8.38. The tests required by section 8.35 need not be conducted if the contractor or owner-builder(1) ascertains that depressurization of at least 42 kPa created by the manufacturer in the interstitial space of the tank is maintained after it has been placed in the excavation; or
(2) has conducted a vacuum test on the interstitial space at a pressure of at least 42 kPa for at least one hour, if such a test is authorized by the manufacturer.