Secondary Containment Systems: Choosing a Containment Pallet or DeckBack to The PIG® Library
Containment systems are always there for you to catch leaks and spills that may spring from the primary container. But are you using the right containment system for the job? Read on as we walk you through the process of how to choose the containment pallet or deck that best suits your needs.
Secondary containment devices provide a backup system to prevent the release of a spill should a primary container fail.
Custom-made secondary containment products – usually consisting of an impervious concrete pad and curbing – are commonly designed by engineering firms and help facilities comply with regulations. But with hundreds of prefabricated containment options available today, there's a ready-made solution for almost every need. Pre-fabricated systems save time and money. They can also be relocated as needs or processes change.
Traditionally, secondary containment systems were designed for compliance with the Environmental Protection Agency's (EPA) hazardous waste storage regulation, 40 CFR 264.175. However, other regulations, such as the EPA's Spill Prevention Control and Countermeasures (SPCC) rule, also require active and/or passive containment. Providing containment can also be considered a Best Management Practice (BMP) for the EPA's stormwater regulations.
Depending on the materials stored, fire codes can also play a role in containment requirements, as does the location of the containment system. Storing flammable liquids outdoors, for example, is more involved than storing them inside.
Being aware of regulations and applying knowledge of the liquids being contained are key steps in choosing a prefabricated containment system that will meet a variety of needs, and also be versatile enough to grow and change with the facility.
- Engineered secondary containment systems are costly and hard to adapt as facility needs change
- Prefabricated containment systems are less expensive but just as effective as engineered systems
- Being aware of regulations will help ensure that the proper containment products are purchased
Federal EPA secondary containment regulations (40 CFR 264.175) apply to large quantity hazardous waste generators. To meet this regulation, containment systems must meet the following specifications:
- The base must be free of cracks or gaps and must be sufficiently impervious to contain leaks, spills and accumulated precipitation (264.175(b)(1)).
- The base must be sloped or the system must be designed so that spilled liquids can be removed. This is not necessary, however, if the container is elevated (e.g., on pallets) or otherwise protected from contacting accumulated liquids (264.175(b)(2)).
- The secondary containment system must have the capacity to contain at least 10 percent of the total volume of the containers or 100 percent of the volume of the largest container, whichever is greater. (264.175(b)(3)).
- Stormwater run-on must be prevented from entering the system unless the collection system has sufficient capacity to contain any run-on entering the system in addition to the capacity requirements (264.175(b)(4)).
Containment is also a key provision in the EPA's SPCC rule (40 CFR 112). In a guidance document, the EPA states, "Secondary containment systems provide an essential line of defense in the event of a failure of an oil container." Two forms of containment are outlined:
- General secondary containment requirements address the most likely oil discharge from bulk storage containers; mobile/portable containers; production tank battery, treatment and separation installations; a particular piece of oil-filled operational or process equipment; (non-rack) transfer activity; or piping in accordance with good engineering practice
- Specific secondary containment requirements are intended to address a major container failure (the entire contents of the container and/or compartment) associated with a bulk storage container; single compartment of a tank car or tank truck at a loading/unloading rack; mobile/portable containers; and production tank batteries, treatment and separation installations
The rule also specifies procedures for active and passive containment. Active containment measures are those that require deployment or other specific action by the owner or operator. Passive measures do not require deployment or action by the owner/operator.
A goal of EPA's Stormwater Regulation is to prevent "illicit discharges," which are broadly defined as any discharges into a storm drain system not composed entirely of stormwater. The regulation calls upon facilities to use proactive Best Management Practices (BMPs) to prevent discharges. Properly maintained containment systems can be considered BMPs because they capture liquids at the source of the spill, preventing discharges.
Too often, a spill containment system is designed and installed to satisfy an isolated need: to comply with a specific state or local environmental regulation, to meet a specific objective, or maybe the desire to eliminate the slippery floor around waste collection containers. Unfortunately, engineered systems are hard to adapt if processes or the facility layout changes, or if additional needs are uncovered later.
Pre-fabricated containment devices help satisfy a number of different environmental, health and safety requirements, and can help lower insurance premiums. Because they are not "built in," they can be moved or relocated as processes or needs change without extensive deconstruction and reconstruction time and costs.
The wide variety of pre-fabricated containment pallets and spill decks available means that, for most facilities, the products needed for compliance are not more than a phone call away. Considering the following factors will aid you in selecting a system that best meets your facility needs.
Containment Pallet or Spill Deck?
Containment Pallets are stand-alone sumps capable of supporting one to eight 55-gallon drums. They have the ability to retain the entire contents of a 55-gallon drum should the primary container fail. Containment Pallets are typically preferred when:
- The number of containers stored per unit is eight or less
- Regulations require the sump to hold 100% (or more) of the largest container stored
- Storage space is limited
- The unit does not need to be portable
- The containers are not loaded/unloaded frequently
- The unit is not being used for fluid dispensing or waste collection
Modular Spill Decks are inter-connectible sumps capable of individually supporting one to four 55-gallon drums. These units have the ability to be linked physically and hydraulically to provide spill containment for several 55-gallon drums. They can also be used independently to capture nuisance leaks and spills if full containment is not desired or necessary. Modular Spill Decks are typically preferred when:
- Space is available to link multiple units together to achieve regulation-required sump capacity
- The number of containers stored is eight or more
- The unit does not need to be portable
- Low profile is desired for drum top accessibility or frequent loading/unloading
- The unit is used for fluid dispensing and/or waste collection
- A single device is used for "housekeeping" purposes rather than "containment"
Bladder Decks, while similar in design to Modular Spill Decks, feature a unique, concealed bladder that deploys only if a leak would overflow the Deck. Bladder Containment Decks are typically preferred when:
- Containment is required for one to four containers
- Floor space is limited, yet space aisle space is available for the bladder to deploy when needed
- Low-profile is desired for drum-top accessibility or frequent loading/unloading
Polyethylene, Fluorinated Polyethylene or Steel?
Chemical resistance of polyethylene or steel is often the primary factor when choosing materials for a containment device. Fluorinated polyethylene, with its increased chemical resistance, offers another choice when handling chlorinated solvents or other liquids that degrade regular polyethylene.
- Corrosive or reactive chemicals are stored
- Temperature extremes are not involved
- Corrosion of steel in high-humidity/corrosive environments is a factor
- Dedicated bonding/grounding points are not required
- Cost is a primary concern
- Polyethylene-degrading liquids are stored
- Temperature extremes are not involved
- Dedicated bonding/grounding points are not required
- Cost of steel is a concern
- Solvents, fuels or polyethylene-degrading liquids are stored
- Temperature extremes are involved
- High-humidity/corrosive environments are not a factor
- Bonding/grounding points are required
- Ability to resist damage from repeated forklift handling is a concern
Storing flammables or combustibles?
Flammable liquid storage and handling is a highly-regulated subject, yet there is little guidance offered by OSHA, the NFPA or the Uniform Fire Code on using — or not using — polyethylene spill containment devices when storing flammables and combustibles.
When polyethylene or fluorinated polyethylene is compatible with a flammable or combustible liquid, consider these factors when determining if a steel containment unit is needed:
- Fire or heat resistance of the containment device
- Control of static accumulation/discharge through bonding and grounding
- Proximity of the containment device to heat or ignition sources within the facility
- OSHA regulations as well as local fire codes regarding collection and storage of flammables
- Property insurer requirements regarding storage of flammable liquids
If the containment system will be used as a fluid dispensing or waste collection station for flammable materials, OSHA requires bonding and grounding of the containers when fluids are being transferred. This cannot be accomplished with a polyethylene unit. When in doubt, contact a local OSHA office, fire marshal or "authority having jurisdiction" over fire codes in the locality.
Flammable liquids to be stored outdoors have many additional requirements that vary greatly from state to state. Reputable suppliers can help guide facilities through the process of obtaining a building or structure that meets state and local safety codes.
Stationary or Mobile?
Consider the current and future physical requirements of spill containment devices when choosing between a pallet and deck.
- Will the containment area need to be expanded or reconfigured in the future?
- Will the containment units need to be moved while the containers are on them?
- Is drum top height at waste collection stations a concern?
- Will high-specific gravity liquids be stored on the pallets?
Modular Spill Decks feature inter-connectable bulkheads that allow multiple units to be connected on all four sides. These ports may be linked or closed as future needs require. The low profile also allows easier drum loading/unloading along with convenient access to drum tops.
Spill Pallets are recommended for a fixed installation of a small number of drums. If the spill pallet must be moved while the containers are fully loaded, carefully consider the design of the spill pallet and how the weight will be supported during the move — especially if the unit is not made of steel. For polyethylene pallets:Choose low-cost, low-weight rating pallets when:
- The unit will not be moved while loaded
- Liquids do not have a high specific gravity
- Liquids are stored in steel drums
- The pallet may need to be moved while loaded
- Liquids on the pallet have a high specific gravity, such as acids or caustics
- Liquids are stored in plastic drums
- Various-sized containers are being stored
When the spill pallet must be mobile or hold high-load forces, the slightly increased cost of a heavy-duty spill pallet will prove to be a worthy investment.
For facilities that have varying stock levels, collapsible containment systems may be the answer. These systems are capable of holding one drum to several totes of product. They can be used indoors or out, and fold compactly when not in use.
Security or Protection from the Elements in Outdoor Use?
When drums must be stored outdoors on a spill containment device, security of the containers and prevention of water accumulation in the sump are two factors to consider. In addition, the means of protection must not interfere with access to the containers for visual inspections and should not hamper workers who will access the drums for pumping or waste collection.
Several types of products are available to cover containers and protect sumps from precipitation. These products include:
- Tarps with elasticized bottoms and grommets
- Low cost. Good for storage when containers are not accessed frequently
- Hard plastic covers hinged to swing upward - Good when containers are rotated more frequently, but not when the station is used for pumping or waste collection
- Complete plastic enclosures with doors and roll-up upper panels
- Ideal for storage of containers that are frequently rotated, or for pumping and waste fluid collection stations
Today's modern spill-containment devices offer a range of uses and flexibility which can be tailored to suit virtually any need — indoors or outdoors. Careful planning prior to making a selection will help ensure that your containment device provides years of protection of the environment and efficient, convenient service for your employees.