Current through August 26, 2024
(1) A secondary
containment system shall be all of the following:
(a) Designed, installed, and operated to
prevent any migration of materials or accumulated liquid out of the system to
the soil, ground water, or surface water at any time during the use of the tank
system.
(b) Capable of detecting
and collecting releases and accumulated liquids until the collected material is
removed.
Note: If the collected material is a hazardous
waste under ch. NR 661, it is subject to management as a hazardous waste in
accordance with all applicable requirements specified in chs.
NR
662 to 666 and 668. If the collected material is
discharged through a point source to waters of the state, it is subject to the
requirements specified in ss.
283.31 and
283.33,
Stats. If discharged to a publicly owned treatment works or POTW, the collected
material is subject to s.
283.21(2),
Stats. If the collected material is released to the environment, it may be
subject to the reporting requirements of 40 CFR part 302 and the requirements
specified in s.
292.11,
Stats., and chs.
NR 706 to 726.
(2) To meet the requirements under
sub. (1), a secondary containment system shall be at a minimum all of the
following:
(a) Constructed of or lined with
materials that are compatible with the materials to be placed in the tank
system and shall have sufficient strength and thickness to prevent failure
owing to pressure gradients, including static head and external hydrological
forces, physical contact with the material to which it is exposed, climatic
conditions, and the stress of daily operation, including stresses from nearby
vehicular traffic.
(b) Placed on a
foundation or base capable of providing support to the secondary containment
system, resistance to pressure gradients above and below the system, and
capable of preventing failure due to settlement, compression, or
uplift.
(c) Provided with a
leak-detection system that is designed and operated so that it will detect the
failure of either the primary or secondary containment structure or the
presence of any release of hazardous secondary material or accumulated liquid
in the secondary containment system at the earliest practicable time.
(d) Sloped or otherwise designed or operated
to drain and remove liquids resulting from leaks, spills, or precipitation.
Spilled or leaked material and accumulated precipitation shall be removed from
the secondary containment system within 24 hours, or in as timely a manner as
is possible to prevent harm to human health and the environment.
(3) Secondary containment for
tanks shall include one or more of the following devices:
(a) A liner external to the tank.
(b) A vault.
(c) A double-walled tank.
(4) In addition to the
requirements under subs. (1) to (3), a secondary containment system shall
satisfy all of the following requirements:
(a) An external liner system shall be all of
the following:
1. Designed or operated to
contain 100 percent of the capacity of the largest tank within its
boundary.
2. Designed or operated
to prevent run-on or infiltration of precipitation into the secondary
containment system unless the collection system has sufficient excess capacity
to contain run-on or infiltration. The additional capacity shall be sufficient
to contain precipitation from a 25-year, 24-hour rainfall event.
3. Free of cracks or gaps.
4. Designed and installed to surround the
tank completely and to cover all surrounding earth likely to come into contact
with the material if the material is released from the tank.
(b) A vault system shall be all of
the following:
1. Designed or operated to
contain 100 percent of the capacity of the largest tank within its
boundary.
2. Designed or operated
to prevent run-on or infiltration of precipitation into the secondary
containment system unless the collection system has sufficient excess capacity
to contain run-on or infiltration. Such additional capacity shall be sufficient
to contain precipitation from a 25-year, 24-hour rainfall event.
3. Constructed with chemical-resistant water
stops in place at all joints, if any.
4. Provided with an impermeable interior
coating or lining that is compatible with the stored material and that will
prevent migration of material into the concrete.
5. Provided with a means to protect against
the formation of and ignition of vapors within the vault, if the material being
stored or treated is ignitable or reactive.
6. Provided with an exterior moisture barrier
or be otherwise designed or operated to prevent migration of moisture into the
vault if the vault is subject to hydraulic pressure.
(c) A double-walled tank shall be all of the
following:
1. Designed as an integral
structure, an inner tank completely enveloped within an outer shell, so that
any release from the inner tank is contained by the outer shell.
2. Protected, if constructed of metal, from
both corrosion of the primary tank interior and of the external surface of the
outer shell.
3. Provided with a
built-in continuous leak detection system capable of detecting a release within
24 hours, or at the earliest practicable time.
Note: The provisions outlined in the Steel
Tank Institute's "Standard for Dual Wall Underground Steel Storage Tanks" may
be used as guidelines for aspects of the design of underground steel
double-walled tanks.
(6) Ancillary equipment shall be provided
with secondary containment, such as trenching, jacketing, or double-walled
piping that meets the requirements under subs. (1) and (2) except for the
following:
(a) Aboveground piping, excluding
flanges, joints, valves, and other connections, that are visually inspected for
leaks on a daily basis.
(b) Welded
flanges, welded joints, and welded connections that are visually inspected for
leaks on a daily basis.
(c)
Sealless or magnetic coupling pumps and sealless valves that are visually
inspected for leaks on a daily basis.
(d) Pressurized aboveground piping systems
with automatic shut-off devices, such as excess flow check valves, flow
metering shutdown devices, or loss of pressure actuated shut-off devices that
are visually inspected for leaks on a daily basis.
