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Unlike Steel which will rust when exposed to weathering and chemicals, fiberglass structural shapes are highly corrosion resistant. Features of both pultrusions and steel structural shapes are compared on a point-for-point basis below.
| Pultruded Fiberglass | Steel | |
| Corrosion Resistance | Pultrusions are available in either polyester or vinyl ester resin for resistance to a broad range of chemicals. Painting required only when exposed to direct sunlight. |
Subject to oxidation and corrosion. Requires painting or galvanizing for many applications. |
| Weight | Lightweight - weighs 75% less than steel. 1/2" thick plate = 4.7 lbs./sq. ft. |
Could require lifting equipment to move and place. 1/2" thick plate = 20.4 lbs./sq. ft. |
| Conductivity | Does not conduct electricity. Low Thermal Conductivity 4 (BTU/SF/HR/Fo/IN). |
Conducts electricity. Grounding potential. Thermal Conductivity 260-460 (BTU/SF/HR/Fo/IN). |
| Strength | Pultrusions have a high strength-to-weight ratio, and pound-for-pound are stronger than steel in the lengthwise direction. Ultimate flexural strength (Fu) LW = 30 ksi CW = 10 ksi |
Homogeneous material. Yield strength (Fy) 36 ksi |
| Stiffness | Modulus of elasticity LW = 2.5 x 106 psi CW = .8 x 106 psi Will not permanently deform under working load. |
Modulus of elasticity 29 x 106 psi |
| Impact Resistance | Glass mat in pultruded parts, distributes impact load to prevent surface damage even in sub-zero temperatures. Will not permanently deform under impact. | Can permanently deform under impact. |
| EMI / RFI Transparency | Transparent to EMI/RFI transmissions. | Can interfere with EMI/RFI transmissions. |
| Versatility | Pigments added to the resin provide color throughout the part. Special colors available. | Must be painted for color. To maintain color and corrosion resistance, repainting may be required. |
| Easy Field Fabrication | Pultruded fiberglass can be field fabricated using simple carpenter tools with carbon or diamond tip blades. Lightweight for easier erection and installation. |
Often requires welding and cutting torches. Heavier material requires special handling equipment to erect and install. |
| Cost | Lower installation and maintenance costs in industrial applications often equals lower lifecycle costs. | Lower initial material cost. |