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Field inspection manual—volumetric measuring devices

Part 4, section 31—Specialised test procedures—line drainage test (calibrated tanks)


This procedure is used when performing accuracy tests on any fixed, mobile or vehicle mounted tanks.


To determine if the piping and calibrated portions of a calibrated tank will drain completely, or retain less product than the allowable limit of error.

Legislative references

R.317(2), R.325 (2), R.325(6) and R.326.


Ensure lines are empty.

Open all valves downstream of the tank compartments.

Drive the truck up a small incline or with appropriate jacks raise the front and rear of the tank. Manipulation of air suspension may raise the rear satisfactorily.

Close the emergency valve for the tank or compartment under test.

Lower vehicle to normal (level) position.

Deliver into the compartment an amount equal to 0.125% (see R.326) of the smallest declared volume which the tank is intended to deliver (lowest indicator ).

Open the emergency valve and confirm that at least some product exits from the outlet at the end of the delivery line.

Repeat for each compartment.

Note: Because of piping configurations, it cannot be assumed that the lowest indicator in one compartment represents the allowable lower indicator for all the compartments in a tank.

Interpretation of results

If no product at all can be delivered in the above test, there shall be no indicator at the volume under test in that particular compartment for a new tank; and a previously calibrated tank must be non-verified.

The total inaccuracy of measurement by the tank due to different factors shall not exceed the applicable limits of error. See R. 325(6).


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