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Tank Dike / SPCC Secondary Containment Calculator

NFPA 30 §22.11 + 40 CFR 112 SPCC §112.7

Size a secondary-containment dike around tank-farm aboveground storage tanks. NFPA 30 requires containment ≥ 100% of largest tank; 40 CFR 112 SPCC requires 110% for facilities > 1,320 gal aggregate. Provided volume = (dike footprint − other tank base areas) × (dike H − freeboard).

Compliance & Site

in
in

Tanks (each)

Tank #Diameter (ft)Height (ft)
1
2
3

Dike Footprint

ft
ft
ft

Method

Required volume:

Vreq = M · Vlargest tank + Vrain

Where M = 1.10 (SPCC) or 1.00 (NFPA); Vrain = (rain_in/12) · footprint · 7.4805/42 bbl.

Provided volume:

Vprov = (L · W − Σ Aother tank bases) · (Hdike − freeboard/12) · 7.4805 / 42