Quick answer: Tempered glass is heat-treated to be 4x stronger than annealed glass and breaks into small, dull-edged pieces. Laminated glass is two layers of glass bonded to a tough plastic interlayer (PVB or SGP) that holds the assembly together when broken. Tempered is required in 'hazardous locations' (doors, sidelights, near floors). Laminated is required for impact-rated openings in Florida's WBDR and HVHZ zones, as well as for security and acoustic applications.
Tempered glass is heated to about 1,200°F and then rapidly cooled. This creates compressive stress on the surface and tensile stress in the core. The result: 4-5x stronger than regular glass and a safer break pattern (small granular pieces, no sharp shards). Tempered glass cannot be cut or drilled after tempering.
Laminated glass bonds two layers of glass to a plastic interlayer — typically polyvinyl butyral (PVB) or SentryGlas Plus (SGP). When the assembly breaks, the interlayer holds the broken glass together. This is what makes laminated glass impact-resistant: even if the outer layer breaks, the opening remains sealed.
FBC and IBC require tempered (or laminated) safety glazing in 'hazardous locations': doors and sidelights, glass within 24" of a door, glass within 18" of a floor, glass within 60" of a tub or shower, and glass facing stairs.
Impact-rated openings in HVHZ and WBDR zones must be laminated (or use approved shutters). FBC also requires laminated glass for skylights, overhead glazing, and certain railing applications.
Tempered glass adds roughly 25-40% to base annealed glass cost. Laminated glass adds 60-90% over annealed (depending on interlayer thickness and type). Insulated laminated impact glass (the typical HVHZ assembly) adds roughly 100-150% over plain annealed insulated glass.
Acoustic environments (hotels, restaurants near roads) — laminated with thick PVB hits STC 38+. Security (jewelry stores, banks) — laminated with SGP interlayer resists forced entry. Solar control — laminated allows custom interlayer colors and films.
Tempered glass is heat-treated for strength and breaks into small dull pieces. Laminated glass is two layers bonded to a tough interlayer that holds the assembly together when broken. Tempered is safer; laminated is impact-resistant and stays in place after impact.
It depends on the application. Tempered is safer for collision impacts because it breaks into dull granules. Laminated is safer for security and storm exposure because it doesn't fall out of the opening when broken.
Yes — Florida Building Code requires tempered (or laminated) safety glazing in storefront doors, sidelights, and glass adjacent to doors. The specific zones are defined by FBC Chapter 24.
All impact-rated glass is laminated, but not all laminated glass is impact-rated. Impact-rated assemblies must pass specific missile and pressure tests (TAS 201/202/203 or ASTM E1996/E1886). Plain laminated glass without testing doesn't qualify as impact-rated.
Laminated glass typically costs 60-90% more than tempered glass on the same nominal thickness. Insulated laminated impact glass costs 100-150% more than plain insulated tempered glass.
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