When selecting fiberglass-reinforced polymer (FRP) grating or structural shapes, customers often have questions about the differences between resin systems and which option is best for their application.
The answer depends on the product type and the conditions it will be exposed to. This guide breaks down the most common resin types used by resin manufacturers, helping you choose the right solution for your needs.
Why Resin Systems Matter in FRP
In any FRP composite, the resin system plays a critical role in performance. It determines:
- Corrosion resistance
- Fire retardancy
- UV protection
- Long-term durability
Whether you’re using a polyester resin or a vinyl ester resin, the resin is what protects the material from its environment — especially in demanding industrial and chemical applications.
These composite resin systems are engineered to deliver specific levels of performance depending on the exposure conditions.
PROGrid® Molded Grating Resin Systems
Bedford Reinforced Plastics’ PROGrid molded grating is available in three resin systems, each offering a different level of corrosion protection. All meet Class 1 Flame Spread Rating per ASTM E-84 test standards.
GP — General Purpose Polyester
An orthophthalic polyester resin system designed for cost-effective performance.
- Good corrosion resistance
- Economical option
- Standard colors: Yellow, Light Gray
Best for: General industrial use and less aggressive environments.
IFR — Isophthalic Fire Retardant Polyester
A premium-grade isophthalic polyester resin system with enhanced durability.
- Excellent corrosion resistance
- Fire retardant
- Standard colors: Green, Yellow, Dark Gray, Light Gray
Best for: Moderate to high chemical exposure and applications requiring longer service life.
VFR — Vinylester Fire Retardant
A high-performance vinyl ester resin system delivering maximum protection.
- Superior corrosion resistance
- Fire retardant
- Standard colors: Orange, Dark Gray
Best for: Harsh chemical environments, wastewater facilities and demanding industrial applications.
PROGrate® Pultruded Grating Resin Systems
Bedford’s PROGrate pultruded grating is available in two resin systems, each offering different levels of corrosion protection. Both meet Class 1 Flame Spread Rating per ASTM E-84 test standards.
IFR — Isophthalic Fire Retardant Polyester
A premium-grade isophthalic polyester resin system designed for strong corrosion resistance and long-term durability.
- Excellent corrosion resistance
- Fire retardant
- Standard colors: Yellow, Gray
Best for: Industrial applications requiring reliable corrosion protection and fire performance.
VFR — Vinylester Fire Retardant
A high-performance vinyl ester resin system providing the highest level of corrosion protection available for PROGrate products.
- Superior corrosion resistance
- Fire retardant
- Standard colors: Yellow, Gray
Best for: Highly corrosive environments and demanding chemical applications where maximum durability is required.
PROForms® Structural Shapes Resin Systems
Bedford’s PROForms structural shapes are offered in three resin series, designed to meet varying environmental and performance requirements.
STD — Standard Polyester (Non-Fire Retardant)
A general-purpose isophthalic polyester resin system with a UV inhibitor.
- Good corrosion resistance
- Not fire retardant
- Color: Olive Green
Best for: Applications where fire retardancy is not required and environments are less demanding.
FR — Fire Retardant Polyester
A fire-retardant isophthalic polyester resin system with UV protection.
- Good corrosion resistance
- Fire retardant
- UV inhibitor included
- Colors: Dark Gray, Yellow
Best for: General industrial environments where fire performance is required.
VE — Vinylester Fire Retardant
A premium vinyl ester resin system built for maximum durability.
- High corrosion resistance
- Fire retardant
- UV inhibitor included
- Colors: Beige, Yellow
Best for: Highly corrosive environments and long-term performance in extreme conditions.
Key Differences at a Glance
While all three product lines use similar resin technologies, the naming and structure differ slightly:
| Product Line | Entry-Level | Mid-Level | Highest Performance |
| PROGrid Molded Grating | GP | IFR | VFR |
| PROGrate Pultruded Grating | — | IFR | VFR |
| PROForms Shapes | STD | FR | VE |
While naming differs by product line, the resin systems generally align as follows:
- GP ≈ STD (general-purpose polyester)
- IFR ≈ FR (fire-retardant polyester)
- VFR ≈ VE (vinylester, highest corrosion resistance)
How to Choose the Right Resin System
Selecting the right resin for FRP applications comes down to a few key factors:
- Chemical exposure and severity
- Need for fire retardancy
- UV exposure
- Desired service life
- Budget constraints
If your environment is mild, GP or STD may be sufficient. As conditions become more aggressive, IFR/FR or VFR/VE provide increased protection and longevity.
A Note on Corrosion Resistance Data
While resin selection guidelines are helpful, real-world conditions can vary. Corrosion resistance data is developed using a combination of:
- Field service history
- Laboratory testing
- Recommendations from FRP resin manufacturers
This information is intended as a guide. For critical applications, testing in the actual chemical environment is recommended to confirm performance.
Need Help Choosing a Resin System?
Get detailed chemical compatibility data and guidance for your application. Download the corrosion resistance guideand contact our team by email or call 814-623-8125 to find the right FRP resin system for your project.