Polyurea and the Rules of Secondary Containment

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Polyurea and the Rules of Secondary Containment

Federal law requires that hazardous wastes and constituents be contained under the Code of Federal Regulations 40 (CFR), Protection of the Environment. There are two deadlines rapidly approaching: one for underground storage tanks (USTs) and the other for aboveground tanks (ASTs). Polyurea spray-elastomer technology is one polymer membrane that can meet the new requirements.

Federal law requires that hazardous wastes and constituents be contained under the Code of Federal Regulations 40 (Protection of the Environment). The 1987 regulation by the Environmental Protection Agency (EPA), under CFR 40, required a secondary method of containing spilled materials containing hazardous chemicals. (Section 265.190-265.933, 40 CFR). However, enforcement is only now beginning.

There are two deadlines rapidly approaching: one for underground storage tanks (USTs) and the other for aboveground tanks (ASTs).

  • December 31, 2009 – Corrosion-protected single wall USTs and small diameter piping in direct contact with soil must have secondary containment.
  • January 1, 2010, Single-wall, field-erected ASTs must contain secondary containment below the tank. Single-wall bulk product piping that comes into contact with soil must also contain secondary containment unless an API 570 Integrity Assessment is deferred.

Both cases require that the secondary containment function sufficient time to permit proper spill cleanup and not cause damage to the environment (Section 265.196; 40 CFR).

Concrete is used in many USTs and ASTs. Concrete is porous, and a liquid-applied monolithic polymer membrane is the best way to secondary contain concrete. The polyurea spray-elastomer technology meets the new requirements.

Polyurea Spray Technology

Polyurea spray technology, a plural-component, quick-set, elastomeric membrane, provides a monolithic and waterproof layer. Many formulated systems address secondary containment requirements, such as adhesion to various substrates. Geomembranes can also be used in containment areas without solid substrates. They can be applied with a layer of a low-shear polyurea system that has been specifically designed for this area.

Polyurea spray technology has a quick set time, which allows for rapid return to service in any environment. Polyurea systems are also flexible at low temperatures and eliminate cracking problems found in liquid-applied coatings or sheet-good membranes.

Leakage can occur in many tanks and piping areas. It has been proven that leakages in these areas can be caused by overfilling storage tanks. This could be due to operator error or faulty equipment.

The Florida Department of Environmental Quality (DEQ) has evaluated the polyurea spray-elastomer technology under secondary containment liner system requirements. This technology passed the testing and has been classified as an acceptable secondary containment liner material.

For containment areas where solid substrates are not present, geomembranes can be used with an applied layer of a polyurea system. Photo courtesy of GlasCraft, Inc.

Polyurea Installations

The U.S. military is well aware of environmental regulations and has successfully used polyurea technology to line various fuel storage areas. This technology is currently being specified by engineering firms that work with the U.S. Navy and U.S. Air Force. The work includes applications at Patrick Air Force Base, Cape Canaveral Air Force Station, and AUTEC U.S Navy Base. There are also a variety of fuel storage areas for municipal aircraft (see sidebar). These areas are covered with an epoxy paint system. Due to concrete’s movement over time, the epoxy has cracked. This can lead to a leakage in the containment and possible environmental problems. Polyurea technology is an elastomeric material that bridges cracks and provides a superior containment liner material.

These cases use a polyurea system specially formulated to have a low cure shrinkage when applied to the unsupported geotextile. The polyurea system can be applied to existing asphalt, earthen-berm, or gravel containment areas. The polyurea system bonds with the geotextile membrane and existing tanks, pipe penetrations, sump areas, and sump areas. It allows for seamless installation without the need to use mechanical fastening as required with sheet-good material. Major fuel, oil, and chemical storage facilities have seen many of these applications completed. Projects in North America that have been completed recently range from 300,000 to 450,000 feet (28,000 to 422,000 m2) in size. These large projects are usually completed in one month with application-trained crews.

Because of the rise in oil and gas exploration, each site must have a containment area for the fractionation fluid. A designed containment area is created, metal support walls are built, and a polyurea spray system is used to apply the polyurea system over a geotextile cloth. The polyurea system bonds with the geotextile fabric and wall to create a seamless, leak-free environment. The storage tanks are placed in the area and piped the same day as the installation of the linear system.

A compliant solution

The new secondary containment rules will be a major issue for any company or organization that deals with hazardous materials. Companies can comply with the new regulations using polyurea spray-elastomer technology without requiring excessive downtime.

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