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OIL STORAGE TANKS - home
ABANDONING OIL TANKS
ABOVE GROUND OIL TANK (AST) GUIDE
BURIED OIL TANK (UST) GUIDE
HEATING OIL TYPES & PROPERTIES - home
HOME BUYERS GUIDE TO OIL TANKS
OIL SPILL CLEANUP / PREVENTION
OIL TANK ABANDONING PROCEDURE
OIL TANK INSPECTION & TROUBLESHOOTING
OIL TANK LEAKS & SMELLS
OIL TANK PIPING & PIPING DEFECTS
OIL TANK REGULATIONS
OIL TANK REMOVAL COs
OIL TANK SPILL CLEANUP / PREVENTION
OIL TANK LEAK TEST METHODS
OIL TANK TESTING & REMOVAL COs
OIL TANK WATER CONTAMINATION
Oil tank leaks at the fill or vent piping:
Tthis article discusses the causes of leaks at oil tank fill or vent piping, what the leak and other hazards are, and what to do about oil tank piping leaks.
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It is very common for there to be leakage around the oil filler pipe or vent pipe where they are connected to the top of an oil tank.
If the tank is buried these leaks may go undetected for some time, but on an above ground oil tank, inside or outside, the seepage is quickly visible and also can be smelled by most owners shortly after an oil delivery.
[Click to enlarge any image]
There are the reasons for the leakage:
Heating oil leak problems at oil tank fittings and pipe threads
The pipe threads (NPT) which are cut into an oil tank top tapping intended to accept the filler pipe or vent pipe are not precisely machined - they are a bit rough.
So are the threads on most large-diameter iron piping used to screw into the tapping.
Having installed a few of these, we can testify that it requires some very careful workmanship to make a leak-tight joint, combining cleaning of the threads, use of a high quality pipe dope rated for use on petroleum products, and turning the pipe into the tapping with sufficient force to seal it without damaging threads. In sum, often the connection is simply not very tight.
Heating oil leak problems due to pressurized oil storage tank fill procedures
Wrong. Oil companies recognize that the time needed to complete an oil delivery is part of their profit or loss picture. Modern oil delivery trucks are designed to pump heating oil into the tank under pressure in order to speed the delivery process.
Photo at left: the oil delivery operator is demonstrating the correct and thoughtful way to fill an indoor or buried oil storage tank.
During oil tank filling the driver is listening to the tank whistle or tank alarm to avoid over-filling the tank - a common source of seepage and occasional heating oil or fuel oil spills. If the plumber or installer locates oil fill and vent pipes where they are difficult to access, don't expect such careful oil deliveries.
In fact most modern oil tank filler caps have a special fitting, often different from one oil company to the next, that permits the installer to "lock" the filler hose to the filler pipe during the fill-up procedure.
Usually an oil storage tank is filled right to its top during an oil delivery. This is because the way that the delivery driver knows that the tank is full is that s/he is (supposed to be) listening at the filler pipe. Tank fill or vent valves are (supposed to be) equipped with a whistling noisemaking device that indicates when the tank is full as the heating oil reaches the sounding device.
So if, unlike the driver in our photo above, the oil delivery pumper is not listening, say s/he went aside to smoke a cigarette or make a cell call, or if the tank top fittings are not absolutely tight, it is common to see some leakage around the tank top after a fill-up. We discuss details of oil tank pressures created during the oil tank filling operation
When and what should you do something about a leak at the top fittings of an oil tank?
Continue reading at OIL TANK LEAK POINTS or select a topic from the More Reading links shown below.
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