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A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | R | S | T | U | V | W

A
AAMA American Architectural Manufacturers Association. A national trade organization that establishes voluntary standards for the fenestration industry.
ACOUSTICS The science of sound and sound control.
ACRYLIC A non-crystalline thermoplastic with good weather resistance, shatter resistance, and optical clarity; sometimes used for safety glazing.
ACTUAL SIZE The true horizontal and vertical dimensions of a window or door, as opposed to nominal or call sizes. inside frame dimensions and tip-to-tip dimensions are measurements of the actual size of a window or door.
ADHESION The ability of a compound or sealant to stick or bond to the surface to which it is applied.
ADHESIVE FAILURE Failure of a compound or sealant to stick or bond to the surface to which it is applied. (See COHESIVE FAILURE)
AIR INFILTRATION The movement of outdoor air into the interior of a building through cracks in and around windows, doors, walls, etc.
ALLOY A metal to which another element (usually another metal) was added while forming.
ANCHOR Any device used to secure a window/door or its parts to a building frame or to each other.
ANNEAL To heat metal, glass, or other materials above the critical or re-crystallization temperature, then control cooling to eliminate the effects of cold-working, relieve internal stresses, or improve strength or other properties.
ANNEALED GLASS Standard Sheet or Plate Glass, which has not been tempered.
ANODIZE To provide an extremely hard, non-corrosive oxide film on the surface of metals by electrolytic action. The electrochemical process produces an anodic coating by converting the metal into metal oxide. Appearance depends on both the metal involved and surface preparation.
ANSI American National Standards Institute. A clearinghouse for all types of standards and specifications.
ASTM American Society for Testing and Materials. A society of engineers that sets standards for testing of materials and products.
ASTRAGAL A vertical member placed at the meeting edges of two door panels to provide a weather seal and to anchor the fixed panel.
AWNING WINDOW A window with a top-hinged sash that swings either inward or outward.
BACK BEDDING The fluid glazing compound used in a wet glazed window or door that is applied between the glazing leg of the sash/frame and the glass being placed into the sash/frame. After setting, it forms the primary bond between the sash/frame and glass.
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B
BALANCE A mechanical device used in single- and double-hung windows as a means of counterbalancing the weight of the operable sash(es) during opening and closing.
BAY WINDOW An arrangement of three window units (a unit may be one or more windows) attached in such a way as to project from the building line. The two-flanker units project at 45º angles from the building line, while the center unit is parallel to the building line.
BEAD 1) A strip of metal, vinyl, or wood used around the periphery of a pane of glass to secure it in a frame or sash; also called a Glazing Bead. 2) A strip of sealant, such as a caulking or glazing compound.
BENT GLASS Flat glass shaped while hot into cylindrical or other curved shapes.
BEVEL A sloped surface or edge; also the act of creating this edge.
BEVELED GLASS Glass with its edges ground to a beveled angle. Beveled glass can also include patterns that have been formed by grinding away a beveled valley into the surface.
BITE The dimension by which the glazing leg overlaps the glass edge.
BOTTOM RAIL The lower horizontal edge of a window sash or door panel.
BOW WINDOW An arrangement of four or more window units (a unit may be one or more windows) attached in such a way as to project from the building line. The units are attached at 13º angles from each other.
BRITTLE Stiff, able to break or shatter easily; opposite of elastic.
BTU (BRITISH THERMAL UNIT) The amount of heat energy necessary to raise the temperature of one pound of water one degree Fahrenheit. The energy used for heating and cooling is measured in BTU’s.
BURR A rough or sharp edge left on metal or wood by a cutting tool.
BUTYL Synthetic rubber formed by the co-polymerization of isobutylene with isoprene. It is used in compounding for wet applied seals and glazing tapes.
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C
CALIPERS A measuring instrument with two legs or jaws that can be adjusted to determine the thickness or diameter of an object, or the distance between two objects. Commonly used to check tolerances of window and door components.
CALL SIZE OR CALL-OUT SIZE< The nominal (describing in name only) size of a window or door that is used when ordering standard sizes. An example is “3050” (3 feet, 0 inches wide by 5, feet 0 inches high). Call Size does not necessarily equal the Inside Frame Dimension or the Tip-to-Tip Dimension. (See INSIDE FRAME DIMENSION and TIP-TO-TIP DIMENSION)
CAM LOCK A spring-loaded locking device that engages by rotating a flat cam (disk) into a cavity and is positively stopped in its projected position. Typically, the cam lock is attached to the lock rail of the operating sash and engages into the fixed meeting rail of the frame.
CASEMENT WINDOW A window with a side-hinged sash that swings either inward or outward.
CATALYST A material that initiates the cure of another reactive substance.
CAULKING A compound used as a sealant in construction to block air and/or moisture leaks.
CFM (CUBIC FEET PER MINUTE) A measure of air or water flow. Also denoted as ft3/min.
CHALKING A process which causes a paint finish to develop a loose powdery surface. This results from decomposition of the binder principally through the action of ultraviolet rays (sunlight).
CHEMICAL CURE A change in the properties of a material due to polymerization or vulcanization. Heat, catalysts, exposure to the atmosphere or any combination of the above may effect this change.
CLEARANCE The space or distance intentionally left between two objects.
COEFFICIENT OF THERMAL EXPANSION A unit for measuring the change in dimension of a material due to temperature change. Usually expressed in inches per inch per°F.
COHESION The molecular attraction which holds the body of a sealant or adhesive together, or the internal strength of an adhesive or sealant.
COHESIVE FAILURE The separating and opening of a compound within itself due to overextension of the compound resulting in the adhesive material applied between two surfaces remaining on both surfaces. (See ADHESIVE FAILURE)
COMPATIBILITY The ability of two or more materials to exist in close and permanent association with no adverse effects of one on the other.
COMPOUND A substance containing two or more materials chemically combined in fixed amounts. The materials lose their individual characteristics while the compound acquires new characteristics. Common compounds are back bedding, caulking, insulated glass sealant and thermal break materials.
CONDENSATION Water vapor in the air that becomes liquid and forms in droplets on a cold surface. This happens when the water vapor in the air comes in contact with a surface that is below the “dew point temperature” and becomes liquid. An example would be water droplets formed on the outside of a glass of ice water because the surface of the glass is below the dew point temperature of the air. (See DEW POINT and HUMIDITY - RELATIVE).
CONDUCTION Heat transfer through a material from a warm surface to a cool surface.
CONVECTION Heat transfer by the movement of fluid or air caused by the difference in density of the fluid or air and the action of gravity.
CONVERSION COATING A chemical treatment that reacts with a metallic surface to improve corrosion resistance as well as paint adhesion.
CORROSION The deterioration of metal by chemical or electrochemical reaction resulting from exposure to weather, moisture, chemicals, etc.
COUNTERSINK To bevel the edge of a hole to receive the head of a screw.
CRF (CONDENSATION RESISTANCE FACTOR) An indication of a window or door’s resistance to condensation. A higher CRF means less chance for condensation.
CURING TIME The time required for a compound to complete the chemical reaction to reach its final physical form.
CYLINDRICAL LOCK A lock which uses the key-in-the-knob principle.
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D
DAYLITE OPENING The glass portion of a window or door not covered by any part of its sash, panel or frame members. (see EXPOSED GLASS AREA)
dBA (DECIBEL) A unit for expressing the relative intensity of sounds on an exponential scale from zero (absolute silence) to about 130 (average pain level). Normal speech is about 60 dBA and a jet take-off is about 120 dBA.
DEADLOCK or DEADBOLT LOCK A lock in which a bolt is moved by means of a key or thumbturn, and is positively stopped in its projected position.
DEBRIDGE The process of cutting away the metal on the bottom of a thermal break cavity after the two-part polyurethane compound has cured, leaving a thermally broken extrusion. (See THERMAL BREAK)
DEFLECTION A deviation or turning aside from a setline; bending of a beam or any part of a structure under an applied load.
DEGREE DAY A unit that represents a 1 °F deviation from some fixed reference point (usually 65 °F) in the mean outdoor temperature. For example, if on a given winter day the high is 40° and the low is 20°, the daily mean temperature is 30°. This is 35° below the base temperature of 65°, so that day would result in 35 Heating Degree Days. Temperatures higher than 65° would result in Cooling Degree Days.
DESICCANT One or more extremely porous crystalline substances used to absorb vapors from within the sealed air space of an insulated glass unit. (See MOLECULAR SIEVE and SILICA GEL
DEW POINT The temperature at which the condensation of water vapor in a space begins, depending on humidity and pressure. As the dew point temperature is decreased, the resistance to forming condensation increases.
DIAMETER A straight line passing through the center of a circle from one side to the other; also the length of that line.
DICE A cubical pattern of fracture of tempered glass. The edges of the dice are roughly equal to the thickness of the glass.
DIE In general, any of the various tools used to mold, cut, stamp, or shape an object or material. In the extrusion process, this is a piece of metal with a pattern of holes and slots used for forming the desired shape. (See EXTRUDE)
DIFFUSION The scattering or dispersing of a substance. An example would be sunlight partially diffused by obscure glass.
DOOR A structure with one or more moveable panels for opening or closing an entrance to a structure. Below are listed some of the different types of doors. For a description of each type, please see their individual definitions found elsewhere in this glossary.

Pocket Door      Hinged Door      Slider Door

DOUBLE GLAZE, -ED, or -ING; also DOUBLE PANE The use of two panes of glass within an opening, separated by an air space, to improve insulation against heat/cold transfer and sound transmission. The air space between the panes may or may not be factory sealed. (See SEALED INSULATED GLASS UNIT)
DOUBLE HUNG WINDOW A window with two vertically moving sashes that can be raised and lowered independent of each other. Balances offset the weight of the sashes to allow the sashes to remain raised in the desired position. Opposed to a single hung window in which the top lite/sash is fixed.
DRIP CAP Sheet metal or other material placed over the upper horizontal frame member of a window/door to prevent the migration of water into a building.
DROP GLAZING A method of glazing in which the glass is placed into the sash/frame and then secured, as opposed to marine glazing, in which the sash/frame is secured around the glass.
DRY GLAZING A method of glazing in which the glass is secured into the sash/panel/frame using a dry, flexible gasket, without the use of glazing compounds.
DUROMETER An instrument for measuring the relative hardness of pliable materials such as rubber. Durometers are graduated from 0 (softest) to 100 (hardest).
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E
EGRESS A way out or exit; the act of exiting.
EGRESS WINDOW A window used for emergency escape. By code, this is a sleeping room window used below the fourth floor with a 20” minimum horizontal opening, a”24” minimum vertical opening, and a 5.7 ft² minimum total open area. The code varies with state and local building codes.
ELASTIC Pliable, able to expand and contract; opposite of brittle.
ELASTIC LIMIT Maximum stress that a material will stand before permanent deformation occurs.
ELONGATION The amount of stretch exhibited by a compound.
ENAMEL A glassy, colored, opaque substance fused to metal or other materials as an ornamental and protective coating. Also, a paint that dries to a smooth, hard, glossy surface.
EPOXY A synthetic two-part resin with superior adhesion/cohesion properties.
EQUAL LEG FRAME A window or doorframe having its inside face perimeter identical to its outside face perimeter. Generally regarded as the best frame design.
EXPOSED GLASS AREA Another term for DAY-LITE OPENING.
EXTERIOR (or OUTSIDE) GLAZED Glass set from the exterior of the building.
EXTRUDE To force material (aluminum, vinyl, etc.) through a die (a metal plate containing a pattern of holes and slots) to produce a desired shape. Most materials must be heated before being forced through the die.
EXTRUSION Any item made by extruding. Aluminum and vinyl window and door members are typically extrusions, as well as vinyl glazing beads.
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F
FASCIA Exterior perimeter of the roof just below the roofline, perpendicular to the overhang.
FENESTRATION A term encompassing the design, arrangement, manufacture, and installation of windows, doors, skylights, and other openings in a building.
FIN SEAL WEATHER STRIP A form of conventional pile weather strip with the added feature of a plastic fin or fins centered in the pile to further reduce air and water infiltration.
FIXED The part of a window or door which does not move, such as a fixed window sash or a fixed door panel. Also, a window, which is stationary, such as a picture window. Indicated by the letter “0” as in “OX” or “OXXO”.
FIXED JAMB The jamb (side vertical frame member) on a sliding window or door that is adjacent to the fixed lite/sash/panel.
FIXED MEETING RAIL The middle horizontal member of a single hung window, which serves to anchor the top lite/sash and interlock with the moving sash.
FIXED WINDOW A window with its glass or sash permanently fastened in the frame so that it cannot be opened.
FLANGE An integral extension of the window. It is a fin, typically on or near the exterior face of a window and parallel to the face of the window. A flange is used in place of a nailing fin for block installations.
FLANGE SCREEN A screen with a flange on its outer face to provide a better seal around the perimeter of the screen and tighter installation.
FLANGE WINDOW A window incorporating a flange instead of a nailing fin. A flange window is measured from the outer edge of one flange to the outer edge of the opposite flange (called Tip-to-Tip Dimension).
FLANKER WINDOW A smaller window mounted beside a main window at any angle to the plane of the main window, as in a bay window.
FLASHING Sheet metal or other material used to weatherproof joints and edges on a building’s exterior. An example would be a drip cap. (See DRIP CAP)
FLAT GLASS A general term embracing flat, float, roller and sheet glass.
FLORIDA SIZING A special sizing system used in Florida and, normally, only for flange windows used in cinder block construction.
FOGGING A deposit of contamination left on the inside surface of a sealed, insulated glass unit due to failure of the airtight seal.
FORCED ENTRY RESISTANCE An AAMA test to evaluate the ability of a window in the locked position to resist opening under a specified load such as an intruder might apply.
FRAME The perimeter of a window or door unit. Also, a general term referring to a structure comprised of parts fitted together to support or enclose an object.
FROSTED GLASS Glass with one or both surfaces acid etched, which improves distribution of transmitted light and reduces glare.
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G
GAUG or GAUGE A standard measure or scale of measurement. There are many different scales, such as those used for measuring the thickness of sheet metal, the diameter of wire and screws, etc. Also, the act of measuring, as well as a tool used for measuring.
GASKET Preformed shapes or strips of rubber or other elastic materials used to fill and seal a joint opening.
GLASS A hard, brittle substance, usually transparent or translucent, formed by melting together silicates (sand) with soda, potash, lime and other materials, then cooled without crystallization. Below are listed some of the different types of glass. For a description of each type, please see their individual definitions found elsewhere in this glossary.

Annealed Glass Heat Absorbing Glass
Low Emissivity Glass Sandblasted Glass
Bent Glass Heat Resisting Glass
Beveled Glass Heat Strengthened Glass
Obscure Glass Tempered Glass
Flat Glass Laminated Glass
Patterned Glass Tinted Glass
Frosted Glass Leaded Glass
Reflective Glass Wired Glass
Spandrel Glass  

GLAZING The act of installing glass panes, insulated glass units or other materials into a window sash/frame or a door panel/frame. Also, called Setting.
GLAZING BEAD A formed or extruded metal or vinyl section used to secure the glass in the sash/frame. It is generally snapped in or screwed in and wedges the glass into place.
GLAZING BLOCK A small piece of neoprene or other pliable material used to position the glass in the sash/frame during glazing.
GLOSS The luster, shine or image reflection of a surface; directly related to the smoothness of that surface.
GLOSS METER An instrument for measuring gloss, usually at 60? from the horizontal plane. A mirror would have a gloss of 100%.
GUSSET A plate attached to one or both sides of a joint to increase its strength.
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H
HANDING The designation (right-handed or left-handed) of the moving sash of a horizontal sliding window, the swing of a casement window, the moving panel of a sliding door, the swing of a hinged door or the direction of rise of a specialty window.
HEAD or HEADER The upper, horizontal member of a window or doorframe.
HEAT-TREAT To heat and cool a metal or other material in order to change its physical properties. Aluminum extrusions are heat-treated to increase strength.
HEAT ABSORBING GLASS Glass (usually tinted) formulated for absorbing appreciable portions of radiant energy, especially solar energy.
HEAT RESISTING GLASS Glass able to withstand high thermal shock, generally, because of a low coefficient of expansion.
HEAT STRENGTHENED GLASS Glass, which is reheated, after forming, to just below the melting point and then cooled. A compressed surface is formed, which increases its strength. Specifically, it has a surface compression of not less than 3,500 psi or an edge compression of not less than 5,500 psi.
HEAT GAIN The transfer of heat from the outside to the inside of a building by means of conduction, convection and/or radiation.
HEAT LOSS The transfer of heat from the inside to the outside of a building by means of conduction, convection and/or radiation. Both heat gain and heat loss is measured in terms of the fuel consumption required to maintain a comfortable indoor temperature (BTU’s).
HINGE A hardware device on which door panels, window sashes, etc. may turn or swing to open or close. Hinges generally consist of two metal plates with loops formed on one edge that engage and rotate about a common pivot rod or “pin”.
HINGED DOOR A door with one or more panels that swing outward or inward on a hinged axis.
HOPPER WINDOW A window with a bottom-hinged sash that swings inward.
HORIZONTAL Parallel to the plane of the horizon, or side-to-side.
HORIZONTAL SLIDING WINDOW A window with one or more sashes that slide horizontally on a track in the sill. Also, called Horizontal Slider or simply Slider
HUMIDITY- RELATIVE The percentage of moisture in the air in relationship to the amount of moisture the air could hold at the given temperature.
HUNG WINDOW A window with one or more vertically moving sashes. The weight of the sashes is offset by balances to allow them to remain raised in the desired position. Examples are single hung and double hung windows.
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I
INDOOR VISIBLE REFLECTANCE The percentage of visible light energy reflected away from the interior surface. The higher the percentage, the more mirror-like the surface will appear.
INFRARED ENERGY The portion of solar radiation wavelengths which are longer than those in the visible range. This radiation, like ultraviolet energy, is invisible.
INSECT SCREEN A fine mesh screen provided for the purpose of excluding insects, sometimes with a flexible fin around the edge to close off any gaps.
INSIDE FRAME DIMENSION An important window or door dimension. The Inside Frame Dimension is measured on the inside face of the window or door, with the horizontal dimension measured between the outermost edges of the jambs, and the vertical dimension measured from the uppermost edge of the head to the lowermost edge of the sill.
INSULATION Construction materials used to provide protection from sound, heat, cold or fire.
INTERIOR (or INSIDE) GLAZED Glass set from the interior of the building.
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J
“J” CHANNEL A channel used to trim off siding to window and doorframes.
JAMB The side vertical members of a window or doorframe.
JAMB DEPTH An important window or door dimension. The Jamb Depth is the overall width of a jamb section or the distance between the inside and outside faces of a window or door.
JAMB STILE The vertical member of a fixed window sash or fixed door panel that is adjacent to the fixed jamb.
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K
KD (KNOCKED DOWN) All unassembled components of a window or door, except glass.
KEEPER A device that receives a window or door lock or latch.
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L
LAMINATED GLASS Two or more sheets of glass with an inner layer of plastic to hold the glass together if broken. Used for overhead glazing, safety glazing and sound reduction.
LATCH A hardware mechanism with a retractable bolt or hook, but no locking device, and designed to hold a moving sash/ panel in a fixed position.
LEADED GLASS Small panes of glass joined together and framed with lead.
LIFT HANDLE or TAB A handle incorporated into the moving sash of a hung window for the purpose of raising and lowering the sash.
LIFT RAIL The horizontal member of a moving hung window sash that incorporates a lift handle or tab for raising or lowering the sash.
LITE A pane of glass or a sealed insulated glass unit.
LOCK A hardware mechanism designed to hold a window or door securely closed against unauthorized opening.
LOCK RAIL The horizontal extrusion of a window sash that houses the locking mechanism of the window.
LOCK STILE The vertical extrusion of a window sash or door panel that houses the locking mechanism of the window or door.
LOUVER A slatted opening for ventilation in which the slats are so placed to exclude rain, sunlight, or vision.
LOW EMISSIVITY GLASS (or LOW-E GLASS) Glass treated with a transparent metallic or metallic oxide coating to reflect long-wave infrared energy for improved U-value. There are two basic types of Low-E coatings:
  1. Pyrolytic (or Hard) Coat - A tin oxide coating is applied while the glass is still hot and thus baked into the surface. Pyrolytic coating is much more moisture and abrasion resistant than sputter coated glass, but also has higher emissivities.
  2. Sputter (or Soft) Coat - The glass surface is coated with a layer of silver, followed by two layers of zinc oxide. Sensitive to moisture and abrasion, this type is suitable only inside a sealed insulated glass unit.
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M
MARINE GLAZING A glazing method in which a soft vinyl channel (gasket) is wrapped around the perimeter of the glass before the sash members are secured around the glass. The gasket cushions the glass and provides a weather seal.
MASTIC A plastic material, typically non-drying, used in sealing joints.
MEETING RAIL A horizontal member of a hung window sash that interlocks with another horizontal member to create a weather barrier.
MEETING STILE A vertical member of a sliding window sash or sliding door panel that interlocks with another vertical member to create a weather barrier.
MILL FINISH The original gray metallic finish produced on aluminum by cold rolling or extruding.
MITER JOINT A joint formed when two members are joined at the ends, with the ends beveled at equal angles. Opposed to a coped joint or a square joint.
MOISTURE MIGRATION The passage of water vapor into or through a material due to the difference in vapor pressure between the inside and outside faces.
MOLECULAR SIEVE An extremely porous crystalline structure used, primarily, to absorb water vapors from within the air space of a sealed insulated glass unit.
MOVING A window sash or door panel that slides in one plane. Examples are a single hung sash that is raised or a sliding door panel that is slid horizontally. Indicated by the letter “X” as in “OX” or “OXXO. (See OPERATING)
MULL or MULLION An intermediate member used to connect a window or door adjacent to or above another window or door. Mullions can also be designed to give added strength to the connection for structural stability.
MULL CLIP A clip or plate used in conjunction with a mull when joining a window or door to another window or door.
MUNTIN A bar in a window or door that divides the glass either visually or physically. There are four basic types of muntin:
  1. Interior - Muntin bars inside sealed insulated glass units.
  2. Glue-On - Muntin bars glued onto the glass surface.
  3. Painted - Muntin grids painted on the glass surface.
  4. True - Muntin bars that physically separate small panes of glass. The name for windows or doors with this type of muntin is True Divided Lite.
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N
NAILING FIN An integral extension of the window or doorframe. It overlaps the conventional stud so that nails can be driven through it to secure the window or door in place.
NEOPRENE A synthetic rubber with physical properties closely resembling those of natural rubber, but not requiring sulfur for vulcanization. Offers extremely good resistance to weather, heat, cold and ultraviolet rays.
NFRC (NATIONAL FENESTRATION RATING COUNCIL) An organization consisting of manufacturers of fenestration products and whose purpose is to establish equitable procedures for rating the performance of fenestration products.
NOMINAL Describing in name only.
NOMINAL SIZE Another term for Call Size.
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O
OBSCURE GLASS A form of rolled glass that has a small random design on one or both surfaces. Used for light diffusion and privacy.
OPENING An open or clear space provided in a wall for installation of a window or door. Also called Rough Opening.
OPENING SIZE The size of the opening in the wall for installation of the window or doorframe. This is equal to the Actual Size of the window or door plus clearances. Also called the Rough Opening Size .
OUTDOOR VISIBLE REFLECTANCE The percentage of available visible light energy reflected away from the exterior surface. The higher the percentage, the more visible light is reflected and the more mirror-like the surface will appear.
OUTSIDE FRAME DIMENSION A measurement of the outside face of the window or door, with the horizontal dimension measured between the outermost edges of the jambs and the vertical dimension measured from the uppermost edge of the head to the lowermost edge of the sill. (See FLANGE WINDOW and EQUAL LEG FRAME)
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P
PAN The bottom metal section of a garden window.
PANE A single piece of glass.
PANEL The portion(s) of a door that includes the glass and extrusions attached to the glass. Panels can either be moving, operating or fixed, and should not be confused with the doorframe into which the panels are fitted.
PATTERNED GLASS A form of rolled glass having a pattern impressed on one or both surfaces. Used for light control and decorative glazing.
PICTURE WINDOW A window with its glass or sash permanently fastened in the frame so that it cannot be opened. Also called a Fixed Window.
PICTURE WINDOW SLIDER A variation of a horizontal sliding window that includes two moving sashes separated by a fixed lite/sash (“XOX”).
PILE WEATHERSTRIP A type of weather strip with fibers (pile) extending from it to reduce air and water infiltration.
PIVOT BAR The small bar attached to a tilt window sash and extending into a tilt shoe, allowing the sash to tilt about that axis. (See TILT SHOE)
PLUMB An instrument used to determine an even vertical plane. Also, the act of making a surface perfectly vertical or an adjective describing an even vertical surface. (See VERTICAL)
POCKET DOOR A sliding door with one or more moving panels that slide into a "pocket" in the wall.
PRE-HUNG DOOR An assembled doorframe with the panels factory installed.
PRIMER A special initial coating designed to enhance the adhesion of sealant, paint or other applied substances.
PRIME WINDOW A window installed during initial construction and serving as an integral part of the structure. Not to be confused with storm windows which serve as a secondary weathering device.
PSF (POUNDS PER SQUARE FOOT) A measurement used to describe pressure, such as wind velocity and barometric pressure. Also denoted as lbs/ft².
PSI (POUNDS PER SQUARE INCH) A measurement used to describe pressure, such as wind velocity and barometric pressure. Also denoted as lbs/in².
PSYCHROMETER An extremely accurate instrument used to determine the relative humidity of air by determining its wet bulb temperature.
PULL STILE The vertical member of a sliding window sash or door panel that includes a handle to move the sash or panel along its path.
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R
RADIATION The emission of energy from a surface in the form of electromagnetic waves. The energy waves are absorbed by objects not transparent to them. An example is sunlight warming your skin on a cold winter day.
RADIUS A straight line from the center of a circle to its perimeter. Also, the length of that line.
RAIL Any internal horizontal member in a window or door; not to be confused with the frame head or sill.
REFLECTIVE GLASS Glass with a reflective surface film to reduce heat and light transmission.
RELATIVE HEAT GAIN A number used to compare fenestration products based on a fixed set of conditions. These conditions are a solar heat gain factor of 200 BTUh/ft²/ft² and an indoor-outdoor temperature difference of 14° F.
REPLACEMENT UNIT A window or door designed to fit an existing opening.
RETROFITTING Adding or replacing items to an existing building.
REVERSIBLE The ability to change the handing on a sliding window, a sliding or hinged door, or a casement window. (See HANDING)
RISE The vertical distance from the shortest jamb of a window to the tallest jamb of a window. Commonly used when describing specialty windows such as eyebrows and rakeheads.
ROCKWELL HARDNESS TEST A standard method for measuring the hardness of metals. The hardness is expressed as a number related to the depth of an imprint made by a steel bail or a diamond cone “brale”.
ROLLER The wheel(s) upon which a sliding window or door rolls. Also, a guide used to form materials in the roll forming process.
ROLL FORMING A process in which a material is bent, shaped, or patterned between rollers of a shape designed for that process.
ROLLER HOUSING The device that holds the roller in place in a sliding window or door.
ROUGH OPENING An open or clear space provided in a wall for installation of a window or door.
ROUGH OPENING SIZE The size of the opening in a wall for installation of a window or doorframe. This is equal to the Actual Size of the window or door plus clearances. Also called Opening Size.
R-VALUE The measure of resistance to heat gain or loss, or the ability to insulate. Higher R-Values indicate better insulating properties.
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S
SALT SPRAY TEST An accelerated corrosion test in which a finish or metal is exposed to a fine mist of salt water either continually or intermittently.
SANDBLASTED GLASS Glass which has been sprayed with hard particles in order to chip out and roughen the surface. The effect increases obscurity and diffusion, but also makes the glass very fragile.
SASH The portion(s) of a window that includes the glass and extrusions attached to the glass. Sashes can be moving, operating or fixed, and should not be confused with the window frame into which the sashes are fitted.
SASH GUIDE An insert or button made of nylon or other material that helps the moving sash of a window travel along its intended path.
SASH STOP A metal section or other object attached to one or both jambs of a hung window to prevent the moving sash (es) from traveling too far.
SCREEN An assembly consisting of a mesh supported by a lightweight frame. It is fitted on windows and doors to provide a barrier against insects when the moving sash or panel is opened. A screen can also provide additional shading. Screens do not provide a secure barrier against forced entry or exit.
SCREEN MESH The plastic, fiberglass, or wire fabric that covers a screen.
SCREEN SPLINE The cord that holds the mesh in the screen frame.
SCREW BOSS A continuous screw port on an aluminum extrusion designed to accept a specific diameter screw and to provide a secure means of fastening without the use of any reinforcement.
SEALANT An elastomeric material with adhesive qualities that joins components to provide an effective barrier against the passage of undesired elements.
SEALED INSULATED GLASS UNIT Two or more panes of glass separated by an air space and factory sealed to produce a unit that improves insulation against heat transfer and sound transmission. The moisture is removed from the air space to eliminate possible condensation. To further improve the thermal properties, the air space can be filled with gas and/or the glass used can be tinted or Low-E coated. Also, when three panes are used, a thin plastic film with various coatings could be substituted for the middle pane of glass to produce similar or better results. The registered name General Aluminum uses for its sealed, insulated glass units is SPACEGLASS®.
SECURITY LOCK A secondary locking device for windows and doors that allows the sash or panel to be double-locked in the closed position.
SETTING Another term for Glazing. Also, the action of a compound as it becomes firm after application.
SETTING BLOCK Another term for Glazing Block.
SHADING COEFFICIENT A measurement used to describe the solar heat gain properties of transparent or translucent materials. A shading coefficient of 1.0 would be equal to 1/8” clear glass. The lower the shading coefficient, the lower the heat gain through the material, and thus the better the solar control performance.
SHADOWGRAPH A device for examining glass to reveal distortion and other defects.
SHORE HARDNESS Measures of firmness of a compound by means of a durometer hardness gauge. Two scales are used: Shore A and Shore B.
SHRINKAGE The loss of volume of a compound due to evaporation of the solvent or loss of oil or vehicle into a porous surface.
SIDE LITE A fixed window on one or both sides of a door.
SIGHT LINE The imaginary line around the perimeter of lites/sashes/panels that defines the area of vision after glazing or installation into the frame.
SIGMA (SEALED INSULATED GLASS MANUFACTURERS ASSOCIATION) An organization that establishes voluntary standards for the sealed insulated glass industry.
SILICA GEL An amorphous, highly absorbent material used, primarily, to absorb chemical vapors within the air space of a sealed insulated glass unit.
SILL The bottom horizontal member of a window or doorframe.
SILL INSERT A frame member, used typically on a horizontal slider, that is attached, to the sill for the purpose of raising the fixed lite to the same level as that of the moving lite.
SINGLE GLAZE, -ED, or –ING The use of a single pane of glass in a window or door, as opposed to double or triple glazing.
SINGLE HUNG WINDOW A window with a fixed top lite/sash and a vertically moving bottom sash. Balances offset the weight of the sash to allow it to remain raised in the desired position.
SKIN The outer surface that forms on a sealant compound as it dries.
SKYLIGHT A fenestration product designed to be installed in a roof or ceiling and to allow the passage of light and optional ventilation.
SLIDING DOOR A door with one or more moving panels that slide horizontally on one or more tracks in the head or sill.
SLIDING WINDOW or SLIDER Another name for a horizontal sliding window.
SOLAR ENERGY Electromagnetic wave energy from the sun, divided into three types: ultraviolet, visible, and infrared. When solar energy strikes a transparent or translucent material, it can be reflected, absorbed, or transmitted through the material. All three types of radiant energy are converted to heat when they are absorbed.
SOLAR ENERGY TRANSMITTANCE A measure of the amount of total solar energy (ultraviolet, visible, and infrared) that is allowed to pass directly through a transparent or translucent material. It is expressed as a percentage of the sun’s total radiant energy. The lower the percentage, the more effective the material is in blocking out solar energy.
SOLARIZATION Change in transmission and/or color of glass as a result of exposure to sunlight or other radiation.
SOLVENT A thinner that is used to lower viscosity, such as mineral spirit.
SPACEGLASS The registered name General Aluminum uses for its sealed insulated glass units.
SPACER CHANNEL Roll-formed aluminum tubes or other materials used to maintain the space between the two panes of glass in a sealed insulated glass unit.
SPANDREL GLASS Heat strengthened glass with a colored, opaque ceramic coating applied by a heat fusing process. It has twice the strength of annealed glass of the same thickness.
SQUARE Two surfaces meeting at right angles to each other. Also, the act of producing these two surfaces and a tool used to check such surfaces.
STC (SOUND TRANSMISSION CLASS) The sound transmission loss rating of a material over a selected range of sound frequencies. The higher the number, the less sound is transmitted.
STILE Any internal vertical member in a window or door.
STORM WINDOW A secondary window installed on the outside or inside of a prime window to provide additional insulation against heat transfer and sound transmission.
STRAIN Deformation per unit of length. The strain factor is determined by the change in length divided by the original length of a test specimen. Also, to pull or push with force.
STRESS Force per unit area, usually expressed in pounds per square inch. The opposing reaction or cohesiveness of a body resisting such force.
STP (STRUCTURAL TEST PRESSURE) The pressure a window is tested at for AAMA Certification of Structural Load Capacity. Usually 1.5 times the design pressure.
STRIKE An opening or retaining device for receiving a lock or latch. Typically housed in the head or jamb of a doorframe or in the edge of the meeting stile of a fixed door panel.
STUCCO A mixture of sand, Portland cement, lime and water which may be tinted and applied (like plaster) as an exterior wall coating.
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T
TEMPERED GLASS Glass which has been reheated to just below the melting point then quickly cooled. Tempered glass cannot be cut after tempering. When shattered, it breaks into many small pieces (dice), which are more or less cubical. It is four to five times stronger than standard annealed glass of the same thickness. Building codes require its use as safety glazing in doors, side lites, and other hazardous locations. Fully tempered glass has a surface compression of not less than 10,000 psi and an edge compression of not less than 9,700 psi.
TEMPLATE A precise detailed layout or pattern for constructing an object.
TENSILE STRENGTH The breaking-strength of a material when subjected to a tensile (stretching) force. Tensile strength is commonly expressed as pounds per square inch of original cross-section area. Also called Ultimate Strength.
THERM 100,000 BTU’s of energy or heat.
THERMAL BREAK A material of low conductivity placed between materials of higher conductivity to reduce the flow of heat and cold. Thermal breaks typically involve two metal sections separated by a plastic or polyurethane section, but the design and procedure to produce the thermal break varies greatly. General Aluminum uses the Thermal Fill technique, which involves pouring a two-part polyurethane into a pocket designed into an extrusion, allowing it to cure, and cutting away the bottom of the pocket (debridging). This produces an extrusion with two aluminum sections bonded together by the polyurethane thermal break. Thermally broken extrusions greatly improve the thermal performance of aluminum windows and doors.
THERMAL CONDUCTANCE (C-VALUE) The amount of heat conducted through a specific thickness of material. C-Value is determined from the K-Factor and is the inverse of the R-Value.
THERMAL CONDUCTIVITY (K-FACTOR) The amount of heat transfer per unit area in a given period of time of a homogenous material. The lower the number, the lower the conductivity.
THERMAL ENDURANCE The relative ability of glass to withstand thermal shock.
THERMAL PANE Another term for a Sealed Insulated Glass Unit.
THERMAL TRANSMITTANCE (U-VALUE) The overall coefficient of heat transfer. U-Values refer to the total heat flow through the complete heat barrier from inside air to outside air. Lower numbers indicate greater insulating capability. (See U-VALUE)
THROW The distance that a lock bolt or latch projects when in the locked position.
THRESHOLD An extrusion that is placed over the sill of a door to meet with the bottom of the moving panel when closed and provide a flat surface to step over.
THUMBTURN A permanently attached small lever which, when turned, operates the bolt on a lock in the same manner as a key.
TIP-TO-TIP DIMENSION An important flange window dimension. The Tip-to-Tip Dimension is measured horizontally between the outermost edges of the jamb flanges, and vertically from the uppermost edge of the head flange to the lowermost edge of the sill flange. (See FLANGE and FLANGE WINDOW)
TILT LATCH The hardware mechanism attached to the moving sash (es) of a tilt window that protrudes into the jambs to keep the sash (es) vertical in the frame.
TILT SHOE The hardware mechanism housed in the jambs of a tilt window that receives the pivot bars to secure the bottom of the moving sash (es) and allow the sash (es) to tilt about the pivot bars.
TILT WINDOW A single or double hung window whose operable sash (es) can be tilted into the room for ease of cleaning.
TINTED GLASS Glass with specific ingredients added while still in the molten state that causes the glass to be colored or tinted. The advantages of tinted glass are reduced light transmission and/or heat absorption.
TOLERANCE Permissible deviation from a nominal or specified dimension or value.
TOP RAIL The upper horizontal member of a window sash or door panel.
TOTAL SOLAR REFLECTANCE A measure of the percent of solar energy (ultraviolet, visible, and infrared) reflected away from a surface. The higher the percentage, the better the performance of the solar control product.
TRANSOM A crosspiece separating a door from a window above it.
TRANSOM WINDOW A window directly attached above a door or window.
TRIPLE GLAZE, -ED, or -ING; also TRIPLE PANE The use of three panes of glass within an opening, each separated by an air space, to improve insulation against heat transfer and sound transmission. The air spaces between the panes may or may not be factory sealed. (See SEALED INSULATED GLASS UNIT)
TRIPLE HUNG WINDOW A window with three vertically moving sashes which can be moved independently of each other. Balances offset the weight of the sashes to allow the sashes to remain raised in the desired position.
TRUE DIVIDED LITE A term describing a window or door containing true muntins (horizontal and vertical bars) that support small panes of glass, instead of the sash or frame glazed with a single pane of glass or a single insulated glass unit. (See MUNTIN)
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U
UBC (UNIFORM BUILDING CODE) A code published by the International Conference of Building Officials to regulate the methods and materials used in construction.
ULTRAVIOLET ENERGY The portion of solar radiation for which the wavelengths are shorter than those in the visible range. This radiation is invisible and can cause sunburn and fabric fading.
U-VALUE The measurement used in determining the ability of fenestration products (windows and doors) to conduct heat. The U-Value of a window or door is measured by the number of BTU’s per hour that will pass through each square foot of area per degree of temperature difference from one side to the other. Lower U-Values indicate better insulating properties.
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V
VAPOR BARRIER A shield to resist the flow of water vapor through the ceiling, walls, and floors of a structure. Often used as one side of insulating sheathing.
VENT Another term for the operating sash in window. Also, any small opening designed to allow airflow.
VENT JAMB The jamb (vertical frame member) on a horizontal sliding window/door that meets with the moving sash/panel when in the closed position.
VENT OPENING Pertaining to windows, the net clear opening area when the operating sash is fully open.
VENT STILE The stile (internal vertical member) on the moving sash/door in a horizontal sliding window/door that meets with the vent jamb when in the closed position.
VINYL A chemical compound used in making numerous resins and plastics. Extruded vinyl glazing beads and molded vinyl parts are examples of plastics made from polymerized vinyl compounds or copolymers of vinyl and other resins.
VISCOSITY The internal resistance to flow exhibited by a fluid. The higher the number the thicker the fluid.
VISIBLE LIGHT The portion of solar radiation that the human eye can see.
VISIBLE LIGHT TRANSMITTANCE The percentage of available visible light energy that is allowed to pass through a transparent or translucent material. The higher the percentage, the more visible light is transmitted through the material.
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W
WEATHERING Attack on a material surface by atmospheric elements.
WEATHERSTRIP A seal used around a window or door opening for protection against water and air infiltration.
WEEP A small opening in a wall or window/door sill member through which water may drain to the outside of the structure.
WET GLAZING A method of glazing in which the glass is secured into the sash/panel/frame by a glazing compound or sealant.
WINDOW A unit assembly installed in walls of a building to provide light or vision, and optional ventilation. Below are listed some of the different types of windows. For a description of each type, please see their individual definitions found elsewhere in this glossary.

Awning Window Garden Window
Single Hung Window Bay Window
Horizontal Sliding Window Hopper Window
Sliding Window or Slider Hung Window
Bow Window Storm Window
Casement Window Tilt Window
Double Hung Window Picture Window
Transom Window Fixed Window
Picture Window Slider Triple Hung Window
Flanker Window Prime Window

WIRED GLASS Rolled Glass having a layer of meshed or stranded wire completely imbedded as nearly as possible to the center of the thickness of the sheet before entering the rollers. This glass is obtainable as polished glass and patterned glass. Approved wired glass is used as fire retardant glazing as well as security glazing. It breaks more easily than unwired glass of the same thickness, but the wire restrains the fragments from falling out when broken.
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