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Accurate Dorwin Company's Fibreglass Window Systems featuring high-tech fibreglass lineals offer an exciting alternative to metal, plastic or wood frame windows. All the advantages of competing systems with none of their disadvantages.
The ultimate window-frame material, "pultruded" fibreglass, differs from common fibreglass used in pools, boats and storage tanks. Continuous strands of glass are saturated in a thermoset resin and pass through a heated die. They are pulled through, rather than pushed, hence the term "pultrusion". Dorwin Industries of Winnipeg introduced the first fibreglass window in 1983. Over the past decade, Dorwin has developed a system which combines the most dimensionally stable window frame material with foam insulation and high efficiency insulating glass - the ultimate window.
Accurate Dorwin Company's Fibreglass Window System meets the needs of designers and builders who wish to go beyond the limitations inherent with metal, plastic or wood frame fenestration. Pultruded fibreglass has proven to be a superior material in four ways:
- Dimensional Stability
- Thermal Insulation
- Durability and Aesthetics
- Environmental Friendliness
While traditional window framing materials are dimensionally stable on the shop floor, how they perform in extremes of humidity, heat and cold is quite a different story. It has long been known that wood is prone to warping and shrinking. But even extruded materials such as aluminum and vinyl can cause problems, owing to their relatively high rates of thermal expansion.
Ideally, a window frame will expand and contract at the same rate as glass, an ideal easily achieved with glass fiber technology. On the other hand, aluminum has a coefficient of expansion which is twice that of glass and the corresponding figure for vinyl is seven times that of glass.
Extensive cold chamber testing by Natural Resources Canada has shown how window framing materials perform in real world conditions. The results show that vinyl operable windows, although well weather-stripped, suffered massive air leakage under simulated cold weather conditions. The massive air leakage occurred because the cold outside face of the sash contracted, pulling the top and bottom comers of the sash away from the frame and the weather-stripping.
Testing by others has shown that, while white vinyl frames can stand up to full summer sun, colored profiles were subject to significantly higher temperatures, resulting in permanent shrinkage of as much as 4%.
Pultruded fibreglass window frames are better insulators than vinyl, wood and, of course, aluminum frames which must incorporate non-metallic thermal breaks in order to provide even a minimal degree of insulation. But beyond any side-by-side comparisons of fibreglass as an insulator, consider how it is used to produce the most highly insulating frame system in the world.
The high tensile strength of the material allows it to be used in relatively thin-walled hollow profiles which are completely foam-filled. This results in un-matched thermal resistance in a given volume of framing. Vinyl profiles can also be foam-filled, yet this process is impeded somewhat by internal webbing and thicker walls. Insertion of metal stiffeners, which compromise thermal performance, are often required in vinyl profiles.
The new Energy Rating (ER) numbers show the fibreglass frame window at the top of the list. Developed jointly by the Canadian government and the window industry, the new ER numbers better indicate the overall performance of a window. The ER considers heat loss, resistance to air leakage losses and heat gain. Heat loss is a weighted average of all components: center of glass, edge of glass and frame. Heat gain is an average of the solar radiation for each direction (north, south, east and west). When combined with equally high-performance insulating glass, Accurate Dorwin Company's Fibreglass Window gets the highest rating of any commercially available product and is also Power Smart endorsed.
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Structurally, pultruded fibreglass is both stronger and harder than wood and vinyl. Fibreglass profiles are carefully engineered so that the fiber strands impart some of the highest longitudinal and transverse strength amongst window framing material. Yet unlike aluminum, fibreglass is a resilient material which resists denting.
In terms of weatherability, Accurate Dorwin Company's Fibreglass Window System features KTM-4 acrylic architectural finishes. It is applied to the fibreglass lineals using the same equipment as is used for architectural aluminum, and accelerated aging tests have shown the same resistance to UV and minimal weathering. Vinyl, especially when tinted, tends to discolor and become brittle over time.
Notwithstanding the durability of the factory-applied finishes, it is nevertheless possible to paint over these coatings. Fibreglass thus offers a truly low maintenance finish, as well as design flexibility. Change the look of one room or an entire building without changing the windows. This is another feature which distinguishes fibreglass framing from vinyl, which has a history of premature fading of colors and does not hold paint well.
Long service life is but one factor in an assessment of the environmental impact of any product. Obviously, a durable window system based on pultruded fibreglass uses less resources than a system which would have to be replaced one or more times during the same period. But how does pultruded fibreglass compare to other window frame options in terms of, say, pollution during manufacture, embodied energy and other environmental concerns?
The matter of "true environmental friendliness" can be complex. Enermodal Engineering of Waterloo, Ontario however, did an environmental assessment of three competing window frame technologies and the results led them to select pultruded fibreglass for the Waterloo Region Green Home demonstration project. Aluminum clad windows and vinyl windows, on the other hand, were rejected as they did not compare favorably in the six point evaluation.
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