Are Above Ground Storage Tanks Regulated?
Aboveground Storage Tanks (ASTs)
A container (i.e. storage tank) cannot be used for the storage of oil unless its material and construction are compatible with the material stored and conditions of storage such as pressure and temperature.
All installations of bulk storage containers must be built so that a secondary means of containment is given for the full capacity of the largest single container and adequate freeboard to accommodate precipitation. Diked areas must be impervious enough to withstand the discharged gasoline. Although dikes, containment curbs and pits are widely used for this purpose, it is also possible to use an alternative system consisting of a drainage trench enclosure that needs to be arranged so that any discharge can be terminated and contained safely in a catchment basin or holding pond.
The installation of bulk storage containers must be planned or modified in accordance with good engineering practice to prevent discharges, including at least one of the following devices:
- high liquid level alarms with an audible or visual signal at a constantly attended operation or surveillance station (NOTE: In smaller facilities an audible air vent may suffice.)
- high liquid level pump cutoff devices set to stop flow at a predetermined container content level
- direct audible or code signal communication between the container gauge and the pumping station
- a fast response system for determining the liquid level of each bulk storage container such as digital computers, telepulse, or direct vision gauges (NOTE: If you use this alternative, a person must be present to monitor gauges and the overall filling of bulk storage containers.)
By monitoring the steam return and exhaust lines for pollution from internal heating coils which discharge into an open watercourse, or bypassing the steam return or exhaust lines through a settling tank, skimmer, or other separation or retention system, the controlled leakage through defective internal heating coils.
The runoff of uncontaminated rainwater from the diked area into a storm drain or the discharge of an effluent into an open watercourse, lake or pond that bypasses the treatment system of the facility, unless the facility is permitted:
- normally keeps the bypass valve sealed closed
- inspects the retained rainwater to ensure that its presence will not cause a discharge
- opens the bypass valve and reseals it following drainage under responsible supervision
- keeps adequate records of such events, for example, any records required under permits (i.e., NPDES).
Every container above ground must be checked on a regular schedule for quality, and whenever material repairs are completed. The duration and method of testing shall take into account the size and configuration of the container (such as floating top, skid-mounted, raised, or partially buried). In July 2012 EPA issued a valuable fact sheet on inspections of bulk storage containers.
The facility may incorporate visual inspection with other monitoring methods such as hydrostatic testing, radiographic testing, ultrasonic testing, acoustic testing of emissions, or other non-destructive shell testing system. Records of reference must be maintained and the structures and frames of the container checked as well. Personnel must inspect the outside of the container frequently for signs of deterioration, discharges or accumulation of oil inside the diked areas.
To ensure proper operation, the liquid level sensing systems must be tested regularly.
Effluent treatment facilities should be monitored often enough to detect possible device upsets which could result in a discharge.
When field-built containers undergo a repair, modification, reconstruction or service change that may affect the risk of discharge or failure due to fragile fracture or other disaster, or if oil has been discharged or failed due to fragile fracture failure or other disaster, the container shall be evaluated for the risk of discharge or failure due to fragile fracture or other disaster.