weather
• regularly inspected
Discovered defects should be corrected
as soon as possible.
Transportation
Damage
This occurs when tanks are
mishandled during transportation
from the factory, warehouse and/
or from the supply house to the job
site.
To prevent transportation damage,
tanks should always be secured
during shipping and handled
with care when being loaded and
unloaded. When tanks are pushed
along the truck bed or dropped
from the truck, the tank’s structure
can be weakened and the tank
often suffers visible damage.
Manufacturing Defects
This accounts for the lowest
percentage of oil tank failures. UL
listed tanks are tested to ASME
standards and most must pass a
series of tests before being shipped.
Thus, the majority of defects are
discovered before a tank leaves
the factory. The defective tanks
identified through testing are not
shipped to a distributor.
Preventing Premature Tank
Failure
The best way to ensure tanks
perform reliably is to make sure
that everything is done correctly:
Tank type selection must be
appropriate for its use and environment.
Secure tanks during transport
to the job site and use the proper
equipment to load the tank on the
truck and place the tank in position
at the job site to eliminate
most transportation damage.
Installation must be in accordance
with manufacturers instructions
and all applicable codes and
regulations.
A schedule of maintenance and
inspection needs to be put in place
and imaintained.
Future articles will cover these
and more. ICM
All the paste has changed color indicating that the
water level may be higher than indicated. Paste
should be cleaned off and reapplied to a higher level to
determine the actual level of water in the tank.
6 ICM/July/August 2020