How to Make the Most of FRP Trench Drain Grate Covers

Trench drain grate covers are used in a wide range of industries to help manage water drainage, protect underground utilities, and ensure pedestrian and vehicle safety. However, traditional materials like steel and cast iron, often used for trench drain covers, can pose significant challenges. 

FRP vs. Steel Trench Drain Grate Covers

One of the most significant drawbacks of traditional metal trench drain covers is their susceptibility to corrosion. When exposed to moisture, salts, or other corrosive elements, steel and cast iron can deteriorate rapidly. This corrosion weakens the structural integrity of the covers, leading to potential safety hazards like collapsing grates or uneven surfaces. Additionally, repairs or replacements due to corrosion create unnecessary project delays and increased costs.

The sheer weight of traditional metal trench drain grate covers, among other factors, can raise costs considerably in the best of times. However, since the Suez canal crisis in 2021, steel transportation costs are 150% higher than they were before, according to Eurometal. Additionally, labor costs associated with moving and handling heavy covers can be substantial, and projects can be delayed due to the physical demands of installation. Furthermore, the weight of these covers can restrict their use in certain applications, such as areas with limited weight capacities. 

In contrast, FRP trench grate covers offer a significant advantage due to their lightweight design. Composed of fiberglass fibers embedded in a durable resin matrix, FRP boasts remarkable strength while being significantly lighter than steel or cast iron. This translates to numerous benefits:

• Reduced Labor Costs: The lighter weight of FRP trench grate covers simplifies transportation, installation, and on-site cutting. Crews can handle and install FRP covers efficiently, reducing labor costs and project timelines.
• Improved Efficiency: Faster installation minimizes project downtime, saving time and resources during construction or maintenance projects.
• Versatility: The lighter weight of FRP makes these trench grate covers suitable for a wider range of applications. This includes areas with weight restrictions or limited access, where traditional metal covers may not be feasible.

There is also the issue of cost. While traditional metal trench grate covers may come with a lower initial cost for some use cases, they require regular maintenance to maintain their integrity and appearance. FRP trench grate covers are virtually maintenance-free in the long term. Their non-corrosive properties minimize cleaning needs, and their durable construction eliminates the need for frequent repainting. This translates to significant cost savings over the lifespan of the trench drain system.

According to Steven Whitehead, a territory manager in Fibergrate’s sales team in Texas, FRP can be used for trench gratings, covers, and embeds. The right combination of products matters. For example, with a standard FRP grating, replacing a steel embed with a one made of FRP is a good way to extend the lifespan of the trench. If the embed is made of steel, this can cause issues over time. “Once it corrodes, the concrete in the trench will often crack. Then, it’s a big mess and costly to repair. So using FRP embed, which is what the grating rests on, prevents corrosion and prevents cracking of the concrete, which lengthens the life of the trench itself.”

If the trench grating cover itself is going to receive heavy vehicle traffic, then choosing a high load pultruded grating is often a better option than traditional molded grating. According to Steve, product selection is part of the picture, but there are also engineering factors to consider. “We make a high-load grating that is non-corrosive and it can withstand the load of an 18-wheeler. When it comes to creating a solution, what we look at is the span, which is from one side of the trench to the other including the concrete that the grating is resting on. Then we look at the clear span which is the area that is over a void where there is no support. That clear span distance is the number we’re looking for to decide what we can and can’t do with FRP to support a heavy load.”

There are two main factors that affect the decision for having a grating with a cover vs leaving it open. One reason is to improve the load bearing capacity of the grating if it will be exposed to heavy vehicle traffic.

The other reason is to protect materials that may be laid in the trench. Sometimes, cabling, electrical wiring, or pipes are run through the trench. While access will be needed occasionally for maintenance, it is often best to ensure that rainwater, debris, and other materials don't run through the grating to contaminate, disrupt, or damage the trench contents. Fortunately, FRP trench covers are lightweight and can typically be manually removed (without the use of heavy equipment) for maintenance. 

According to TJ Looper, Fibergrate's Regional Sales Manager in the Oklahoma area, "Our trench covers can have recessed grab handles so the covers are easily removable by one or two people. It's not uncommon to have a weight problem with a steel trench cover being so heavy that you have to use a forklift to remove it. With FRP, you are putting a product in there you can easily handle and it will outlast the concrete around it."

TJ also pointed out that, if the goal is to reduce the amount of debris getting into a trench, another option is to use grating with bars that are closer together. With galvanized steel, using that much metal rapidly increases both the weight and the cost of the grating. FRP turns out to be significantly cheaper, especially in the long run.

A car wash tunnel in Boston further exemplifies the advantages of FRP in harsh environments. The traditional metal trench drain covers they were using were prone to corrosion due to constant exposure to water, chemicals, and harsh weather conditions. This led to frequent repairs and replacements, increasing maintenance costs. By replacing the metal covers with FRP trench drain covers, the facility was able to significantly reduce maintenance expenses. The FRP covers' corrosion resistance ensured long-term durability, while their slip-resistant surface improved safety for workers and customers. Additionally, the lightweight nature of FRP made installation and maintenance easier and more efficient.

This real-world example demonstrates the significant cost savings and improved safety that can be achieved by choosing FRP trench drain covers over traditional metal options.

The client was facing challenges with the weight and maintenance requirements of traditional cast iron covers at a water treatment plant. These heavy, cumbersome covers required specialized equipment and labor for installation and maintenance, significantly increasing costs and posing safety risks to workers. Additionally, the cast iron covers were susceptible to corrosion, leading to premature failure and the need for frequent replacements.

Fibergrate provided a customized solution for utility trench covers. By switching to FRP, they were able to reduce installation costs, improve worker safety, and enhance the overall efficiency of their operations. The FRP covers' lightweight design allowed for easier handling and installation, while their corrosion resistance ensured long-term durability. Additionally, the slip-resistant surface of the FRP covers provided a safer working environment.

Fibergrate is a leading manufacturer of FRP trench grate covers, offering a wide range of products to meet your specific needs. Our in-house engineering team can provide expert guidance and support to ensure the optimal selection and installation of FRP trench grate covers.

Fibergrate's FRP trench grate used in hangar

Contact Fibergrate today to learn more about how our products can benefit your project.

Keep reading: 

• What is FRP Material and How Is It Used?
• Stepping Up Your Infrastructure: The Power of FRP Floor Grating