Heating oil Underground & Aboveground Oil Storage Tanks

Home heating oil tank leaks and subsequent environmental contamination risks are major concerns for home and building owners as tank replacement costs and extensive cleanup can be involved.

Buried oil tanks raise environmental, safety, and economic concerns for home owners and buyers because oil leaks can lead to environmental damage and can cost a lot for cleanup. Having to install a new aboveground indoor oil storage tank can be costly. Around $2,000 to $4,000 to remove an old tank and replace a new one. Costs can be higher in the event of extensive leakage and soil damage. Removing or abandoning a buried tank costs more. If a tank has leaked, the cost to clean up the soil can be huge.

Home heating oil tanks are not included from federal regulations regarding oil storage tank reporting and monitoring. But most U.S states and Canadian provinces, storage tanks are addressed by state or local agencies and regulations. In the event that a home heating tank causes a release into the environment, at that point the owner or operator is not exempt from other provisions of the State or Federal regulations. The leak needs to be reported, the source of the leak stopped, and a site characterization performed. Also cleanup needs to be initiated and the incident reported.

Aboveground oil tanks and clues for the presence of buried tanks are not usually inspected during a pre-purchase home or building inspection, unless prior test arrangements are made. Oil tank inspection, other than visual inspection for leaks are not performed by inspectors. Tests for oil tank leaks, soil contamination, tests for soil corrosivity, screening for evidence of prior or abandoned tanks, as well as the removal or abandonment of tanks require you to use an expert.

The common life expectancy of an oil tank is 20 years, but it can last longer. The risk of leaks from buried oil tanks is significant. Leaks can occur if the tank was damaged at installation, or the pipes were not properly installed. Even if the tank is okay, it should be tested for water in the tank bottom and must be pumped out to avoid corrosion. It is best to ask your fuel supplier about using an additive or other methods to remove water.

Oil leaks may appear at buried piping connections. At least one study found that 82% of petroleum storage tank leaks are caused by the piping. Underground fuel or heating oil tanks usually fail from rust due to several effects caused by the combination of water with sulfur in the fuel, bacteria etc. External rust on oil tanks is not connected with internal rust. Leaks may take place due to damage in the tank or at the piping connections. Leaks can most possibly develop if the tank has been covered in corrosive soil or if it was damaged during set up.

Delivery oil spills happen around the fill pipe and range from minimal to a more extensive spill, which requires soil removal and cleaning. These leaks are obvious on the ground around the tank or tank filter.

Insufficient vent or fill pipe diameter is the reason for some leaks in buried, or aboveground oil tanks. Assuming that oil is pumped at high pressure from the truck, a damaged, corroded, or unsatisfactorily-plumbed oil tank may not withstand the pressure.

Oil spills from a leaking tank or during tank fill range from minor cleanup to a serious contamination problem when an oil tank bursts during delivery, and on occasions when someone removes the tank but leaves the fill pipe installed on the structure. Hence, when oil deliveries are mistakenly made, the oil seeps into the empty basement or crawl on the space floor.

Before hiring a tank testing company for inspection and testing, some information like the age of the property and tank, location of the tank, and type of oil tank. For above ground tanks, a visual inspection of the tank and its piping can give you an idea of the risks involved.

Check for leaks like oil stains on the ground or floor under or around the tank, and around the oil fired equipment. You must look at the lower portion of the tank, since most leaks take place in that area.

There are companies who have devices meant to check for leaks in buried tanks. Low-pressure testing, soil testing, and electronic testing are commonly used.

In addition to inspecting the tank and piping, as well as testing the tank, more sophisticated tests are available to see if the tank has leaked, or is likely to be leaking soon. This includes a tank corrosion analysis, which is included to the basic tank inspection and gives an assessment of the corrosion levels on the tank walls, and thus its chances of it leaking or failing. Soil corrosivity evaluation may also be used, which includes an evaluation of soil samples for corrosion, and how it will contribute to the corrosion of the steel tank.

Testing for water on an oil tank indoors, or outdoors is simple and can be done by anyone. Tank testing methods vary in risk, cost, invasiveness, amount of time and more. Since water in an oil tank can lead to a loss of heat and related building damage, it is important to know if the water in your tank is a problem in the property.

Water may enter the tank via condensation as temperature differ, air containing moisture may be drawn into, then out of an oil tank. Air escapes the tank as oil is consumed, and enters and leaves through the tank vent. Air entering the tank can bring water, which then enters the cooler tank interior, causing it to condense into water, which accumulates overtime. Water enters a fill pipe via roof spillage onto the tank or filler top or from surface runoff entering the oil tank.
An outside filler cap left off for some time is not itself a source of the problem unless there was exposure to heavy rain, roof overflow spillage, or surface drainage entering the tank.

Water leaks into a buried oil tank via an actual tank perforation that takes in ground water, or from bad plumbing on the tank. It is not common, but it is possible, to get a delivery of water-contaminated fuel oil particularly if the oil truck fills up at the oil storage depot at the same time an oil barge is off-loading oil since water is usually kept at the depot storage tanks which may stir-up. Most companies know how to avoid this problem, and some have water filters installed in their oil trucks.
There are proper methods of abandoning old unused tanks, without removing them. If a tank is not to be used, it can involve a significant expense. A proper abandonment procedure involves draining out all remaining fuel, confirming that no leak has taken place, cleaning the tank, and filling the tank with an approved filler, or removing it entirely.
Buried tank removal is handled by environmental services companies, who arrange the testing, excavation and disposal. Thermal variations as crawl area temperatures change could make the tank warp and produce a “bang” sound. If the tank is not sealed, then it is caused by temperature change alone.

The U.S and many other countries have programs in terms of the registration of buried tanks that store more than 1,100 gallons of heating oil. Specifications for gas and different fuels may be different. Eventually this concern may reach to smaller residential tanks, particularly the issue of leaks contaminating the environment. Tanks leaking into local waterways or water supply is a special environmental concern.

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