| |
Pultruded Fiberglass Provides a Window Frame for the 90's and Beyond
by S. Philip Wake, Vice President, Sales and Marketing
Manufacturers are increasingly using pultrusions alone and in combination with traditional materials
Pultruded fiberglass is experiencing increasing acceptance in North America and abroad as a framing material in the fenestration industry. A recent Freedonia Group study predicted pultruded fiberglass will soon enjoy a tenfold increase in its annual growth rate from that of the 1983-1993 period. Demand in the U.S. is also expected to advance at more than double the rate of growth of the fenestration industry as a whole.
Fiberglass provides excellent physical and mechanical properties desired in a window frame including:
Low thermal conductivity
Dimensional stability over the temperature spectrum
Resistance to moisture and corrosion
Ready acceptance of colored finishes.
These characteristics make pultrusion attractive for use not only as a single window framing material, but also in combination with other traditional materials such as wood, PVC, and aluminum. These designs allow full utilization of the specific advantages of various materials,resulting in significantly improved windows that feature unique qualities that would be impossible to obtain with a single material.
In Europe and North America, pultrusion has the positive perception of being environmentally sensitive and a viable substitute for other framing materials where there is concern for resource depletion or other environmental hazards. It is also a material of choice for use in designs responsive to the needs of environmentally hypersensitive people, as was demonstrated by the Healthy House recently built by Canada Mortgage and Housing Corporation.
The first all-fiberglass windows were introduced in Canada in 1984 by Omniglass  . A look at activity among windows and door manufacturers across North America reveals a growing use of composite or multi-material designs.
Some window manufacturers have combined pultruded fiberglass to the exterior with wood to the interior  . The structural properties of the pultrusion permit to replace part of the wood frame and its cladding of aluminum or PVC - a common practice in conventional design. A recent and more comprehensive design in pultrusion and wood has been incorporated by another large manufacturer of traditional wood windows. The combination of materials results in a maintenance free exterior combined with the natural warmth of wood to the interior.
Another leading window company on North America's West Coast has taken the pultrusion/wood concept one step further. The intricate frame and sash components are made completely of pultruded fiberglass and then finished to the interior with a thin layer of real wood applied by a process known as profile wrapping. The result is a durable, maintenance free energy efficient window accented with the beauty of wood in a manner that maximizes the conservation of that natural resource.
Co-pultrusion is a relatively new development. Omniglass licensees in Europe have co-pultruded woodgrain polyester veil to simulate the red mahogany popular in doors and solariums. It represents a strong and aesthetic substitute for the mahogany that is becoming increasingly difficult to obtain. Co-pultrusion can be a cost effective alternate to laminating by eliminating a labor intensive secondary operation.
Architectural details often feature very large windows, requiring strong framing systems. Innovative and energy efficient new windows have been developed that combine aluminum, pultruded fiberglass and wood as advancements to replace its aluminum and wood predecessors.
The strength and dimensional stability of pultruded fiberglass is also exhibited in a new garden door which is marketed as being "warp free". Test results show that under identical loading conditions the door with a pultruded core experiences about 75 percent less deflection than a comparable solid wood door.
A more complex variation of the use of pultrusion in doors has been developed by a Canadian door manufacturer. An excellent illustration of a composite design, the company's door combines pultruded fiberglass, aluminum. granite, structural foam, and wood to present an aesthetically pleasing and energy efficient entrance door system that avoids both moisture-related warp and the phenomenon of "cold weather bowing" characteristic of steel doors in the harsh Canadian winters.
With the technology available to make the complex thin wall shapes required in windows, pultrusion has many inherent properties that make it desirable as a framing material.
To see some examples of the Omniglass FiberthermTM Systems put to use, visit the following companies' sites:
|
|
