Seven Benefits of a Looping Underground Fueling System

Seven Benefits of a Looping Underground Fueling System

Seven Benefits of a Looping Underground Fueling System

by Ed Kammerer

Car buying isn’t anyone’s idea of an enjoyable activity, but imagine how difficult, inconvenient, time-consuming and, yes, silly it would be if the purchaser had to work with different suppliers in order to procure the vehicle’s many components. For example, finding the right steering would require a trip to the steering-wheel store, the perfect engine would need to be acquired directly from the motor manufacturer, selecting the tires would demand a stop at the wheel shop, etc.

It just makes sense that the vehicle manufacturer does the heavy lifting of acquiring the components and putting them together, so the buyer has a complete, fully operational vehicle to purchase. So, why can’t that same logic be used by convenience-store fuel retailers when outfitting their sites with an underground fuel-delivery system?

As it turns out, they do have that option in the patented FlexWorks Loop System from OPW, which consists of all the components in the underground fuel-delivery and containment-sump systems, along with other ancillary equipment pre-assembled at the OPW factory. The loop system signaled a paradigm shift as the industry’s first plug-and-play underground-fueling system when it was introduced more than a decade ago – so it pays to reiterate the benefits it can offer the fuel-site operator:

Regulatory Compliance: All underground fuel-storage and delivery systems are regulated by local, provincial and federal regulations. These standards have become stricter over the years and the loop fuel-delivery system has been designed to not only meet, but also exceed, the demands for leak-free fuel containment.

Leak Prevention: The development and implementation of double-wall piping systems and sealed containment sumps mean that there are substantially fewer fuel leaks than in the past. This has created a safer fuel-delivery process for drivers, fueling sites and the environment.

Leak Detection: Secondary-containment systems lose their effectiveness when fuel leaks go undetected for a period of weeks or months; at that point, they have become primary containment systems. The loop fuel-delivery system makes it easier for the fuel-site operator to check if any leaks have occurred, thus allowing them to more quickly remove any fuel that has gathered in the containment sump and repair the leak.

Reduction in Piping Connections: Every pipe-connection point is a potential leak point. The loop fuel-delivery system reduces the number of pipe joints by as much as five times when compared to traditional systems, meaning fuel leaks are at least five times less likely to happen.

Accessible Pipe Joints: Some piping systems require the pipe joints to be buried, making them inaccessible from ground level. In addition, when these buried joints leak, they leak directly into the ground, creating an environmental hazard. Since the pipe joints in the loop fuel-delivery system are all contained and accessible at ground level, they are easy to inspect, repair and replace, with any leaks easier to detect and prevent from entering into the ground.

Easier Dispenser-Sump Installation: Deep-lying dispenser-containment sumps are labor intensive to install, service and inspect. The dispenser-containment sumps in the loop fuel-delivery system lie closer to the surface, with all piping and entry fittings easily accessible from the forecourt surface.

Optimized Entry-Boot Design: Legacy entry boots have proven to not be sufficiently robust to provide a secure long-term seal to the sump. The entry boots on the loop fuel-delivery system have been designed to form a safe, long-lasting seal with    the sump and have been pre-installed at the factory, eliminating the need to install in the field.

How It Works

The true innovation in the loop fuel-delivery system – which is virtually failsafe – is the use of a combination of revolutionary new types of piping connections, dispenser-sump designs, minimized piping joints and streamlined in-field fabrication requirements.

To explain, the loop fuel-delivery system features a double-wall coaxial piping setup that is contained within a larger access pipe, which allows a pipe section to be removed and replaced without needing to break concrete. All of the piping connections and fittings are secondarily contained in containment sumps that are easily accessible from forecourt level, which simplifies inspection, testing, repair and replacement.

The dispenser sumps are prefabricated and assembled at the factory in order to eliminate potential installation errors at the job site. Dispenser sumps are shallow and have angled sidewalls that will also not deform or crack under burial loads. All piping penetrations into the sumps are sealed with flexible or rigid double entry boots that are compatible with long-term exposure to fuel and the environment, as well as ground forces and movement. The entry fittings are installed and tested at the factory, ensuring that they are in the exact location for proper connection to the dispenser’s piping inlets.

All piping enters and exits the shallow dispenser sumps at a 45-degree angle instead of horizontally, which makes them easier to install and connect near the top of the sump instead of at the bottom of a traditional sump. The ends of the sections of coaxial piping are fitted with double-wall swivel couplings or barbed NPT fittings that connect directly to shear valves that have angled connection ports. This method of coupling and connection eliminates the need for rubber interstitial test boots, additional pipe fittings and field-fabricated steel riser pipes or flex connectors that are required for use with deep-lying dispenser sumps.

OPW will soon be expanding the range of the FlexWorks Loop System as it finalizes development of a high-flow version. This looping fuel-delivery system will be targeted toward large retail truck stops and the increasingly popular hybrid c-store sites that house truck-fueling islands. The plug-and-play high-flow loop system will have all the benefits of the legacy system, but will feature components compatible with high-speed fuel dispensers and large-diameter OPW FlexWorks piping that will allow higher fuel flow rates, thus enabling quicker refueling of trucks, which will mean less time at the pump for the driver and higher vehicle throughput for the fuel-site operator.


A decade ago, the FlexWorks Loop System created a new state-of-the-art standard in completely integrated, environmentally secure underground fuel-delivery systems that combine factory-assembled components from a single supplier with less field labor. The capabilities that made it a revelation back then are still applicable today for fuel-site operators who are looking to optimize leak prevention and detection, installation times, and the inspection, repair and maintenance of their underground fuel-delivery systems. 

Ed Kammerer is the director of Global Product Management for OPW, based in Cincinnati, OH, USA. He can be reached at 
For more information on OPW, go to

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Tanknology largest company in the world devoted to compliance solutions for petroleum systems. If you operate an underground or an aboveground petroleum fueling system, you are no doubt governed by multiple environmental regulations. In our blog, we discuss topics of interest to our industry community; whether it be a regulatory development, our take on breaking industry news, news from our company, or anything else we believe may be of interest the tank compliance community. We hope you will join us in the conversation.