Spill Volume & Containment Calculator

RCRA 40 CFR 264.175 applies to areas storing containers of hazardous waste, and its greater-of-10%-or-largest-container test exists because a yard of many similar drums has no single container large enough to drive meaningful containment on its own. SPCC 40 CFR 112.8(c)(2) applies to bulk storage containers of oil at facilities that could discharge to navigable waters, and requires the entire capacity of the largest single container plus freeboard for precipitation — with no 10% alternative. A facility can be subject to both for different areas. If you are writing a plan, cite the rule that actually applies to that area; citing the wrong one is a compliance finding regardless of whether the number happens to be conservative.

Because 110% is not what either regulation says. SPCC calls for the largest container's entire capacity AND sufficient freeboard for precipitation as two separate requirements; RCRA's greater-of figure likewise does not include rainfall, and 264.175(b)(4) handles run-on separately. The 110% convention is the two things already added together — 100% plus a 10% buffer. Reporting them as one number and then adding another 10% on top, which this calculator used to do, counts the rainfall allowance twice. The 10% buffer here is a simplified stand-in; a real plan sizes freeboard from the site's own design storm, commonly the 25-year, 24-hour event over the exposed containment area.

Yes. The containers standing inside the dike take up part of its interior, so they displace containment volume that would otherwise hold liquid. Net capacity is (floor area minus container footprint) times wall height, which means the floor must be at least the container footprint PLUS the area needed for the liquid. At the defaults ten 55-gallon drums occupy about 26.6 sq ft on their own, so a dike smaller than that could not physically hold them, let alone contain a release. Raising the Dike Wall Height is the direct lever if floor space is constrained.

Both are realistic; they are different materials. Polypropylene sorbent pads and socks hold roughly 3 to 5 gallons per pound of product, so a large release needs surprisingly little weight of pad. Clay, diatomaceous earth and similar granular absorbents hold roughly 0.10 to 0.15 gallons per pound — a 40-pound bag soaks up about 4 to 6 gallons — so the same release needs tons of granular. Stock according to the material you will actually deploy, and remember that spent absorbent becomes waste at the volume and weight you just calculated, which is often the binding constraint on disposal cost.

No — this applies the core containment-volume test from whichever rule you select, as a planning estimate. A facility subject to SPCC under 40 CFR Part 112 needs a full written plan, in many cases certified by a licensed Professional Engineer, covering facility diagrams, spill history, personnel training, inspection schedules and site-specific containment design; a RCRA container storage area has its own inspection, base, and run-on requirements under 264.175 beyond the capacity figure. Use this tool to understand the underlying volume math, not as a substitute for a compliance plan.