SPCC Secondary Containment Calculator

Calculate 40 CFR 112 applicability and sized secondary containment requirements.

Worksheet Information

Dike / Berm Parameters

* Freeboard accounts for precipitation (e.g., 25-year 24-hour storm event). 10% is a common rule-of-thumb.

Tanks in Containment

List all containers inside this specific secondary containment area. Footprint = π × r² for cylindrical tanks.

Container Name / ID Capacity (gal) Footprint (sq ft)

Analysis Results

Total AST Capacity: 0.00 gal
SPCC Applicability: N/A

* 42,000 gal buried threshold not evaluated.

Largest Single Container: 0.00 gal
Required Containment Vol: 0.00 gal
Gross Dike Volume: 0.00 gal
Displaced Vol (Other Tanks): 0.00 gal
Net Containment Vol: 0.00 gal
Awaiting Input

Self-Test Diagnostics


                

            

        

    


    






About the SPCC Secondary Containment Calculator
Environmental compliance managers can accurately size spill control structures using this SPCC secondary containment calculator. It helps facilities over the 1,320-gallon threshold comply with EPA rules by computing the exact containment volume required. By accounting for the largest primary container and factoring in appropriate freeboard for precipitation, you can guarantee your infrastructure meets rigorous 40 CFR 112 standards.
How it works
  1. Enter the volume of the single largest oil storage tank positioned within the proposed containment area.
  2. Specify the internal dimensions (length, width, and height) of the planned secondary containment berm or dike.
  3. Input the footprint volume of any other tanks or equipment located inside the containment area to account for displacement.
  4. Add the required freeboard percentage to verify if the total available capacity is adequate to contain a spill plus rainfall.
Frequently asked questions
What triggers the need for an SPCC plan?
A facility needs a Spill Prevention, Control, and Countermeasure (SPCC) plan if it stores more than 1,320 gallons of oil in total aboveground capacity (in containers 55 gallons or larger) and could reasonably discharge oil into navigable waters.
How large must secondary containment be for a single tank?
General EPA guidance states that sized secondary containment must hold 100% of the capacity of the largest single container within the berm, plus sufficient freeboard to contain precipitation.
What is the standard freeboard requirement?
While the EPA does not mandate a specific national percentage, the industry standard and common professional engineering practice is to add at least 10% extra capacity, or specifically calculate the volume of a localized 25-year, 24-hour storm event.
Do I need to deduct the volume of other tanks in the containment area?
Yes. Any additional tanks, equipment, or solid concrete pads situated below the containment berm's height physically displace available liquid volume, meaning the berm walls must be larger to compensate.
References