FenestrationMasters flashcards

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

NAFS Performance Class

A designation in AAMA/WDMA/CSA 101/I.S.2/A440 that groups windows by intended use and minimum performance: R, LC, C, HC, and AW, from lowest to highest design pressure and water resistance.

Performance Grade (PG)

A number on a NAFS label expressing the product's design pressure in psf; PG 40 means the unit is rated for 40 psf design pressure and meets associated water and structural criteria.

Safety glazing label

A permanent, legible mark required by 16 CFR 1201 on glazing used in hazardous locations; it identifies the manufacturer and confirms the product passed the CPSC safety glazing test.

Egress window opening

An emergency escape opening in a sleeping room, typically requiring at least 5.7 sq ft net clear opening, 20 in. minimum width, 24 in. minimum height, and sill no more than 44 in. high.

Casement window

A window with a sash hinged on one vertical side and operated by a crank or lever; it swings outward and compresses against the frame seal, giving good air and water performance.

Insulated glass unit

Two or more glass lites separated by a spacer and sealed at the perimeter, with a desiccant-filled spacer and dry gas or air in the cavity to improve thermal performance.

Warm-edge spacer

A low-conductivity spacer made of polymer, foam, or hybrid materials that reduces heat flow at the glass edge compared with aluminum, raising edge temperature and reducing condensation.

Thermal break

A low-conductivity separator, such as polyamide or polyurethane, placed between interior and exterior aluminum frame members to reduce conducted heat flow through the frame.

Fully tempered glass

Glass heat-treated to at least 10,000 psi surface compression; it is stronger than annealed glass and breaks into small dice-like fragments, qualifying it as safety glazing.

Laminated glass

Two or more glass lites bonded by a PVB, SGP, or EVA interlayer; the interlayer holds fragments in place after breakage and adds safety, security, and acoustic benefits.

Solar heat gain coefficient

The fraction of incident solar radiation admitted through a fenestration system as heat, including directly transmitted and absorbed-then-inward-released energy; it ranges from 0 to 1.

Low-E coating

A thin metallic or metal-oxide film on glass that reflects long-wave infrared radiation, reducing radiative heat transfer; soft-coat is sputtered and hard-coat is pyrolytic.

Design pressure

The wind pressure a fenestration product must resist, calculated from ASCE 7 wind parameters; NAFS structural testing applies 1.5 times this pressure to verify performance.

Mullion

A vertical or horizontal framing member that separates and supports individual glazed units; structural mullions must be engineered for the tributary wind area they carry.

Setting blocks

Small pads, usually EPDM or silicone, placed under the glass at the quarter points of the lite to carry dead load and keep glass from bearing directly on the frame.

Structural silicone glazing

An assembly where silicone structural sealant transfers wind load from glass to frame; design follows ASTM C1401 and often includes a secondary mechanical retention system.

Whole-window U-factor

The area-weighted heat transfer coefficient of the complete assembly, combining center-of-glass, edge-of-glass, and frame performance; lower values indicate better thermal insulation.

Condensation resistance

A relative index, such as NFRC CR or AAMA CRF, indicating how well a fenestration product resists interior condensation; higher values mean warmer interior surfaces and less condensation.

Light-to-solar-gain ratio

The ratio of visible light transmittance to solar heat gain coefficient; a higher ratio means more daylight per unit of admitted solar heat, desirable in cooling-dominated climates.

Argon gas fill

A dense, inert, colorless gas used in IGU cavities; it reduces conduction and convection compared with air, improving U-factor, and is most effective in moderate cavity widths.

Sill pan flashing

A sloped, watertight flashing installed beneath a window sill and integrated with the weather-resistive barrier to collect and drain water that penetrates the assembly.

Weep hole

A small opening at the sill or glazing pocket that allows water to drain to the exterior; it must remain unobstructed and be located at the lowest point of the sill.

Pressure-equalized rainscreen

A wall design with a vented air cavity and compartmentalization that equalizes pressure across the cladding, reducing wind-driven water penetration through joints and openings.

Vapor retarder placement

The climate-dependent location of a low-perm material in a wall; cold climates place it on the warm interior side, while hot-humid climates require drying potential to avoid trapped moisture.

Air leakage rate

The volume of air passing through a fenestration product per unit area at a specified pressure differential, typically tested per ASTM E283 and rated under NFRC 400.

Sound Transmission Class

A single-number rating from ASTM E413 derived from ASTM E90 laboratory measurements, expressing how well an assembly reduces airborne sound between interior spaces.

Outdoor-Indoor Transmission Class

A single-number rating from ASTM E1332 that weights low-frequency sound such as traffic and aircraft, used to rate exterior façade assemblies and generally lower than STC.

Acoustic interlayer

A specially formulated PVB or similar film in laminated glass that damps vibration and improves sound reduction, especially at coincidence frequencies, compared with monolithic glass.

Backer rod

A flexible foam rod placed in a joint before sealant to control sealant depth, support the sealant, and allow proper joint movement; it also helps prevent three-sided adhesion.

Bond breaker

A material or tape applied to the joint bottom so sealant adheres only to the two faces, allowing movement and preventing three-sided adhesion that can cause sealant failure.

Shingle-lap flashing

An installation sequence in which upper water-shedding layers overlap lower ones, so water flows outward and downward over the weather-resistive barrier and flashing without entering the assembly.

NFRC Certified Products Directory

The official listing of fenestration products certified under the NFRC program, showing U-factor, SHGC, VLT, and air leakage ratings that can be verified against the product label.