Tom Wright | Bedford Reinforced Plastics

| IMAGE 1: FRP grating provides a durable walking surface that withstands harsh conditions like wastewater and chemical exposure. (Images courtesy of Bedford Reinforced Plastics)

In water and wastewater treatment plants, corrosion is not a possibility—it is a certainty. Constant moisture, chemical exposure, ultraviolet (UV) radiation and demanding operating conditions create an environment where traditional materials such as steel, aluminum and concrete are continuously under attack. For facility managers tasked with maintaining safe, reliable infrastructure, material selection can have a major impact on maintenance costs, worker safety and asset longevity.

Fiberglass-reinforced polymer (FRP) grating has become an increasingly common choice for walkways, platforms, drainage trenches and even structural components. Yet for many engineers and facility managers, questions remain about selecting the right FRP system and ensuring long-term performance.

Part of the hesitation stems from unfamiliarity with resin systems, questions about performance and concerns about installation requirements. Despite FRP’s decades of successful use in water and wastewater applications, some facilities remain reluctant to specify it as a replacement for traditional materials. A better understanding of the factors that influence durability and life cycle performance can help address those concerns.

This guide examines resin selection, environmental durability and installation considerations to help facility managers make more confident decisions about where and how FRP grating fits within their operations.

Why FRP Performs Well in Water & Wastewater Applications

Water and wastewater facilities expose infrastructure to a relentless combination of moisture, chemicals and environmental stressors that can quickly degrade traditional materials. FRP is well suited to these conditions because it resists corrosion while maintaining strength and durability in challenging environments.

Much of that performance comes from the resin system, which acts as the primary barrier against moisture, chemicals and environmental exposure. As a result, selecting the appropriate resin is one of the most important decisions in any FRP project.

FRP grating is commonly used in:

Walkways and access platforms
Clarifiers and settling basins
Chemical feed areas
Wet wells
Pump stations
Potable water and coastal applications

The material’s corrosion resistance, lightweight construction and low maintenance requirements make it particularly attractive for facilities seeking long-term life cycle value.

Choosing the Right Resin System

When it comes to FRP materials, the resin system largely determines how well the material will perform when exposed to chemicals, moisture, UV radiation and other environmental factors. In water and wastewater applications, three primary resin families are commonly used:

General-purpose polyester resins: General-purpose polyester resins provide good corrosion resistance and cost-effective performance for applications with relatively mild environmental conditions and limited chemical exposure, such as equipment rooms and indoor areas.
Isophthalic polyester resins: Isophthalic polyester resins offer enhanced chemical resistance and durability, making them well suited for wastewater facilities where structures are regularly exposed to moisture, chemicals and fluctuating environmental conditions.
Vinylester resins: Vinylester resins provide the highest level of corrosion resistance and are commonly specified for digesters, chemical storage areas, coastal facilities and other highly corrosive environments where maximum durability is required.

Key Factors in Resin Selection

When selecting a resin system, facility managers should evaluate:

Chemical exposure and concentration
Temperature conditions
UV exposure
Fire performance requirements
Desired service life
Budget considerations

Because every facility operates under unique conditions, chemical compatibility data and real-world operating environments should always be reviewed during the specification process.

UV Protection & Environmental Durability

While corrosion resistance is often the primary reason facilities choose FRP, environmental exposure also deserves consideration.

Many water and wastewater facilities include outdoor walkways, platforms and access structures that remain exposed to sunlight, heat, humidity and changing weather conditions year-round. Although FRP is naturally corrosion resistant, prolonged UV exposure can affect composite materials if appropriate protective measures are not incorporated into the design.

Modern FRP systems often incorporate UV inhibitors within the resin system and may include UV-resistant surface coatings to help preserve appearance, maintain surface quality and reduce the potential for fiber bloom.

Because water and wastewater infrastructure is often expected to remain in service for decades, addressing UV protection during design and specification can help maximize service life and reduce long-term maintenance costs.

Potable Water Applications & NSF Certification

When FRP products are specified for contact with drinking water, additional considerations come into play. Beyond corrosion resistance and durability, engineers must ensure materials are safe for potable water environments and comply with applicable regulatory standards.

National Sanitation Foundation (NSF)/American National Standards Institute (ANSI)/Controller Area Network (CAN) 61 certification is commonly used to verify that materials intended for drinking water contact meet established requirements for safety and performance. Certification involves extensive testing, material evaluation and ongoing quality verification to help ensure products are suitable for use in potable water systems.

Applications that may require NSF-certified materials include:

Potable water storage tanks
Drinking water treatment facilities
Fish hatcheries
Water distribution infrastructure

For engineers and facility managers working in potable water environments, verifying certification requirements early in the FRP specification process can help avoid costly redesigns, material substitutions and project delays while ensuring compliance with drinking water standards.

| IMAGE 2: A durable, low-maintenance alternative to traditional metal flooring, FRP grating ensures safe operator footing in demanding environments.

Installation Best Practices

Unlike steel systems that often require welding, specialized equipment or extensive field modifications, FRP grating can typically be fabricated and installed using common tools and standard installation methods. Key installation considerations include:

Cutting panels to size using standard circular saws with diamond-coated or carbide-tipped blades
Securing panels with hold-down clips and mechanical fasteners
Allowing proper spacing to accommodate thermal expansion and contraction
Verifying support spacing based on load requirements, grating type and manufacturer recommendations

Because FRP is lightweight and easy to handle, installation often requires less labor and equipment than traditional materials.

In addition, many FRP grating products are also available in a range of panel sizes, configurations and colors, providing a degree of customization that allows facilities to better match project requirements and reduce the need for field cutting or modifications.

The Plant Operator’s Inspection Checklist

Routine inspections can help identify aging infrastructure before minor issues become costly repairs, safety concerns or unplanned downtime. During daily walk-throughs and maintenance inspections, operators should watch for warning signs that existing steel, aluminum and concrete structures may be nearing the end of their service life and may warrant evaluation of more durable alternatives. Key warning signs include:

Visible corrosion: Rust, pitting and surface deterioration may indicate advancing corrosion that can compromise structural integrity and lead to increased maintenance costs.
Coating failure: Peeling paint, damaged coatings and exposed materials can leave infrastructure vulnerable to moisture and chemical attack, accelerating deterioration.
Slip hazards: Worn or deteriorated walking surfaces can increase the risk of slips, trips and falls, particularly in wet environments.
Cracking or structural damage: Concrete cracking, steel section loss and visible deformation may indicate declining load-carrying capacity and should be investigated promptly.
Frequent maintenance requirements: Repeated repairs, repainting and corrosion mitigation efforts often signal that infrastructure has entered a cycle of ongoing maintenance and may warrant evaluation of alternative materials.

For many facilities, rising maintenance demands are often the first indication that FRP grating should be considered for a more durable, long-term solution.

A Long-Term Solution for Demanding Environments

Water and wastewater facilities face constant pressure to improve reliability, reduce maintenance costs and protect worker safety. Selecting the appropriate FRP grating system can play an important role in achieving those goals.

In environments where corrosion is unavoidable and maintenance budgets are constantly under pressure, material selection becomes more than a specification decision—it becomes a life cycle cost decision. By understanding resin systems, environmental durability considerations, potable water requirements and installation best practices, facility managers can select FRP grating systems that not only perform today, but continue delivering value for decades to come.

Tom Wright is business development director for Bedford Reinforced Plastics. For more information, visit bedfordreinforced.com.

In This Issue

Cover Series Wastewater