(1) Any individual primary containment capable of storing
more than 500 U.S. gallons or 4,500 pounds and in-service for more than 14
consecutive days and its associated appurtenances must be placed within
secondary containment that meets the following requirements:
(a) secondary containment not protected from
precipitation shall contain at least 125% of the volume of the largest primary
containment within the secondary containment plus the displacement of all other
primary containment, appurtenances, and other items which cause displacement
within the secondary containment.
(b) secondary containment located indoors or
under a roof to prevent accumulation of precipitation shall contain at least
110% of the volume of the largest primary containment plus the displacement of
all other primary containment, appurtenances, and other items which cause
displacement within the secondary containment.
(c) the walls and floors of secondary
containment shall be constructed of steel, poured reinforced concrete, precast
concrete modules, solid masonry, synthetic liners, or other materials that will
provide secondary containment. Floors and walls constructed of clay, natural
soil, natural soil clay mixtures or clay bentonite mixtures are prohibited.
Materials used in the secondary containment shall be chemically compatible with
the pesticides being stored. A written conformation of compatibility from the
manufacturer and kept on file at the PSF or at the nearest office from which
the PSF is administered is recommended.
(d) walls shall withstand a full hydrostatic
head of any spill, and shall be sealed to prevent leakage.
(e) piping through the outside walls of a secondary
containment is prohibited.
(f) the secondary containment floor shall slope
to a liquid tight collection point or sump that allows spilled or deposited
material to be easily removed. Any pump used for recovering materials from the
secondary containment shall be manually activated.
(g) synthetic liners shall be installed under
the supervision of a qualified representative of the manufacturer, a contractor
certified by the manufacturer, or a certified engineer. All seams shall be
tested and repaired, if necessary, in accordance with the manufacturer's
recommendation. A record regarding installation date, life expectancy and
chemical compatibility must be kept.
(h) a prefabricated secondary containment shall
be composed of a rigid prefabricated basin having a base and walls constructed
of steel or synthetic materials which are resistant to corrosion, puncture and
(i) the prefabricated secondary containment
shall withstand all foreseeable loading conditions, including the primary
containment load and a full hydrostatic head of any spill. Multiple basins
shall be connected in a manner which assures an adequate transfer of discharge
(j) discharge outlets, valves or gravity drains
shall comply with ARM 4.10.1103(5) .
(k) secondary containment for pesticides must be
separate from containment for fertilizer, but they may have a common wall or