Glass and Glazing Materials
What this domain tests
Glass and Glazing Materials tests selection and limitations: annealed, heat-strengthened, tempered, laminated, insulating glass units, coated, spandrel, and fire-rated products. You need to match code, safety, and performance requirements to the right product.
Core rules
- Annealed float glass is the base product; it can be cut and drilled but is not safety glazing.
- Heat-strengthened glass is roughly twice as strong as annealed and breaks into larger shards; tempered is roughly four times as strong and breaks into small dice. Tempered and heat-strengthened glass cannot be cut or drilled after heat treatment.
- Laminated glass uses a PVB or SGP interlayer; it holds together after breakage and can be safety glazing. SGP is stiffer and retains integrity better than standard PVB.
- An insulating glass unit has two or more lites, a spacer with desiccant, primary and secondary seals, and often argon or krypton. Low-E coatings are typically on surface 2 or 3; soft-coat requires careful handling.
- Safety glazing at hazardous locations must meet CPSC 16 CFR 1201 or ANSI Z97.1. Fire-rated glazing must carry the listed rating; wired glass is not automatically impact safety glazing.
Worked example
A school corridor door vision lite is a hazardous location. Specify impact safety glazing-tempered or laminated meeting CPSC 16 CFR 1201. If the opening also requires a 20-minute fire rating, do not assume ordinary tempered glass works; select a listed fire-rated glazing assembly with the required impact rating.
Traps that cost marks
Specifying tempered glass and then expecting field cutting; confusing heat-strengthened with tempered; putting low-E on the wrong surface; and treating all laminated glass as fire-rated are frequent mistakes. Also verify whether the insulating glass unit coating is durable enough for exposed handling.