Glass Contractors, Glaziers Industry Terminology

AAMA/FGIA standards

Benchmarks and test methods published by the Fenestration & Glazing Industry Alliance (formerly AAMA) governing performance of windows, curtain walls, storefronts, and components (air/water/structural testing, finishes, installation).

We’ll test the wall per AAMA 501.2 for field water spray and 501.4 for dynamic structural performance.|Specify FGIA AAMA 2605 coatings on the aluminum for long-term durability.|Our submittals will reference FGIA standards to align with the project spec.

Annealed glass

Standard float glass that is slowly cooled to relieve internal stresses. It is the baseline glass type but is not a safety glazing and breaks into large, sharp pieces.

Interior office lites can be annealed since they’re not in hazardous locations.|We can’t use annealed glass in doors; it must be a safety glazing.|Annealed is cheaper but breaks into large shards—consider laminated if impact is a concern.

ANSI Z97.1

U.S. safety glazing standard establishing impact and breakage criteria for materials used in hazardous locations like doors and adjacent panels.

The sidelites must meet ANSI Z97.1 as safety glazing.|Make sure the labels show compliance with ANSI Z97.1 and CPSC 16 CFR 1201.|Our tempering plant is certified to test to ANSI Z97.1.

ASTM E1300

Standard practice for determining the load resistance of glass in buildings, used to size glass thickness and type for wind, snow, and other loads.

We designed the IGU thicknesses per ASTM E1300 for the specified wind pressures.|ASTM E1300 calculations show a need for heat-strengthened outboard.|Provide the E1300 load charts in the engineering submittal.

Backer rod

Compressible foam rod placed in joints to control sealant depth, shape the hourglass profile, and prevent three‑sided adhesion for better movement capability.

Use closed-cell backer rod to control sealant depth to half the joint width.|Install backer rod before the perimeter silicone.|We need larger diameter backer rod due to the widened joint.

BIM (Building Information Modeling)

A digital 3D model-based process for planning, coordinating, and documenting building systems, including curtain wall geometry, embeds, tolerances, and interfaces.

We’ll coordinate embeds and mullion penetrations in the BIM model.|Clash detection flagged a conflict between our unitized panel and the beam.|Let’s export our shop drawings from the BIM family.

Bonding capacity

The maximum surety bond limits a contractor can secure, indicating financial strength to guarantee performance and payment on projects.

Our bonding capacity easily covers this $8M facade package.|The GC requested proof of single and aggregate bonding capacity.|We’ll need to increase bonding capacity before bidding the tower.

Butt-glazed joint

Glass-to-glass vertical joint without a vertical mullion; the joint is sealed (often with structural or weather silicone) to create a clean, uninterrupted appearance.

The lobby wall is butt-glazed with a clear silicone vertical joint.|We need tempered-laminated lites for the butt-joint glass fins.|Add a cap at the head to protect the butt-glazed silicone from UV.

Change order

A formal modification to the contract scope, price, or schedule due to changes, unforeseen conditions, or owner-directed revisions.

The switch to laminated spandrel will be a change order.|We submitted CO pricing for the added door sidelites.|Ensure the change order extends the schedule and covers re-engineering.

Cold-bent glass

Flat glass elastically bent during installation to create curvature. Requires careful limits on bend radius, glass type, and edge quality to avoid breakage.

The canopy uses cold-bent lites to achieve the curve.|Confirm the allowable cold-bend radius from the fabricator.|Cold-bending increases edge stress—use heat-strengthened.

CPSC 16 CFR 1201

U.S. federal safety standard for architectural glazing materials in doors and other hazardous locations, specifying impact categories and testing.

Vision panels in doors must comply with CPSC 16 CFR 1201 Cat II.|We need certification labels for CPSC compliance.|Tempered or laminated can meet 16 CFR 1201.

Curtain wall

Non-load-bearing exterior wall system, typically aluminum framing with glass infill, designed to resist air, water, and wind loads and transfer loads to the structure.

The tower facade is a unitized curtain wall system.|Design mullions for L/175 under the design wind per the curtain wall spec.|We’ll test the mock-up for air, water, and structural per the curtain wall standard.

Deflection limit

Maximum allowable bending (often expressed as span/ratio, like L/175 or L/240) for framing or glass under load, to control serviceability and seal performance.

Mullion deflection is limited to L/175 per spec.|We added a steel reinforcing to meet the head deflection limit.|Excess deflection can pop gaskets and cause water leaks.

Desiccant

Moisture-absorbing material placed in IGU spacers to prevent condensation within the air space during the unit’s service life.

The IGU spacer contains desiccant to absorb moisture vapor.|Edge seal failure saturates the desiccant and causes fogging.|Specify molecular sieve desiccant compatible with the sealant.

Edge deletion

Removal of thin-film coatings (e.g., sputtered low‑E) near the glass perimeter to improve adhesion and compatibility of IGU edge seals or spandrel opacifiers.

Delete 1/2 inch of the low‑E at the edge before IGU sealing.|Spandrel units require edge deletion to avoid sealant incompatibility.|Confirm the edge delete width with the coater.

Environmental Product Declaration (EPD)

Third-party verified document reporting a product’s environmental impacts (e.g., global warming potential) across its life cycle; used for sustainability goals.

Provide product-specific EPDs for the curtain wall and glass.|The owner is targeting a low-carbon facade per the EPD data.|Use the EPD to compare embodied carbon between interlayers.

Fire-rated glazing

Special glazing assemblies that maintain integrity and/or insulation during fire exposure for a rated time (e.g., 20, 45, 60, 90 minutes) per UL/NFPA standards.

The stair enclosures need 60-minute fire-rated glazing.|Check listings for the fire-rated frames to match.|We can’t use standard tempered in that sidelite—it must be fire-rated.

Float glass

Flat glass made by floating molten glass on a bed of molten tin, producing uniform thickness and smooth surfaces; the base for most architectural glazing.

Base material is 6 mm clear float.|Low‑iron float improves clarity for the museum facade.|Roller-wave distortion can occur during float and tempering.

Frit (ceramic frit)

Ceramic ink applied to glass and fired to fuse permanently, used for patterns, shading, bird-friendly designs, or spandrel opacity.

Use a white ceramic frit dot pattern for bird-friendly glazing.|The spandrel will get a black frit on surface 2.|Confirm frit opacity to hide insulation behind spandrels.

Gaskets

Elastomeric seals (EPDM, silicone, etc.) used to weather-seal and retain glass within framing systems, accommodating movement and pressure differences.

Replace shrunken EPDM gaskets at the sill.|Use a wedge gasket to retain the IGUs.|Gasket durometer must match the system designer’s spec.

General Contractor (GC)

The prime contractor responsible for overall construction management, scheduling, coordination, and contracting with trades including the glazing subcontractor.

Coordinate our crane picks with the GC’s site plan.|The GC issued the latest schedule—we’re now week 24 for glazing.|All RFIs go through the GC’s portal.

Glazing bead

A removable or fixed profile in framing that retains the glass; can be snap-in, pressure plate with cover, or structurally bonded alternatives.

Install the interior snap-in glazing beads after setting blocks.|Bead length must account for thermal expansion.|Paint scratches on the bead need touch-up.

Guard glazing

Glazing used as a protective barrier (guards/railings) required to resist specific line and point loads; typically laminated for post-breakage safety.

The railing infill is laminated to meet guard loading.|Edge seals on guard glazing must be durable against weather.|Confirm code loads for guards—50 plf and 200 lb concentrated.

Heat-Soak Test (HST)

A post-tempering process heating glass to accelerate failure of panes containing nickel sulfide inclusions, reducing spontaneous break risk in service.

Specify HST on all tempered lites to reduce NiS breakage risk.|Lead time increases two weeks due to HST.|We need HST certificates from the temperer.

Heat-strengthened glass

Heat-treated glass with roughly twice the strength of annealed; breaks into larger fragments than tempered and is often used where tempered is not required.

Outboard lite is heat-strengthened to control thermal stress.|HS is not a safety glazing by itself—laminate if required.|We’re using HS for the ceramic frit spandrel.

IGU (Insulating Glass Unit)

Two or more glass panes separated by a sealed spacer cavity (often with argon) to improve thermal performance and reduce condensation.

Provide a 1 inch IGU with argon and warm-edge spacer.|Seal failure in the IGU is causing fogging.|Surface 2 low‑E in the IGU reduces U‑factor.

Impact-resistant glazing

Glazing assemblies designed and tested to resist missile impacts and cyclic pressures (e.g., hurricane zones or security applications).

Fenestration in HVHZ zones needs impact-rated glazing.|Test to ASTM E1886/E1996 for wind-borne debris.|Use SGP interlayer for stronger post-breakage performance.

Interlayer (PVB, SGP, EVA)

Polymeric layer bonding glass plies in laminated glass. PVB offers adhesion and acoustics; SGP adds structural rigidity and edge stability; EVA for specialty uses.

Use SGP interlayer for the cantilevered glass canopy.|PVB is fine for interior acoustic laminates.|Check interlayer thickness for the guard loading.

Laminated glass

Two or more glass plies bonded with an interlayer, providing safety, security, acoustic control, UV filtering, and post-breakage integrity.

The stairwell needs laminated for fall protection.|We specified a low‑iron laminated for color fidelity.|Laminated helps with STC/OITC acoustic targets.

Lead time

The duration from order to delivery, affected by material availability, coatings, tempering, lamination, heat soak, and logistics.

Tempered-laminated IGUs have a 10–12 week lead time.|HST and frit will extend the lead time.|Lock finishes early to protect the curtain wall lead time.

Low-E coating

Microscopic metallic coatings that reduce thermal emissivity, improving U-factor and solar control while maintaining visible light transmission.

Specify a low SHGC low‑E on surface 2 for solar control.|Hard-coat low‑E is more durable for monolithic exterior.|Edge delete the sputter-coat low‑E before sealing.

Mock-up (Performance Mock-Up)

Full-scale assembly built to verify aesthetics and performance via laboratory or field testing (air, water, structural, thermal, seismic).

The PMU will undergo air, water, and structural testing next week.|Let’s review the visual mock-up for color and reflection.|AAMA 501.4 dynamic testing is included in the PMU.

Mullion

Vertical or horizontal framing members in curtain walls/storefronts that support and retain glazing and transfer loads to the structure.

The vertical mullion needs steel reinforcement.|Thermal breaks in mullions reduce condensation risk.|Check mullion spans against deflection limits.

NFRC ratings

Standardized thermal performance ratings (U-factor, SHGC, VT, CR) certified by the National Fenestration Rating Council for fenestration products.

Provide NFRC labels showing U, SHGC, and VT.|Our IGU meets NFRC 100 U‑factor targets.|The owner is comparing NFRC-certified performance options.

OITC/STC

Acoustic ratings: STC gauges sound reduction for interior airborne noise; OITC emphasizes exterior traffic/low-frequency noise—both relevant for facade acoustics.

We need OITC 35 minimum for the facade near the highway.|Laminated glass improved STC without changing the framing.|Sealant continuity is key to achieving the specified OITC.

Point-supported glazing

Glass supported at discrete points via bolts or fittings (e.g., spider fittings), often requiring tempered-laminated glass with drilled holes and special analysis.

Use tempered-laminated with countersunk point fittings.|Check edge stresses around the drilled holes.|Spider fittings interface with the steel backup frame.

QA/QC

Quality Assurance/Quality Control processes to prevent defects (QA) and verify conformance (QC) in design, fabrication, and installation.

Add IGU seal checks to the QC plan.|QA will verify the water test setup before E1105.|Our QC punchlist flagged several gasket discontinuities.

RFI (Request for Information)

A formal question submitted to resolve design ambiguities, conflicts, or missing information before or during construction.

Submit an RFI to clarify the spandrel insulation requirement.|The RFI response approved SSG in lieu of pressure plates.|We’ll issue an RFI about the edge deletion width.

Safety glazing

Glazing that meets impact safety standards (ANSI Z97.1, CPSC 16 CFR 1201) in hazardous locations, typically fully tempered or laminated assemblies.

Door lites and adjacent sidelites require safety glazing.|Tempered or laminated can satisfy the safety glazing code.|Verify safety markings are visible after installation.

Setting blocks

Load-bearing supports placed at the bottom of glazing lites to distribute weight, prevent edge contact, and maintain proper clearances and sightlines.

Place setting blocks at quarter points under the IGU.|Use silicone-compatible setting blocks for SSG lites.|Adjust block thickness to maintain sightline.

SHGC

Solar Heat Gain Coefficient: fraction of incident solar radiation that enters through the glazing as heat; lower values reduce cooling loads.

Target SHGC 0.25 on the west elevation.|Switching to a different low‑E lowered SHGC but kept VT.|Balance SHGC with heating loads for overall energy savings.

Shop drawings

Contractor/fabricator-produced drawings detailing how the glazing system will be fabricated and installed, including dimensions, anchors, and materials.

Our shop drawings show anchor details and tolerances.|Submit revised shops reflecting the change order.|Engineer of record must stamp the shop drawings.

Spandrel glass

Opaque glazing used to cover floor lines, columns, or mechanical areas in curtain walls; typically uses ceramic frit, opacifier, and insulation behind the glass.

Use an opaque spandrel with insulation and backpan.|Confirm color match between vision and spandrel zones.|Edge deletion and ceramic frit will be needed at spandrels.

Structural Silicone Glazing (SSG)

Method of retaining glass by bonding it to the framing with structural silicone adhesive, eliminating exterior captures for a clean appearance.

This facade uses 4‑sided SSG for a flush glass look.|Design the SSG bite per ASTM C1401 and substrate limits.|Only use sealants approved for SSG by the manufacturer.

Tempered glass

Heat-treated safety glass approximately four times stronger than annealed; on breakage, it dices into small particles, reducing injury risk.

Doors and sidelites are tempered for safety.|Expect roller-wave and anisotropy in tempered lites.|All tempered lites above walkways will be heat-soaked.

U-factor

Rate of heat transfer through a glazing system; lower U-factor means better insulation. Expressed in Btu/hr·ft²·°F (US) or W/m²·K (SI).

We need a U-factor of 0.30 or better for the energy code.|Switching to triple-silver low‑E improved the U-factor.|NFRC-rated U-factors are center-of-glass vs whole-product—verify which.

Unitized curtain wall

Curtain wall fabricated and glazed in factory-assembled panels that are shipped to site for rapid installation, improving quality and speed.

Panels are unitized and factory-glazed for quality control.|Unitized improves schedule by installing from the building interior.|Field tolerances must accommodate unitized stack joints.

Visual Light Transmittance (VT)

Percentage of visible light that passes through glazing; higher VT improves daylighting but must be balanced with glare and solar heat gain.

The owner wants VT around 60% for daylighting.|Lowering SHGC while keeping VT high maintains clarity.|Ceramic frit will reduce the effective VT.

Water penetration testing (ASTM E1105)

Standard test method for field or lab evaluation of water penetration through fenestration systems using a calibrated spray and static pressure differential.

Schedule ASTM E1105 on the PMU after the structural test.|We had no water at the specified differential pressure.|Sealant continuity at corners is critical for E1105.

Wind load

Pressure and suction forces from wind acting on the facade; used to size glass, framing, anchors, and sealants for structural performance.

Design glass per ASCE 7 wind loads for each zone.|Mullion sizes increased to meet the corner wind pressures.|Check anchor fasteners for negative (suction) wind load.