NCCER Glazier key terms

Heat-treated glass that breaks into small, relatively blunt fragments rather than sharp shards, making it a common choice for doors, sidelights, and other hazardous locations. It cannot be cut or drilled after tempering.

Two or more glass plies bonded to a plastic interlayer, usually PVB, that holds fragments in place when broken. Used for overhead glazing, security, sound control, and locations requiring a retained shard barrier.

Glass cooled more slowly than tempered glass, giving roughly twice the strength of annealed glass but breaking into larger, more hazardous pieces. It is not considered safety glazing and is often used in spandrels and wind-loaded facades.

Ordinary float glass that has been slowly cooled to relieve internal stresses. It is the baseline product from which tempered and heat-strengthened glass are made and breaks into large, sharp shards.

Flat glass produced by floating molten glass on a bath of molten tin, yielding uniform thickness and a fire-polished surface. It is the starting material for most architectural glass products.

A microscopically thin metallic or metal-oxide film applied to glass to reduce radiant heat transfer. Soft-coat versions are typically applied to sealed insulating glass surfaces and require careful handling to avoid damage.

An assembly of two or more glass panes separated by a sealed spacer containing dehydrated air or gas. The sealed cavity improves thermal performance and reduces condensation on interior surfaces.

The component that separates panes in an insulating glass unit and contains the primary seal and usually a desiccant. Spacer design and material influence edge-of-glass thermal performance and condensation resistance.

A moisture-absorbing material, commonly in granular or matrix form, placed inside the spacer of an insulating glass unit to keep the sealed cavity dry and prevent fogging between panes.

Glass or glazing material that meets established impact-resistance criteria for hazardous locations such as doors, tub enclosures, and low windows. Tempered and laminated glass are common compliant products.

A glazing position where broken glass could cause injury, such as within reach of a doorway, near a walking surface, or in a shower enclosure. Codes require safety glazing at these locations.

Opaque or ceramic-fritted glass used to conceal floor slabs and structural elements in curtain walls. It is often heat-treated to withstand thermal stress from uneven heating.

A non-load-bearing exterior wall assembly that carries only its own weight and environmental loads, transferring them to the building frame. It typically consists of aluminum framing, glass, and weather seals.

A ground-floor framing system, usually aluminum, that holds large glass panels and entrance doors. Unlike a curtain wall, it is generally supported by the building structure at its head and sill.

A vertical or horizontal framing member that divides and supports glazing within a window, storefront, or curtain wall system. Mullions transfer wind loads to anchors and the building structure.

A fastener or bracket that attaches framing to the building structure and transfers loads such as wind, dead load, and seismic forces. Anchor spacing and embedment are set by structural design.

The top (head) and bottom (sill) framing members of a window or storefront opening. The sill often includes a weep system to drain water that enters the frame.

A small opening in framing or sill that allows water collected inside the system to drain to the exterior. Weep holes must remain unobstructed for the assembly to perform as designed.

A small block, usually neoprene or EPDM, placed under the bottom edge of glass to support its weight and keep it off the frame. Correct placement prevents glass-to-metal contact and distributes dead load.

A removable trim member that holds glass in place against the frame and covers the edge of the glazing. Beads may be wet-glazed or dry-glazed and are often vented in drained systems.

A glazing method in which a sealant or glazing compound is applied to bed and seal the glass in the frame. It provides a continuous seal but requires careful tooling and cure time.

A glazing method that uses preformed gaskets or tapes rather than liquid sealant to weather-seal the glass. It allows faster installation and easier replacement but depends on correct gasket compression.

A preformed elastomeric strip, often EPDM or silicone, that seals joints between glass and framing. Proper compression and continuous corners are needed to resist air and water infiltration.

A double-sided or pressure-sensitive foam tape used to bed and seal glass against framing in dry-glazed systems. It also helps isolate glass from metal and control vibration.

A flexible material applied to joints to prevent air and water passage and accommodate movement. Selection depends on substrate compatibility, joint movement, and exposure conditions.

A compressible foam rod inserted into a joint before sealant is applied to control sealant depth and provide a bond break at the back. Correct sizing helps achieve the proper sealant profile.

The dimensional change in a joint caused by thermal expansion, structural deflection, or building settlement. Sealants must be selected with enough movement capability to accommodate this change without tearing.

Any gasket, sealant, or weatherstrip detail that blocks air and water from entering the building envelope. Continuous, properly lapped weather seals are essential to a watertight assembly.

A system in which silicone sealant bonds glass directly to the frame, transferring wind load without visible exterior stops. It requires compatible substrates, precise joint geometry, and strict adhesion testing.

The permanent downward force from the weight of glazing, framing, and attached components. Setting blocks and anchors must be designed to carry dead load without overstressing glass edges.

The lateral force exerted by wind on a glazed facade, which the glass and framing must resist. Design wind pressure depends on building height, exposure, and local code requirements.

A thin piece of material used to level, plumb, or align framing and glass during installation. Shims are temporary or permanent depending on the system and must not create point loads on glass.

The condition of being exactly vertical (plumb) and exactly horizontal (level). Accurate alignment of frames and glass is checked with levels, transits, or laser tools before final fastening.

A tool with rubber cups that use vacuum to grip and lift glass panels safely. Lifters are rated by capacity and must be inspected for seal condition before each use.

The safe practices for moving, storing, and setting glass, including edge protection, proper lifting technique, and controlled transport. Most glazier injuries involve cuts, strains, or dropped panels.

Safety gear worn to reduce injury risk, such as safety glasses, cut-resistant gloves, hard hats, and fall protection. PPE must be inspected, properly fitted, and appropriate to the task.

Hand protection made with high-strength fibers or wire mesh that reduces laceration risk when handling glass edges. Gloves must fit well and be rated for the level of cut hazard present.

Systems and procedures, such as guardrails, harnesses, and anchor points, that prevent workers from falling from heights. Glazing work at elevated openings requires a planned fall protection method.