Minnesota Administrative Rules
Agency 167 - Pollution Control Agency
Chapter 7151 - ABOVEGROUND STORAGE OF LIQUID SUBSTANCES
STANDARDS FOR EXISTING ABOVEGROUND STORAGE TANKS
Part 7151.6400 - SECONDARY CONTAINMENT
Current through Register Vol. 48, No. 39, March 25, 2024
Subpart 1. Requirement.
Subp. 2. Volume.
All secondary containment systems for existing aboveground storage tanks must meet the volume requirements of part 7151.5400, subpart 2.
Subp. 3. Materials.
All secondary containment systems for existing aboveground storage tanks must meet the materials requirements of subpart 5 or part 7151.5400, subpart 3.
Subp. 4. Design.
Subp. 5. Soils.
A secondary containment area constructed of soils must:
Substance Classification | Groundwater or Bedrock < 10 Feet from Grade or Class 2 Surface Water within 100 Feet of Aboveground Storage Tank | Groundwater and Bedrock e 10 Feet from Grade and Class 2 Surface Water not within 100 Feet of Aboveground Storage Tank |
Type A | Minimum of three feet of soil at 1 x 10-5 cm/sec | Minimum of three feet of soil at 1 x 10-4 cm/sec |
Type B | Minimum of three feet of soil at 1 x 10-4 cm/sec | Minimum of three feet of soil at 1 x 10-3 cm/sec |
Type C | Minimum of three feet of soil at 1 x 10-3 cm/sec | No minimum permeability standard |
Subp. 6. Containment area evaluation.
Owners and operators shall perform postinstallation permeability testing on containment areas constructed of native soils, amended soils, or imported clay liners requiring a minimum permeability standard under subpart 5. A qualified soil technician or testing company shall evaluate the top three feet of soil, below any cover material, for vertical soil permeability. Evaluation must:
Secondary Containment Area Size (Square Feet) | Minimum Number of Soil Samples Necessary |
<10,000 | 3 |
10,000 - 50,000 | 4 |
>50,000 | Equal to the number of tanks contained in the secondary containment basin (minimum of 4 samples); and |
Subp. 7. Timing of compliance.
Statutory Authority: MS s 115.03