Industrial, Commercial, Institutional and Residential Glass and Glass Substitute Work
This domain tests how well you match glass and glass-substitute products to service conditions and code requirements across industrial, commercial, institutional and residential work. Expect questions on tempering and lamination, safety-glazing locations, edge and face clearances, setting blocks, sealant selection and the limits of acrylic, polycarbonate and wired glass.
Product properties that drive selection
- Annealed glass is the baseline product. Heat-strengthened glass is roughly twice as strong and breaks into large shards. Tempered glass is roughly four times as strong, breaks into small dice, and cannot be cut, drilled or edge-ground after tempering.
- Laminated glass uses PVB, EVA or ionoplast (SGP) interlayers. It retains fragments and can provide security, acoustic or structural performance; SGP is stiffer and is used for structural and blast applications.
- Insulating glass units (IGUs) combine panes with a sealed spacer and desiccant. Edge-seal failure shows as fogging or visible desiccation.
- Wired glass may carry a fire rating but does not qualify as safety glazing for human impact.
- Acrylic and polycarbonate substitute for glass where impact resistance or weight matters. Polycarbonate is far tougher but scratches easily, and neither substitute is suitable where a fire-rated assembly is required.
Safety glazing and clearances
Model Canadian codes require safety glazing in doors, in sidelights within 300 mm of a door, in glazing within 500 mm of the floor, in shower and bathtub enclosures, and in guard applications. Tempered glass is marked to CAN/CGSB-12.1; laminated glass to CAN/CGSB-12.2.
- Provide edge clearance, typically 3 mm, and face clearance so glass can expand; do not hard-set glass against metal.
- Setting blocks should be EPDM or silicone, 85–90 durometer, placed at quarter points and never at corners.
Sealants and glazing methods
Wet glazing uses silicone or polysulfide; dry glazing uses EPDM gaskets and tape. Neutral-cure silicone is required near mirror backing, concrete and stone because acid-cure silicone can corrode these materials. Never seal weep holes.
Worked example
A 1200 mm × 2400 mm annealed lite is specified for a school corridor with its bottom edge 400 mm above finished floor. Safety glazing is required because the bottom edge is less than 500 mm above the floor. For an institutional corridor, specify tempered 6 mm glass and verify the label. If fire resistance is also needed, use a rated ceramic or laminated product-not wired glass. Setting blocks go 300 mm from each side (quarter points), each at least 100 mm long.
Traps that cost marks
- Treating wired glass as impact safety glass.
- Trying to cut or drill tempered glass on site.
- Placing setting blocks in corners, which concentrates stress and causes breakage.
- Sealing weep holes or over-tightening glazing stops.
- Using acid-cure silicone against mirror backing or masonry.