Resources

Glossary of Terms C – G

Casement

A window sash that swings open on side hinges: in-swinging are French in origin; out-swinging are from England.

Casing

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.

CFM

Cubic Feet per Minute.

Check rail

The bottom horizontal member of the upper sash and the top horizontal member of the lower sash which meet at the middle of a double-hung window.

Clerestory

A window in the upper part of a lofty room that admits light to the center of the room.

Composite frame

A frame consisting of two or more materials – for example, an interior wood element with an exterior fiberglass element.

Condensation

The deposit of water vapor from the air on any cold surface whose temperature is below the dew point, such as 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.

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 standard.

Degree day

A unit that represents a one-degree Fahrenheit deviation from some fixed reference point (usually 65F) in the mean, daily outdoor temperature. See also heating degree day.

Desiccant

An extremely porous crystalline substance or used to absorb moisture from within the sealed air space of an insulating glass unit.

Dewpoint

The temperature at which water vapor in air will condense at a given rate of humidity and pressure.

Divided light

A window with a number of smaller panes of glass separated and held in place by muntins.

DOE-2.1E

A building-simulation computer program used to calculate total annual energy use.

Double glazing

In general, two thicknesses of glass separated by an air space within an opening to improve insulation against heat transfer and/or sound transmission. IN factor-made double glazing units, the air between the glass sheets 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 operating in a rectangular frame, in which both the upper and the lower halves can be slid up and down. A counterbalance mechanism usually holds the sash in place.

Double-strength glass

Sheet glass between 0.115” and 0.133” (3-3.38 mm.) thick.

Drip

A projecting fin or a groove at the outer edge of a sill, soffit, or other projecting member in a wall designed to interrupt the flow of water downward over the wall or inward across the soffit.

Dry-Wall Remove

Ability to remove Sashes and Astragal in new construction single-hung and/or sliding windows (0100, 0102, 0103) and new construction picture window (0104) to allow for oversize access such as entering dry-wall in to a newly constructed structure.

Edge effect

Two-dimensional heat transfer at the edge of a glazing unit due to the thermal properties of spacers and sealants.

Electrochromics

Glazing with optical properties that can be varied continuously from clear to dark with a low-voltage signal. Ions are reversibly injected or removed from an electrochromic material, causing the optical density to change.

Electromagnetic spectrum

Radiant energy over a broad range of wavelengths.

Emergency exit windows

Fire escape window (egress window) large enough for a person to climb out. 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.

Emittance

The ratio of the radiant flux emitted by a specimen to that emitted by a blackbody at the same temperature and under the same conditions.

Evacuated glazing

Insulating glazing composed of two glass layers, hermetically sealed at the edges, with a vacuum between to eliminate convection and conduction. A spacer system is needed to keep the panes from touching.

Exterior stop

The removable glazing bead that holds the glass or panel in place when it is on the exterior side of the light 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.

Fanlight

A half-circle window over a door or window, with radiating bars. Also called circle top transom.

Fenestration

The placement of window openings in a building wall, one of the important elements in controlling the exterior appearance 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.

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 sliding glass door or slider window.

Fixed window

A window with no operating sashes.

Flashing

Sheet metal or other material applied to seal and protect the joints formed by different materials or surfaces.

Float glass

Glass formed by a process of floating the material on a bed of molten metal. It produces a high-optical-quality glass with parallel surfaces, without polishing or grinding.

Fogging

A deposit of contamination left on the inside surface of a sealed insulating glass unit due to extremes of temperatures or failed seals.

Frame

The fixed frame of a window which holds the sash or casement as well as hardware.

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 glass or plastic panes in a window, door, or skylight.

Glazing bead

A molding or stop around the inside of a window frame to hold the glass in place.

Greenhouse window

A three-dimensional window that projects from the exterior wall and usually has