Resource Type: Glossary Term

A rating that measures resistance to heat flow; higher numbers generally indicate better insulation.

A rating that measures how well a window or glass assembly resists heat transfer; lower numbers generally mean better insulation.

How glass behaves after it breaks, including whether it falls out, stays bonded to an interlayer, or breaks into smaller pieces.

A rare impurity in tempered glass that can contribute to spontaneous breakage after installation.

A crack caused by uneven heating or cooling across a glass pane, often seen when part of the glass is shaded and another part is hot.

The ability of a glass assembly to withstand impact or reduce the consequences of impact.

Glass selected and installed to meet applicable building, safety, energy, or fire requirements for that location and use.

A small permanent mark or logo on safety glass, often used to identify tempered or certified glass.

A permanent mark on tempered glass showing that the glass has been safety-treated and identifying the manufacturer or certification information.

A building-code term for areas where glass is more likely to be impacted and may need safety glazing.