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Documentation - Molded Grating - Coupon Properties
3.3 Coupon Properties
Coupon-Tested Material Properties
The mechanical, electrical, thermal, and fire-retardant properties presented in this section are based on coupon testing.
Coupon definition: A coupon is a small, standardized
sample cut from a molded FRP/GRP panel and tested under controlled
laboratory conditions to determine material performance. Coupon testing
provides consistent and comparable data for properties such as tensile
strength, modulus, flexural performance, impact strength, flame spread,
dielectric strength, electrical resistance, density, and water
absorption.
Coupon results establish baseline characteristics for the material system. Actual full-panel performance may vary based on panel dimensions, mesh geometry, panel depth, reinforcement distribution, support span, load direction, load distribution, surface finish, fabrication, and installation conditions.
FR-P
Fire-retardant isophthalic polyester molded FRP material.
FR-VE
Fire-retardant vinyl ester molded FRP material.
Raw Material Properties
Table 14: Raw Material Properties
| Property | Fiberglass Rovings | Resin |
|---|---|---|
| Hardness (Barcol) | 45 | 73–78 |
| Tensile Strength | 1,950–2,200 MPa | 59 MPa |
| Modulus of Elasticity | 60–75 GPa | 3 GPa |
| Flexural Strength | 190 MPa | 130–150 MPa |
| Density | 2.6 g/cm3 | 1.12 g/cm3 |
| Maximum Operating Temperature | 200°C | 120°C |
| Water Absorption | — | 0.1% |
Material Properties: Longitudinal Direction
Table 15: Material Properties – Longitudinal Direction
| Property | Test Method | FR-P (Imperial) | FR-P (Metric) | FR-VE (Imperial) | FR-VE (Metric) |
|---|---|---|---|---|---|
| Ultimate Tensile Strength | ASTM D638 | 30,000 psi | 207 MPa | 35,000 psi | 241 MPa |
| Ultimate Compressive Strength | ASTM D695 | 30,000 psi | 207 MPa | 35,000 psi | 241 MPa |
| Ultimate Flexural Strength | ASTM D790 | 30,000 psi | 207 MPa | 35,000 psi | 241 MPa |
| Tensile Modulus | — | 2.5 × 106 psi | 17.2 GPa | 2.5 × 106 psi | 17.2 GPa |
| Compressive Modulus | — | 2.5 × 106 psi | 17.2 GPa | 2.5 × 106 psi | 17.2 GPa |
| Flexural Modulus | — | 1.8 × 106 psi | 12.4 GPa | 1.8 × 106 psi | 12.4 GPa |
| Ultimate Shear Stress | — | 5,000 psi | 34.5 MPa | 5,500 psi | 37.9 MPa |
| Ultimate Bearing Stress | — | 18,000 psi | 124 MPa | 18,000 psi | 124 MPa |
| Bearing Stress at 0.125 in Hole | — | 20,000 psi | 138 MPa | 20,000 psi | 138 MPa |
| Poisson’s Ratio | — | 0.34 | 0.34 | 0.34 | 0.34 |
| Izod Impact Strength | — | 25 ft-lb/in | 1.34 kJ/m | 25 ft-lb/in | 1.34 kJ/m |
Material Properties: Transverse Direction
Table 16: Material Properties – Transverse Direction
| Property | Test Method | FR-P (Imperial) | FR-P (Metric) | FR-VE (Imperial) | FR-VE (Metric) |
|---|---|---|---|---|---|
| Ultimate Tensile Strength | — | 7,500 psi | 51.7 MPa | 10,000 psi | 68.9 MPa |
| Ultimate Compressive Strength | — | 15,000 psi | 103 MPa | 20,000 psi | 138 MPa |
| Ultimate Flexural Strength | — | 10,000 psi | 68.9 MPa | 15,000 psi | 103 MPa |
| Tensile Modulus | — | 1.2 × 106 psi | 8.27 GPa | 1.2 × 106 psi | 8.27 GPa |
| Compressive Modulus | — | 1.2 × 106 psi | 8.27 GPa | 1.2 × 106 psi | 8.27 GPa |
| Flexural Modulus | — | 1.2 × 106 psi | 8.27 GPa | 1.2 × 106 psi | 8.27 GPa |
| Ultimate Shear Stress | — | 5,000 psi | 34.5 MPa | 5,000 psi | 34.5 MPa |
| Bearing Stress at 0.125 in Hole | — | 5,000 psi | 34.5 MPa | 5,000 psi | 34.5 MPa |
| Barcol Hardness | ASTM D2583 | 40 | 40 | 50 | 50 |
Electrical Properties
Table 17: Electrical Properties
| Property | Test Method | FR-P (Imperial) | FR-P (Metric) | FR-VE (Imperial) | FR-VE (Metric) |
|---|---|---|---|---|---|
| Electric Strength | ASTM D149 | 300 V/mil | 11.8 MV/m | 300 V/mil | 11.8 MV/m |
| Dielectric Constant, 60 Hz | ASTM D150 | 4.5 | 4.5 | 4.5 | 4.5 |
| Dissipation Factor, 60 Hz | ASTM D150 | 0.015 | 0.015 | 0.015 | 0.015 |
| Volume Resistivity | ASTM D257 | 1 × 1012 ohm-cm | 1 × 1010 ohm-m | 1 × 1012 ohm-cm | 1 × 1010 ohm-m |
| Breakdown Voltage | — | 18 kV | 18 kV | 18 kV | 18 kV |
| Surface Resistance | — | Insulating | Insulating | Insulating | Insulating |
Fire-Retardant Properties
Table 18: Fire-Retardant Properties – ASTM E84
| Property | Test Method | Requirement (Class A) | Requirement (Class B) | Requirement (Class C) | Fiberr FR Result |
|---|---|---|---|---|---|
| Flame Spread Index (FSI) | ASTM E84 | 0–25 | 26–75 | 76–200 | 20 |
| Smoke Developed Index (SDI) | ASTM E84 | ≤450 | ≤450 | ≤450 | 22 |
| Classification | ASTM E84 | Class A | Class B | Class C | Class A |
Full-Section and Bending Properties
Table 19: Full-Section & Bending Properties
| Property | Test Method | FR-P (Imperial) | FR-P (Metric) | FR-VE (Imperial) | FR-VE (Metric) |
|---|---|---|---|---|---|
| Modulus of Elasticity | — | 1.8 × 106 psi | 12.4 GPa | 1.8 × 106 psi | 12.4 GPa |
| Shear Modulus | — | 0.7 × 106 psi | 4.83 GPa | 0.7 × 106 psi | 4.83 GPa |
| Shear Strength | — | 5,000 psi | 34.5 MPa | 5,000 psi | 34.5 MPa |
Thermal Properties
Table 20: Thermal Properties
| Property | Test Method | FR-P (Imperial) | FR-P (Metric) | FR-VE (Imperial) | FR-VE (Metric) |
|---|---|---|---|---|---|
| Thermal Conductivity | — | 5.0 BTU-in/hr-ft2-°F | 0.72 W/m-K | 5.0 BTU-in/hr-ft2-°F | 0.72 W/m-K |
| Coefficient of Thermal Expansion | — | 5.0 × 10−6 in/in/°F | 9.0 × 10−6 m/m-K | 5.0 × 10−6 in/in/°F | 9.0 × 10−6 m/m-K |
Other Physical Properties
Table 21: Other Properties
| Property | Test Method | FR-P (Imperial) | FR-P (Metric) | FR-VE (Imperial) | FR-VE (Metric) |
|---|---|---|---|---|---|
| Specific Gravity | ASTM D792 | 1.9 | 1.9 | 1.9 | 1.9 |
| Density | — | 0.069 lb/in3 | 1.91 g/cm3 | 0.069 lb/in3 | 1.91 g/cm3 |
| Water Absorption, 24 hr | ASTM D570 | 0.25% | 0.25% | 0.25% | 0.25% |
Thermal Contraction and Expansion
Table 22: Thermal Contraction & Expansion
| Temperature Differential | Fiberglass | Steel | Aluminum |
|---|---|---|---|
| 30°F (−1°C) |
1.8 × 10−6 in/in/°F
(3.2 µm/m-K) |
12 × 10−6
(21.6 µm/m-K) |
39 × 10−6
(70.2 µm/m-K) |
| 60°F (16°C) |
3.6 × 10−6
(6.4 µm/m-K) |
24 × 10−6
(43.2 µm/m-K) |
78 × 10−6
(140 µm/m-K) |
| 120°F (49°C) |
7.2 × 10−6
(12.8 µm/m-K) |
48 × 10−6
(86.4 µm/m-K) |
156 × 10−6
(281 µm/m-K) |
| 180°F (82°C) |
10.8 × 10−6
(19.2 µm/m-K) |
72 × 10−6
(129.6 µm/m-K) |
234 × 10−6
(421 µm/m-K) |
| 240°F (116°C) |
14.4 × 10−6
(25.6 µm/m-K) |
96 × 10−6
(172.8 µm/m-K) |
312 × 10−6
(561 µm/m-K) |
Interpretation: FRP has substantially lower thermal
movement than steel or aluminum. Expansion joints, edge clearances, and
fastener details should still account for the panel length, expected
temperature range, support material, and differences in thermal movement
between the grating and the supporting structure.
Use and Interpretation of Coupon Data
Material Comparison
Coupon data is suitable for comparing resin systems, reinforcement
directions, and general material characteristics under controlled test
conditions.
Structural Design
Full-panel load tables, support spans, deflection criteria, fastener
requirements, and project-specific loading should govern structural
grating selection.
Project Verification
Critical applications may require project-specific testing,
certification, engineering review, or confirmation of the exact resin,
reinforcement, surface, and manufacturing configuration.
Important: Values shown are representative material
properties and should not be treated as guaranteed design allowables
unless expressly stated in the applicable product specification,
engineering submittal, or certified test report.