ABOVEGROUND TANK SAFETY ISSUES
The most significant threat to an
aboveground tank is that someone is going to overfill the vessel by some amount and that fuel will escape the containment
and find its way to the ground. This event as documented is 94 percent of the risk. Most often the environment
will suffer because the overfilled fuel will go unnoticed or unreported. Tank fires, when they occur, are a result
of this overfill event when the fuel finds an ignition source.
The second most common event is leaking
pipes, valves or fittings releasing fuel to the environment; this event is five percent of the problem, and poses
the proportionate threat. The remaining reasons are ignorance, vandalism, ballistics and arson in that order. The
SuperSafe Tank system approaches the risks with clear solutions to break the fire triangle by removing from the
equation the three elements: fuel, ignition, and oxygen.
Tests conducted by UL, PM, SWR, Omega
and others have demonstrated that tank failure brought on by the worst possible fire exposure occurs when a pool
fire situation exists. In this condition, it is clear that ignited fuel heat flux is permitted to impact the belly
of the vessel. With the SuperSafe Tank design, the engineered boxed runner continuous supports block flames from
impacting on the bottom of the vessel, effectively eliminating that risk. The boxed runners also are designed in
such a way that should they be impacted by fire and the steel weaken, they will uniformly sag and settle without
putting a point load on the outer Cylindrical Dike or the primary tank contained within. The SuperSafe tank's boxed
runners hold the system three inches above grade; further, the fire dam between each longitudinal support prohibits
flames from sweeping or being sucked under the bottom of the assembly.
In these tests, water or water foam
is applied to the shell of the heated vessel. This test is more of an issue for spauling concrete tanks however;
with SuperSafe, the water cannot be brought to bear directly onto the primary tank as it's fully contained within
the Cylindrical Dike. This eliminates the danger of fire fighting professionals approaching the fire event with
equipment to cool the vessel. Where flooding the dike is appropriate as a precautionary measure, a 3" adapter
can be extended from the Dike to a hydrant or safety point where equipment can approach and flood the C-Dike if
deemed appropriate.
Full-scale fire tests conducted by
many laboratories have proven that a properly vented vessel filled with various amounts of flammable liquids will
after time heat, creating vapors which escape from the emergency vents, then ignite and burn until the vessel runs
out of fuel or until the ignition source is removed. Even concrete tanks will perform the same way. Unfortunately,
concrete tanks like their common double-walled tank cousins, cannot perform the most important function: They cannot
and will not contain the overfilled fuel during this statistically most common and dangerous event that leads to
fire event. Only the SuperSafe Tank can contain an overfilled primary tank and take the fuel out of fire triangle.
No escaped fuel, no fire!
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