NCCER Glazier flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Annealed glass

Standard flat glass cooled slowly with low surface compression. It breaks into large sharp shards, so it cannot be used where safety glazing is required.

Tempered glass

Glass heated and rapidly cooled to create surface compression of 10,000 psi or more. It breaks into small dice-like fragments and cannot be cut or drilled after tempering.

Heat-strengthened glass

Glass with surface compression around 3,500 to 7,500 psi. It resists thermal stress better than annealed glass but breaks into larger pieces than tempered glass.

Laminated glass

Two or more glass lites bonded with a PVB or SGP interlayer. It stays in the opening after breakage, and interlayer thickness sets the safety and security rating.

IGU primary seal

The polyisobutylene seal around the perimeter of an insulating glass unit. It blocks moisture vapor entry, while the secondary seal provides structural strength.

Low-E soft coat

A sputtered coating applied to a surface inside an IGU. It is fragile and must face the air space, unlike durable hard-coat pyrolytic coatings.

Safety glazing locations

Hazardous locations include glazing within 24 inches of a door edge, under 18 inches above the floor, and in bathrooms and stairways.

Fall protection threshold

OSHA requires fall protection at 4 feet in general industry and 6 feet in construction. Guardrails have a 42-inch top rail and a midrail.

Glass weight formula

Weight in pounds equals area in square feet times thickness in inches times 13.0. One-quarter-inch glass weighs about 3.25 pounds per square foot.

Ladder angle rule

Set ladders at a 4:1 ratio, one foot out for every four feet up, and extend three feet above the landing. Secure top and bottom before climbing.

Cut-resistant gloves

Gloves rated ANSI/ISEA 105 level A4 or higher are used for handling cut glass. Safety glasses with side shields are required as well.

Waste glass disposal

Broken glass goes into a rigid, labeled container, never a trash bag or open bin. It is never compacted by hand because shards cause cuts.

Storefront system size

Storefront members are typically 1-3/4 by 4-1/2 inches nominal tube, designed for heights up to about 10 feet. Taller walls use curtain wall.

Curtain wall definition

A non-load-bearing envelope hung from the structure that carries only its own weight and wind load. It is not a structural frame.

Frame deflection limit

Glazing frames are commonly limited to L/175 for spans up to 13 feet 6 inches, and L/240 plus 1/4 inch for longer spans.

Glass bite

The depth the glass edge engages the frame, typically 1/2 to 3/4 inch in wet-glazed storefront. Insufficient bite causes edge loading and breakage.

Setting block location

Blocks are placed at the quarter points, each about one-quarter of the lite width from the edge, not at the corners, to support weight and allow movement.

Dry versus wet glazing

Dry glazing uses a compression gasket pressed into the frame. Wet glazing uses sealant or glazing tape, and the two are not interchangeable.

Glazing tape compression

Closed-cell PVC or butyl tape must be compressed 25 to 30 percent of its thickness to seal. Under-compression is a common cause of leaks.

Structural silicone bite

The bond depth of structural silicone is calculated from design wind load. It is at least 1/4 inch and never less than the joint width.

Vacuum lifter safety factor

Lifter capacity must exceed the lite weight by a safety factor of two or more. Verify pad seal and gauge reading before lifting.

Sealant joint ratio

Joint width is at least 1/4 inch and depth at least 1/4 inch. Depth-to-width is 1:1 up to 1/2 inch wide, then 1:2 for wider joints.

Backer rod purpose

Closed-cell polyethylene rod sets sealant depth and prevents three-sided adhesion. Sealant bonds only to the two faces, never the joint back.

Sealant movement capability

Silicone handles plus or minus 50 percent movement, polyurethane 25 percent, and acrylic 12.5 percent. Match sealant to calculated joint movement.

Sealant cure rate

Silicone skins in 10 to 30 minutes and cures at roughly 1/8 inch per 24 hours. Do not water-test or clean until fully cured.

Weep hole spacing

Drained-and-vented systems need weeps at the sill at manufacturer spacing, commonly 12 to 24 inches, kept clear of sealant and debris.

AAMA 501.2 water test

A field water test that sprays at 5 gallons per hour per nozzle for at least 5 minutes. Failure shows water at the interior face.

Fire-protective glazing

Glazing that blocks smoke and flame but not radiant heat. Fire-resistive glazing also limits temperature rise and is required in some rated walls.

Sill flashing laps

Upper flashing laps over lower, side flashing laps over the sill pan, and the sill pan laps over the building wrap, so water drains outward.

Score-and-break cutting

A glass cutter scores the surface and the break follows the score. This applies only to annealed glass; tempered and laminated glass cannot be field-cut.

Glass storage angle

Lites are stored on an A-frame rack at 5 to 10 degrees from vertical, never flat or leaning, with the bottom edge on a soft pad.

ASTM E1300

The standard that gives load resistance of glass based on type, thickness, area, aspect ratio, and load duration. It is used to select thickness.