Tank sumps are a last line of defense in underground fuel-storage and dispensing systems against many of the occurrences that can put the safety and effective operation of the system, along with its fuel quality, at risk. Their main job is to capture and prevent any fugitive fuel – whether through leaks or accident – from escaping into the soil around an underground storage tank (UST) and, potentially, finding its way into surrounding groundwater reservoirs. Additionally, tank sumps keep water from entering the fueling system, which can foul the gasoline or diesel fuel and damage the fueling-system components of the vehicle into which that fouled fuel is dispensed.
Therefore, it is critical that fuel retailers outfit their UST systems with high-quality tank sumps. This is important because any fugitive fuel that enters the soil, water supply or UST can eventually result in service interruptions, prohibitive regulatory fines, and expensive cleanup and reparation costs, with site shutdown a worst-case scenario.
In order to ensure that their fueling systems are outfitted with tank sumps of the highest quality, reliability, durability and integrity, retailers should consider the following three questions before making their next tank-sump purchase:
1. Are your sumps constructed using the most up-to-date methods and materials?
For many years, polyethylene (PE) was the material of choice in the manufacture of tank sumps – and it performed admirably. However, tank-sump manufacturers realized that constructing their products from fiber-reinforced polymer (FRP), or fiberglass, offered many advantages over traditional PE sumps. Chief among these advantages are compatibility with most common fuel formulations and additives; advanced corrosion resistance; higher structural strength; and a lifespan that can reach 30 years or more.
Within the FRP tank-sump realm are four distinct methods of construction:
- Hand Layup: Also known as “wet” layup, with this method the resin and glass are hand-painted onto a single-sided mold with a roller before a thin layer of gel coat is applied to seal any holes in the fiberglass.
- Chopper Gun Layup: Similar to hand layup, except that a spray gun is used to apply the mixture of resin and glass to a single-sided mold before a gel coat is applied.
- Filament Wound: A mold is placed on a steel mandrel that slowly rotates as a fine string of glass/resin filament is sprayed on the mold to create the sump.
- Vacuum-Assisted Resin Transfer Molding (RTM): A carefully controlled process in which a male and female sump mold are mated together around a glass mat while a vacuum is used to form an airtight seal between the two molds as the resin is pulled into the space between the molds. This provides a controlled and consistent ratio of resin and glass, as well as consistent wall thicknesses in every sump.
The hand/wet layup and chopper gun layup construction methods are the least expensive, but they are of the lowest quality. These manufacturing methods can produce sumps that are inconsistent in wall thickness, wall sections that are brittle and rough surfaces that are difficult to work with. The result is a sump that does not possess the durability and reliability needed to successful perform its duties.
Meanwhile, the vacuum-assisted RTM manufacturing process eliminates the concerns associated with the hand/wet and chopper gun layup processes while offering a long list of benefits, including the use of metal inserts in the mold to ensure consistency of shape; consistent wall thicknesses; solid build with low permeability; a smooth finish on both sides; no gel-coating needed to achieve watertightness; and adherence to the new UL-2447 standard for tank-sump operation.
2. Is your tank sump truly watertight?
Preventing the insidious intrusion of water into the fueling system is a constant concern for fuel retailers. Water that enters the UST can have far-reaching negative effects for retailers and their customers.
The next generation of RTM-constructed FRP tank sumps have been designed to function as watertight isolation chambers that provide secondary containment for tank-valve fittings, pumps and pipe fittings. This capability is achieved through the incorporation of a stainless-steel ring and sealing gasket that make the cover watertight and keep water from entering the UST and, subsequently, the fuel-dispensing equipment. Many sump manufacturers do not use gaskets or mechanisms to compress and truly make their lids or covers watertight.
The design of these watertight sumps also allows easy access to the UST itself, with any service or maintenance needs able to be performed in a clean and dry environment. The sump’s height-adjustable “top hat” can also accommodate a wide variety of tank-bury depths, making them easily customizable for the unique needs of individual sites.
The result is a tank sump that offers a “best of both worlds” combination of water-intrusion prevention and ease of installation and maintenance.
How To Eliminate Water Intrusion in Your Fuel System
There are a few key components that can protect fueling sites, customers and owners from the dangers of UST water intrusion. Does your site have these key components?
3. Does your sump come with factory-installed conduit ports and electrical wiring box?
The latest tank-sump innovation from OPW Retail Fueling is the ElectroTite No-Drill Tank Sump. What makes the ElectroTite a step forward in the design, installation and operation of tank sumps is that it is the industry’s first and only sump that has factory-installed conduit ports and electrical wiring box. This means that the sump can be installed as-is at the fueling site, with no drilling required. This eliminates the risk that unintended leak points will form in the system due to the drilling of entry points. This feature also helps optimize installation time.
Other features and benefits of the ElectroTite sumps include:
- Vacuum-assisted RTM manufacturing process that ensures consistent wall thickness, a smooth finish and watertight, leak-free operation
- Sealed conduit threads on the outside of the sump, which allows entry above the water table
- UL-listed, single-piece cast aluminum explosion-proof junction box with bolt-on access cover that allows space to re-route communication wires and loop additional sensors without entering the sump
- A shield that enables high-voltage and sensor wires to be separated in the same junction box
- Availability in a wide range of shapes and sizes to accommodate virtually any tank-sump application
And one final question: Are you ready to optimize the performance of your fuel-storage and -dispensing system?
Visit opwglobal.com to learn more about the retail-fueling industry’s best tank-sump products and how they can protect you, your customers and the environment.
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