tanks on a hillside. Use MIL-HDBK-1005/3, ICBO UBC 902, and
BOCA F2315, as well as the following criteria for spill
a) Construct the drains of petroleum-resistant,
fire-resistant, impervious material.
b) Construct the impoundment as generally described
for diked enclosures and make the volumetric capacity not less
than 110 percent of the full content of the largest tank which
able to contain the flow of the fire protection system for a
period of 20 minutes.
c) Follow the requirements of MIL-HDBK-1005/3 and
sufficient to contain the storm runoff from the entire
tributary area for rainfall from a 5-year, 1-hour duration
d) Slope the area within the dike basin at no less
than 1 percent to carry drainage away from the tank to a sump
located at the low point of the enclosure.
e) Control drainage from the sump to the outside of
the enclosure by a lockable knife gate valve with indicator
post located outside of the enclosure in an area that will be
safely accessible during a fire.
f) Do not allow fuel to run off or escape from the
diked area under any circumstances. Provide means for
treating or disposing of contaminated water from the dike to
meet the most stringent of applicable federal, state, or local
Stormwater Collection Systems. Design a stormwater
collection system to contain, transport, treat, and discharge
any stormwater that collects in the tank enclosure. Refer to
Section 2 of this handbook for information on design and
sizing of oil/water separators. Review state and local
stormwater treatment systems.