Secondary spill containment is required under EPA SPCC (Spill Prevention, Control, and Countermeasure) rules for any facility with above-ground oil storage exceeding 1,320 gallons aggregate or 660 gallons in a single container. State environmental regs often extend this to non-oil chemistries. Here’s the math and the practical setup.
The 110% rule
SPCC requires the containment area to hold at least 110% of the largest container, plus precipitation if outdoors uncovered. For a single 330-gallon tote, that’s 363 gallons of containment minimum. For four totes stored together with one acting as “largest,” same 363 gallons (the rule says largest, not aggregate — the assumption is that all totes won’t fail simultaneously).
Precipitation allowance
If your containment is outdoors and uncovered, you need to add a precipitation allowance: typically 10–15% of the containment area at design rainfall. Cleveland 25-year storm event is roughly 4 inches over 24 hours; figure 30–50 gallons of precipitation per 25 square feet of pan area. Most operations cover the containment or add drainage with manual valves that stay closed unless inspecting.
Pan options
Three common pan types:
- Poly secondary containment pallet: $380–$650 for a single-tote unit, $750–$1,400 for a two-tote. Drop-in, no construction required. Drains via a removable plug. Standard for small-shop installations.
- Concrete-curbed area: Permanent installation, requires a sealed concrete floor with a curb or berm. Costs from $1,800 for a small pour to $15,000+ for a large area. Required for many state-permitted bulk storage installations.
- Modular plastic berm: Lay-flat berms with an internal liner. $200–$800 depending on size. Lower profile, easier to install, but punctures more easily than rigid pans.
Common errors
Sizing to total inventory instead of largest container: usually overspecs, sometimes underspecs depending on container sizes. Read the actual rule.
Forgetting precipitation: outdoor uncovered installations almost always fail their first inspection on this.
Drain valves left open: the containment is useless if the drain is permanently open. Most regs require it closed and locked, with a manual procedure to drain after inspection.
Containment under stacked totes: a containment pan rated for one tote will overflow if a stacked top tote fails. If you stack, size containment for the total stack’s top container.
SPCC plan
For oil storage at or above the SPCC thresholds, you need a written SPCC plan, certified by a PE for facilities above certain thresholds. The plan covers spill response, training, inspections, and recordkeeping. We can’t write your SPCC plan but we can suggest local consultants — email us.
Questions on this one? Email info@ibctankscleveland.com. We answer everything inside one business day — usually inside four hours.