Top OEMs for Structural Fiberglass & Composite Equipment

1. INTRODUCTION

In the municipal and industrial water and wastewater sectors, the battle against corrosion is a primary driver of capital expenditure and maintenance operational costs. Traditional materials such as carbon steel, galvanized steel, and even aluminum often degrade rapidly when exposed to the aggressive chemical and biological environments found in treatment facilities. Hydrogen sulfide (H2S), chlorine, ferric chloride, sodium hypochlorite, and high-humidity environments create conditions where metallic oxidation leads to structural failure, safety hazards, and repeated replacement costs.

Structural Fiberglass Reinforced Polymer (FRP) and composite equipment have evolved from niche alternatives to standard specifications for walking surfaces, structural supports, baffle walls, and containment systems. Unlike metals, FRP composites offer inherent corrosion resistance, high strength-to-weight ratios, electrical non-conductivity, and electromagnet transparency. However, not all FRP is created equal. The performance of these materials relies heavily on the quality of the resin matrix, the glass reinforcement architecture, the manufacturing process (pultrusion vs. molding), and strict adherence to manufacturing standards.

Read more4D-Printed Smart Materials For Water Treatment

For municipal consulting engineers and plant operations management, selecting the right Original Equipment Manufacturer (OEM) for structural composites is not merely a purchasing decision; it is a structural safety and lifecycle cost decision. Low-quality composites can suffer from UV degradation (fiber blooming), osmotic blistering, structural delamination, and catastrophic failure under load. Conversely, high-specification composites from reputable OEMs are engineered to last 20 to 50 years with minimal maintenance.

This article provides a comprehensive technical analysis of the structural FRP market, focusing on the five primary OEMs that define the standard for North American water and wastewater infrastructure. The discussion includes material science, selection criteria, detailed OEM capabilities, and practical application guidance for engineers designing headworks, clarifiers, chemical feed systems, and aeration basins.

2. HOW TO SELECT THIS SYSTEM OR EQUIPMENT

Read moreActivated Carbon Filtration in Water: Essential for Clean, Safe Drinking Supplies

Selecting structural fiberglass and composite equipment requires a fundamental shift in engineering mindset from isotropic materials (like steel) to anisotropic materials (composites). Engineers must define the functional requirements, environmental exposure, and structural loads with precision to ensure the specified product meets the application’s demands.

Resin Systems: The First Line of Defense

The corrosion resistance and structural integrity of an FRP component are dictated primarily by the resin system used. Engineers must specify the resin type based on the chemical environment:

• Isophthalic Polyester: The standard “industrial grade” resin. It offers good corrosion resistance to acidic environments and moisture but has lower resistance to strong caustics and solvents compared to vinyl esters. It is suitable for general walkways and handrails in non-critical areas.
• Vinyl Ester: The premium standard for wastewater applications. Vinyl ester resins provide superior resistance to a broad range of acids, alkalis, bleaches, and solvents. They also offer higher fatigue resistance and toughness. In headworks areas or chemical containment, vinyl ester is typically mandatory.
• Phenolic: Specified primarily for applications requiring low smoke and low flame spread properties (e.g., enclosed tunnels, offshore platforms, or confined spaces with strict fire codes). While excellent for fire resistance, they may have different structural properties than polyester or vinyl ester.

Manufacturing Processes: Pultrusion vs. Molding

Understanding the difference between pultruded and molded products is critical for structural specification:

• Pultrusion: A continuous process where glass rovings and mats are pulled through a resin bath and a heated die. This creates a profile with a very high glass content (up to 70%) aligned primarily in the longitudinal direction. Pultruded shapes (I-beams, angles, channels, tubes) function similarly to structural steel shapes, offering high unidirectional strength and stiffness. Pultruded grating allows for wider spans but is assembled from bars.
• Open Molding (Molded Grating): A process where continuous glass fibers are laid in a mold in alternating layers and thoroughly wetted with resin. This results in a product with bi-directional strength (isotropic in the X-Y plane). Molded grating is excellent for applications requiring extensive field cutting (penetrations for pipes) because it does not require edge banding to maintain structural integrity. However, it generally has a lower glass-to-resin ratio (approx. 35% glass) and is less stiff than pultruded grating.

UV Stability and Surface Veils

Fiberglass exposed to sunlight will degrade over time if not protected. UV radiation attacks the resin, causing “fiber blooming,” where the glass fibers become exposed on the surface. This creates an irritation hazard for operators and compromises the material’s barrier properties. High-quality OEMs incorporate UV inhibitors throughout the resin matrix and apply a synthetic surfacing veil (a resin-rich layer) to the exterior of pultruded shapes to act as a primary UV and corrosion barrier.

Fire Retardancy Standards

For municipal applications, fire safety is non-negotiable. Engineers should specify that FRP products meet a Class 1 flame spread rating of 25 or less when tested in accordance with ASTM E84 (Standard Test Method for Surface Burning Characteristics of Building Materials). Additionally, self-extinguishing capabilities per ASTM D635 are standard requirements for industrial composites.

Structural Deflection and Safety Factors

FRP has a lower modulus of elasticity compared to steel (approx. 2.6-3.0 x 10^6 psi for pultruded shapes vs. 29 x 10^6 psi for steel). Consequently, design is almost always governed by deflection rather than ultimate strength.

• Walking Surfaces: Typical specifications limit deflection to L/240 or 0.25 inches, whichever is less, under a uniform live load of 50-100 psf.
• Creep: Composites can experience creep (permanent deformation) under sustained long-term loads. Engineers must apply reduction factors for temperature and load duration during the design phase.

Anti-Slip Surfaces

Slips, trips, and falls are major liabilities in wet treatment plants. The method of applying grit to grating and stair treads matters.

• Integrated Grit: The grit is embedded into the top surface of the resin before it cures. This offers the best longevity.
• Post-Applied Grit: Grit is glued to the surface after manufacturing. This is prone to peeling off in high-traffic areas.

3. COMPARISON TABLE

The following table compares the five primary OEMs for structural FRP and composites. It outlines their core manufacturing strengths, typical product applications in the water sector, and specific differentiators relevant to engineering specifications. While all listed manufacturers produce high-quality composites, their specific focus areas (e.g., custom pultrusion vs. modular systems vs. molded grating) vary.

4. TOP OEMs / SYSTEM INTEGRATORS

Enduro Composites

Enduro Composites has established itself as a versatile manufacturer with a particularly strong foothold in the water and wastewater industry. Unlike manufacturers who focus strictly on the production of linear shapes or grating, Enduro emphasizes “systems”—engineered solutions that combine various composite technologies to solve specific plant problems.

Technical Differentiators:
One of Enduro’s flagship offerings is the Tuff Span series. This includes roofing and siding panels that are widely used for covering large process tanks, protecting equipment from environmental elements while containing odors. Tuff Span panels are engineered with high glass content and specific bidirectional reinforcement to allow for long spans with minimal structural support, reducing the cost of the underlying steel or FRP substructure.

Water/Wastewater Portfolio:
Enduro is a dominant player in baffle walls and partition walls for aeration basins and flocculation tanks. Their baffle panels are designed to withstand the hydraulic forces associated with flow diversion and mixing. They utilize a specialized slide-guide installation system that simplifies the mounting of panels to concrete walls or columns, accounting for thermal expansion and hydraulic load transfer.

Additionally, Enduro produces a comprehensive line of fiberglass cable trays. In wastewater plants, electrical conduits and trays are highly susceptible to corrosion. Enduro’s cable management systems are compliant with NEMA FG 1 standards and are available in both polyester and vinyl ester resins, offering a direct, drop-in replacement for corroded aluminum or coated steel trays.

Strongwell

Strongwell is widely recognized as the world’s largest pultruder of fiber reinforced polymer composites. For many consulting engineers, Strongwell’s design manual is the definitive reference for FRP structural design. Their brand name, EXTREN®, is often used generically to refer to pultruded structural shapes (angles, channels, I-beams, tubes) in specifications.

Technical Differentiators:
Strongwell’s primary strength lies in the consistency and structural integrity of their pultrusion process. EXTREN® Series 500 (Isophthalic Polyester) and Series 625 (Vinyl Ester) are the benchmarks for structural profiles. The Series 625 shapes include a synthetic surfacing veil that provides a resin-rich layer to protect against UV degradation and chemical attack, a critical feature for outdoor plant installations.

Beyond standard shapes, Strongwell manufactures COMPOSOLITE®, a building panel system used for covers, platforms, and enclosures. This system features an interlocking design that creates a solid, heavy-duty surface capable of bearing significant loads. It is frequently used for clarifier covers and trench covers where odor containment and worker access are both required.

Structural Reliability:
Strongwell maintains rigorous quality assurance protocols. Their in-house laboratory capabilities allow for physical property verification that exceeds ASTM requirements. For engineers designing critical support structures—such as pump support frames or pipe bridges—Strongwell’s load tables provide the necessary data on allowable uniform loads, concentrated loads, and deflection limits based on varied span conditions.

Bedford Reinforced Plastics

Bedford Reinforced Plastics differentiates itself through a strategy of “modularity and speed.” While they produce high-quality pultruded shapes and grating, their significant value proposition to the municipal market is their ReadySeries line of pre-engineered systems.

Technical Differentiators:
The ReadySeries includes modular platforms, ladders, stairs, and handrails that are designed to bolt together without the need for complex custom fabrication or welding. For plant managers facing a safety audit or needing to replace a corroded stairway quickly, Bedford’s system allows for components to be shipped from stock and assembled on-site using standard hand tools.

Material Quality:
Bedford utilizes their PROSeries structural shapes for these systems, which meet standard structural requirements. Their focus is on the practical application of FRP in maintenance-heavy environments. They have addressed common failure points in FRP assembly, such as connection integrity, by developing robust connection hardware and detailing clear assembly instructions that prevent overtightening (which can crush FRP tubes) or under-tightening.

Bedford is also strong in the grating market, offering both pultruded and molded options. Their logistics capability allows them to bundle grating, structural supports, and connection hardware into single shipments, simplifying project management for contractors working on plant retrofits.

Creative Pultrusions

Creative Pultrusions is a heavy-hitter in the composite industry, often associated with large-scale infrastructure and custom profile development. They excel in applications requiring high-performance resins and unique geometrical profiles that standard pultruders cannot achieve.

Technical Differentiators:
Their Pultex® line of standard structural profiles competes directly with other top-tier pultrusions. However, Creative Pultrusions distinguishes itself with products like SuperLoc® composite sheet piling. In coastal wastewater treatment plants or facilities with retention ponds, SuperLoc serves as a permanent, non-corroding retaining wall solution, replacing steel sheet pile that eventually rusts at the waterline.

Advanced Resin Technologies:
Creative Pultrusions has invested heavily in polyurethane (PUR) resin technologies, which can offer superior strength and impact resistance compared to traditional polyester or vinyl ester systems. While traditional resins are standard for most W/WW applications, their capabilities in high-performance matrices make them a go-to for specialized, high-load applications such as bridge decks or heavy equipment foundations within industrial treatment zones.

Their FLOWGRIP® flooring panels are another key product, providing a solid, non-porous surface that is often preferred in areas where odor control is paramount, as opposed to open mesh grating which allows odors to escape.

Fibergrate

Fibergrate Composite Structures is arguably the most recognized name specifically for fiberglass grating. While they offer structural shapes, their identity and primary innovation have always centered on walking surfaces and safety flooring. They originated the molded fiberglass grating technology.

Technical Differentiators:
Fibergrate offers the widest range of resin formulations for molded grating, marketed under the Vi-Corr® (premium vinyl ester), Corvex® (isophthalic polyester), and FGI-AM® (food grade) brands.

• Vi-Corr®: This is the industry standard for extreme chemical environments. It is specifically formulated for superior resistance to acidic and alkaline environments found in chemical feed rooms.
• High Load Capacity (HLC): Fibergrate manufactures a specific line of high-load molded grating designed for forklift traffic and heavy equipment placement, which is unique in the molded grating market segment.

Safety Focus:
Fibergrate emphasizes slip resistance and ergonomic safety. Their Safe-T-Span® pultruded grating is designed for longer spans and is available in varying open areas to balance drainage with pedestrian comfort. They also offer the Dynarail® handrail system and Dynaround® safety gates, providing a complete safety ecosystem. Their focus on NSF-61 certification for potable water applications makes them a frequent specification for drinking water plants involving contact with treated water.

5. APPLICATION FIT GUIDANCE

Successful deployment of FRP relies on matching the specific OEM strengths to the plant area.

Headworks and Grit Removal

This is the most corrosive area of a wastewater plant due to high H2S concentrations.

• Recommendation: Use Strongwell or Creative Pultrusions for structural supports (channels/beams) using Vinyl Ester resin. Use Fibergrate Vi-Corr molded grating for walkways. Molded grating is preferred here because complex piping penetrations are common, and molded grating does not lose structural integrity when cut, unlike pultruded grating which may require additional support at cut ends.

Aeration Basins

Aeration basins require baffle walls to prevent short-circuiting and massive amounts of handrail.

• Recommendation: Enduro Composites is the top choice for baffle wall systems due to their specialized panel and slide-guide designs. For handrails, Bedford’s modular systems can accelerate installation over the long perimeters of aeration tanks.

Chemical Feed Rooms

Containment of spills (Sodium Hypochlorite, Alum, Ferric) is critical.

• Recommendation: Fibergrate or Enduro. Fibergrate’s chemically resistant resin systems are extensively tested against specific reagents. Enduro’s tank and containment covers are ideal for sealing chemical storage tanks to prevent fume off-gassing.

Clarifiers and Settling Tanks

These large tanks often require weir plates, scum baffles, and density current baffles.

• Recommendation: Enduro Composites and Strongwell. Both offer excellent baffle panels (Stamford baffles) and weir plates. Strongwell’s COMPOSOLITE panels are excellent for covering launder channels to control algae growth and odors.

Potable Water Contact

Applications involving direct contact with drinking water (e.g., filters, clearwells) require NSF/ANSI 61 certification.

• Recommendation: Fibergrate and Strongwell. Both manufacturers have specific product lines and resin formulations that are third-party certified for potable water contact. Engineers must explicitly verify the NSF listing for the specific resin batch being ordered.

6. ENGINEER & OPERATOR CONSIDERATIONS

Installation Best Practices

Sealing Cut Edges: The most common cause of premature FRP failure is the failure to seal cut edges. When FRP is cut in the field, glass fibers are exposed. If left unsealed, these fibers wick moisture and chemicals into the laminate, leading to delamination and structural weakening. Specifications must mandate that all field cuts be sanded smooth and sealed with a resin kit compatible with the base material (typically vinyl ester).

Dust Control: Cutting FRP generates fine glass dust, which is a respiratory irritant and can damage electrical equipment. Contractors must use diamond-tipped blades and vacuum-assisted cutting tools. Operators should ensure that nearby electrical panels are sealed during installation to prevent conductive dust or glass dust from fouling contactors.

Thermal Expansion

FRP has a coefficient of thermal expansion roughly twice that of steel. In long walkway runs (e.g., across an aeration basin), engineers must design for expansion joints. Failure to do so can cause grating to buckle or handrails to bow. Connection clips should allow for slight movement, and bolt holes at expansion points should be slotted.

Fastening Systems

The hardware is often the weak link in an FRP system.

• Material: 316 Stainless Steel is the minimum standard. For highly aggressive environments (e.g., ferric chloride rooms), Hastelloy or Monel fasteners may be required.
• Clip Types:
  • M-Clips: Saddle clips that secure two load bars to the support. Standard for molded grating.
  • J-Clips: Used for securing grating to supports from the top surface when the underside is not accessible.
  • C-Clips: Used to join two panels of molded grating together to minimize differential deflection (tripping hazards).

Maintenance and Inspection

While FRP is “low maintenance,” it is not “no maintenance.” Operators should inspect grating annually for:

• Clip Loosening: Vibration from pumps can loosen grating clips.
• Surface Wear: The grit surface can wear down in high-traffic areas, reducing slip resistance. Most OEMs sell grit kits for field re-application.
• UV Bloom: If fiber bloom appears (fuzzy texture), the surface should be cleaned and a polyurethane or epoxy UV coating applied to extend life.

7. CONCLUSION

The transition from metallic infrastructure to structural fiberglass and composites in water and wastewater facilities is a proven engineering strategy for extending asset life and reducing maintenance overhead. However, the success of this strategy hinges on rigorous specification and the selection of reputable OEMs who understand the chemistry and mechanics of composite materials.

Enduro Composites, Strongwell, Bedford Reinforced Plastics, Creative Pultrusions, and Fibergrate represent the tier-one capability in this sector. Each brings specific strengths—from Enduro’s integrated baffle and cover systems to Strongwell’s pultrusion dominance, Bedford’s modularity, Creative Pultrusions’ heavy civil profiles, and Fibergrate’s safety flooring expertise.

Engineers must move beyond generic “FRP” specifications. By specifying exact resin systems (Vinyl Ester vs. Polyester), manufacturing methods (Pultrusion vs. Molding), and requiring adherence to ASTM structural and fire standards, utilities can ensure their composite infrastructure delivers the 50-year service life it promises. The cost of premium resin and quality manufacturing is negligible compared to the cost of a safety failure or the premature replacement of critical plant access structures.