A Fenestration/Glazing/Double Glazing Glossary of Common Terms
Common double glazing terminology- we hope you find it useful.
Absorptance The ratio of radiant energy absorbed to total incident radiant energy in a glazing system.
Acoustic Insulation Acoustic insulation, such as double glazing, is used to reduce the nuisance caused by outside noise. Acoustic insulation works by reducing a sound wave’s energy.
Acrylic A thermoplastic with good weather resistance, shatter resistance and optical clarity, used for glazing.
Air Infiltration Term used to describe one of the tests required by AS2047. The window shall not exceed air leakage requirements as specified for either air conditioned buildings or non-air conditioned buildings<
Air Space (Air Gap) The space in the cavity between two panes of glass in an insulated glass unit.
Argon Gas An odorless, colorless, tasteless, non-toxic gas which is six times more dense than air. It is used to replace air between the glass panes to reduce temperature transfer.
Australian Standard AS3959 “Construction of buildings in bushfire-prone areas.“ Incorporates Bushfire Alert Level Ratings (BAL)
Australian Standard AS 2047 Windows in Buildings- Selection and Installation.
Awning Window A top-hinged window that swings outward for ventilation.
Bay Window An angled combination of three windows that project out from the wall of the home. The windows are commonly joined at 30- or 45-degree angles.
Casement Window A window with a side-hinged sash that opens outward for ventilation.
CKD Completely Knocked Down. A window or door supplied in component parts only
Colonial Windows A window that is configured with horizontal and vertical bars to recreate the early colonial style of windows. Can be achieved with applied bars adhered to the glass or individually glaze.
Clerestory. A window near the top of an outside wall.
Composite Frame A frame consisting of two or more materials, eg an interior wood element with an exterior aluminium element,
Condensation The accumulation of water vapors or droplets as the result of warm, moist air coming in contact with a cold surface and cooling to its dew point temperature. Condensation may occur when a cold window glass or frame is exposed to humid indoor air. Low-conductivity, insulated glass and warm-edge spacers reduce condensation. Read more about condensation.
Conduction Heat transfer through a solid material by contact of one molecule with the next. Heat flows from a higher temperature area to a lower temperature one.
Dormer A space which protrudes from the roof, usually including one or more windows.
Double Glazing Glazing that incorporates two panels, separated with an air space, for the purpose of thermal and acoustic insulation.
Double Hung Window A window that has two operable sashes which slide vertically.
Emittance Measures the ability of a surface to emit long-wave infrared radiation, compared with the emittance of a ‘perfect black body’, equal to 1.0. The emittance of uncoated, clear glass is 0.84. A very good low-emittance coating will have an emittance of 0.5 or less.
Extrusion Aluminium or uPVC profiles used in a window. An extrusion is produced by pushing material through a die with an aperture of the shape of the section.
Fenestration Any opening in a building’s envelope including windows, doors and skylights. (NFRC def.)
Frame That part of a window assembly surrounding the sashes or fixed glazing.
French Door A particular design of swing door, all or a large part consisting of divided glass panes.
Gasket A pliable, flexible continuous strip of material used to affect a watertight seal between a sash and frame much like the seal around a refrigerator door.
Glazing The process of sealing the glass to the sash.
Hopper Window A window unit, hinged at the bottom to open inward (or outward) from the top
I.G. Unit (Insulating Glass Unit) Two or more plates of glass separated by a spacer and hermetically sealed at the glass edges.
Jamb Vertical sections of the main frame.
Laminated Glass Specially designed glass where two panes of glass are bonded to a durable interlayer, providing increased safety, UV protection and noise reduction. If the window or door gets broken the glass will adhere to the to the plastic interlayer-preventing glass fallout in the home.
Lintel A horizontal framing member placed across the top of the rough opening of a window or door opening to prevent the weight of the wall or roof from resting on the window frame.
Low E (Emissivity) Glass Glass with a transparent metallic oxide coating applied onto or into a glass surface. The coating allows short-wave energy to pass through but reflects long-wave infrared energy which improves the U-value.
Main Frame The head, sill and jambs sections of a window.
Mullion A vertical or horizontal connecting unit between two or more windows.
Obscure Glass Glass that has been made translucent instead of transparent.
Pane A sheet of glass for glazing a window.
Patio Door A glass door that slides open and close on adjustable tandem rollers. Available in 2- or 3-lite configurations with the operable panel available in any position.
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 The part of the window which contains the glass.
Sill The horizontal, bottom section of the main frame.
Single Hung Window A window in which one sash slides vertically and the other sash is fixed.
Single-strength Glass Glass with a thickness of approximately 3/32?.
Slider Window A window in which the sash move horizontally. Sliders are available in a 2- or 3-lite configuration, with the 3-lite having operable end vents.
Sloped Sill The sill of the window that has a downward slope to the outside. This sill has sufficient degree of slope to aid in water runoff.
Solar Heat Gain Coefficient (SHGC) The percentage of heat gained from both direct sunlight and absorbed heat. The smaller the number, the greater the ability to reduce solar heat gain.
Spacer Material placed between two or more pieces of glass in order to maintain a uniform width between the glass, and prevent sealant distortion.
Tempered Glass Glass with a surface compression of not less than 10,000 psi, or an edge compression of not less than 9,700 psi. When broken, the glass breaks into pebbles instead of shards.
Tilt & Turn Windows Windows with fittings that make it possible to rotate the window through 180º so that the exterior pane is facing inwards. This is very practical when washing windows.
Transmittance The percentage of radiation that can pass through glazing. Transmittance can be defined for different types of light or energy, e.g. visible light transmittance, UV transmittance or total solar energy transmittance
Triple Glazing Glazing that incorporates three panes of glass, enclosing two separate air spaces.
uPVCWA UPVC Window Alliance
U-value Amount of heat transferred through a material. The lower the U-value, the slower the rate of heat flow and the better the insulating quality.
Visible Light Transmittance The percentage of light that is transmitted through glass in the visible light spectrum (380 to 720 nanometers). The higher the number the higher the percentage of visible light transmitted through the window.
Weather Seal sash glazed with three lights of glass, enclosing two separate air spaces.
Weep Slots Slots or holes in the sill (bottom) member of the sash frame that allows water to escape. Weep flaps add a vinyl flap to keep insects out.
WERS Australia’s Window Energy Rating Scheme.
Wind Load The wind pressure in Pascals that the window has to meet. Wind load varies according to location and exposure.