Tank Tightness Testing for Release Detection and Investigation
(1)An owner and permittee using tightness testing in combination with a primary release detection method or as a method for investigating a suspected release must use a test method or procedure that:
(a)Is able to detect a 0.1 gallon per hour leak rate from any portion of the UST system that routinely contains a regulated substance, while accounting for the effects of thermal expansion or contraction of the regulated substance, vapor pockets, tank deformation, evaporation or condensation and the location of the water table;
(b)Meets a probability of detection of at least 95 percent and a probability of false results (or false alarm, depending on method used) of no more than 5 percent; and
(c)Is an approved leak detection method or equipment as listed by a national organization (e.g., the National Work Group on Leak Detection).
(2)All tightness testing must be performed by a service provider or supervisor licensed by DEQ, except as provided by OAR 340-150-0156 (Performance of UST Services by Owners or Permittees).
(3)Some automatic tank gauge equipment may meet the leak rate and probability requirements and may be used in place of a separate tightness test. To qualify as a tightness test, the automatic tank gauge must meet the requirements of section (1) of this rule.
(4)If an UST system fails a tightness test (after the tank tester has ensured that all test protocols were properly performed), an owner and permittee must report the failure to DEQ within 24 hours of receipt of the results as a suspected release (OAR 340-150-0500 (Reporting Suspected Releases)) and immediately begin an investigation under OAR 340-150-0510 (Suspected Release Investigation and Confirmation Steps).
Rule 340-150-0445 — Tank Tightness Testing for Release Detection and Investigation,