Measuring the heel

The tool and the move

1. Drain it fully. Pump or pour until nothing more comes out, then close the valve.
2. Level it. A tote on a slope has a heel that pools to one side and reads wrong.
3. Drop a clean rod through the fill cap. A steel rule or a wooden dowel marked in inches.
4. Touch the bottle floor. Keep the rod vertical and feel it land.
5. Pull it out and read the wet line. Write the depth down in inches.
6. Compare it with the limit. One inch for the depth test.

That is the dipstick on this site's home page. Wipe the rod between totes so one tote's product does not move to the next, and wear what the SDS says to wear.

From inches to gallons and pounds

The bottle floor of a caged tote is close to the 48 by 40 inch pallet footprint. That is 1,920 square inches. One inch of depth is 1,920 cubic inches, and a gallon is 231 cubic inches, so one inch is about 8.3 gallons. At water weight that is about 69 pounds. The real floor is a little smaller, so this is an upper bound.

The weight test, if you have a scale

The other test is 0.3% of the capacity by weight. For a 275 gallon tote of water-weight product that is 0.83 gallon, about 6.9 pounds. At a specific gravity of 1.20 it is 8.3 pounds. You can only prove it with a scale or a calibrated pump, so most sites rely on the inch.

The RCRA empty guide explains why either test is enough. A tote that meets the inch is empty, and if you measured more than that, drain further and measure again.

Common mistakes

• Measuring a sloped tote. Level it first, or measure at the low corner and the high corner and take the larger.
• Reading a wetted rod, not the line. The wet line is a clean edge; the film above it is not the heel.
• Forgetting the valve. Product sits in the valve body and outlet. It is not the heel, but it can weep onto a floor.
• Measuring a tote with a liner. A bag-in-box liner has no hard floor; see the bag-in-box page.

When you have the number, run the Empty Check.

Common mistakes

• Reading the dry part of the rod instead of the wet line.
• Measuring on a tilted floor.
• Using a dirty rod that picks up residue from the cap.
• Measuring once and not repeating.

Two readings that agree are worth more than one that is careful.