What is the difference between active and passive spill containment?
Responding is Karen Hamel, technical writer, New Pig Corp., Tipton, PA.
Providing secondary containment for containers, tanks, processes and waste storage areas limits the potential for hazardous chemical releases. It also minimizes the amount of time that will be spent cleaning up spills. In some cases, it can even allow spilled product to be recovered for reuse.
The Environmental Protection Agency’s Spill Prevention Control and Countermeasures (SPCC) Rule allows both active and passive secondary containment methods to be used to meet certain requirements of the rule. Secondary containment methods often can be applied to other EPA and OSHA standards as well.
Active secondary containment includes products, devices or tools that are used either proactively or reactively and require someone to physically deploy or engage them. Drain covers, absorbents and retractable containment walls all are examples of active secondary containment.
When choosing active secondary containment methods, it is important to have clear plans in place that describe how and when these methods will be used. If proactive methods such as placing a cover over drains before fuel deliveries will be used, incorporate the practice into standard operating procedures. If devices and tools will be used reactively when a spill occurs, regular training and drills will help these practices become second nature for responders.
Passive secondary containment systems are permanently put in place to contain potential spills. They do not require anyone to deploy or activate them. Berms, dikes, sloped flooring and spill-containment pallets all are examples of passive secondary containment.
In many cases, passive secondary containment devices are designed to contain a worst-case scenario spill. For example, the berms around a tank farm are typically designed to capture the full volume of the largest tank stored at the site. (This is referred to as “sized secondary containment” in SPCC regulation.) Passive secondary containment also can address smaller, more common spill scenarios, such as tank overfills or breaks to a pipe or hose line. (This is called “general secondary containment” in SPCC regulation.)
OSHA’s Process Safety Management Standard and EPA’s Risk Management Plan both require facilities with threshold quantities of certain chemicals to assess chemical and process hazards and create plans to prevent chemical releases from harming employees, surrounding communities and affecting the environment.
Because both the PSM and RMP standards are performance-based, facilities that choose to use secondary containment methods as good engineering practices have the liberty of using various types to meet their needs. Secondary containment is an added line of defense to help keep employees and the environment safe.
Editor's note: This article represents the independent views of the author and should not be construed as a National Safety Council endorsement.