Two EPA requirements are now in full effect for secondary containment in underground storage tanks, and another to cover aboveground tanks. The Code of Federal Regulations 40, Protection of the Environment requires that all hazardous components or wastes are completely kept in a sealed container. A polymer membrane that is able to meet the new standards can be described as the polyurea spray elastomer technique.
The Code of Federal Regulations 40, Protection of the Environment requires that all toxic wastes or constituents be contained in a positive manner. In 1987 The Environmental Protection Agency passed a regulation under CFR 40 requiring a secondary method to contain spilled materials that contain dangerous chemicals but the regulation is being enforced.
- Single-wall corrosion-proofed USTs and piping with small diameters must be equipped with secondary containment when in contact with soil.
- Field-erected ASTs with a single wall need to be equipped with secondary containment underneath the tank. Single-wall bulk product pipes that is in contact with soil must be protected by secondary containment unless deferred by an API 570 Integrity Assessment.
In both instances both containments must be in place. secondary containment must function effectively for a period of time enough to allow for the proper cleanup of spills without causing any harm to the environment.
Many aboveground and underground storage tanks are constructed of concrete. The regulations states the fact that concrete is porous and the most secure method for secondary containment on concrete is using a liquid-applied monolithic polymer membrane. A polymer membrane that can meet the new regulations are polyurea spray elastomer technique.
Polyurea Spray Technology
Polyurea spray technology can be described as a fast-set, plural-component elastomeric membrane that provides an unidirectional, waterproof layer of protection. Many formulated systems meet the numerous requirements associated with secondary containment and adhesion to various substrates commonly found in containment zones. For containment zones that do not have solid substrates in use, geomembranes could be applied using the applied layer of an polyurea system that has characteristics with low shrinkage that are specifically designed to be suitable for the location.
The short setting time that is a feature of polyurea spray technology permits an immediate return to the service zone in a variety weather conditions, such as cold weather. The polyurea systems are also able to flex in low temperatures, thereby the absence of cracking problems that are common on other liquid-applied coatings and sheet-good membranes.
A variety of piping and tanks are susceptible to leaks. However it has been found that the majority of leaks found in these areas are caused by overfilling the storage tanks, which may result due to faulty equipment or an operator mistake.
This polyurea spray elastomer technique has been tested under the Florida Department of Environmental Quality standards regarding secondary containment liner system. The technology passed the test and is considered to be suitable secondary containment lining material.
For containment areas that do not have solid substrates available, geomembranes may be employed together with the applied layer of an polyurea system. Photo by GlasCraft, Inc.
Being aware of the imminent environmental regulations The U.S. military has used the polyurea technology to successfully lining different storage areas for fuel containment areas. The technology is currently being developed by engineering contract companies working in conjunction with both the U.S. Air Force and U.S. Navy. The work includes applications for Patrick Air Force Base, Cape Canaveral Air Force Station, AUTEC U.S. Navy Base and numerous storage facilities for fuel at airports with municipal status (see the right-hand sidebar). The majority of these locations are covered by an epoxy paint method applied on the concrete. The epoxy has cracked due to the movement of concrete over time and has caused cracks to the containment area , and a possibility of environmental problems. Since it is it is an elastomeric system it is polyurea technology can bridge those cracks, and provides a better containment lining material.
To cover the existing asphalt, earthen berms, and gravel containment areas for gravel containment areas, the polyurea method is applied over the geotextile membrane as previously mentioned. The polyurea system is bonded with the membrane the tanks, pipe penetrations and sump zones and allows seamless installation without the need for mechanical fastening, which is the case with sheet-good material. A number of these applications were completed at large oil, fuel, oil, and chemical storage facilities. The polyurea systems utilized in these applications are specially designed to offer a minimal cure shrinkage when applied over the geotextile membrane. Recently completed work across North America includes projects in the 300,000-450,000 feet2 (28,000 up to 42,000 square meters) size range. The vast projects are generally completed in a month with trained installation crews.
In the wake of the revival of oil and exploration for gas across the U.S., containment areas for the fractionation fluid must be provided at each drilling location. A planned containment space is created for this purpose, then support walls made of metal are built as well as a polyurea spray technique is applied over an edging material. The polyurea system is bonded to the wall space and the geotextile fabric to create an unbroken, leak-free space. Tanks for storage are placed within the space and piped the same day as liner installation.
A Compliant Solution
For all organizations or companies dealing with dangerous materials and hazardous substances, the new secondary containment regulations are already ahead. Thanks to polyurea spray elastomer technique businesses can comply with the new rules by using a long-lasting coating solution without requiring excessive downtime.
The author’s notes: Many thanks for Steve DeReu at GlasCraft, Inc. (www.glascraft.com) for his help with this article.
Case Study: Cape Canaveral Air Force Station
Cape Canaveral Air Force Station (CCAFS) is the East Coast space launch facility of the U.S. Department of Defense. It is located in Cape Canaveral, Brevard County in Florida It is part of Patrick Air Force Base, which is home to the 45th Space Wing, and is situated near the John F. Kennedy Space Center.
The 11,000 sq ft2 fuel truck pad needed the improvement of the liner system. The previous concrete pad was suffering from massive cracks, and there was concern about possible spills of fuel that could seep through the groundwater. CCAFS decided to go with the polyurea method (PV 350, manufactured by PolyVers International) due to its outstanding performance record with the same application areas, its flexibility as well as its toughness in high traffic and the speed of installation.
The installation of polyurea spray elastomer technique was completed in December of 2007. The formulated concrete was a 3D profile CSP 4 – 5, that will ensure a strong bonds to lines of the applied liner technology. It was concrete surface was pressure washed with the hot water solution that contained BioSolve(r) (supplied from The Westford Chemical Corp.) to get rid of any contaminants. Then, it was rinsed.
The complete area was primed with a proprietary polyurethane primer system for adhesion enhancement and reduction/elimination of outgassing in the concrete area. This PV 350 polyurea system was applied with a minimum thickness of 100 millimeters (2.5 millimeters). A 1/4-inch (6.35 millimeters) saw-cut joint was utilized to aid in completing an PV 350-based system in the perimeter. The area was prepped over the course of a day. It was then primed as well as applied for the PV 350 process over the following days. A texture for the finish was applied to aid in slip resistance.
It was applied with an GUSMER(r) H-25/25 unit that is fitted with an GlasCraft(r) Probler(r) P2 spray gun that has an “02” chamber and tip that provides an output that is controlled and a spray pattern with a of 2000 PSI (138 bar) processing pressure.
Case Study: BBL Falcon Industries
Many companies have taken maximum advantage of the revival of oil drilling activity across Texas, Oklahoma, and New Mexico. Fieldwork is where secondary containment areas are constructed prior to the installation for condensate tanks. These containment areas, which are typically 24 56x 2.3 feet, are built on site. ArmorLiner polyurea system made by ArmorThane USA Inc. is applied over the geotextile, and on the walls around it unlike sheet-good liner systems which are sewed and can leak. This ArmorLiner system is applied at the minimum of 80 millimeters (2 millimeters) on the 12 oz geotextile fabric.
ArmorThane’s specialized containment applicator has a patent-pending procedure for the rehabilitation of existing drilling sites for tank construction as well as new installation sites. The areas that are designed have been cleaned, leveled, and sanded, the steel perimeter is put in place and the geotextile material laid. This is applied upwards and then onto the geotextile, and the border wall area. After the material is in its place and sprayed with the ArmorLiner inside the tanks and piping.
This system applied by using the PMC PHX-40 proportioning device that is fitted with a PMC Extreme spray gun. A “02” chamber is utilized along with the “01” tips for inserting that allows for a precise flow and spray pattern with a 2500 psi (138 bar) processing pressure.