Glossary of Terms

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AAMA

American Architectural Manufacturers Association. A national trade association that establishes voluntary standards for the window and door industry.

Acrylic (plastic)

A non-crystalline thermoplastic with good weather resistance, shatter resistance, and optical clarity; sometimes used for glazing.

Anodize

To provide an extremely hard non-corrosive oxide film on the surface of aluminum, by electrolytic action. Anodic coatings may be transparent, of varying shades of silver, gray, brown, or colors may be incorporated by the use of dyes.

Argon

An inert, colorless, and harmless gas used instead of air in sealed spaces between panes of glass in insulating glass units to increase insulation. Argon is less conductive to heat than air. It is injected in the airspace of an insulating unit, to improve energy efficiency.

Awning Window

A type of window with a top-hinged sash that swings out at the bottom, letting in fresh air while keeping rain out.

Balance

A mechanical device used in vertically operating windows that counter-balances the weight of the sash during opening and closing.

Basement Window

A sash unit, usually of the in swinging awning type, used for basement or cellar sash openings. Products may include screens or storm sash and may include provisions for emergency evacuation from the basement area.

Bay Window

A type of window consisting of a central picture window flanked by a pair of narrow casement windows set at an angle – provides a panoramic view.

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.

2) A strip of sealant, such as caulking or glazing compound.

Block

A small piece of lead, neoprene or other suitable material used to position the glass in a frame.

Blocking

To shim, level and plumb windows in required position.

Bow Window

A type of window made of equal-sized casement/picture units in a gentle outward curve – allows for a wider view and more living space.

Casement Window

A type of window with a side-hinged sash that opens like a door – the best window for catching breezes and crosswinds. The sash are usually operated by means of roto-operators or a handles.

Double Hung Window

A type of window that has an upper (outside) sash that slides down, and a lower (inside) sash that slides up. A vertical operating 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.

Drywall

Interior cladding with panels of gypsum board, fiber board or plywood, a dry operation as opposed to wet plaster.

Emissivity

A measure of an object’s ability to emit long-wave infrared radiation or room temperature radiant heat energy. Emissivity varies from 0 (no emitted infrared) to 1 (100% emitted infrared). The lower the emissivity, the lower the resultant U-value.

Enamel

A type of paint consisting of an intimate dispersion of pigments in a resin vehicle.

Fenestration

The placement and arrangement of the windows and doors of a building.

Frame

Consists of a head, jambs, and sill to form an opening into which sash or door panels fit. An assembly of structural members which surrounds and supports the sash, ventilators, doors, panels or glazing which is installed into an opening in the building envelope or wall.

Glazing

The installation of glass into a window or door sash

Glazing Bead

A molding or stop along the inside perimeter of the frame that assists in holding glass in place.

Grilles/Grids

Decorative inserts for windows or door glazing that adds a traditional touch – available in fixed or removable inserts

Head

The main horizontal member forming the top of the window or door frame.

Hinge

A device on which doors or windows may turn or swing, to open and close

Horizontal Sliding Window

A window where the movable panels slide horizontally. These windows consist of one or more horizontally operable sash in a sealing frame.

Insulating Glass

Insulating glass refers to two or more pieces of glass spaced apart and 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 air space.

Insulation

Construction materials used for the protection from sound, heat, cold, or fire. A material with high resistance that is used to retard heat flow. Air, argon, or krypton gas spaces between panes of glass provide insulation.

Interlock

A set of meeting rails or meeting stiles which contains a provision for each of rails or stiles to physically engage one another over their entire length.

Jambs

Vertical, or side members of the window’s or door’s main frame.

Laminated Glass

Two or more sheets with an inner layer of transparent plastic to which the glass adheres if broken. This process produces glass four times more impact resistant than non-tempered glass. Used for overhead, safety glazing, and sound reduction.

Lift Rail

A rail in a vertical window provided with an operator to raise and lower the operable sash.

Lock

The device on a window or door that secures it in a closed position

LoE2

Sputtered Low E glazing.

Low E Glass

Low-emissivity glass with a transparent coating which acts as a thermal mirror – used to increase a window’s insulating value, block or increase heat flow, and reduce fading.

Marine Type Glazing

A glazing system which begins by wrapping the full perimeter of the glass unit with a soft vinyl channel which serves to cushion the glass, as well as provide positive protection from water. Marine type glazing is typically round on high quality window products.

Meeting Rail

A rail which overlaps another rail. The part of a sliding glass door or a sliding window where two panels meet and create a weather barrier.

Mullion

An intermediate-connecting member used as a means to “join” two or more window products together in a single rough opening.

Muntin Bar

A small bar that divides window or door glass.

Nailing Fin

An integral extension of a window frame which generally laps over the conventional stud construction and through which nails are driven to secure the frame in place.

NRFC

National Fenestration Rating Council, measures and compares the energy component of windows and doors.

Obscure Glass

Mainly used for decoration, diffusion, or privacy. The design is pressed into the glass during the rolling process. There are many patterns available.

Operator

A component or means of gripping that is used to move, pivot or to adjust the position of an operable sash, ventilator, or panel in a window or door assembly.

Pane

A framed sheet of glass.

Panel

A part of fenestration product, composed of a lite of glass and surrounded by a frame. Panels can be fixed in place or be movable.

Panning

Used in replacement window work. Panning refers to the outside aluminum trim that can extend around the complete perimeter of the window opening. It is used to cover up the old window material, such as wood or steel.

Radiation

The direct process of heat transfer through space by means of electromagnetic waves. Energy in the form of rays of light is transferred from body to body without heating the intermediate air.

Rail

A horizontal surrounding edge member of a sash, ventilator, or panel.

Receptor

Framing system consisting of one or two aluminum extrusions used to contain a window or door frame, head and/or jambs in a masonry type opening. Allows for deflection and inconsistencies in the openings.

Roto-operator

A window opening device that has a handle to crank open a window.

Sash

The portion of a window which includes the glass and the framing sections which are directly attached to the glass. Normally the moving segment of a window, although sash are sometimes fixed. Not to be confused with the main frame into which the sash sections are fitted.

Screen

A product used with a window or door, consisting of a four-sided frame surrounding a mesh of wire or plastic material used to keep out insects. The screen can be fixed in place or it can be rolled side-to-side as on a sliding glass door.

Sill

The main horizontal member forming the bottom of the frame of a window or door.

Single Glazing

The use of single thickness of glass in a window or door.

Single Hung Window

Single hung windows are vertically operating windows in which the sash weight if offset by a counterbalancing mechanism mounted in the window. The single hung window features a stationary top and a movable bottom half. One or more locking devices are furnished to secure the sash in the closed position.

Slider Window

A slider window may have one or two movable panes of glass. Whatever the type, the windows slide horizontally in the frame.

Sliding Glass Door

Sliding glass doors consist of one or more pieces of glass contained in panels, which are contained within an overall frame designed so that one or more panels are movable in a horizontal direction. Panels shall be all sliding or some sliding and some fixed. Panels shall lock or interlock with each other or shall contact a jamb member where the panel is capable of being securely locked. Doors shall be designed and assembled so that panel to panel contact between horizontal members moving relative to each other does not occur.

Spacers

In glazing, small blocks of neoprene, nylon, or other material placed on both sides of the edges of glass, during its installation, to center it in the glazing channel to maintain uniform width of sealant bands and prevent excessive sealant distortion under lateral loading.

Stile

The upright or vertical surrounding edge members of any sash, ventilator, or panel.

Tempered Glass

The glass is reheated to right below the melting point then suddenly cooled. When shattered, it breaks into small pieces. It is approximately five times stronger than standard annealed glass. It cannot be re-cut after tempering.

Tinted Glass

A mineral Admixture is incorporated in the glass, resulting in a degree of tinting. Any tinting reduces both visual and radiant transmittance.

Ultraviolet

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.

Vinyl

Polyvinyl chloride (PVC) material that can be either rigid or flexible, used in glazing channels and weathering of both windows and doors.

Warm Edge Spacers

Insulating spacers used to seal panes of glass in the manufacture of insulated glass units – edge conductivity is lessened for improved window energy performance and reduced condensation problems.

Weather stripping

Thin sections of material used to prevent air leakage around operable windows and doors – usually foam gasketing, metal strips, or vinyl.

Window

An opening constructed in a wall or roof and functioning to admit light or air to an enclosure, usually framed and spanned with glass mounted to permit opening and closing.