Underground flammable and combustible liquid tank closure in placeSection 66.21.7.4.3.3 is amended to read as follows: 66.21.7.4.3.3 Underground Tanks Permanently Closed in Place. Underground tanks may be permanently closed in place only if a certified structural engineer confirms that the removal of the tank will jeopardize the structural integrity of the existing building. An affidavit attesting to this determination shall be submitted to the AHJ prior to taking permanent closure measures. Tanks permanently closed in place shall meet all the following requirements:
(1) All applicable AHJs shall be notified;(2) A safe workplace shall be maintained throughout the prescribed activities;(3) All flammable and combustible liquids and residues shall be removed from the tank, appurtenances, and piping and shall be disposed of in accordance with regulatory requirements and industry practices, using a written procedure;(4) The tank, appurtenances, and piping shall be made safe by either purging them of flammable vapors or inerting the potential explosive atmosphere. Confirmation that the atmosphere in the tank is safe shall be by testing of the atmosphere using a combustible gas indicator if purging, or an oxygen meter if inerting, at intervals in accordance with written procedures;(5) Access to the tank shall be made by careful excavation to the top of the tank;(6) All exposed piping, gauging and tank fixtures, and other appurtenances, except the vent, shall be disconnected and removed;(7) The tank shall be completely filled with an inert solid material;(8) The tank vent and remaining underground piping shall be capped or removed;(9) The tank excavation shall be backfilled; and(10) A record of tank size, location and date of permanent closure shall be retained by the owner and a copy submitted to the AHJ. Haw. Code R. tit. 3, Building Code Council, State Fire Code, 122