|
Hazardous Materials Program Guidance:UST Overfill Prevention-Page 5 of 7
<br /> G. Overfill Activation Height
<br /> If USTs were rectangular, calculating activation height would be a simple matter. To activate at 90% of
<br /> capacity, you would merely locate a point that is 90%of the distance between the tank floor and tank roof.
<br /> Since USTs are cylinders,this approach will not work. [Note:1"of product at 50%of a cylindrical tank height
<br /> holds many more gallons than 1" of product at 90% since the tank is much wider in the middle. This is
<br /> compounded in the case of fiberglass tanks, which are cylinders with rounded ends, and thus are both wider
<br /> and longer in the center than they are near their tops and bottoms. Also, compartmented fiberglass tanks
<br /> will have a BASE TANK that has two convex ends and an END TANK that has one convex end and one concave
<br /> end.] It is necessary to consult the manufacturer's tank calibration chart to determine the height above the
<br /> tank bottom that corresponds to 90%of the liquid capacity.
<br /> BASE TANK END TANK
<br /> The following tables use data from the manufacturers' tank calibration charts and provide 90% and 95%
<br /> capacity data for several types of commonly encountered USTs.They are accurate to approximately±0.1",
<br /> intended merely for quick checks of contractor's calculations, and are NOT a substitute for the contractor
<br /> performing their own calculations when installing or certifying equipment.
<br /> Data for only a few of the more common tanks are included. If the tank you are dealing with is not on one
<br /> of these charts,you need to obtain the UST manufacturer's tank calibration chart. Multiply the tank's actual
<br /> capacity by 0.9 or 0.95 to determine the number of gallons that equals 90% or 95% of tank capacity, then
<br /> find the number of inches on the tank chart that corresponds to that number of gallons.
<br /> Containment Solutions Double-Wall Stand-Alone USTs:
<br /> Size Diameter Actual Actual 90%Volume 90%Height 95%Volume 95%Height
<br /> (Gallons) (Feet) Capacity Diameter (Gallons) (Inches) (Gallons) (Inches)
<br /> (Gallons) (Inches)
<br /> 4,000 8 3,998 91.625 3,598 76.1 3,798 81.8
<br /> 6,000 8 5,897 91.625 5,307 76.5 5,602 82.1
<br /> 8,000 8 7,796 91.625 7,016 76.7 7,406 82.3
<br /> 12,000 8 11,595 91.625 10,436 76.9 11,015 83.5
<br /> 15,000 8 14,545 91.625 13,091 76.9 13,818 82.5
<br /> 10,000 10 10,257 119.625 9,231 99.2 9,744 106.4
<br /> 12,000 10 11,873 119.625 10,686 99.4 11,279 106.7
<br /> 15,000 10 15,104 119.625 13,594 99.7 14,349 107.0
<br /> 20,000 10 19,951 119.625 17,956 100.0 18,953 107.3
<br /> 25,000 10 24,970 119.625 22,473 100.2 23,722 107.4
<br /> 30,000 10 29,816 119.625 26,834 100.3 28,325 107.5
<br /> 40,000 10 39,854 119.625 35,869 100.2 37,861 107.6
<br /> HMPG-025 5/7-Rev.09/20/18
<br />
|