74:56:01:26Release

detection requirements -- Tank tightness testing and inventory reconciliation. A combination of tank system tightness testing and product inventory reconciliation or another test of equivalent performance may be used to meet release detection requirements if they meet the following requirements: (1) The tightness test testing is conducted at least once every five years until ten years after the tank is installed or upgraded under §§ 74:56:01:09 and 74:56:01:10, whichever is later, and the testing is capable of detecting a 0.1 gallon per hour leak rate with a probability of detection of 0.95 and a probability of false alarm of 0.05 from any portion of the UST system; (2) Inventory reconciliation or another test of equivalent performance is conducted monthly to detect a release of at least one percent of flow-through plus 130 gallons on a monthly basis, in the following manner: (a) Inventory volume measurements for regulated substance inputs, withdrawals, and the amount still remaining in the tank are recorded each operating day; (b) The equipment used is capable of measuring the level of product over the full range of the tank's height to the nearest 1/8 of an inch; (c) The regulated substance inputs are reconciled with delivery receipts by measurement of the tank inventory volume before and after delivery; (d) Deliveries are made through a drop tube that extends to within one foot of the tank bottom; (e) Product dispensing is metered and recorded within an accuracy of six cubic inches for every five gallons of product withdrawn; and (f) The measurement of any water level in the bottom of the tank is made to the nearest 1/8 of an inch at least once a month.

Source: 14 SDR 76, effective November 29, 1987; transferred from § 74:03:28:11, 18 SDR 62, effective October 10, 1991; transferred from § 74:03:28:11.01, July 1, 1996; 23 SDR 131, effective February 24, 1997; 44 SDR 192, effective June 28, 2018.