# Accurate measurement of home oil tank volume

Are there published calculations to calculate the contents of my home oil tanks (using the dip stick method) if I already know the rated size? I have 2 tanks. (275gal and a 330gal) both seem to have the same shape however the 330 is longer.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

Remember your high school mathematics, the tank (at least the ones I recognize as oil tanks), are simply two half cylinders with a cube between them, so figure the volume of the round parts, and then the cube part, and add them.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Actually, this is a popular problem in a calculus class. It is not simple to solve using calculus, but there are non-calculus ways to figure it out. I seriously doubt you will have much luck finding this already tabulated for your tank, but here is something simple you can do that will probably answer your purpose. To begin with, you are likely not interested in the case where the level of oil is below the bottom of the rectangular section, because in this case you are getting pretty low on oil and need to get some delivered. Likewise, you are probably not too interested in the case where the oil level is up in the top circular section--in this case you have plenty of oil. If the oil level is in the rectangular section, then the volume of oil is half a cylinder plus the rectangular depth times the rectangular area.
If you want to work this out you will have to make accurate measurements of the tank (correct for the thickness of the steel walls; they are about 1/16" thick) and then compute some volumes. One gallon is 231 cubic inches.
If you are really interested in getting a dipstick calibrated for all cases, I'll go into greater detail. You will need a scientific calculator.

have
the
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

http://pages.cthome.net/edhome
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

No calculus is required just simple trig. The only hard part is the half cyclinder. R = Inside radius of the cylinder (1/2 outside width of tank minus 2 x gauge of sheetmetal) L = Inside length of tank (Outside length minus 2 x lap flange depth minus 2 x gauge of sheemetal) H = Inside height of tank (Outside height minus 2 x gauge of sheetmetal) h = measured depth of oil from bottom of tank
1. Area of a circle sector = R^2*arcos(R-h/R) 2. Area of circle segment = R^2*arcos((R-h)/R) - (R-h)*sqrt(R^2-(R-h)^2) 3. Volume of oil in gallons (h <= R) = L*(R^2*arcos((R-h)/R) - (R-h)*sqrt(R^2-(R-h)^2))/231 4. Volume of oil in gallons (h > R and h <= (H - r) =L*(2*R*(R-H)+Pi*R^2/2)/231 5. Volume of oil in gallons (h > (H-R) L*(Pi*R^2/2-R^2*arcos((h+R-H)/R)+(h+R-H)*sqrt(R^2-(h+R-H)^2)+Pi^2/2+2*R(H-2*R))/ 231
All dimensions in inches Angles (arcos) in radians Cu.in. per Gallon = 231 Pi = 3.1416
It would be easiest to do in a spread sheet. A correction factor could be incorporated to allow for the flexing in the sides and end caps of the tank, but this should be a small percent.
Regards,
John
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Frank wrote:

Check out this shareware:
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

have
the
I have a card from an oil company that has various tank sizes listed and the capacity at every 2" of filled height. If these tanks are existing buried tanks, knowing the dimensions could be difficult. You should know the height from previous sticking and you obviously know the galon capacity. If you know the height and the capacity, you can see if the oil company charts have a tank that matches those two numbers. Some are oval, some are cylindrical, so this could be hard to calculate if you don't know the shape.
A last alternative way would be to fill the tank from various oil levels and keep records. You should be able to see the pattern.
-- Mark Kent, WA
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
That was all very good info. Thank you all.

have
the
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

## Site Timeline

• ### "correct" way to prep walls for tile in shower?

• - next thread in Home Repair
• ### Any down side to installing a roof Sky light? Tube sky light?

• - previous thread in Home Repair

• ### Need help INTERPRETING these test results police cruiser SAE J866a Chase Test

• - last updated thread in Home Repair
• ### your oldest power tool

• Share To

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.