Discharge containment for 12 inch pipes and up is:

• A. 2 barrels
• B. 3 barrels
• C. 4 barrels
• D. 5 barrels

Answer: (C)

The key idea is sizing secondary containment to the amount of liquid that could be released from a line. For larger piping, especially 12 inches and up, the potential spill volume from a break in the line is bigger, so the containment must be large enough to hold that volume and provide a buffer for response. Four barrels is the minimum containment capacity specified for pipes of this size, equating to about 168 gallons (since a barrel is 42 gallons). This level helps ensure that a leak won’t immediately overwhelm the area and gives responders time to stop the release. Smaller pipe sizes have smaller minimum containment requirements, so choosing less than four barrels would not meet the standard for 12-inch and larger pipes.