Common Terminology
When we discuss glazing systems we must first learn the common terms and phrasing used within the industry. Below are common terms and their meanings:
- Annealed glass: standard float glass.
- Air infiltration: the amount of air leaking in and out of windows, walls, doors, etc.
- Air space: the space in the cavity between the two panes of glass in an I.G.U.
- Bite: amount of glass recessed into the framing.
- Butyl: synthetic rubber used as a sealant and architectural glazing tape.
- Curtain wall: exterior cladding system made mostly of metal and glass, can be used in high rise applications
- CRF: condensation resistance factor.
- EPDM: Ethylene Propylene Diene Monomer – many setting blocks are made from this
- Extrusion: the process of producing an aluminum shape by forcing heated material through an orifice in a die. Gaskets, PVC, etc. can also be extruded in similar fashion.
- Gasket: pre-formed shape of rubber or rubber-like material used to fill and seal openings. Typically installed between the glass and metal components of glazing systems.
- Heat gain: transfer of heat from the outside to inside of the building.
- Heat loss: transfer of heat from the inside to outside of the building.
- I.G.U. (insulated glass unit): two or more glass panes separated by a spacer and sealed at the edges.
- Jamb: the vertical member of a framing system adjacent to the rough opening.
- Laminated glass: glass composed of two sheets of glass which are fused together with an inter-layer commonly made of clear PVB.
- Lite: another term for pane or piece of glass.
- Low-E (emissivity) coating: transparent coating applied to an inside face of an I.G.U. to improve the units energy efficiency.
- Mullion: the vertical member of a framing system.
- PSF: pounds per square foot.
- Setting block: block which the glass sits on within the glazing system.
- Shim: small pieces of material used to hold the glazing system away from the surrounding conditions.
- Solar heat gain coefficient: refers to the solar gain through the glass relative to the current solar radiation.
- Spacer: material placed between two or more pieces of glass to create an I.G.U. This can consist of aluminum or a different material, such as available “warm edge spacers.”
- Spandrel glass: glass which has a coating on the inside which keeps the inside of the building hidden from the outside.
- Storefront: exterior cladding system made mostly of metal and glass, used for mainly low rise and first floor applications.
- Tempered glass: glass which has been through a tempering oven creating specific surface tension to strengthen the glass and cause it to break into small pieces instead of shards when broken.
- Tinted glass: glass that has had a mixture incorporated into it to provide color and protection from the sun.
- U-value: measurement used to determine the ability of the glazing systems (and other components) to conduct heat. Typically, the lower the number the more efficient your window is.
