Great Lakes Window Glossary A AAMA. American Architectural Manufacturers Association. A national trade association that establishes voluntary standards for the window, door, and skylight industry. ANSI. American National Standards Institute. A clearing house for all types of standards and specifications. ASHRAE. American Society of Heating, Refrigerating and Air Conditioning Engineers. ASTM. American Society for Testing and Materials. An organization that sets standards for the testing of materials. Absorptance. The ratio of radiant energy absorbed to total incident radiant energy in a glazing system. Acrylic. A non-crystalline thermoplastic with good weather resistance, shatter resistance, and optical clarity; sometimes used for glazing. Adhesion. The property of a coating or sealant that measures its ability to stick or bond to the surface to which it is applied. Adhesive Failure. Failure of a compound by pulling away from the surface with which it is in contact (seal failure/cohesive failure). Air Infiltration. The amount of air leaking in and out of a building through cracks in walls, windows, and doors. Air Leakage Rating. A measure of the rate of infiltration around a window or skylight in the presence of a specific pressure difference. It is expressed in units of cubic feet per minute per square foot of window area (cfm/sq ft) or cubic feet per minute per foot of window perimeter length (cfm/ft). The lower a window's air leakage rating, the better its air tightness. Annealed Glass. Standard float glass. Annealing. To heat above the critical or recrystallization temperature, then controlled cooling metal, glass, or other materials to eliminate the effects of cold-working, relieve internal stresses, or improve strength, ductility, or other properties. Anodize. To provide an extremely hard, non-corrosive oxide film on the surface of aluminum using electrolytic action. The electrochemical process produces an anodic coating by converting aluminum into, essentially, aluminum oxide. Appearance depends upon both the alloy involved and the surface preparation. Anodic coatings may be transparent or of varying shades of silver, gray, or brown; colors may be incorporated by the use of dyes or pigments. Argon. An inert, nontoxic gas used in insulating glass units to reduce heat transfer. Argon is 40denser than air, resulting in improved thermal efficiency of the IG unit. Astragal. Type of decorative molding. A narrow convex molding, often taking the form of beads. Awning. Similar to a casement except the sash is hinged at the top and always projects outwards. B BOCA. Building Officials and Code Administrators. BTU. British Thermal Unit. The energy used for heating and cooling is measured by the number of BTUs needed to keep a building at a comfortable temperature. Scientifically, it is the amount of heat energy necessary to raise the temperature of one pound of water one degree Fahrenheit. Balance. A mechanical device (normally spring loaded) used in single and double-hung windows as a means of counterbalancing the weight of the sash during opening and closing. Bay Window. An angled combination of three windows that project outwards from the wall of the home. The windows are commonly joined at 30- or 45-degree angles. Bead. A sealant or compound after application in a joint, irrespective of the method of application, such as caulking bead, glazing bead, etc. Also, a molding or stop used to hold glass or panels in position. Bedding. The bead of a compound applied between a lite of glass or a panel and the permanent stop or sight bar of the sash or frame, and usually the first bead of compound to be applied when setting glass or panes. Beveled Exterior. An angled extension from the frame that adds an aesthetically pleasing dimension to the exterior of the window. Blocking. To shim, level, and plum windows in the required position. Bow Window. A bow window can be arranged with three or more equal-width units. They can be fixed or operable, or mixed in any combination. They are usually mulled together in 10-degree angles. Bottom Rail. The bottom horizontal member of a window sash. Butyl. A synthetic rubber prepared by co-polymerization of isobutylene with a small amount of isoprene (both ingredients are gaseous hydrocarbons). It can be used as a sealant and architectural glazing tape. Brick Molding. A standard trim piece that covers the gap between the window frame and masonry. C CFM. Cubic feet per minute. CRF. Condensation Resistance Factor. An indication of a window's ability to resist condensation. The higher the CRF, the less likely condensation is to occur. Based on AAMA standards. Cam Action Lock. Type of sash lock used on a double-hung and slider window. When engaged, the lock securely pulls the two sash meeting rails together, providing a strong and weather resistant adhesion at a prime area of duress. Came(ing). A slender, grooved lead bar that holds together the panes in stained glass or latticework windows. Casement. A window sash that swings open on side hinges; in-swinging is French in origin, out-swinging is English in origin. For opening preference, the term OSLI (outside looking in) is used. With casements, location described by hinge location (R or L). Casing. Exposed molding or framing around a window or door, either on the inside or outside, to cover the space between the window frame or jamb and the wall. Caulking. A mastic compound for filling joints and sealing cracks to prevent leakage of water and air. Commonly made of silicone, bituminous, acrylic, or rubber-based material. Channel. A three-sided, U-shaped opening in a sash or frame to receive lite or panel, as with sash or frame units in which the lite or panel is retained by a removable stop. Contrasted to a rabbet, which is a two-sided, L-shaped opening, as with a face-glazed window sash. Channel Depth. The measurement from the bottom of the channel to the top of the stop, or measurement of sight line to base of the channel. Check Rail. In double-hung windows, this is the bottom rail of the upper sash and the upper rail of the lower sash, where the lock is mounted. It is also known as a meeting rail. Cohesive Failure. Failure of a compound when placed under a strain in which, because of insufficient elasticity and elongation to absorb the strain, the compound splits and opens. Composite Frame. A frame consisting of two or more materials - for example, an interior wood element with an exterior vinyl element. Compression. Pressure exerted on a compound in a joint, as by placing a lite of glass or panel against bedding, or placing a stop in position against a bead of compound. Condensation. The deposit of water vapor from the air on any cold surface whose temperature is below the dew point, such as a cold window glass or frame that is exposed to humid indoor air. Conduction. Heat transfer through a solid material by contact of one molecule to the next. Heat flows from a higher temperature area to a lower temperature one. Convection. A heat transfer process involving motion in a fluid (such as air) caused by the difference in density of the fluid and the action of gravity. Convection affects heat transfer from the glass surface to room air, and between two panes of glass. Corian. An advanced blend of natural materials and pure acrylic polymer. Its nonporous nature helps resist stains and makes it easy to clean. Due to its solid composition, it can be renewed. Available in a large variety of colors. D DFT. Demand Flow Technology. A manufacturing system that relies upon a team approach to focus on quality. DFT allows a work team to produce the highest quality windows. Unlike a manufacturing line dedicated to producing one product, DFT gives the team the capability of producing different windows at any time during the workday, driven by the customer. Damage Weighted Transmission. Measures the amount of damaging wavelengths that will pass through a glazing. The lower the number, the higher the protection. Decibel. A unit for expressing the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 130 for the average pain level. Degree Day. A unit that represents a one-degree Fahrenheit deviation from some fixed reference point (usually 65 degrees F) in the mean, daily outdoor temperature. Desiccant. An extremely porous crystalline substance used to absorb moisture from within the sealed air space of an insulating glass unit. Desiccated Matrix. A material used in insulating glass to absorb water vapor that causes fogging. Dew Point. The temperature at which the condensation of water vapor in a space begins, at a given state of humidity and pressure, as the temperature is reduced. Used in testing sealed insulated glass. The lower the number, the higher the resistance to forming condensation. Double Glazing. In general, any use of two lites of glass, separated by airspace, within an opening, to improve insulation against heat transfer and/or sound transmission. In factory-made, double-glazing units the air between the lites is thoroughly dried and the space is sealed airtight, eliminating possible condensation and providing superior insulating properties. Double Hung Window. A window consisting of two sashes of glass operating in a rectangular frame. Both the upper and lower halves can be slid up and down and usually use a counter balance mechanism to hold the sash in place. Double Strength Glass. Sheet glass between 0.115" and 0.133" (33.38mm) thick. Drip-cap. A molding placed on the top of the head brick mold or casing of a window frame. Dry Glazing. A method of securing glass in a frame using a dry, preformed resilient gasket, without the use of a compound. Dual Durometer. Two separate vinyl components in one extrusion to increase seal protection around an IG unit. Usually combines rigid and flexible vinyl. Most often utilized with glazing beads and sashes. E Edge Effects. Two-dimensional heat transfer at the edge of a glazing unit due to the thermal properties of spacers and sealants. E-Gard. A chemical-, corrosion-, and ultraviolet-resistant hardware that will hold its beauty for the life of a window. E-Gard's manufacturing process is environmentally friendly; it does not consume or create hazardous materials. Egress. An opening or means of going out; exit. Elasticity. Pliability. The ability to take up an expansion and contraction; opposite of brittleness. Electromagnetic Spectrum. Radiant energy over a broad range of wavelengths. Emergency Exit Window. Fire escape window (egress window) large enough for a person. In U.S. building codes, each bedroom must be provided with an exit window. The exact width, area, and height from the floor are specified in the building codes. Energy Star Window Program. A voluntary partnership between the U.S. Department of Energy and participating window manufacturers. Energy Star performance requirements are tailored to fit the energy needs of the country's different regions - northern, central, and southern states. Exterior Casing. A casing that trims the exterior of a window. Exterior Glazed. Glass set from the exterior of the building. Exterior Stop. The removable glazing bead that holds the glass or panel in place when it is on the exterior side of the lite or panel, in contrast to an interior stop located on the interior side of the glass. Extrusion. The process of producing vinyl or aluminum shapes by forcing heated material through an orifice in a die. Also, any item made by this process. Eyebrow Windows. Low, inward-opening windows with a bottom-hinged sash. These attic windows built into the top molding of the house are sometimes called "lie-on-your-stomach" or "slave" windows. Often found on Greek Revival and Italianate houses. F FCR. Fenestration Cooling Rating. A rating number developed by the National Fenestration Rating Council to indicate relative performance during the cooling season. A higher FCR indicates better cooling season performance. FHR. Fenestration Heating Rating. A rating number developed by the National Fenestration Rating Council to indicate relative performance during the heating season. A higher FHR indicates better heating season performance. Fabricator. The person or firm that assembles the component parts into a complete window, door, or sash unit. Fanlight. A half-circle window over a door or window, with radiating bars. Also called "circle top transom." Fascia. Exterior perimeter of the roof just below the roofline, perpendicular to the overhang. Often covered with aluminum for a maintenance-free exterior. Fenestration. The placement of a window opening in a building wall, one of the most important elements in controlling the exterior appearances of a building. Also, a window, door, or skylight and its associated interior or exterior elements, such as shades or blinds. Fiberglass. A composite material made by embedding glass fibers in a polymer matrix. May be used as a diffusing material in sheet form, or as a standard sash and frame element. Fin Trim. Also called "nail fin." Used to secure the window into a rough opening. Used to convert replacement windows to prime windows. Fixed Light. A pane of glass installed directly into non-operating framing members; also, the opening or space for a pane of glass in a non-operating frame. Fixed Panel. An inoperable panel of a sliding glass door or slider window. Fixed Window. A window with no operating sashes. Flanker. A window unit placed along side another window unit. A picture window may be flanked by a double-hung on each side. Flashing. Sheet metal or other material applied to seal and protect the joints formed by different materials or surfaces. Float Glass. Glass which has its bottom surfaces formed by floating on molten metal, the top surface being gravity formed, producing a high optical quality of glass with parallel surfaces and, without polishing and grinding, the fire-finished brilliance of the finest sheet glass. Float is replacing plate glass. Fogging. A deposit of contamination left on the inside surface of the sealed insulating glass unit due to extremes of temperatures. Usually happens with failed SIG. Four-Point Pinch Fusion Welding. In the normal PVC welding process, a welded corner will be cut oversize by 1/4" and then the PVC is melted and held together under high pressure to form a welded corner. hen this welding process happens, the extra material that is melted is forced away from the weld surface. This weld flashing is limited or controlled to approximately 0.080". The extra weld flashing is then removed in a process called "cleaning." The cleaning process will scrape or machine off this weld flashing, leaving a seam of approximately 0.080", which is visible. In a "pinch" welding process, all conditions are the same, as just discussed; however, the weld flash is limited to an average of .020", which is just slightly thicker than a human hair. Therefore, the appearance on welded sashes, particularly those with wood laminates, has significantly improved appearance after the cleaning process. Frame. An open structure or rim for encasing, holding, or bordering something (window frames). Consists of a head at top, sill at bottom, and two jambs at the side. French Door. An interior or exterior door consisting of stiles, top and bottom rails, and divided glass panels or lights; often used in pairs as a casement or terrace door. G Garden Window. A three-dimensional window projecting from an exterior wall that usually has glazing on all sides except the bottom, which serves as a shelf. Gasket. A preformed shape of rubber or rubber-like composition used to fill and seal joints or openings along or in conjunction with a supplemental application of a sealant. Gas Fill. A gas other than air, usually argon or krypton, placed between window or skylight glazing panes to reduce the U-factor by suppressing conduction and convection. Glass. An inorganic transparent material composed of silica (sand), soda (sodium carbonate), and lime (calcium carbonate) with small quantities of alumina, boric, or magnesia oxides. Glazing. The process of sealing the glass to the sash. Glazing Bead. A molding or stop around the inside of a frame to hold the glass in place. Glazing Compound. A soft dough-like material used for filling and sealing the space between a pane of glass and its surrounding frame. H Hard-Coat Low-E. A typical pyrolytic (hard coat) coating is a metallic oxide, most commonly tin oxide with some additives, which is deposited directly onto a glass surface while it is still hot. The result is a baked-on surface layer that is quite hard and thus very durable, which is why it is referred to as "hard coat." A pyrolytic coating can be 10 to 20 times thicker than a sputtered coating but is still extremely thin. The tradeoff for increased durability and better handling qualities is reduced thermal performance. Head/Header. The upper horizontal member of a window frame. Heat-Absorbing Glass. Window glass containing chemicals (with gray, bronze, or blue-green tint), which absorb light and heat radiation while reducing glare and brightness. Heat Gain. The similar transfer of heat from outside to inside. Both heat loss and heat gain are measured in terms of the fuel consumption required to maintain a comfortable indoor temperature. Most often the result of conduction, convection, and radiation through all surfaces of a house. Heat Loss. The transfer of heat from inside to outside by means of conduction, convection, and radiation through all surfaces of the house. Heating Degree Day. Heating and cooling engineers have found a way to relate the typical climate conditions of different areas to the amount of energy needed to heat and cool a building. The term they use is "Degree Days" using a base temperature of 65 degrees F. A heating degree day is counted for each degree below 65 degrees reached by the average (between the highest and lowest) daily outside temperatures in the winter. For example, if on a given winter day the high is 40 degrees and the low is 20 degrees, the daily average temperature is 30 degrees. This is 35 degrees below the base temperature of 65 degrees. So, on that day, you would have gone through 35 degree heating degree days. Heat Strengthened Glass. Glass that is reheated, after forming, to just below the melting point and then cooled. A compressed surface is formed, which increases its strength. Used for spandrel glass. Heel Bead. Compound applied at the base of channel after setting lite or panel, and before the removable stop is installed. Its purpose is to prevent leakage past the stop. Hermetically Sealed Unit. An insulated glass unit made up of two lites of glass, separated by a spacer system. The unit is then completely sealed, creating a moisture-free and clean dead-air space. Hinged Patio Door. An in-swing patio door with operating panel hinged on the center astragal. Hinged Windows. Windows (casement, awning, and hopper) with an operating sash that has hinges on one side. Hi R Plus. Original Hi R Plus features a 7/8" single-surface, vacuum-deposition Low-E insulated glass unit filled with argon gas. Original Hi R Plus delivers an R-factor of 4.2, which is 40more energy efficient than many other types of Low-E glass and over twice as energy efficient as ordinary insulating glass. Hi R Plus5. Uses higher performance krypton gas between two panes of vacuum-deposition Low-E glass to deliver an R-factor of 5. Hi R Plus10 - Maxuus. Delivers an R-factor of 10 by combining two panes of vacuum-deposition Low-E glass with an interior glass substrate and two insulating chambers of Krypton gas. The result is an insulated glass unit that is five times more energy efficient than clear insulating glass. Hopper. Window with a sash hinged at the bottom. The top of the sash swings inward. Horizontal Slider. A window where the moveable panel slides horizontally. Humidity Relative. The percentage of moisture in the air in relationship to the amount of moisture the air could hold at that given temperature. 100relative humidity would be rain. The amount of degree of moisture in the air. I Infiltration. The inadvertent flow of air into a building through breaks in the exterior surfaces of the building. It can occur through joints and cracks around window and skylight frames, sash, and glazings. Infini-Trim. Vinyl-laminated interior trim. Eight molding styles are available, selected to match the most popular wood designs. Moldings are manufactured from dimensionally stable MDF (Medium Density Furniture board) and laminated with seven-mil PVC film. Infrared Radiation. Invisible, electromagnetic radiation beyond red light on the spectrum, with wavelengths greater than 0.7 microns. Insulating Glass (IG). Two pieces of glass spaced apart and hermetically sealed to form a single-glazed unit with an air space between. Heat transmission through this type of glass may be as low as half that without such an airspace. It is also called "double-glazing." Insulation. Construction materials used for protection from noise, heat, cold, or fire. Intercept Spacer. Intercept spacers feature a unique, one piece, tin-plated, U-channel design that creates an effective thermal barrier to help reduce conducted heat loss through the window. Its sealed, one-piece design makes Intercept spacers stronger and better at retaining insulating gas than many conventional designs. InterForce II. Internal fiberglass reinforced sash meeting rails provide unsurpassed strength and security. On average, structural fiberglass provides 50higher tensile strength than hot roll steel and possesses greater impact resistance. Expansion and contraction of pultruded fiberglass is 24less than aluminum and 50less than hot rolled steel. Pultruded fiberglass also offers an extremely low coefficient of thermal conductivity. Interior Glazed. Glass set from the interior of the building. Interlock. A horizontal or vertical member of a sash which engages with a corresponding member in the adjacent sash, providing increased strength at the meeting rails and creating a double barrier to air and water. J Jalousie. The jalousie window is made up of horizontally mounted louvered glass that abut each other tightly when closed and extend outward when cranked. Jamb. A vertical member at the side of a window frame, or the horizontal member at the top of the window frame as in head jamb. Jamb Liner. In a modern double-hung window, the track installed inside the jambs on which the window sashes slide. K Keeper. Normally a device into which a window or patio door locking latch hooks over for security. Cam action locks, which are positioned on the lock sash, engage into the keeper. Knocked Down. Unassembled window or door unit. Krypton. Krypton is part of a family of inert gases called "Nobel gases." Inert simply means the gases are chemically stable. The inert gas will not affect the IG unit or the glass for the life of the window. Krypton is 190denser than air, which increases the thermal efficiency of the IG unit. Nobel gases are also called "Rare Gases" because all together they represent less than 1of the earth's atmosphere. Krochmann Damage Function. A means of estimating fading protection. This method, expressed in percentages, measures the amount of all damaging radiation (ultraviolet, infrared, visible light, and heat) transmitted through window glass. L Laminated Glass. Two or more sheets of glass with an inner layer of transparent plastic to which the glass adheres if broken. Used for overhead, safety glazing, and sound reduction. Laminator. Manufacturer of laminated glass. Lift. Handle for raising the lower sash in a double-hung window. Also called "sash lift." Lift Rail. A handhold for raising and lowering the sash. Rail implies that the handhold is continuous across the sash. Light-to-Solar-Gain- Ratio. A measure of the ability of a glazing to provide light without excessive solar heat gain. It is the ratio between the visible transmittance of a glazing and its solar heat gain coefficient. Abbreviated as "LSG." Lite. Another term for pane of glass used in a window. Frequently spelled "light" in the industry. Lock Rail. The top horizontal section of the sash to which a cam lock is fastened. On sliders, the lock rail is vertical. Long-Wave Infrared Radiation. Invisible radiation, beyond red light on the electromagnetic spectrum (above 3.5 micrometers), emitted by warm surfaces such as a body at room temperature radiating to a cold window surface. Low-Conductance Spacers. An assembly of materials designed to reduce heat transfer at the edge of an insulating window. Spacers are placed between the panes of glass in a double-hung or triple-hung window. Low-Emittance (Low-E) Coating. Microscopically thin, virtually invisible metal or metallic oxide layers deposited on a glass surface primarily to reduce the U-factor by suppressing radiative heat flow. A typical type of Low-E coating is transparent to the solar spectrum (visible light and short-wave infrared radiation) and reflective of long-wave infrared radiation. L Laminated Glass. Two or more sheets of glass with an inner layer of transparent plastic to which the glass adheres if broken. Used for overhead, safety glazing, and sound reduction. Laminator. Manufacturer of laminated glass. Lift. Handle for raising the lower sash in a double-hung window. Also called "sash lift." Lift Rail. A handhold for raising and lowering the sash. Rail implies that the handhold is continuous across the sash. Light-to-Solar-Gain- Ratio. A measure of the ability of a glazing to provide light without excessive solar heat gain. It is the ratio between the visible transmittance of a glazing and its solar heat gain coefficient. Abbreviated as "LSG." Lite. Another term for pane of glass used in a window. Frequently spelled "light" in the industry. Lock Rail. The top horizontal section of the sash to which a cam lock is fastened. On sliders, the lock rail is vertical. Long-Wave Infrared Radiation. Invisible radiation, beyond red light on the electromagnetic spectrum (above 3.5 micrometers), emitted by warm surfaces such as a body at room temperature radiating to a cold window surface. Low-Conductance Spacers. An assembly of materials designed to reduce heat transfer at the edge of an insulating window. Spacers are placed between the panes of glass in a double-hung or triple-hung window. Low-Emittance (Low-E) Coating. Microscopically thin, virtually invisible metal or metallic oxide layers deposited on a glass surface primarily to reduce the U-factor by suppressing radiative heat flow. A typical type of Low-E coating is transparent to the solar spectrum (visible light and short-wave infrared radiation) and reflective of long-wave infrared radiation. M Mastic. Descriptive of compounds that remain elastic and pliable with age. Meeting Rail. The part of a sliding door, a sliding window, or a hung window where two panels meet and create a weather barrier. Mesh. Fabric made of fiberglass or aluminum used in the making of screens. Metal Clad Windows. Exterior wood parts covered with extruded aluminum or other metal, with a factory-applied finish to deter the elements. Mitered Corners. The 45-degree butted flush joints produced in some sashes where vertical jamb members meet horizontal head and sill members. Moisture Vapor Transmission Rate. The rate at which moisture diffuses through a substance. Generally given in the following units: grams/meters squared x 24 hours. The lower the MVT rate, the greater the resistance of the sealant to moisture penetration. Mull. The term used to join two or more windows at the jamb or by the mainframe. Mullion. An intermediate connecting member used to "marry" or mull two or more windows or patio doors together in a single rough opening without sacrificing air or watertight performance. A mullion also can give added strength to the connection for structural stability. Muntins. A decorative design in cut-ups of glass lites, such as painted muntin grids (enamelite) applied to an interior lite of glass in a sealed insulated glass unit to simulate cut-ups of glass lites either in colonial or diamond patterns. Or the use of an aluminum muntin bar between lites of glass in a sealed insulated glass unit to simulate glass cut-ups. Or the use of actual vertical and horizontal bars to divide windows into smaller lites of glass. The bars are known as "muntin bars." N Nailing Fin. An integral extension of a window or patio door frame that generally overlaps the conventional stud construction and through which nails are driven to secure the frame in place. New Generation uiPVC. Unplasticized, high-impact-resistant polyvinyl chloride. PVC compositions, which do not incorporate plasticizers, are commonly referred to as "unplasticized" PVC (uPVC). With the addition of high-impact modifiers, PVC can be classified as uiPVC, (unplasticized, high-impact-resistant polyvinyl chloride). uiPVC has higher impact resistance and reduced expansion and contraction. NFRC. National Fenestration Rating Council. NFRC is a non-profit, public/private organization created by the window, door, and skylight industry. It is comprised of manufacturers, suppliers, builders, architects and designers, specifiers, code officials utilities, and government agencies. NFRC has established a voluntary national energy performance rating and labeling system for fenestration products. The NFRC label rates (1) u-factor, or how well a window keeps heat inside a home, (2) solar heat gain, or a window's ability to block warming caused by sunlight and (3) visible light transmittance, or how much light gets through a product. O Obscure Glass. Any textured glass (frosted, etched, fluted, ground, etc.) used for privacy, light diffusion, or decorative effects. Octagon Window. An eight-sided specialty window. Operable Window. Window that can be opened for ventilation. Operator. Crank-operated device for opening and closing casement or jalousie windows. Oriel Window. A double-hung window with a larger proportioned bottom sash. P Pane. One of the compartments of a door or window consisting of a single sheet of glass in a frame. Panel. A major component of a sliding glass door, consisting of a lite of glass in a frame installed within the main (outer) frame of the door. A panel may be sliding or fixed. Panning (coil stock). In replacement window work, the outside aluminum trim that can extend around the perimeter of the window opening; used to cover up the old window material. Panning can be installed in the opening before the window installation or can be attached directly to the window before installation. Permeability. The rate of diffusion of a pressurized gas through a porous material. Picture Window. A large, fixed window, framed so that it is usually, but not always, longer horizontally than vertically to provide a panoramic view. Plate Glass. Polished plate glass is a rolled, ground, and polished product with true flat parallel plane surfaces affording excellent vision. It has less surface polish than sheet glass and is available in thicknesses varying from 1/4" to 1-1/4". Now replaces by float glass. Polyfoam Wrap. A foam wrap applied to the exterior of the mainframe to provide a tighter installation. Polyisobutylene. Polymer manufactured from gaseous hydrocarbons. The polymer is a major portion of butyl rubber, which also contains a small percent of isoprene. Polyurethane. Any of a group of thermoplastic polymers that are used in resins, coatings, insulation, adhesives, foams, and fibers. They contain the NHCOO chemical group. Polyvinyl chloride (PVC). A modern synthetic material and an important member of the extensive plastics "family." It is made from chlorine (derived from salt) and ethylene (composed of hydrogen and carbon and obtained from crude oil). PVC resin is combined with additives such as stabilizers, plasticisers, and coloring agents and pigments that assist with its conversion into finished products with the desired characteristics. Projected Window. A window fitted with one or more sashes opening on pivoted arms or hinges. Refers to casements, awnings, and hoppers. Q Quick-Trim. The Quick-Trim System is designed to complement both standard and specialty-shaped windows. Most popular casing profiles and jambs are available in paintable and stainable wood-like materials so that homeowners may perfectly match their home's interior. Trim components are made from custom blended PVC for a beautiful appearance, minimal expansion and contraction, low maintenance, and easy installation. Quick-Trim eliminates peeling, splintering, and decay, and will not absorb moisture. Quick-Trim casings and jamb extensions provides the ability to saw, rout, drill, paint, nail, and stain. R Rabbet. A two-sided, L-shaped recess in a sash or frame to receive lites or panels. Racking. Movement and distortion of sash or frame because of a lack of rigidity or because of adjustments to ventilator sections. Places excessive strain on the sealant and may result in joint failure. Radiation. The transfer of heat via electromagnetic (usually infrared) radiation; this is the principal mechanism through which a fireplace warms a room. Rail. Horizontal member of a window sash. R-Core Insulation. Polyurethane insulation inserted into the mainframe. R-Core is a patented process of Great Lakes Window, a process that increases the per-linear-inch R-factor of a vinyl window frame from less than 1 to 7.14. Reflectance. The ratio of reflected radiant energy to incident radiant energy. Refraction. The deflection of a light ray from a straight path when it passes at an oblique angle from one medium (such as air) to another (such as glass). Relative Humidity. The percentage of moisture in the air in relationship to the amount of moisture the air could hold at that given temperature. At 100 percent relative humidity, moisture condenses and falls as rain. RESFEN. A computer program used to calculate energy use based on window selection in residential buildings. Retrofitting. Adding or replacing items on existing buildings. Typical retrofit products are replacement doors and windows, insulation, storm windows, caulking, weather-stripping, vents, and landscaping. Reverse Oriel. A double-hung window with a larger proportioned top sash. Rough Opening. The opening in a wall into which a door or window is installed. Round Top Window. A window where the height is always half the width. R-Value. A measure of the resistance of a glazing material or fenestration assembly to heat flow. It is the inverse of the U-factor (R=1/U) and is expressed in units of hr-sq ft- F/Btu. A high R-Value window has a greater resistance to heat flow and a higher insulating value than one with a low R-value. S Safety Glass. A strengthened or reinforced glass that is less subject to breakage or splintering. Sash. The portion of a window that includes the glass and the framing sections which are directly attached to the glass. Not to be confused with the master frame into which the sash sections are fitted. Screen. Woven mesh of metal, plastic, or fiberglass stretched over a window opening to permit air (but not insects) to pass through. Sealant. Compound used to fill and seal a joint, as contrasted to a sealer, which is a liquid used to seal a porous surface. Setting Blocks. Use of small blocks made of neoprene (preferred) or lead to distribute the weight of the glass or panel to the strong point of a sash, aid in centering the glass or panel, and prevent glass-to-metal contact. Shading Coefficient. The ratio of the solar heat gain through a specific glazing system to the total solar heat gain through a single layer of clear, double-strength glass. Shear. Strain put on a compound between two surfaces where there is a slipping movement of the two surfaces parallel to and in opposite directions along the length of the joint, such as what occurs when an aluminum channel expands to a greater length than a glass panel when both are subjected to the same pronounced rise in temperature. This kind of strain tends to rub or knead the compound in opposite directions along the joint, as contrasted to other forms of strains, which may try to pull the compound apart because the strain is at a right angle to the joint. Sheet Glass. A transparent, flat glass found in older windows, now largely replaced by float glass. Shims. Small blocks of composition, neoprene, etc., placed under the bottom edge of a lite or panel to prevent its settling down onto the bottom rabbet or channel after setting, thus distorting the sealant. Shim Installation. Generally a wedge-shaped spacer (such as cedar shingles in residential work) used to firmly locate a window or door frame into a rough opening. Anchors are normally set through the shim so as to maintain the correct frame placement after installation. Sidelights. Narrow, fixed units mulled or joined to door units to give a more open appearance. Sight Line. Imaginary line along the perimeter of lites or panels corresponding to the top edge of stationary or removable stops. Also, the line at which sealants contacting the lites or panels are sometimes finished. Sill. The lowest horizontal member in a door, window, or sash frame. Sill Angle. An extrusion that is placed on the exterior sill of a window to fill in any gap from the rough opening to the exterior windowsill. Sill Track. The track provided at the sill of a sliding glass door. Also, the sill member incorporating such a track. Single Frame Casement Set. One-piece frame with two to four fixed or operating sashes. This system eliminates the necessity for mulling units together which results in a stronger, cleaner-looking window set. Single-Glazing. Single thickness of glass in a window or door. Single-Hung Window. A window consisting of two sashes of glass, the top one stationary and the bottom movable. Single-Strength Glass. Glass with thickness between 0.085" and 0.100" (2.16-2.57). Slider. A slider window may have one or two movable panes of glass. Soft-Coat Low-E. A sputtered coating is multilayered (typically, three primary layers, with at least one layer of meta1) and deposited on glass or plastic film in a vacuum chamber. The total thickness of a sputtered coating is only 1/10,000 of the thickness of a human hair. Sputtered coatings often use a silver layer and must be protected from humidity and contact. For this reason, they are referred to as "soft coat." Since sputtering is a low-temperature process, these coatings can be deposited on flat sheets of glass or thin plastic films. While sputtered coatings are not durable in themselves, when placed into a sealed double- or triple-glazed assembly, they should last as long as the sealed glass unit. Sputtered coatings typically have lower emittances than pyrolytic coatings. Solar Heat Gain Coefficient. (SHGC) The fraction of solar radiation admitted through a window or skylight, both directly transmitted and absorbed and subsequently released inward. The solar heat gain coefficient has replaced the shading coefficient as the standard indicator of a window's shading ability. It is expressed as a number between zero and one. The lower a window's solar heat gain coefficient, the less solar heat it transmits, and the greater its shading ability. SHGC can be expressed in terms of the glass alone or can refer to the entire window assembly. Solar Radiation. The total radiant energy from the sun, including ultraviolet and infrared wavelengths, as well as visible light. Sound Transmission Class. (STC) The sound transmission loss rating of a material over a selected range of sound frequencies. The higher the number, the better. Stained Glass. Glass that is colored by fusing colored metallic oxides onto the glass, or by painting and baking transparent colors on the glass surface. Stile. The upright or vertical edges of a door, window, or screen. Stool. The shelf-like board of the interior part of the windowsill, against which the bottom rail of the sash closes. Stop. The molding on the inside of a window frame against which the window sash closes. In the case of a double-hung window, the sash slides against the stop. Also called bead, stop, window stop, and parting stop. Storm Windows. A second set of windows installed on the outside or inside of the primary windows to provide additional insulation and wind protection. Super Spacer. A patented structural foam spacer system incorporating a blend of silicates and moisture- absorbing desiccant material manufactured with millions of tiny insulating air pockets. Super Window. A window with a very low U-factor, typically less than 0.15, achieved through the use of multiple glazings, low-e coatings, and gas fills. Swiggle Spacer. A spacer system that pre-blends a desiccant into an extremely moisture-resistant sealant with a solid metal barrier. T Tank-Type Roller System. A breakthrough system that spreads a sliding patio door's weight over many rollers at once, eliminating the flat spots that can develop on conventional rollers. Tempered Glass. As with heat-strengthened glass, it is re-heated to just below the melting point, but suddenly cooled. When shattered, it breaks into small pieces. It is approximately five times stronger than standard annealed glass. It must be used as safety glazing in patio doors, entrance doors, side lites, and other hazardous locations. It can't be re-cut after tempering. Thermal Break. An element of low conductivity placed between elements of higher conductivity in an effort to reduce the flow of heat and cold; i.e., insulation. Thermal Breakage. Glass, which is not heat-treated, (tempered) can, under some conditions, experience thermal breakage. The risk of thermal breakage is greatest when the center area of the glass becomes hotter than the edge. This condition can occur when the sun heats the center of the glass and the edges remain cool. Under these conditions, the center of the glass expands, but is restricted from natural expansion by the edges, which remain cool. This results in stress within the glass that can cause thermal breakage. Thermal Expansion. Change in dimension of a material as a result of temperature change. Threshold. The member that lies at the bottom of a sliding glass door or swinging door; the sill of a doorway. Tilt Window. A single- or double-hung window whose operable sash can be tilted into the room for interior washability. Tinted Glass. A mineral admixture is incorporated in the glass, resulting in a degree of tinting. Any tinting reduces both visual and radiant transmittance. Tolerance. Permissible deviation from a nominal or specified dimension or value. Transmittance. The percentage of radiation that can pass through a glazing. Transmittance can be defined for different types of light or energy, e.g., visible light transmittance, UV transmittance, or total solar energy transmittance. Transom. A horizontal transverse beam or bar in a frame; a crosspiece separating a door or the like from a window or fanlight above it. Also, a window above a door or other window, built on and commonly hinged to a transom. Trim. Millwork, primarily moldings and/or trim, that finishes window and door openings, fireplaces, walls, and other members. Triple Glazing. Three panes of glass or plastic with two air spaces between. True Divided Light. Refers to windows in which multiple individual panes of glass or lights are assembled in the sash using muntins. True Sloped Sill. Great Lakes manufacturing processes lowered the height of the vinyl sill, removed the weep cavities and added a true slope. This sill is then processed to accept the jambs, to create a low- profile welded sloped sill. U Ultraviolet Light. The invisible rays of the spectrum, which are outside of the visible spectrum at its violet end. UV rays are found in everyday sunlight and can cause fading or chalking of dark paint finishes. Extreme UV exposure can cause certain plastic materials to distort. United Inches. The addition of the dimensions of one length and one width of a lite of glass. Example: A window that is 24" wide and 72" high is 96 U.I. U-Value. A measure of the rate of non-solar heat loss or gain through a material or assembly. It is expressed in units of BTU/hr-sq ft-F (W/sq m-C). Values are normally given for NFRC/ASHRAE winter conditions of 0 degrees F (18 degrees C) outdoor temperature, 70 degrees F (21 degrees C) indoor temperature, 15 mph wind, and no solar load. The U-factor may be expressed for the glass alone or the entire window, which includes the effect of the frame and the spacer materials. The lower the U-factor, the greater a window's resistance to heat flow and the better its insulating value. V Vent. The movable framework or sash in a glazed window that is hinged or pivoted to swing open. Ventilation-Limit Locks. Stops in the sash, which permit windows to be partially opened while retaining security. V-Grooved Glass. Precision glass-cutting process involving a diamond-cutting wheel, water, and a polishing wheel. The depth of the V-Groove is 1mm, which is grooved on 4.7-4.8mm glass. This still provides a 3.7-3.8mm thickness in the glass, which is thicker than double-strength or 1/8" (3.1mm) glass. Vinyl. Vinyl is composed of two simple building blocks: chlorine, derived from common salt, and thylene, from crude oil. The resulting compound, ethylene dichloride, is converted at very high temperatures to vinyl chloride monomer (VCM) gas. Through the chemical reaction known as polymerization, VCM becomes a chemically inert powder, polyvinyl chloride resin. Resin is used in the extrusion process. Vinyl can be either rigid or flexible, and is an efficient material for window frames. Vinyl-Clad Windows. A window with exterior wood parts covered with extruded vinyl. Visible Light. The portion of the electromagnetic spectrum that produces light that can be seen. Wavelengths range from 380 to 720 nanometers. Visible Transmittance (VT). The percentage or fraction of the visible spectrum (380 to 720 nanometers) weighted by the sensitivity of the eye that is transmitted through the glazi W Warm-Edge Technology. The use of low-conductance spacers to reduce heat transfer near the edge of insulated glazing. Weather-stripping. A strip of resilient material for covering the joint between the window sash and frame in order to reduce air leaks and prevent water from entering the structure. Weep Hole. A small opening in a wall or window member through which water may drain to the building exterior. Wet Glazing. A method of sealing glass in a frame by using a knife- or gun-applied glazing compound or sealant. Wind load. Force exerted on a surface by moving air. Wood grain. The wood grain process involves a tremendous amount of technical precision and complex calculations to custom bond the wood grain material to each individual vinyl extrusion. Great Lakes Window has enhanced this process using new finishing equipment with .002" precision. These wood grain finishes have proven themselves over time to resist fading, chipping, peeling, and blistering. Great Lakes Window uses only the highest quality wood grain laminate (7 mils thick). It is backed by a lifetime warranty.