subject: Using Secondary Containment to Prevent Environmental Contamination [print this page] Using Secondary Containment to Prevent Environmental Contamination
Holding a substance inside a container is not enough to prevent a spill. Although drainage control is used in these instances to prevent environmental contamination, secondary containment is a necessary precaution. As a liner, sump, pallet, or larger container, a secondary containment method needs to catch all liquids and spills and prevent them from reaching a drain.
If a hazardous liquid or solid is kept inside a portable container or tank, secondary containment needs to be used in order to prevent a leak or spill from spreading. For more information, the Environmental Protection Agency's Resource Conservation and Recovery Act (RCRA) 40 CFR 264 lists guidelines for using secondary containment methods with portable containers and tanks.
Secondary containment for portable containers must be able to hold 10 percent of the total volume of all containers or the full amount of the largest container. To prevent spills from spreading and reaching a drain, a secondary containment system must be free of cracks and gaps and needs to be impervious to leaks, spills, and precipitation.
The chemical, however, cannot stay in the secondary containment system, and the method you use must be able to drain liquids, unless the primary container does not have direct contact with the secondary system. Any spills or leaked chemicals need to be removed from the sump or secondary containment as quickly as possible.
Secondary containment for tanks follows a similar set of guidelines. Whatever method is used must prevent contamination of soil, ground, and surface water. The container, as well, needs to be compatible with the stored chemical and must be able to handle pressure, climate conditions, and daily operations.
Secondary containment for tanks comes in the form of an external liner, vault, or a double-walled device. The sump or secondary containment method needs to hold 100 percent of the largest stored tank.
Instances involving the storage of solids or liquids require secondary containment. For solids, an extra container to catch spills must be used if a single 550-pound container or multiple containers totaling up to 10,000 pounds is holding a chemical. For liquids, secondary containment is necessary for liquids greater than 1.1 gallons.
