Empire Pacific Windows®

RESOURCES | Glossary

A
Apron: A piece of horizontal sash or window trim applied against the wall immediately below the stool. It serves to conceal the joint made by the sash of window frame sill and the plaster on interior wall finish.
Awning Window: A projecting window hinged at the top--opening up and out like an awning.
 
B
Basement Sash Unit: A sash unit, usually of the in-swinging or hopper sash type, used for basement or cellar sash openings. Usually consists of one, two or three glass lites.
Bay Window: Composed of three or more individual windows, generally with the side or flanker units at 45- or 30-degree angles to the wall of the structure.
Blind Stop: A sash or window frame member applied to the exterior vertical edge of the side and head jamb in order to serve as a top for the top sash and to form with the brick molding and/or casing a rabbet for the storm sash, screens, blinds and shutters.
Bow Window: Composed of three or more individual windows in a gently curved contour. Bow windows also project from the wall of the structure.
Brick Molding: A standard milled trim piece to cover the gap between the window frame and masonry in a masonry opening.
 
C
Casement Window: A projecting window with a single sash hinged at the sides and usually opening outward like a door and operated by a crank handle that turns to open or close the unit.
Casing (Trim): Exposed molding or framing around a window or door, on either 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.
Cottage Style Window: Hung window (single or double) that has a larger bottom sash (lite) than the tope sash.
 
D
Desiccant: A drying agent (such as silica gel) used by some manufacturers between the panes of insulating glass (in the edge spacer) to prevent “fogging” between the panes.
Double Hung Window: Two sash which move vertically, by-passing each other in a single frame. Sash may be counter-balanced by weights or springs.
Double Strength Glass: Sheet glass with a thickness between 0.115” to 0.1233” (3 to 3.38mm) or approximately 1/8” used in larger window units.
Drip Cap: A horizontal molding to divert water from the top casing of a window or door unit so that the water drips beyond the outside of the frame.
Eyebrow Window: Used to identify certain arch-topped or radius topped windows that have a curved top like the shape of a human eyebrow.
 
F
 
Fenestration: The placement of window openings in a building wall; one of the important elements in controlling the exterior appearance of a building, its ventilation, light, etc.
Fixed Light (Fixed Sash): Window that is non-operative (does not open).
Frame: Outside member of a window (or door) unit that encloses the sash. Composed of side jambs, head jamb and sill.
 
G
 
Glass: A transparent, translucent or opaque material formed by fusing silicates with soda or potash, lime and sometimes various metallic oxides.
Glass (Insulating): Two sheets of glass bonded together in a unit to enclose a captive air space.
Glazing: The glass panes or lites in the sash of a window. Also the act of installing the glass in a window sash.
Glazing Bead: A removable trim that holds the glass in place in a window sash.
Glazing Block: A small, hard rubber block placed around the edges of the glass unit in a window sash to position the glass and prevent it from shifting.
Glazing Tape: Double-sided tape used to adhere glass to sash and form an airtight, watertight seal.
Grids: Ornamental or simulated bars which don’t actually divide the lites of glass. Generally made of vinyl and fitted on the inside of the sash against the glass surface for easy removal. Grilles or grids between the glass are usually made of aluminum and sealed inside the insulating glass unit.
 
H
 
Head: The top or upper member of any elementary structure; in windows, it refers to the top of the frame, as in Round Head Window.
Head Board: A flat board cut to fit the contour of a bay or bow window and used to affix to the top of the window units. Heat Mirror: A thin transparent insulating film that is inserted between double glazing which permits transmission of visible light but reflects far-infrared radiation. Heat Transfer Co-efficient (U-value): A value indicating the rate of heat flow through a building construction, expressed in units of “Btu/h per square foot of surface per degree F. difference between indoor and outdoor air temperature.” Hinge: A moveable joint enabling a window or door to swing open.
 
I
 
Infiltration: Leakage of outdoor air into a house, such as through cracks around sash or window frame.
Installation Fin or Flange: A vinyl or metal flange inserted into or an integral part of the side and head jambs of a window unit which is used for installing it in an opening. It also affords a weather seal or flashing around the perimeter of the window frame.
Insulating Glass: Double or triple glazing with an enclosed, dehydrated and hermetically sealed air space between the panes.
Insulated Window: A window with multiple glazing that provides one or more air spaces between layers of glazing.
 
J
 
Jamb: A vertical member at the side of the window frame; also refers to the horizontal member at the top of the window frame.
 
K
 
Keeper: The part of a window lock, mounted on an opposing surface of the window that the lock arm locks under or into to pull the sash into a locked position and fully releases it when opened.
 
L
 
Latch (Catch/Lock): A device that holds a window shut, such as the latch at the meeting of a double-hung window or one mounted on the stile of casement windows, often referred to as the Lock.
Lexan: A trade name for glazing material that is extremely resistant to breakage.
Lite (Light): A window; a pane of glass within a window. Double hung windows are designated by the number of lites in upper and lower sash, as in six-over-six. This is typically spelled “lite” to differentiate from sunlight or other sources of light that shine through a window.
Lock: A fastening device in which a bolt is secured and can be operated by a key.
Low-E Glass: Stands for Low-Emissivity. Glass that has been given a special micro-thin coating (usually silver and metal oxides) that blocks the passage of radiant heat through the glass for better energy efficiency without appreciably affecting the view through the glass.
 
M
 
Meeting Rail (Lock Rail): One of the two horizontal members of a double hung sash that come together.
Miter Joint: Two members joined at an angle, commonly 45 degrees.
Mullion: Vertical or horizontal divisions or joints between single windows in multiple units. Can be either decorative or functional.
 
O
 
Obscure Glass: A glass (frosted, etched, fluted, ground, etc.) for privacy, light diffusion or decorative purposes.
Operable Window: Window that can be opened for ventilation.
Operator: Crank operated device for opening and closing casement or Jalousie windows.
Outside Casing: Trim or molding around a window or door on the exterior of the house.
 
P
 
Pane: A sheet of glass for glazing a window. After installation, the pane is referred to as a lite or window lite.
Parting Bead: A vertical strip on each jamb that separates the sashes of a double hung window.
Picture Window: Large fixed windows introduced in the 1940s.
Pivot Pin (Pivot Bar): Part mounted on or in the end of the sash that fists into the balance shoe and from which the sash may be titled or pivoted in.
  Q
 
Quarter Round Window: Stationary or operating window with glass shaped as a quarter circle; it is often divided into separate panes by a removable grille, installed on the interior or grille between the glass.
 
R
 
Radiation: Energy released in the form of waves or particles, due to a change in temperature within a gas or vacuum.
R-Value (Thermal Resistance): A measure of the resistance a unit of heat has in flowing through a given material or construction; a higher value indicates a better heat insulating property. The R-value of an ordinary single pane sash with a 15mph wind on one side is about 0.9.
Rough Opening: The opening left in a frame wall to receive a window or door unit.
Round Top: a window having a curved (radius) top and a flat bottom. The shape of the window is an exact half-circle with the height being exactly one-half of the width.
 
S
 
Safety Glass: A strengthened or reinforced glass that is less subject to breakage or splintering, such as glass for storm doors and some windows.
Sash: a single assembly of stiles and rails in which the lites of a window are set. The framework holding the glass in a window unit.
Sash Balance: A device for counter-balancing a sash of a double hung window to hold it in the up position.
Sealant: A compressible plastic material used to seal any opening or junction of two parts, such as between the glass and its sash, commonly made of silicone, butyl tape or polysulfide.
Shims: Wood wedges (often wood shingles) used to position the window or door unit in the rough or masonry opening in a square, level and plumb position during and after installation.
Seat Board: A flat board cut to fit the contour of a bow or bay window and installed between the sills and the flat wall surface, providing a seat or shelf space.
Side Lite: A fixed, often narrow, glass window next to a door opening (or window). Single Hung Window: A window that is similar to a double hung window except that the top lite is fixed.
Single Strength Glass: Glass with a thickness between 0.085” to 0.100” (2.16 mm to 2.57 mm) or approximately 3/32.”
Spacer: The material used around the edges of an insulated glass unit to separate the panes of glass. They may be hollow metal tubes of aluminum oar steel, or non-conductive materials such as silicone, butyl or a combination of materials. Specialty or Special-Shaped Window: A window of a “non standard” shape of construction such as a triangle shaped window, round or curved shaped- window, etc.
Spline: for screening, a small strip of metal or flexible tubing or gasket material that fits into a groove in the screen frame to secure the screen cloth.
Stacked Window Units: A vertical grouping of awning, hopper, casement or non-operating windows to form a large, multiple unit.
Stop: A trim member attached to the window frame to stop the sash of a projecting window when closed to prevent it from swinging through the opening.
 
T
 
Tempered Glass: Special heat-treated, high-strength safety glass that shatters into pebble-sized particles but not into slivers when broken.
Tinted Glass: Glass that has been given a slight hading or coloring to it, usually to control sun light in a very bright, high intensity sun locations.
Transom: Generally refers to an opening or stationary sash above a door or window which serves a similar purpose to a side lite. A transom joint is the horizontal joining area between two-window unit which are stacked one on top of the other.
Triple Glazing: Three panes of glass with tow air spaces between, commonly consisting of an insulating glass with a separate storm sash.
 
U
 
U-Value: A value indicating the rate of heat flow through a building construction expressed in units of “Btu/h per square foot of surface per degree F. difference between indoor and outdoor air temperature.”
Ultra-Violet: Type of radiation with wavelengths shorter than those of visible light and longer than those of X-rays. Causes sunburn, fading and breakdown of fabric, wood, furniture and other exposed surfaces.
 
V
 
V-Groove: A V-shaped groove cut into the surface of a glass pane for decorative purposes.
 
W
 
Weather strip: 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: Small holes drilled along the bottom edge of storm sash, combination storm-screens or windows with pocket sills to permit moisture condensation or wind-driven rain to drain away from the sill to the outdoors.
Window Frame: The fixed frame of a window that holds the sash as well as the operating hardware for the window.
Window Hardware: Various devices and mechanisms for the window including catches, cords and chains, fasteners and locks, hinges and pivots, lifts and pulls, pulleys an sash weights, sash balances and stays.
Window Schedule: A listing of windows required in a given house stating types, sizes, number of lites, manufacturer and any special needs.
Window Screen: Woven mesh of metal, plastic, or fiberglass stretched over a window opening to permit air to pass through, but not insects.