Skylight glazing usually consists of either plastic or glass. Other glazing technologies may also be used for solar heat control.
Plastic glazingPlastic glazing is usually inexpensive and less liable to break than most other glazing materials. However, these plastic surfaces scratch easily, and they may become brittle and discolored over time. Many plastics also allow most of the ultraviolet (UV) rays in (unless the glazing is coated with a special film), which increases fading damage to furnishings. Acrylics and polycarbonates are the most commonly used plastic glazing. Acrylics are weaker than polycarbonates, but cost less. Although polycarbonates offer high impact resistance, some yellow with age.
GlassGlass is usually found on the more expensive skylights. Glass is more durable than plastics and does not discolor. All glass used for skylights must be made of "safety glazing," a generic term for both tempered and laminated glass. Tempered glass is the most impact resistant. Laminated glass is fabricated with a thin layer of plastic embedded near the center of the glass. Both keep the glass from breaking into large, sharp pieces. Skylights are often made with a tempered glass on the exterior side and a laminated pane on the interior side. This arrangement gives maximum impact resistance while protecting occupants from falling shards of glass.
Solar heat control glazingBecause skylights are located on the roofs, they can result in large amounts of unwanted summer time solar heat gains and winter time heat losses. Manufacturers use various glazing technologies to reduce these impacts. The most common technologies include those also used for window glazing:
• Heat-absorbing tintsSome manufacturers even install a translucent insulation material between several glazing layers to create a more thermally efficient assembly.
Related category• WINDOWS TOPICS
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