The Vertical Drain Containment system is a simple concept with three major components. A controlled drainage area is one of the most important parts of the design because it determines the amount of protection that is provided and determines the number of drains.

A controlled drainage area is an area around the equipment or tank that contains the organic liquid plus any storm runoff that may fall in this area and separates it from the rest of the facility. The containment structures are typically constructed using a berm, wall, or a recessed area. It is recommended that the containment structure be a minimum of 25 ft. away from equipment such as a transformer and 10 ft. from a distribution breaker. This distance is based on head pressure of the internal liquid and the distance that a puncture would project said liquid.

The second part, and most unique, is a drain filled with a swellable polymer that allows water to drain but will swell when it comes in contact with an organic liquid, for example, transformer oil, and seals off all flow through the drain(s). The typical drain is 2 ft. in diameter and constructed of galvanized metal.

The drain has a removable sand filter to keep the swellable polymer clean and free of debris that might impede the flow. Four 6 in. x 6 in. polymer filled pillows are provided as part of the drain. These are placed on top of the sand filter as the first line of defense against an organic liquid.

These pillows will absorb small amounts of organics and keep them from penetrating the main polymer compartment of the drain. The number of drains needed is based on the size of the area and the amount of rainfall that might occur at the location. The flow rate of the 2 ft. diameter drain is 1080 gallons per hour based on a 6" pressure head. Another factor involved is the amount of time that the water is expected to be drained from the containment area. A typical 50 ft. x 50 ft. controlled drainage area that is required to drain a 100 year flood condition of 4.25 in./hr. in two hours would require three drains to meet these conditions.

The third part and the one that ties everything together is a manifold that allows multiple drains to be combined and only uses one common outlet pipe. These manifolds are typically constructed of corrugated metal or poured-in-place concrete.

This system is suited for new installations or it can be easily be used to retrofit an existing facility.

Probably half of the systems sold have been used to retrofit existing facilities where containment was not included in the original design.

For this system to work efficiently, there needs to be a drop in elevation of 2.5 ft. from inside the controlled drainage area where the manifold is installed to the outflow elevation of the outlet pipe. If the location does not meet the elevation requirements, a sump design has been developed to handle these locations.

This system works in cold and hot climates equally well. Independent laboratory tests are available upon request.

Installation is very simple and everything needed is included. The user installs the drain into the manifold using butyl caulk, then pours a canister of polymer into the drain and a bag of filter sand into the sand basket. An installation manual is included with every system sold.

This system has been in use since 1992 and the users report that very little maintenance has been required. It is recommended that the polymer bed be examined annually for any sign that oil has penetrated the drain.