Choosing the right Leak Berm Secondary Containment System
All leak berms are not created equal. Most end users seeking supplementary containment are secondary spill containment doing so to comply with either Federal or State regulations. The EPA enforces 40 CFR of the Clean Water Act and most other regulations originate from that legislation.
The first question an person must answer in determining what type of containment they are seeking is what are they trying to accomplish? Notice Used to do not mention supplementary containment as the user may not be required to have sized supplementary containment but instead is only interested in drips or water leaks from equipment.
What is sized supplementary containment? 40 CFR addresses containment of certain hydrocarbon (oil) filled equipment. Part 112 specifically calls for sized containment. The containment must be able to contain 100% of the largest oil filled container on the equipment plus enough free board capacity to contain rainwater. The rule of thumb generally accepted is 110%. If sized containment is not needed then the person should buy drip berms or leak pads that are best with hydrocarbons to meet their needs.
Once the person has determined that they are seeking sized supplementary containment the doctor has to decide the actual capacity of the leak berm that they need. Volume is gained through length, width and height of the leak berm. Some locations are challenged with a limited area impact for the leak berm. In these instances, you can improve the height of your wall from the industry standard of 1ft. Length of the leak berm should be customized to your specific need. Seek out berm manufacturer’s that are willing to build the berm to your customized requirements.
Now that you have the size for your berm, the real questions can be asked. What are you going to contain? Where will you contain? How often will you use your leak berm? What type of foot traffic will you have around the leak berm? Answering these questions will define what kind leak berm you choose.
Benefit behind knowing what you would be containing is that the chemical you are containing will determine what type of material is used in the leak berm. There are several materials which they can use in a leak berm including: steel, concrete, sprayed fabrics and film. The vast majority of leak berms are constructed using sprayed fabrics that are best with the chemical that the person is containing. Films are a cheap alternative, typically constructed with polyethylene (PE). These include considered a single use solution as the film easily breaks and breaks when flattened. Without a scrim behind the film, punctures are also likely. A fabric will have a base scrim that the coating is extruded to and will provide higher hole ratings.
For permanent leak berm installs sprayed fabrics, concrete and steel with special coatings are used. Concrete is used for permanent installations that are fixed and will not change. Building permits are typically required when doing a concrete leak berm installation. Once installed the end user is committed to this area being their supplementary containment. There is no capacity to expand and the person must vigilantly inspect the bermed area for breaks. More often than not, the concrete will be asked to be sealed to meet the prerequisites of impervious containment. The price and maintenance of concrete areas are often detractors from this type of solution.
Steel constructed leak berms offer the longevity that many end users require but at a significant price. The steel leak berm can be sprayed with special coatings to protect the unit against weathering and rust. The end user will need to make sure that the coating works with the chemical that they are containing. Steel leak berms are typically moveable with the assistance of a heavy duty crane and may be one piece in construction if possible to avoid water leaks at seams.
Leak berms constructed with sprayed fabrics offer advantages over the other systems. That is why most leak berms are made from sprayed fabrics. The leak berms are portable, safer to install, don’t require enabling and can be a long term solution if cared for properly. Leak berms constructed with sprayed fabrics are far cheaper than steel and concrete berms.
There are several fabrics that are used to construct fabric leak berms. Polyurethane, PVC and modified PVC’s are the primary coatings used in leak berms. Compatibility is a primary concern for fabric selection. For instance, PVC is not long term best with hydrocarbons. When PVC makes contact with hydrocarbons, it will get brittle and crack as the hydrocarbons leach out the plasticizers in the fabric. Modified PVC and Polyurethane are the most common coatings used in combination with Polyurethane being the most expensive choice.
In instances where aggressive acids are increasingly being contained, it is often common for the person to lay down an acid ship inside of the berm. Typically, the ship is a lighterweight PE weaved recording that is flexible and inexpensive in comparison to the cost of the berm. The berm ship can be replaced as it would wear out.
Once you have determined what fabric works with your application, you need to determine what weight fabric to use in your berm ship. Lighter weight fabrics is often more susceptible to punctures. Coating weight alone does not determine the hole rating of the fabric. The beds base scrim and how securely it is weaved will also help out with raising your hole rating.
To assist in keeping your berm hole free, invest in track belts for inside the berm and ground rugs for underneath your leak berm. This will effectively sandwich your berm and protect it from below and above. Fabrics offered for this application vary from manufacturer to manufacturer. The best protection to weight of fabric relation is provided by using a sprayed polyester. This material is often used in conveyor belt construction and is extremely resistant to punctures in the harshest conditions.
Finally, the end user must determine what type of side walls and entry/exit walls they prefer to have in their leak berm. The wall support design and fabric construction are the two key features that set berms apart and rationalize the statement that all berms are not created equally. There are six kinds of berm wall support: angle segment, drift up, foam wall, air inflation, outside live and inside live.
The angle segment is generally the most cost effective method as it requires less time to manufacture. The main benefit of an angle segment design is that it is clean and without any trip hazards. It also provides person the most useable space in the smallest impact. The downside to an angle segment is that there are many parts to the berm and it requires assembly. Entry/exit from the unit requires the end user to disassemble the berm wall, drop the wall and then reassemble the wall when done. For high traffic, this type leak berm is not very functional.
Drift up berm walls have been introduced within the last several years. Drift up booms are used in the entry/exit wall or in all four walls. The main benefit of this type berm is that it has a low profile and the drift walls can be driven over from any direction. The end user does not have to increase or lower the walls to provide containment. The disadvantages of this type leak berm is that the person must be careful and not park equipment on or lay anything across the drift up walls that will keep the walls from sailing up in the event of a leak. It is also noted that this type berm is not recommended for areas where there is any annual compacted snow. The weight of the snowfall on the berm wall will hamper its capacity to drift up. The units are also very cumbersome due to the foam and typically do not last as long as other fabric construction berms.
Foam wall berms are very constraining in their capacity to contain. Regardless of manufacturer, if you go over a height of 6″ the end user runs the risk of berm failure. The fluid pressure that builds on a wall when a berm is filled over 6″ tall is too perfect for the foam construction and buckles the wall. There are manufacturers that offer the foam wall design in over 6″ height but it is advised to steer clear of these designs. With the reduced height, your impact must extend long and or width to accommodate the needed volume. Foam walls also do not last long when continually driven over. These disadvantages coupled with the majority associated with a foam berm wall limits its applications and is therefore, rarely welcomed in use.
Air berms are an adult design that is rarely used today. The hole of the air filled pontoons is a chief concern as you immediately lose containment. Another detractor is the additional equipment necessary to blow up the unit.
Outside live supports come in distinctive designs. A single piece construction that needs no berm assembly as with the patented Quickberm is the most user-friendly. A third party support live that provides no assembly reduces or eliminates the ergonomic desk issues associated with berm assembly. Braces that need assembly or are not attached permanently to the berm body offer the same disadvantages as the angle segment berm. For portable applications, the end user should not be concerned with losing parts in the field. Another disadvantage to the outside live support is that all live support is considered a trip risk to safety around the perimeter of the berm.
Inside live supports are merely available from manufacturer, Basic Concepts, Inc. It is a single piece construction that needs no assembly. The end user simply unfolds the leak berm and drags the walls back to assemble the unit. The berm impact must be slightly oversized to accommodate the medial side live supports. The overall impact takes up the same space as an outside live support berm would when including the outside support braces in the impact. The benefits of the medial side live design are that there are no tripping hazards around the perimeter of the berm, there are no parts to lose in the field, the berm folds up up to the storage impact of any leak berm in the marketplace and set up is quick and easy without the ergonomic desk challenges that leak berms requiring assembly present.
From this article the end user should be able to properly investigate the size of their leak berm, the fabric construction needed, whether they need hole protection and what type of live support is most desirable. Hopefully from this article the end user will understand that all leak berms are truly not created equal.