Glazing Terms

Glass Association of North American Generic Glazing Glossary

Annealed Glass – Glass that has been created using a controlled cooling process which prevents residual stresses.

Air Infiltration – The amount of air leaking in and out of a building through cracks in walls, windows & doors.

Buck (Wood buck) – Pressure treated furring strips that brace a window within the opening.  Used with windows that have a flange.

Bullet-Resistant Glass – A multiple lamination of glass or glass and plastic that is designed to resist penetration from medium-to-super-power small arms & high-power rifles.  NOTE: Our impact rated products ARE NOT BULLET-PROOF.

Butt Glazing (Butt Glass) – The installation of glass products where the vertical glass edges are without structural supporting mullions. Typically you will see a silicon sealant between the vertical glass to seal it.

Casing – Internal return wood on the inside of a fiberglass or steel door.

Caulk – A compound used for sealing that has minimum joint movement capability.

Design Pressure – Specified pressure a product is designed to withstand.

Distortion – Alteration of viewed images caused by variations in glass flatness or inhomogeneous portions within the glass.  An inherent characteristic of heat-treated glass.

Dry Seal – Weather seal between glass and sash by use of strips of gaskets of Neoprene, EPDM, Silicone or other flexible material.

Glazing – The process of installing an glass into a prepared opening in windows, door panels, partitions, etc.

HVHZ – High Velocity Hurricane Zone door.  Term typically used with non-aluminum impact resistant fiberglass/steel doors.

Heat-Strengthened Glass – Glass that has been heat-treated to a specific surface/edge compression range to meet specific requirements.  Heat-strengthened glass is approximately two times as strong as annealed glass of the same thickness.

Interlayer – Any material used to bond two pieces of glass and/or plastic together to form a laminate.

Jambs – The vertical frame members at the perimeter of the opening

Laminated Glass – Tow or more lites of glass permanently bonded together with one or more interlayers.

Laminated-Insulated Glass – Consists of a hermetically sealed piece of glass that consists of five total layers: External laminated glass (3 layers), Air &/or gas (1 layer), internal single piece of glass (1 layer).

Low-emissivity (Low-E) Glass coating –  A coating that is applied to the internal surface of Laminated, and/or laminated-insulated, glass.  This coating allows for external radiant energy, from the sun, to be reradiated back toward the source, sun, further preventing the heat to transfer through the window.

Mullion – A horizontal or vertical member, typically an aluminum tube, that supports an holds two or more windows within a single opening.

Muntins – Horizontal or vertical bars that divide the sash frame (window) into smaller lites of glass. (Grids on windows)

Obscure Glass – Glass that has either a white interlayer, or ceramic grit or etched finish that impedes the visibility through the glass.  Typically used in bathrooms, front doors, garages & where privacy is desired while still allowing light.

Pocket Door &/or Window – A door or window that when fully open, will have no obstruction from the frame of the door throughout the entire opening.

Relative Heat Gain – Term used to represent how much heat the glass will restrict while taking in consideration the solar heat gain (Shading coefficient) & conductive heat gain (U-factor).  The lower the number, the more the glass restricts heat gain.

R-Value – Thermal resistance of glass.  This value is the reciprocal of the U-factor.  The higher the R-Value, the less heat is transmitted through the glass.

Sound Transmission Class (stc)- Number rating derived from individual transmission loss at specified frequencies.  The higher the number, the more noise the window will resist from passing through.

Sandblasting finish –  Typically an after installation process by which any design may be etched into the surface to create an obscured glass.

Sash – The opening part of a window, frame and glass, that can be removed from the installed window frame.

Shims – Spacer to level a window or door.

Sight Line – The line along the perimeter of the window that corresponds to the frame of the window where stationary and/or movable window panels meet.

Substrate – The material the window/door will be secured into using screws.

Transmittance – The ability of the glass to pass light and/or heat, usually expressed in percentages.

Turtle Glass – Glass that limits the transmittance of light such that it meets local turtle code building requirements.

U-factor – Air-to-air heat transmission (loss or gain) due to the thermal conductance and the difference in indoor & outdoor temperatures.  The lower the U-factor.

Weather-stripping – A material used to seal the door/window opening between the frames where they come together.

Water Infiltration – Amount of water pressure a door/window can handle before water will begin to seep through.