Window screen
From Wikipedia, the free encyclopedia
A window screen, insect screen or bug screen is a metal wire, fiberglass, or other synthetic fiber mesh, stretched in a frame of wood or metal, designed to cover the opening of an open window. Its primary purpose is to keep insects, leafs, debris, birds, and other animals from entering a building or a screened structure such as a porch, while permitting fresh air-flow. Most houses in Australia, the United States and Canada have screens on all operable windows, which are most useful in areas that have large mosquito populations. Screens in North America were traditionally replaced with glass "storm windows" in cold climates to insulate the window during the winter, but frames combining both storm and screen panels have become the most common type of screen currently used in cold climates.
The window screens to deny mosquitos are called mosquito screens, and the ones for denying flies would be named fly screens.
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[edit] Installation
For screens installed on aluminium frames, the material is cut slightly larger than the frame, then laid over it, and a flexible vinyl cord, called a spline, is pressed over the screen into a groove (spline channel) in the frame. The excess screen is then trimmed close to the spline with a sharp utility knife.
The spline is often manufactured with parallel ridges running along the length of the spline to provide a better grip and compliance when it is pressed into the channel. A spline roller — a special tool that consists of a metal wheel on a handle — is used to press the spline into the frame. The wheel edge is concave, to help it hold the spline and not slip off to the side. Some spline rollers are double-ended and have both convex and concave rollers; the convex roller can be used to seat the spline deeper into the channel without risk of cutting the screen. If a spline roller is not available to reseat a loose spline, a good substitute is a medium thickness wire clothes hanger. Use a hanger with a wire thickness just a bit smaller than the spline, and use a rounded corner to press the spline back into its groove. Driving the spline into the channel tends to tension the screen on the frame, so the installer must avoid pre-tensioning the screen excessively to prevent the frame from becoming warped.
When installed using wooden frames, the screen fabric is tacked or stapled onto the frame. A narrow wooden molding is then nailed over the ragged edge. The screening fabric needs to be stretched tightly before nailing, but not so tightly as to deform the fabric.
Because of corrosion problems with dissimilar metals, metal screening fabrics other than aluminium should not be used in aluminium frames. Users of aluminium frames should use either aluminium screening, or a non-metallic material such as nylon.
[edit] Types of screening fabric
The most common materials used for insect screening material are aluminum and fiberglass. Aluminum is generally available in natural aluminium or in an applied charcoal color. The charcoal is much less visible and should be preferred where the view through the screens as well as the external appearance of the windows are important considerations. Fiberglass is available in light gray as well as charcoal colors, the charcoal again offering better viewing and appearance. Fiberglass is less expensive, and has the advantage of not "denting" when hit or pushed. However, the fiberglass mesh is somewhat more opaque than aluminum mesh, which darkens the external appearance of the window and reduces the amount of light transmitted from outside. In addition, fiberglass screen degrades rapidly with exposure to UV light, leading to it fraying and breaking after just a few years[citation needed], unlike aluminum which lasts permanently.
For applications requiring greater strength, such as screened doors, nylon, and polyester screening is also available.
The premier material for insect screening is bronze. Bronze will give much longer service than either aluminium or fiberglass. When first installed, it has an unattractive gold color which weathers to an unobtrusive dark charcoal within a year or less. Bronze is somewhat more resistant to denting than aluminium. The very high cost of bronze screening explains why it is not more commonly used. Less common screen fabrics include copper, brass, stainless steel and galvanized steel.
In addition to insect screening, denser screen types that also reduce sunlight and heat gain are available. These offer significant potential energy savings in hot climates.
Several manufacturers offer screens that roll into a pocket when not in use. These are available for casement windows as well as other types of window and door openings.
Do-it-yourself screen and frame replacement kits are widely available at hardware and home improvement stores. These frames are usually composed of straight aluminum sides (which can be cut to size) and plastic corner inserts. Screen replacement kits usually consist of a roll of nylon screening fabric and a generous supply of rubber spline.
[edit] Decorative
Screen painting is a folk art consisting of paintings on window screens.
[edit] History
Mosquitos had been a menace in the Americas from the earliest recorded times. They spread yellow fever, also known as the American Plague through the Massachusetts Bay Colony in 1647 and hit Philadelphia, Pennsylvania hard in 1793, perhaps ending the city's cultural dominance in the newly-formed nation.[1] In 1861 Gilberr, Bennett and Company was manufacturing wire mesh sieves for food processing. An inspired employee realized that the wire cloth could be painted gray and sold as window screens and the product became an immediate success. On July 7, 1868, Bayley and McCluskey filed a U.S. Patent, number 79541 for screened roof-top rail-car windows, allowing ventilation, while preventing "sparks, cinders, dust, etc." from entering the passenger compartment. By 1874, E.T. Barnum Company of Detroit, Michigan advertised screens that were sold by the square foot.[2][3] Apparently, window screens designed specifically to prevent insect ingress were not patented in the United States, although by 1900 several patents were awarded for particular innovations related to window screen design. By the 1950s parasitic diseases were largely eradicated in the United States in part due to the widespread use of window screens.[4] Today most houses in Australia, the United States and Canada have screens on all operable windows.
[edit] References
- ^ "History of and Reasons for Mosquito Control in New Jersey". NJMCA. http://www.rci.rutgers.edu/~insects/hisreas.htm. Retrieved 2008-08-12.
- ^ "The Busy Brush Decorative Art - The History of Screen Painting". 2005. http://www.busybrushart.com/historyofscreenpainting.htm. Retrieved 2008-08-12.
- ^ Ted and Mary, Fried (1978). "America’s Forgotten Folk Arts". Pantheon Books. http://members.aol.com/_ht_a/neddybee/folkart.html. Retrieved 2008-08-12.
- ^ Meador, MD, Clifton K. (2004-04-22). "From Med School: Shoes, Window Screens, and Meat". Med School. Medscape from WebMD. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1395801. Retrieved 2008-08-12.
