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Steel reinforcements dropped from window profiles

September 11, 2012

HOOGLEDE, BELGIUM (Sept. 11, 8 a.m. ET) — Two European window makers have developed uPVC window profiles that do not rely on tubular galvanised steel inserts for strength. While steel acts as an effective reinforcement, its heat-conducting properties impede energy efficiency.

Belgium’s Deceuninck NV calls its new window technology Linktrusion and is using the innovation throughout its Zendow#neo window range.

In its Zendow#neo standard range, Deceuninck has replaced the steel reinforcement with a sandwich of steel-wire reinforced PVC, filled with a PVC foam in both the window frame and sash. In the Zendow#neo premium range, the PVC sandwich is used in the frame but in the sash, where strength is most important, a glass-reinforced PVC is used.

The glass-reinforced PVC is manufactured using up to 260 reels of glass fiber, each containing 7.5km of rovings, which are each made from up to 1,000 individual glass wires. The rovings are heated, calibrated, heated again and melted together to form a thin glass fiber strip. The melted PVC is pressed into a profile tool together with the glass fiber to produce the finished reinforcement.

Deceuninck claims the windows are “almost as strong” as their steel-reinforced counterparts but up to 30 percent better insulated. They also provide a 40 percent saving on materials and weight.

Germany’s Gealan Fenster-Systeme GmbH has introduced its IKD intensive core insulation technology. This uses a foam core in place of the galvanized steel reinforcement. The structural rigidity is maintained by a special adhesive strip that bonds the glass to the casement rebate. Once again, Gealan emphasizes the energy saving benefits of this change, saying it can achieve insulation with a U-factor of 0.78 W/m2K.

The foam is injected into the profile chambers during manufacture. The profiles can be cut, welded and trimmed on existing machinery without the need for modification. Because the foam is kept in place inside the profile through pressure, and not surface bonding, it can be removed easily at end-of-life and recycled separately.