FRP Properties

Strength

FRP composite panels have a high strength-to-weight ratio and are not susceptible to scratching or denting. They are impervious to most mild acids, and will not rot, corrode, stain, peel, or splinter. Generally, FRP panel strength is unaffected by a wide range of temperatures, (-65 °F to 135 °F).

FRP panels are used in designs where a certain measure of strength or modulus of elasticity is required that non-reinforced plastics or alternative materials cannot match either mechanically or economically. As has been mentioned, FRP products are extremely durable compared to many traditional products as the thermosetting resin properties provide chemical, moisture, and temperature resistance, while the fiberglass reinforcement increases strength and provides good performance over a wide temperature range versus thermoplastics which are greatly affected by temperature.

The properties of FRP composites are measured the same way that traditional materials are measured so that comparisons can be made for evaluation. Typical measurements include:

• Compressive strength. Describes how much of a load a material can take before it is crushed or fractured
• Flexural modulus. A number associated with the flexibility or stiffness of a material. It indicates how far a material will bend when a certain load is applied to it. The lower the modulus, the more flexible the material. ASTM D790
• Flexural strength.Measures how much of a load a material can take before it fractures or breaks when it is in the process of being bent. Higher numbers indicate stronger materials that can withstand a heavier load before breaking. ASTM D790
• Impact strength. There are two primary impact tests; one is called IZOD impact and the other is called Gardner impact. IZOD impact measures the energy required to fracture or break a material when it is struck on its edge. Gardner impact measures the energy required to damage or puncture a material when it is struck on its front surface.
• Rockwell or barcol hardness. Measures the surface hardness of a material. A steel point is forced into the material and its resistance to penetration measured. The higher the hardness value, the more resistant a material is to scratching, abrasion, and denting. ASTM D785
• Tensile modulus. A number associated with pulling or stretching a material (tension) and how much it elongates when a certain load is applied to it. The lower the modulus, the more the material will elongate or stretch. ASTM D790
• Tensile strength. Measures how much of a load a material can take before it fractures or breaks when it is in the process of being stretched. Higher numbers indicate materials that can withstand a stronger pull before breaking. ASTM D790

Mold-, Mildew-, Stain- and Bacteria-resistant

Per ASTM D373 or D3274, FRP panels do not support mold or mildew as do wood and paper-faced drywall. The panels are moisture resistant and easy to clean, and can withstand repeated cleanings without surface deterioration.

Photo: Crane Composites, Inc.

FRP finishes can be either smooth or embossed. Testing has shown that either finish cleans up as well as a #3 finish on stainless steel. Tests for bacteria and mold growth, including those conducted by ASTM D3273 and D274 indicate that FRP composites do not support the growth of either.

Some practitioners maintain that an embossed finish has the added benefit of providing a more scuff-resistant surface than a smooth panel. Independent testing by New Zealand-based Mirinz Laboratories of an embossed FRP finish versus a smooth finish at a meat processing facility indicated that over the four week period, "bacterial counts at all levels (eye, waist and knee) were generally within the Mirinz guidelines and found to be no higher in bacteria counts than that of the existing stainless steel and smooth plastic panels." Embossed panels are also applicable in corrosive environments as they have a good track record in cleanability and abrasion resistance. Each bump on the surface face is a solid resin mix. Any abrasion sustained is concentrated on the "bump," protecting the panel itself from abrasion and exposure to bacteria or stains.

Low Maintenance

FRP composite panels do not need painting and require little in the way of maintenance. Cleaning FRP wall or ceiling panels on a regular basis with a mild non-abrasive cleaner is recommended so that soil and dirt will not build up. A 5 to 10 percent trisodium phosphate water solution not to exceed 130°F (55°C) can be used. If trisodium phosphate is not available, a 5 to 10 percent solution of household automatic dishwasher detergent should be used. If a USDA or FDA approved cleaner is required, a neutral cleaner (pH range 6.5 - 7.5) is preferred. In all cases, the manufacturer's directions should be followed.

FRP panels can best be cleaned with a sponge or soft brush. Wire brushes or other abrasive tools or pads will scratch the surface. Apply the cleaner, working it across the surface in a scrubbing or circular motion. Rinse thoroughly to remove all traces of the cleaner; otherwise a film will build up giving the panel a dull, dirty appearance. When using a specialty cleaner, follow the manufacturer's instructions. Test a small area before applying over the entire surface.

To clean hard water deposits, a 10 percent solution of acetic acid in cold water should be used according to the same cleaning procedures outlined above. If the panel surface becomes dull or abraded, complete cleaning may not be possible. FRP panels can withstand repeated cleanings without adverse effect.

Ease of Installation

FRP panels feature a relatively easy installation. They adhere with adhesive or mechanical fasteners with common carpenter's tools sufficient for most installations. FRP is also easy to field cut and can be installed over drywall or other flat, dry surfaces in both renovation and new construction projects. Wall and ceiling panels can be installed directly over ceramic tile. Non-porous surfaces require the use of rivets unless the surface of the tile is opened by sanding or use of chemical abrasive. Adhesive should be used on porous surfaces only. For installation over concrete block, uneven surfaces must be leveled with plaster or concrete compounds. Concrete walls must be well cured and completely dry. If concrete or block walls are below grade where moisture can penetrate and interfere with a good adhesive bond, furring strips should be used and pre-laminated panels installed with mechanical fasteners. The panels are resistant to shrinkage and expansion due to moisture.

To be used with gypsum wallboard and plywood substrates, VOC-compliant adhesives have been specifically formulated for the installation of FRP panels with the "fast grab" and bonding power that greatly reduce the need for extended bracing. Many of these adhesives contain no ozone-depleting chemicals. Unlike solvent-based adhesives, they are nonflammable, emit no harmful fumes and clean up with water. Some of these adhesives exceed the ASTM C557 specification, and provide water resistance while remaining permanently flexible. They are easy to trowel and offer a 30-minute working time to allow precise placement of the working materials.

Decorative Appeal

Traditionally, FRP wall panels were used in back rooms, such as kitchens, storage and non-public areas in commercial facilities. Now they are available in various patterns, textures and colors that are appropriate for dining rooms, lobbies and other front of house areas. Manufacturers' palettes include FRP panels made to simulate the look of tile, as well as in sandstone, linen, cedar, beaded and pebble embossed surfaces.

Photo: Crane Composites, Inc. FRP panels present an attractive, sanitary surface.