Owners and operators using statistical inventory reconciliation (SIR) must comply with the requirements of this section. SIR involves the application of statistical principles to inventory data similar to those described in WAC 173-360A-0620.

(1) Standards. The SIR method must:

(a) Be able to detect at least a 0.2 gallon per hour leak rate or a release of one hundred fifty gallons within a thirty-day period from any portion of the tank or underground piping that routinely contains a regulated substance with a probability of detection of at least 0.95 and a probability of false alarm of no more than 0.05;

(b) Use a threshold that does not exceed one-half the minimum detectable leak rate; and

(c) Be able to report a quantitative result with a calculated leak rate.

(2) Performance. SIR must be performed in accordance with the requirements of this subsection.

(a) Inventory control must be performed in accordance with the requirements in WAC 173-360A-0620 and the SIR vendor's instructions.

(b) SIR must be performed in accordance with any conditions or limitations specified in the certification of the SIR method.

(c) Conclusive SIR results must be obtained within the thirty-day monitoring period.