Sec. 26.10.07.01. Hydrostatic Test for Underground Storage Tanks with a Total Capacity of 1,000 Gallons or Less

A. The precision test requirements of this subtitle may be satisfied by the use of a hydrostatic test if the underground tank to be tested has a total capacity of 1,000 gallons or less and does not contain gasoline or other flammable liquid.

B. Test Guidelines.

(1) When a hydrostatic test is conducted, it shall be conducted according to the guidelines in §B(2)-(5) of this regulation.

(2) Equipment supplied by the tank system shall be turned off. This includes boilers, pumps, engines, etc.

(3) The tank shall be filled to capacity with oil or water.

(4) Use of Calibrated Sight Tube.

(a) A 2-inch diameter calibrated sight tube shall be attached to the tank fill. If necessary, the fill cap assembly may be removed to use the fill pipe threads to achieve a tight connection. If the fill pipe threads cannot be used, the sight tube may be attached to the vent or other tank opening. In this situation, the requirements of §B(4)(b)-(g) of this regulation apply.

(b) A calibrated sight tube may be fabricated from a 2-inch clear cast acrylic tubing.

(c) The tubing should be glued to the appropriate PVC fittings to provide a liquid-tight connection to the tank.

(d) A side plug or petcock may be incorporated near the bottom of the tubing to facilitate draining of the sight tube after the test.

(e) The tube should be calibrated in 1/4-inch increments to simplify measurements. Taking caution to ensure that tank openings below the test level are liquid-tight, the sight tube shall be filled to 2 feet above the ground with oil or water.

(f) The sight tube shall be shielded from direct sunlight and other adverse weather conditions to reduce thermal expansion and evaporation.

(g) The tank pressure and temperature shall be allowed to stabilize for at least 24 hours before beginning the test.

(5) Test Procedures. Upon beginning the test, the liquid level in the sight tube shall be accurately marked. The liquid level shall then be observed for a 1-hour period during which time any fluctuations in the liquid level shall be accurately marked and documented.

(6) Test Results.

(a) A fluctuation of more than 4 inches in the liquid level in the sight tube during the 1-hour test period constitutes a tank system failure.

(b) Failures shall be reported to the Department within 2 hours.

(c) A written record of all tests shall be kept on file at the facility or a location designated by and in control of the owner or operator of the UST system, and shall be made available to the Department upon request.