Current through Register Vol. 48, No. 39, March 25, 2024
Subpart 1.
Transfer.
At least one person must be present during substance loading
or unloading of a tank to visually monitor and terminate the transfer. The
person monitoring the substance transfer shall take immediate action to stop
the flow of the substance being transferred when the capacity of the tank has
been reached or in the event of an equipment failure or emergency. Tank owners
and operators shall recover all contaminated soils and any substance released
during transfer.
Subp. 2.
Weekly monitoring.
Owners or operators of tanks shall conduct visual monitoring
as described in items A to C to verify that no releases have occurred from the
tank system.
A. If the secondary
containment area complies with the standard established in part
7151.5400, the owner or operator
shall visually monitor an aboveground storage tank site at least
weekly.
B. If the secondary
containment area does not comply with the standard established in part
7151.5400, the owner or operator
shall visually monitor an aboveground storage tank site at least every 72
hours.
C. Owners and operators of
double-walled tanks need not conduct weekly monitoring of the containment area
around the double-walled tanks.
Subp.
3.
Monthly monitoring.
The owner or operator shall visually inspect tank systems at
least monthly, including:
A. walking
through the site to identify cracks or other defects in the secondary
containment area and any substance transfer area;
B. a visual examination of the exterior
surfaces of tanks, piping, valves, pumps, and other equipment for cracks,
corrosion, releases, and maintenance deficiencies; and
C. identification of poor maintenance,
operating practices, or malfunctioning equipment.
Subp. 4.
Leak detection.
The owner or operator shall monitor tank systems for leaks as
described in items A to C. Any suspected releases shall be investigated and
resolved.
A. If a tank is designed
pursuant to part
7151.5400, subpart
4, leak detection must be
conducted at least monthly as follows:
(1)
visual monitoring of:
(a) elevated
tanks;
(b) tanks on continuous
concrete slabs for Type B and Type C substances;
(c) tanks on a continuous concrete slab
treated with material that is impermeable to the substance being stored for
Type A substances;
(d) tanks on
containment constructed of fabricated steel; or
(e) tanks on containment constructed of
fiberglass;
(2)
interstitial monitoring between the tank's inner and outer shell or the tank's
shell and the containment area; or
(3) vapor monitoring in the soil directly
under the tank bottom or perimeter and above the water table.
B. If a tank is not designed
pursuant to part
7151.5400, subpart
4, leak detection must be
conducted at least monthly using one or more of the following:
(1) monthly reconciliation of substance
measurements taken pursuant to the interval established in subpart
2, with dispenser meter
readings, shipments, deliveries, and internal transfers; any difference of 2.0
percent or more of monthly throughput shall be investigated and resolved;
or
(2) statistical inventory
reconciliation as approved by the agency.
C. All underground lines must be tested for
leaks at least annually using one or more of the following methods:
(1) tracer gas;
(2) hydrostatic;
(3) lockdown pressure;
(4) double-walled piping with a sump sensor
connected to an audible alarm; or
(5) other approved methods pursuant to part
7151.9400.
Subp. 5.
Annual equipment
check.
Owners and operators shall maintain in functioning condition
all equipment used for release detection, monitoring, or warning. Owners and
operators shall check such equipment for proper function or calibration at
least yearly or in accordance with manufacturer's guidance.
Subp. 6.
Tank inspection.
All field-erected steel tanks must be internally and
externally inspected by a certified tank inspector pursuant to American
Petroleum Institute standard 653. Initial inspections must be completed in
accordance with the following schedule:
A. external inspections shall be conducted by
November 2, 2003, or a maximum of five years after the initial construction
date, whichever is later; and
B.
internal inspections shall be conducted by November 2, 2008, or a maximum of
ten years after the initial construction date, whichever is later.
Subp. 7.
Corrosion
protection monitoring.
A. A qualified
cathodic protection tester shall inspect all cathodic protection systems on
steel tanks and piping as follows:
(1) all
cathodic protection systems must be tested pursuant to the National Association
of Corrosion Engineers RP-02-85 code of practice within six months of
installation and at least every three years thereafter; and
(2) impressed current systems must be
inspected for proper function every 60 days.
B. A lined tank which does not have external
cathodic protection must be internally inspected within ten years after lining,
and every ten years after that. The liner must be structurally sound with the
lining performing pursuant to original design specifications.
C. If corrosion protection monitoring
conducted in conformance with this part indicates inadequate corrosion
protection, corrective measures must be taken within 180 days to ensure that
the measured surface potential conforms to the requirements of this
part.
Statutory Authority: MS s
115.03