Like most products with a long history, fiberglass—for which the first patent was issued in the United States in the 1880s—has evolved over the years. Growing from a basic fiber-reinforced plastic using glass fibers at its inception to the easily recognizable and familiar glass-reinforced plastic that we all know today, fiberglass plays a critical role in the production of many common consumer products, including swimming pools, bathtubs, boats and septic tanks.
Fiberglass also contributes greatly to the safe, reliable and trustworthy performance of a wide array of fuel-storage and containment systems across the world’s retail, commercial and municipal service stations. Today, many of the items used in the storage and control of most fuel types and grades on the forecourt, including manhole covers, skirts, tank and dispenser sumps, and tank-sump lids, are constructed of fiberglass.
The Choice Is Obvious
OPW offers a complete family of containment systems and underground storage tank equipment that take advantage of the specific benefits of the four fiberglass-manufacturing methods.
Methods of fiberglass manufacturing
As the pieces of forecourt equipment that are constructed of fiberglass have grown, so have the ways that fiberglass can be manufactured. There are now four commonly used fiberglass-manufacturing methods:
- Open-mold spray up: Also known as “chop and spray,” this method utilizes a spray gun with a supply of resin to apply a pre-mixed, spooled fiberglass strand to a single-sided mold. The main benefit of this method is that it is easier to produce parts that have irregular shapes (i.e. not circular or square), as well as parts that are not meant to have an airtight or watertight seal or bear heavy loads and forces.
- Resin-transfer molding (RTM): This construction method requires a hydraulic press to compress a composite of glass fibers and resin into a mold, with the glass providing tensile strength and the resin contributing compressive strength to the finished product. This method of construction is effective in developing dense, compact layers of fiberglass for objects that need to bear heavy loads or repeated high-force events. This process is optimal for items such as manhole covers.
- Vacuum-assisted resin-transfer molding (Vac-RTM): This evolutionary stage in the RTM method uses a vacuum to pull, rather than push, the resin into the fiberglass. This creates a better seal without the need of a large, expensive hydraulic press. The finished walls of a Vac-RTM product are incredibly smooth, making it easier to attach other components to it with no diminishment of sealing capabilities and ideal for large items that require watertightness, such as tank sumps.
- Sheet-molded compound (SMC): This manufacturing innovation combines the best of the open-mold spray up and RTM methods. A putty-type mixture of glass fibers and resin is formed into sheets that are molded into a specified length, shape and density. These parts have the highest level of consistency, making SMC the premier way to construct a high number of consistently shaped and formed parts over a short period of time. This method has recently proven extremely efficient for high-volume products demanding smooth sealing surfaces for the maximum prevention of water intrusion, such as under dispenser containment sumps.
A full menu of options
OPW Retail Fueling, based in Smithfield, N.C., utilizes all four fiberglass-manufacturing methods when creating its forecourt products. Using four different fiberglass-manufacturing processes helps OPW identify and utilize the right manufacturing process for the right product or application.
Here are some popular OPW forecourt products and the fiberglass-manufacturing process that is used to build them:
- Top hats and skirts: Top hats are the collar that is positioned on a tank sump. Skirts serve several purposes, both above and below ground. Below grade, they offer an ideal frame for holding and sealing large composite manhole covers. The fiberglass construction offers corrosion resistance unlike other skirts constructed of steel. OPW uses the open-mold spray up technique for the manufacture of its various models of top hats and skirts.
- Composite manhole covers: OPW uses the RTM process for its families of Matador, Conquistador™ and FiberLite manhole covers because RTM manufacturing results in a finished product that can bear heavy loads or repeated high-force events, such as vehicles driving over or parking on them. The composite material again offers superior performance when compared to manhole covers constructed of steel.
- Tank and dispenser sumps: OPW uses the Vac-RTM method to build many of its tank sump products. The result is sumps with a conduitless design that reduces leak risks, thick side walls that can withstand backfill and environmental forces and smooth sealing surfaces for leak-tight entry fittings. OPW recently introduced the SMC method to construct its newest innovation, the DSE dispenser sump, which has been designed and engineered to combine best-in-class quality, lead times and affordability with no compromise in overall performance.
- Latched tank sump lids: For use on OPW fiberglass sumps, these products are manufactured with the SMC method and are designed to be a direct replacement for old, mechanically fastened polyethylene lids. The SMC method gives these lids three times the strength of previous lid models with the six-latch cover design delivering even, leak-free sealing.
Though the methods of manufacturing fiberglass have changed over the years, all still have their advantages when it comes to building components for use in the service-station forecourt. The challenge is finding products and a manufacturer that make the best use of the specific manufacturing method, with the creation of a durable, reliable and safe finished product the ultimate goal.
Visit opwglobal.com to learn more about OPW’s full portfolio of fiberglass-based forecourt equipment.
This post is sponsored by OPW Retail Fueling