Tape balance See: Sash balance.
Tempered glass Glass manufactured to withstand greater than normal forces on its surface. When it breaks, it shatters into small pieces to reduce hazard. Standard on all doors and large fixed windows.
Thermal barrier (Thermal break) - A material of high thermal resistance placed between two metal sash, or installed between adjoining metal framing of metal windows and doors, in order to reduce thermal conduction from indoors to outdoors.
Thermal conduction Heat transfer through a material by contact of one molecule to the next. Heat flows from a high temperature area to one of lower temperature.
Thermal insulation A material that resists heat flow. Material having a high R-value.
Thermal resistance (R-value) - A property of a substance or construction which retards the flow of heat; one measure of this property is R-value.
See: Heat transfer coefficient.
Threshold The member that lies at the bottom of a sliding glass door or swinging door; the sill of a doorway.
Tinted glassSee: Heat absorbing glass.
Transom A smaller window above a door or another window. A transom joint is also the horizontal joining area between two window units which are stacked one on top of the other.
Treated glass Glass that has been coated or tinted to help improve its solar control properties.
Trim Visible molding surrounding a window opening. See: Casing.
Triple glazing Three panes of glass with two air spaces between, commonly consisting of an insulating glass with a separate storm sash.
True divided light A term that refers to windows or doors in which multiple individual panes of glass or lights are assembled in the sash using muntins.
Turtle glass Code Building code requirements intended to maximize protection of sea turtles that nest along the Atlantic and Gulf Coast beaches from May 1 to October 31 of each year. Sixty days after eggs are laid, the newborn hatchlings emerge. When they should head out to sea, the hatchlings, following their inborn tendency to move in the brightest direction, often become confused and are attracted back to the bright lights of the shoreline. As a result a number of local building codes or ordinances require a visible light transmittance of .45 or less on all new construction windows and doors within line sight of the beach. A typical solution is to specify laminated glass with a gray tint that falls within the acceptable visible light transmittance and meets hurricane impact requirements in coastal areas adjacent to turtle nesting.