Secondary containment sumps

Responding is Mandy Marxen, commercial marketing manager, U.S. Chemical Storage, Wilkesboro, NC.

Secondary spill containment is vital to a safe and compliant workplace that handles hazardous liquids. Secondary containment sumps can minimize spill-cleanup efforts and isolate the migration of hazardous materials. They can be constructed out of traditional construction practices or prefabricated portable structures, or they can be standalone and transportable, such as spill pallets and containment berms.

Because most liquids in hazmat buildings are stored in 55-gallon drums or large totes, the likelihood of all containers leaking at the same time would be slim. That’s why the regulatory bodies mentioned below needed to clarify how large the volume of secondary containment sumps should be.

A layman’s guide to sump compliance

Environmental Protection Agency 40 CFR 264.175 specifies the secondary containment must have sufficient capacity to hold at least 10% of the total volume of all containers or 100% of the volume of the largest container, whichever is greater. Uncovered outdoor storage would need to additionally account for routine precipitation of rain or snowmelt.

To add another layer, there’s the EPA’s Spill Prevention, Control, and Countermeasure rule in 40 CFR 112. It specifically refers to a “sufficient freeboard” volume for outdoor secondary containment sumps. What that means isn’t explicitly spelled out, but other definitions of freeboard define it as a volume to contain a 25-year, 24-hour storm event.

Note that EPA is a federal regulatory body that has authority to enforce regulations and can issue fines and penalties for noncompliance.

The following bodies can’t enforce fines or penalties for noncompliance, but many local, state or federal authorities may adopt all or part of their recommendations into their own fire or building codes. Learning your state’s specifics and communicating with your Authority Having Jurisdiction is extremely helpful.

National Fire Protection Association Code 30 mentions storage of liquids in Chapter 9, and Chapter 14 addresses hazardous materials storage lockers constructed out of steel and featuring secondary containment sumps to contain spills. But there are no explicit calculation guidelines.

Uniform Fire Code Articles 79 and 80 follow the EPA calculation of sufficient capacity to hold at least 10% of the total volume of all containers or 100% of the volume of the largest container.

International Fire Code 5004.2 Spill Control and Secondary Containment provides guidance for liquid and solid hazardous materials in a broader scope. It outlines volume calculation of spill containment as the largest single vessel plus the volume of fire protection water from a fire-suppression system for 20 minutes. If outdoors, the calculation is the volume of the largest individual vessel plus sufficient freeboard.

In conclusion

Some local or state regulations may even require more stringent containment capacities than federal standards require, depending on the specific chemical or their weather risks. Always check the latest regulations and consult local authorities for specific requirements for your situation.

Editor's note: This article represents the independent views of the author and should not be considered a National Safety Council endorsement.