Section 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.
