1 Scope

NOTE This standard governs the furnishing and installation of architectural glass and the materials and accessories used to glaze it into framing supplied under other standards. (1.1)

1.3 This standard establishes requirements for the glass products themselves (annealed, heat-strengthened, fully tempered, laminated, coated, and insulating glass units), for spandrel and decorative glass, for the glazing materials and accessories (sealants, gaskets, setting blocks, and tapes) that retain and seal the glass, and for the fabrication, installation, testing, cleaning, and warranty of the glazing work.

NOTE Glass is simultaneously a structural element, an environmental separator, a safety component, and an architectural finish. (1.4)

1.5 A single lite must resist wind and snow load without breaking, survive thermal stress from differential heating, satisfy safety-glazing requirements where it occupies a hazardous location, deliver the energy performance the building's compliance documents require, and present an acceptable visual appearance free of distortion, haze, and edge defects.

NOTE These requirements cross-couple: the heat treatment selected to resist thermal stress changes the glass type factor used in the load-resistance calculation; the coating selected to reduce solar heat gain changes the surface that must carry it within the insulating glass unit; the laminated interlayer chosen for safety or acoustics changes the unit weight and the glazing-pocket bite. (1.6)

1.7 The Contractor shall treat the glass as a coordinated system and shall reconcile structural, thermal, safety, and visual requirements against one another before any glass is ordered.

1.8 The glass type for each opening, the dimensions of each lite, the performance values required at each orientation, and the locations requiring safety glazing shall be as indicated on the contract drawings and the glazing schedule.

1.9 This standard establishes the minimum product, performance, fabrication, and installation requirements applicable to all of those conditions.

1.10 Coordination with Adjacent Work

1.10.1 Coordinate this work with Aluminum Entrances And StorefrontsAluminum Entrances and StorefrontsResolves to the current edition.sync/aluminum-entrances-and-storefronts and Glazed Curtain WallsGlazed Curtain WallsResolves to the current edition.sync/glazed-curtain-walls for the framing systems and glazing-pocket geometry that receive the glass.

1.10.2 Coordinate this work with Doors Frames And HardwareDoors, Frames, and HardwareResolves to the current edition.sync/doors-frames-and-hardware for glazed openings in hollow metal, aluminum, and wood doors.

1.10.3 Coordinate this work with Overhead Coiling DoorsOverhead Coiling DoorsResolves to the current edition.sync/overhead-coiling-doors where vision lites occur in service openings.

1.10.4 Coordinate this work with Building Thermal InsulationBuilding Thermal InsulationResolves to the current edition.sync/building-thermal-insulation for the continuity of the building thermal envelope at the glazing perimeter.

2 Referenced Standards

2.1 Glass products, fabrication, glazing materials, performance testing, and installation shall comply with the latest adopted edition of the referenced standards.

2.2 Where the contract documents or the adopted building code impose more stringent requirements than a referenced standard, the more stringent requirement shall govern.

2.3 The Contractor shall resolve conflicts in writing with the Engineer of Record before proceeding.

2.4 Standards List

Standard	Title
ASTM C1036	Standard Specification for Flat Glass
ASTM C1048	Standard Specification for Heat-Strengthened and Fully Tempered Flat Glass
ASTM C1172	Standard Specification for Laminated Architectural Flat Glass
ASTM C1376	Standard Specification for Pyrolytic and Vacuum Deposition Coatings on Flat Glass
ASTM C1422	Standard Specification for Chromogenic Glazing
ASTM C1503	Standard Specification for Silvered Flat Glass Mirror
ASTM C1349	Standard Specification for Architectural Flat Glass Clad Polycarbonate
ASTM C1464	Standard Specification for Bent Glass
ASTM E1300	Standard Practice for Determining Load Resistance of Glass in Buildings
ASTM E2188	Standard Test Method for Insulating Glass Unit Performance
ASTM E2189	Standard Test Method for Testing Resistance to Fogging in Insulating Glass Units
ASTM E2190	Standard Specification for Insulating Glass Unit Performance and Evaluation
ASTM E546	Standard Test Method for Frost/Dew Point of Sealed Insulating Glass Units
ASTM E576	Standard Test Method for Frost/Dew Point of Sealed Insulating Glass Units in the Vertical Position
ASTM C1651	Standard Test Method for Measurement of Roll Wave Optical Distortion in Heat-Treated Flat Glass
ASTM C1036 / C1048 (frit)	Ceramic-enamel (frit) coatings on heat-treated glass for spandrel and decorative applications
ASTM C920	Standard Specification for Elastomeric Joint Sealants
ASTM C1184	Standard Specification for Structural Silicone Sealants
ASTM C1281	Standard Specification for Preformed Tapes Used in Glazing Applications
ASTM C1401	Standard Guide for Structural Sealant Glazing
ASTM C864	Standard Specification for Dense Elastomeric Compression Seal Gaskets, Setting Blocks, and Spacers
ASTM C509	Standard Specification for Elastomeric Cellular Preformed Gasket and Sealing Material
ASTM E84	Standard Test Method for Surface Burning Characteristics of Building Materials
ASTM E90	Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
ASTM E413	Classification for Rating Sound Insulation (STC)
16 CFR 1201	U.S. Consumer Product Safety Commission Safety Standard for Architectural Glazing Materials
ANSI Z97.1	American National Standard for Safety Glazing Materials Used in Buildings — Safety Performance Specifications and Methods of Test
NFRC 100	Procedure for Determining Fenestration Product U-factors
NFRC 200	Procedure for Determining Fenestration Product Solar Heat Gain Coefficient and Visible Transmittance at Normal Incidence
NFRC 300	Test Method for Determining the Solar Optical Properties of Glazing Materials and Systems
EN 14179	Heat Soaked Thermally Toughened Soda Lime Silicate Safety Glass (heat-soak test protocol)
IBC Chapter 24	International Building Code — Glass and Glazing (including Section 2406, Safety Glazing)
GANA / NGA Glazing Manual	National Glass Association (formerly Glass Association of North America) — Glazing Manual
IGCC / IGMA	Insulating Glass Certification Council / Insulating Glass Manufacturers Alliance — IGU certification

3 Submittals

3.1 Action Submittals

3.1.1 The following submittals shall be submitted for review and returned before glass is fabricated or ordered.

3.1.2 Glass, IGU, and glazing-accessory submittals shall be coordinated into a single review package, keyed to the glazing schedule, so that the glass makeup, heat treatment, coating surface, and safety-glazing designation for every lite are reconciled against the framing system that receives them.

3.1.3 A glazing schedule shall be submitted identifying every glass type by designation, keyed to the contract drawings, listing for each type the glass makeup (monolithic, laminated, or IGU), the thickness and heat treatment of each ply, the coating type and surface number, the interlayer type and thickness for laminated lites, the spacer type and gas fill for IGUs, the safety-glazing designation where applicable, and the locations at which the type is used.

3.1.4 Glass strength and thickness calculations shall be submitted, providing load-resistance calculations per ASTM E1300 for each glass type and the largest lite of that type, demonstrating that the selected glass type, heat treatment, and thickness resist the design wind and snow loads at a probability of breakage not exceeding 8 lites per 1,000 (Pb ≤ 0.008).

3.1.5 For projects where the glass is a designated structural element or where local jurisdiction requires it, the glass strength and thickness calculations shall be signed and sealed by a professional engineer licensed in the project jurisdiction.

3.1.6 Product data shall be submitted, providing the manufacturer's published data for each glass product, coating, interlayer, IGU sealant system, spacer, gas fill, and glazing accessory, including the optical and thermal properties (U-factor, SHGC, VT, and exterior and interior visible reflectance) of each coated and insulating glass configuration.

3.1.7 Insulating glass unit certification shall be submitted, providing evidence that the IGU fabricator is certified under the Insulating Glass Certification Council (IGCC) or the Insulating Glass Manufacturers Alliance (IGMA) program and that the specific unit construction has passed durability evaluation per ASTM E2190 (using the test methods of ASTM E2188 and the fogging test of ASTM E2189).

3.1.8 Where heat-soak treatment of fully tempered glass is required, heat-soak test documentation shall be submitted, providing the fabricator's heat-soak process certification confirming the soak temperature, dwell time, and protocol (EN 14179 or equivalent), and confirmation that the project glass was processed through the documented cycle.

3.1.9 For glass exposed to partial shading, interior shading devices close to the glass, dark-colored or spandrel back-up, or other conditions producing differential heating, a thermal-stress analysis by the glass fabricator shall be submitted confirming the selected heat treatment resists the calculated edge and center stress without breakage.

3.1.10 Samples of each glass type, minimum 12 in. by 12 in., shall be submitted showing color, tint, coating appearance, and (for laminated and spandrel glass) interlayer or frit appearance.

3.1.11 For coated and tinted glass, samples shall be viewed in both transmitted and reflected light and against the actual or a representative background.

3.1.12 Where a project mock-up of the framing system is required, the glass furnished for the mock-up shall be of the project glass type, coating, and makeup so that color, reflectance, and visual quality are evaluated in the installed condition.

3.1.13 Action Submittals Datasheet

Action Submittals Requiredcheckbox

☑ Glazing schedule keyed to drawings

☐ ASTM E1300 glass strength and thickness calculations

☐ Product data with U-factor, SHGC, and VT for each configuration

☐ IGU IGCC/IGMA certification and ASTM E2190 durability evidence

☐ Heat-soak test documentation (where tempered heat-soak required)

☐ Thermal stress analysis (where differential heating conditions exist)

☐ Glass samples (12 in. by 12 in., transmitted and reflected light)

☐ Mock-up glass of project type, coating, and makeup

3.2 Closeout Submittals

3.2.1 At substantial completion the Contractor shall provide the following closeout submittals before final acceptance:

As-built glazing schedule reflecting any field changes to glass type or location
Cleaning and maintenance instructions for the glass, coatings, and glazing sealants, including the glass and coating manufacturers' approved cleaning products and the products that shall not be used
IGU warranty from the unit fabricator
Laminated glass warranty (interlayer delamination) where laminated glass is furnished
Coated glass warranty (coating defects and, for exterior coatings, durability) where applicable
Glazing sealant and structural silicone warranty where wet or structural glazing is used

Closeout Submittals Requiredcheckbox

☑ As-built glazing schedule

☐ Cleaning and maintenance instructions with approved cleaners

☐ IGU warranty (minimum 10 years against seal failure)

☐ Laminated glass warranty (interlayer delamination)

☐ Coated glass warranty

☐ Glazing sealant / structural silicone warranty

4 Quality Assurance

4.1 Fabricator Qualifications

4.1.1 The glass fabricator shall demonstrate not less than five years of continuous production of architectural glass of the types specified.

4.1.2 The insulating glass unit fabricator shall be certified under the IGCC or IGMA durability certification program for the unit construction furnished, and shall maintain that certification for the duration of fabrication.

4.1.3 The laminated glass fabricator shall be experienced in producing laminated architectural glass to ASTM C1172 for the interlayer type specified.

4.2 Glazier Qualifications

4.2.1 The glazing contractor shall employ glaziers experienced in the glazing methods used on the project.

4.2.2 Where structural silicone glazing is used, the glaziers shall be trained and approved by the structural silicone sealant manufacturer, and the sealant manufacturer shall review the structural joint design, confirm substrate compatibility and adhesion, and provide on-site instruction before structural glazing begins.

4.3 Single-Source Responsibility

4.3.1 To the extent practical, all primary glass of a given type shall be obtained from a single primary glass manufacturer and a single fabricator so that color, coating, and visual characteristics are consistent across the project.

4.3.2 Tinted, coated, and spandrel glass shall be from a single production run wherever a continuous expanse of glass is visible as a unified field.

NOTE Lot-to-lot color variation in tints and coatings is visible side by side even when each lot independently meets specification. (4.3.3)

4.4 Visual Quality and Distortion

4.4.1 Glass shall meet the visual quality requirements of ASTM C1036 for the applicable quality designation.

4.4.2 Heat-treated glass shall meet the roll-wave and bow/warp limits of ASTM C1048 and shall be evaluated for roll-wave optical distortion per ASTM C1651 where reflected-image quality is important to the design.

4.4.3 Glass shall be free of visible defects (bubbles, inclusions, scratches, digs, and coating voids) when viewed under the conditions and at the distance prescribed by ASTM C1036.

4.4.4 Flat Glass Visual Quality Designation

Flat Glass Visual Quality Designation (ASTM C1036)select

q3 — glazing select quality (typical architectural vision glazing)

q2 — mirror select quality (mirrors and high-scrutiny applications)

q1 — mirror glazing select (highest quality, special applications)

5 Performance Requirements

5.1 Glass Strength — Load Resistance per ASTM E1300

5.1.1 Each lite shall resist the design wind load and, where applicable, the design snow load and self-weight, determined per ASTM E1300, at a probability of breakage not greater than 8 lites per 1,000 (Pb ≤ 0.008) for vertical glazing.

NOTE ASTM E1300 establishes the load resistance of a lite from its type, thickness, area, support condition, and aspect ratio, applying a glass type factor (GTF) that scales the resistance of annealed glass to account for the higher strength of heat-strengthened (GTF ≈ 2) and fully tempered (GTF ≈ 4) glass. (5.1.2)

5.1.4 The design wind pressure shall be derived from the project structural drawings and the building code wind determination for the project location, height, and exposure.

5.1.5 Increasing glass thickness, selecting a higher heat treatment, or laminating two plies are the available means of increasing load resistance; the selection shall be coordinated with the thermal-stress, safety-glazing, and acoustic requirements so that a single makeup satisfies all governing criteria.

5.1.6 Glass Strength Datasheets

Glass Design Wind Loadrange

psf

152025304050607080100

Per drawings

Probability of Breakage Limit (ASTM E1300)radio

● 8 per 1,000 (Pb = 0.008) — standard vertical glazing

○ 1 per 1,000 (Pb = 0.001) — overhead, sloped, or elevated-consequence glazing

5.2 Thermal Stress Resistance

NOTE Glass breaks from thermal stress when one part of a lite heats and expands while a cooler part (typically the shaded edge captured in the frame) restrains it, producing tensile stress at the edge. (5.2.1)

NOTE The risk increases with absorptive (tinted or coated) glass, partial shading from overhangs or adjacent structures, interior shades or blinds close to the glass, dark spandrel or insulation back-up behind the glass, and damaged or poor-quality glass edges that concentrate stress. (5.2.2)

NOTE Annealed glass tolerates the least thermal stress; heat-strengthened glass roughly doubles the tolerance and is the standard remedy; fully tempered glass tolerates the most but is not selected for thermal stress alone because of its other characteristics. (5.2.3)

5.2.4 Where the thermal-stress analysis indicates that annealed glass is inadequate, the glass shall be heat-strengthened (the preferred remedy) or fully tempered.

5.2.5 The edges of heat-treated glass intended to resist thermal stress shall be clean-cut and free of vents, shells, and serious damage, because edge damage defeats the strength gain of heat treatment.

5.2.6 Thermal Stress Heat Treatment

Thermal Stress Heat Treatment (Where Differential Heating Occurs)radio

○ Annealed acceptable — verified by thermal stress analysis

● Heat-strengthened — standard remedy for moderate thermal stress

○ Fully tempered — high thermal stress or also required for safety glazing

5.3 Thermal Performance — U-Factor, SHGC, and Visible Transmittance

5.3.1 The glass or insulating glass unit shall provide the center-of-glass and, where the unit is rated as part of a fenestration product, the whole-product U-factor, solar heat gain coefficient (SHGC), and visible transmittance (VT) required by the project energy-compliance documentation, with optical and thermal properties determined per NFRC 300 and the product ratings certified per NFRC 100 (U-factor) and NFRC 200 (SHGC and VT).

5.3.2 Thermal Performance Datasheets

Center-of-Glass U-Factorrange

Btu/h·ft²·°F

0.20.240.280.290.350.450.55

Per drawings

Solar Heat Gain Coefficient (SHGC)range

SHGC (unitless)

0.180.220.250.270.30.350.40.55

Per drawings

Visible Light Transmittance (VT)range

VT (unitless)

0.30.40.50.60.70.8

Per drawings

NOTE A standard double-glazed IGU with a single low-emissivity coating, argon fill, and a warm-edge spacer typically achieves a center-of-glass U-factor near 0.24 to 0.29 Btu/h·ft²·°F; a triple-glazed unit with two low-e coatings reaches the 0.10 to 0.18 range. (5.3.3)

NOTE The SHGC and VT are governed by the coating: a high-solar-gain low-e coating delivers a high VT with a moderate-to-high SHGC for heating-dominated climates, while a solar-control (spectrally selective) low-e coating delivers a low SHGC while retaining a usable VT for cooling-dominated climates. (5.3.4)

NOTE The light-to-solar-gain ratio (VT divided by SHGC) describes how much daylight the glass admits per unit of solar heat; spectrally selective coatings push this ratio above 1.25 and are the common default for daylit commercial buildings. (5.3.5)

5.3.6 The Architect shall confirm that the U-factor, SHGC, and VT targets are simultaneously achievable with a single coating before the makeup is finalized.

5.4 Acoustic Performance

5.4.1 Where the contract documents require acoustic performance, the glass makeup shall achieve the specified Sound Transmission Class (STC), tested per ASTM E90 and rated per ASTM E413.

NOTE Acoustic performance is governed primarily by the glass makeup: asymmetric lite thicknesses (which break up coincidence dip resonance), a laminated lite with an acoustic interlayer, and a wider air space improve STC. (5.4.2)

NOTE Standard symmetric double glazing achieves roughly STC 32 to 35; asymmetric and laminated makeups reach STC 38 to 45. (5.4.3)

5.4.4 Acoustic Rating Datasheet

Acoustic Rating Required (STC, per ASTM E90 / E413)select

Not required — no acoustic specification

STC 32–35 (standard double glazing, basic noise control)

STC 36–40 (asymmetric or laminated, moderate noise control)

STC 41–45 (acoustic laminated interlayer, transit-adjacent / healthcare)

Per drawings

5.5 Safety Glazing — Hazardous Locations

5.5.1 Glazing in the hazardous locations defined by IBC Section 2406.4 shall be safety glazing complying with the impact-test requirements of 16 CFR 1201 (the U.S. Consumer Product Safety Commission standard) for the applicable category, or, where the exception applies, ANSI Z97.1 for the applicable class.

NOTE Hazardous locations include glazing in doors; glazing adjacent to doors within the defined arc and distance; glazing in fixed and operable panels meeting the area, edge-height, and walking-surface-proximity tests; glazing in guards and railings; glazing adjacent to stairways, landings, and ramps; and glazing enclosing or adjacent to wet areas such as showers, tubs, pools, and saunas. (5.5.2)

5.5.3 The locations requiring safety glazing shall be as indicated on the contract drawings and glazing schedule and confirmed against IBC 2406.4.

NOTE 16 CFR 1201 defines two impact categories by glazed area and impact energy: Category I, for small lites (less than 9 ft², or 1,296 in²), tested at 150 ft·lbf; and Category II, for large lites (9 ft² and greater) and all glazing in doors, tested at 400 ft·lbf. (5.5.4)

5.5.5 Glazing in doors and in storefront sidelights, and most large vision lites in hazardous locations, require Category II.

5.5.6 Safety Glazing Impact Category Datasheet

Safety Glazing Impact Category (16 CFR 1201)radio

● Category II (400 ft·lbf) — doors, large lites, sidelights, most hazardous locations

○ Category I (150 ft·lbf) — small lites less than 9 ft² not in doors

○ Not a safety glazing location

Per drawings

5.5.7 Safety glazing requirements are satisfied by fully tempered glass or by laminated glass that passes the applicable impact test.

5.5.8 Where post-breakage retention matters — guards, glazing over occupied space, glazing where falling cullet would create a secondary hazard — laminated glass is preferred over monolithic tempered glass because the laminated lite holds together on the interlayer after breakage, whereas tempered glass disintegrates into a curtain of granular cullet that leaves the opening unprotected.

5.5.9 Identification of Safety Glazing

5.5.9.1 Each lite of safety glazing shall bear a permanent label identifying the fabricator, the safety-glazing standard met (16 CFR 1201 category or ANSI Z97.1 class), and the glass type, per IBC Section 2406.3.

5.5.9.2 The label shall be visible after glazing and shall not be removed until the building official has inspected the installation, except where the alternative certificate-of-compliance provisions of the code are used.

5.6 Bird-Friendly Glazing

5.6.1 Where the contract documents require bird-friendly glazing (an increasingly common requirement under local ordinances and green-building credits), the glazing shall present a visual pattern that birds perceive as a barrier.

5.6.2 Patterns qualify when applied per the established spacing convention: continuous lines or elements not more than 2 in. apart in the vertical direction and not more than 4 in. apart in the horizontal direction (the "2 by 4 rule"), with elements at least 1/8 in. wide.

NOTE The most durable patterns are a ceramic frit or an etched/printed pattern on the first (exterior) surface, or a second-surface pattern with the low-e coating placed behind the pattern so the pattern remains visible from outside. (5.6.3)

5.6.4 Where a bird-deterrent pattern is required it shall be as indicated on the contract drawings for pattern, coverage, and surface.

5.6.5 Bird-Friendly Glazing Datasheet

Bird-Friendly Glazing Requiredselect

Not required

First-surface frit or etched pattern (most effective, exterior durable)

Second-surface pattern with low-e behind pattern (durable, visible exterior)

Applied exterior film or marker pattern (where field-applied permitted)

Per drawings

6 Glass Products

6.1 Flat Glass — Float Quality and Tint

6.1.1 Primary flat glass shall be float glass conforming to ASTM C1036, of the type and class indicated.

6.1.2 Clear glass is the default; low-iron glass shall be specified where the green tint and reduced transmittance of standard clear glass are objectionable (large clear expanses, glass with white or light interlayers, display and showcase glazing, and applications requiring the highest visible transmittance).

6.1.3 Tinted (body-colored) glass reduces solar transmittance and visible transmittance and shall be coordinated with the coating selection, since tint and coating both affect SHGC and appearance.

6.1.4 Primary Glass Type Datasheet

Primary Glass Typeselect

Clear float glass (standard)

Low-iron float glass (high clarity, neutral color, highest VT)

Tinted float glass — gray

Tinted float glass — bronze

Tinted float glass — blue-green / green

Per drawings

6.2 Heat Treatment — Annealed, Heat-Strengthened, and Fully Tempered

6.2.1 Heat-treated glass shall conform to ASTM C1048: Kind HS (heat-strengthened) or Kind FT (fully tempered).

6.2.2 Annealed glass (untreated float glass) is used where neither safety glazing nor elevated strength is required.

NOTE Heat-strengthened glass, with a surface compression of roughly 3,500 to 7,500 psi, is the standard choice for resisting thermal stress and for spandrel glass; it breaks into large fragments that tend to stay in the opening but is not a safety-glazing material. (6.2.3)

6.2.4 Fully tempered glass, with a surface compression of 10,000 psi or greater, is a safety-glazing material that breaks into small granular fragments; it is required in hazardous locations where laminated glass is not used.

6.2.5 Glass Heat Treatment Datasheet

Glass Heat Treatment (per Lite, per Location)select

Annealed — no safety glazing or elevated strength required

Heat-strengthened (ASTM C1048 Kind HS) — thermal stress, spandrel, larger lites

Fully tempered (ASTM C1048 Kind FT) — safety glazing locations, doors, sidelights

Per drawings

6.2.6 Heat-strengthened glass shall not be substituted where safety glazing is required.

6.2.7 Fully tempered glass shall not be specified merely as a default "stronger" glass where it is not needed, because tempered glass is more prone to spontaneous breakage from nickel-sulfide inclusions and exhibits more roll-wave distortion than heat-strengthened glass.

6.2.8 Heat-Soak Treatment of Tempered Glass

NOTE Fully tempered glass contains a small statistical population of nickel-sulfide (NiS) inclusions that can, over years in service, undergo a phase change accompanied by a slight volume increase; when an inclusion sits in the central tensile zone of the lite, the resulting local stress can cause spontaneous breakage with no external cause. (6.2.8.1)

NOTE Heat-soak treatment accelerates this phase change in the factory by holding the tempered glass at approximately 290 °C for a sustained dwell (per EN 14179 or an equivalent documented protocol), breaking susceptible lites before they ship and reducing the in-service spontaneous-breakage rate by roughly an order of magnitude. (6.2.8.2)

6.2.8.3 Heat-soak treatment shall be specified for fully tempered glass in overhead glazing, in glass guards and railings, in tall or inaccessible facades, and wherever spontaneous breakage would create a safety hazard or a high replacement cost.

6.2.8.4 Heat-Soak Treatment Datasheet

Heat-Soak Treatment of Fully Tempered Glassradio

● Not required (interior, low-elevation, low-consequence tempered glass)

○ Required — EN 14179 protocol (overhead, guards, tall facades, high-consequence)

6.3 Laminated Glass

6.3.1 Laminated glass shall conform to ASTM C1172, consisting of two or more plies of glass bonded by a continuous interlayer.

NOTE Laminated glass provides post-breakage retention (the broken plies remain bonded to the interlayer), enhanced safety and security, acoustic improvement, and ultraviolet screening. (6.3.2)

6.3.3 The interlayer shall be selected for the governing requirement: polyvinyl butyral (PVB) is the standard general-purpose interlayer; an acoustic PVB (a softer damping layer) is selected where acoustic performance governs; and a stiff ionoplast interlayer is selected where post-breakage structural retention, edge stability, or higher load resistance governs (guards, overhead glazing, and high-load facades).

6.3.4 Laminated Glass Datasheets

Laminated Glass Interlayerselect

Standard PVB (general purpose safety and security)

Acoustic PVB (acoustic-rated, damping interlayer)

Ionoplast / structural interlayer (guards, overhead, high-load, edge stability)

Not laminated — monolithic lite

Per drawings

Laminated Interlayer Nominal Thicknessrange

mil

1530456090

6.3.5 The plies of laminated glass may themselves be annealed, heat-strengthened, or fully tempered.

NOTE Heat-strengthened plies are common because they retain large fragments bonded to the interlayer (preserving residual capacity), whereas tempered plies dice into small fragments that reduce the laminated unit's post-breakage stiffness. (6.3.6)

6.3.7 The ply heat treatment shall be selected with the structural and post-breakage requirements in mind.

6.4 Coated Glass — Low-Emissivity and Solar Control

6.4.1 Coated glass shall conform to ASTM C1376.

NOTE Low-emissivity (low-e) coatings reduce radiative heat transfer across the IGU air space, lowering the U-factor; spectrally selective low-e coatings additionally reject solar infrared, lowering the SHGC while retaining visible transmittance. (6.4.2)

6.4.3 Coatings are produced by two processes: pyrolytic ("hard-coat"), applied at the float line and durable enough for monolithic and exposed use; and magnetron-sputtered vacuum deposition ("soft-coat"), which offers higher performance and more neutral color but must be enclosed within a sealed IGU and, for most products, requires edge deletion at the unit perimeter.

6.4.4 Low-Emissivity Coating Type Datasheet

Low-Emissivity Coating Typeradio

● Sputtered (soft-coat) low-e — highest performance, sealed in IGU (typical)

○ Pyrolytic (hard-coat) low-e — durable, monolithic or surface 4 use

○ No low-e coating (clear or tinted only)

6.4.5 Low-Emissivity Coating Surface

NOTE In an insulating glass unit the surfaces are numbered 1 through 4 from the exterior (surface 1 is the outboard exterior face; surface 2 is the outboard cavity face; surface 3 is the inboard cavity face; surface 4 is the interior room-side face). (6.4.5.1)

6.4.5.2 For cooling-dominated climates the solar-control low-e coating is placed on surface 2 so it rejects solar gain before it crosses the air space.

6.4.5.3 For heating-dominated climates a high-solar-gain low-e on surface 3 admits and retains solar heat.

6.4.5.4 A second low-e on surface 4 (an interior-face pyrolytic coating) can further reduce the U-factor in cold climates but shall be confirmed for cleanability and durability.

6.4.5.5 Low-Emissivity Coating Surface Datasheet

Low-Emissivity Coating Surface (Numbered from Exterior)select

Surface 2 (outboard cavity face) — solar control, cooling climates (typical)

Surface 3 (inboard cavity face) — high solar gain, heating climates

Surface 2 + surface 4 (dual low-e) — high performance, cold climates

Not applicable — no low-e coating

Per drawings

6.5 Insulating Glass Units

6.5.1 Insulating glass units shall be factory-fabricated dual-seal units certified under the IGCC or IGMA program and qualified for durability per ASTM E2190.

NOTE The primary seal (polyisobutylene) controls moisture and gas permeation; the secondary seal (silicone, polyurethane, or polysulfide) provides the structural bond holding the unit together. (6.5.2)

6.5.3 Field fabrication of insulating glass units is prohibited; all units shall arrive sealed from the fabricator.

6.5.4 IGU Makeup Datasheets

IGU Makeupselect

Double-glazed (two lites, one air space) — 1 in. nominal (typical)

Triple-glazed (three lites, two air spaces) — high performance, cold climates

Per drawings

IGU Air Space Thicknessrange

in

0.250.3750.50.6250.75

Per drawings

IGU Cavity Gas Fillradio

● Argon (typical, ~10% U-factor improvement, low cost premium)

○ Krypton (high performance, narrow air spaces and triple glazing)

○ Air (lowest cost, modest thermal performance)

6.5.5 Per ASTM E2190 the certified unit shall maintain a final frost/dew point of −40 °C or colder (measured per ASTM E546 or E576) after durability conditioning, exhibit no fog after the ASTM E2189 fogging test, and — for argon-filled units — retain an average argon concentration of at least 80 percent across the test specimens.

6.5.6 The Architect shall confirm that argon retention and the warranted seal life are consistent with the project's exposure and elevation, since gas fill diffuses slowly over the unit's life.

6.5.7 IGU Edge Spacer

6.5.7.1 The spacer separating the lites and carrying the desiccant shall be a warm-edge spacer (stainless steel, thermoplastic, or structural foam) rather than a conventional aluminum box spacer, except where a specific structural or appearance reason requires otherwise.

NOTE Warm-edge spacers substantially reduce the conductive heat loss and the condensation risk at the glass edge and modestly improve the whole-unit U-factor. (6.5.7.2)

6.5.7.3 IGU Edge Spacer Datasheet

IGU Edge Spacerradio

● Warm-edge (stainless, thermoplastic, or structural foam) — recommended

○ Aluminum box spacer (lowest cost, highest edge conductance, condensation risk)

6.6 Spandrel and Ceramic-Frit Glass

NOTE Spandrel glass conceals the floor-edge, structure, and insulation between vision-glass areas. (6.6.1)

6.6.2 Spandrel glass shall be heat-strengthened (not annealed) because the opaque back-up and the absorbed solar energy create high thermal stress; fully tempered glass is generally not used for spandrel because heat-strengthened glass resists the thermal stress while breaking into larger, retained fragments.

6.6.3 The opacifier shall be a ceramic frit (a fired-on ceramic enamel) on surface 2, or an opaque film or applied opacifier, as indicated.

6.6.4 Ceramic frit shall be fused during the heat-treatment cycle so it is permanent and durable.

6.6.5 Spandrel Glass Opacifier Datasheet

Spandrel Glass Opacifierselect

Ceramic frit (fired-on enamel) on surface 2 — durable, typical

Opaque applied film or coating on rear surface

Not applicable — no spandrel glass on project

Per drawings

6.6.6 Color match between fritted spandrel glass and adjacent vision glass shall be evaluated on samples and on the mock-up under daylight, because the perceived color of spandrel glass differs from vision glass even when the same coating is used.

6.6.7 Where a uniform appearance between vision and spandrel areas is required, the frit color and coating shall be selected together with the vision-glass coating.

7 Glazing Materials and Accessories

7.1 Glazing Sealants

7.1.1 Wet glazing sealants and perimeter glazing sealants shall be elastomeric sealants conforming to ASTM C920, of the type, grade, class, and use compatible with the glazing-pocket geometry and the glass coating.

7.1.2 Structural silicone glazing sealants shall additionally conform to ASTM C1184.

7.1.3 The sealant manufacturer shall confirm compatibility with the glass coating, the IGU secondary seal, the setting blocks and spacers, and the framing finish, because incompatible sealants can attack the IGU secondary seal and cause premature seal failure.

7.1.4 Glazing Sealant Type Datasheet

Glazing Sealant Type (Wet or Perimeter Glazing)select

Silicone — ASTM C920 Type S, Grade NS, Class 50/100 (highest movement, IGU-compatible)

Polyurethane — ASTM C920 Type S, Grade NS, Class 35 (paintable, moderate movement)

Not applicable — dry-gasket glazing only

7.2 Structural Silicone Glazing

7.2.1 Where the glass is retained by structural silicone glazing (the silicone sealant transfers wind load from the glass to the framing without a continuous mechanical capture on one or more edges), the design shall comply with ASTM C1401 (structural sealant glazing guide) and the structural silicone shall conform to ASTM C1184.

7.2.2 The structural bite (the contact dimension of the structural sealant on the glass and the metal) and the glue-line thickness shall be sized by engineering calculation for the design wind load and the dead-load weight of the glass, signed and sealed where required by the jurisdiction.

7.2.3 Structural silicone shall be applied in a controlled (typically factory or shop) environment wherever possible, with adhesion and compatibility verified before production.

7.2.4 Structural Silicone Glazing Datasheet

Structural Silicone Glazing Usedradio

● No — glass is mechanically captured (dry gasket or wet glazed in a pocket)

○ Yes — two-sided structural silicone (two edges captured, two structural)

○ Yes — four-sided structural silicone (all edges structural)

7.3 Setting Blocks, Spacers, and Gaskets

7.3.1 Setting blocks shall be EPDM or silicone, 85 ± 5 Shore A durometer, conforming to ASTM C864, sized to support the full width of the glass edge (the full IGU thickness for insulating units) and long enough to keep the bearing stress within the glass manufacturer's limit.

7.3.2 Edge blocks and spacers shall maintain the glass centered in the pocket and shall preserve the required edge, face, and bite clearances.

7.3.3 Compression gaskets shall conform to ASTM C864 (dense) or ASTM C509 (cellular) as appropriate to the glazing-pocket design.

7.3.4 Setting blocks and gaskets that contact an IGU secondary seal or a coated edge shall be confirmed compatible with those materials.

7.3.5 Setting Block Datasheet

Setting Block Material and Durometerradio

● EPDM, 85 ± 5 Shore A (ASTM C864) — standard

○ Silicone, 85 ± 5 Shore A — where silicone sealant or coating compatibility requires

7.4 Glazing Gaskets and Tapes

7.4.1 Dry-glazing gaskets shall be extruded EPDM, silicone, or thermoplastic, of the durometer and profile specified by the framing system, providing continuous compression against both glass faces.

7.4.2 Preformed glazing tapes, where used, shall conform to ASTM C1281.

7.4.3 Gaskets shall be installed in continuous lengths wherever possible; necessary splices shall be located at corners or at designated locations and shall be sealed.

8 Fabrication

8.1 Cutting, Edgework, and Fabrication Sequence

8.1.1 All cutting, edge treatment, hole drilling, notching, and edge deletion of coatings shall be completed before heat treatment and before lamination or IGU assembly.

8.1.2 Heat-treated and laminated glass and insulating glass units shall not be cut, drilled, or edge-worked in the field; field modification destroys the temper, breaks the laminate or seal, and voids the warranty.

8.1.3 Edges of heat-treated glass shall be clean-cut and free of vents, shells, and damage that concentrate stress and defeat the strength benefit of heat treatment.

8.1.4 Exposed Glass Edge Treatment Datasheet

Exposed Glass Edge Treatmentselect

Clean-cut (concealed edges within glazing pocket) — typical

Seamed / arrised (light edge dressing, semi-exposed edges)

Ground / flat-polished (fully exposed edges, butt joints, glass doors)

8.2 Coating Edge Deletion

8.2.1 Where a sputtered (soft-coat) low-e coating is used in an insulating glass unit and the coating is not durable at the unit perimeter, the coating shall be deleted (removed) at the edge so that the IGU secondary seal bonds to bare glass, ensuring a durable seal.

8.2.2 Coating edge deletion shall be performed by the glass fabricator before unit assembly, to the coating manufacturer's required deletion width.

9 Installation

9.1 General Glazing Requirements

9.1.1 Glazing shall comply with the GANA/NGA Glazing Manual, the framing manufacturer's published glazing instructions, and the glass and IGU fabricators' requirements.

9.1.2 Glazing shall not begin until the framing is installed plumb, level, square, and weather-protected and the glazing pockets are clean and dry.

9.1.3 Each lite shall be set on setting blocks, centered in the pocket with the required edge and face clearances and the required glazing bite, and sealed by the gasket or sealant system specified for that pocket.

9.2 Setting Blocks and Clearances

9.2.1 Setting blocks shall be located at the quarter-points of the sill, unless the lite is large or has an unusual aspect ratio, in which case the glass fabricator's setting-block locations shall govern.

9.2.2 Edge clearance, face clearance, and bite shall comply with the GANA/NGA Glazing Manual and the framing manufacturer's published instructions for the glass thickness and lite size.

NOTE Inadequate edge clearance allows glass-to-metal contact and edge stress concentration; inadequate bite allows the glass to disengage under wind load. (9.2.3)

9.3 Glazing Orientation and Coating Position

9.3.1 Coated, laminated asymmetric, and tinted glass shall be installed with the correct face toward the exterior and the coating on the specified surface.

9.3.2 The fabricator's orientation marking shall be verified at installation; a unit installed reversed delivers the wrong U-factor, SHGC, and appearance and shall be replaced, not reused.

9.3.3 Insulating glass units shall be installed with the weep system (where the pocket is drained) clear and functioning so that incidental water in the pocket drains to the exterior and does not stand against the IGU edge seal.

9.4 Protection of the Edge Seal

9.4.1 Insulating glass units shall be glazed so that the unit edge seal is not continuously immersed in standing water and is not exposed to incompatible sealants, solvents, or continuous high temperature.

NOTE Standing water and incompatible materials are the leading causes of premature IGU seal failure. (9.4.2)

9.4.3 Glazing-pocket weeps shall not be blocked by sealant, gaskets, or setting blocks.

10 Testing

10.1 Field Quality Control

10.1.1 The Architect or the Owner's testing agency may inspect installed glazing for correct glass type and orientation, setting-block placement, edge and bite clearance, gasket continuity, sealant tooling, and weep function.

10.1.2 Glazing found with incorrect glass type, reversed orientation, inadequate clearance or bite, or a compromised edge seal shall be corrected or the affected lites replaced.

10.2 Water Penetration of Installed Glazing

10.2.1 Where the framing standard or the contract documents require field water testing of the installed glazing (typically as part of the framing system test), the glazing shall be tested as part of that assembly.

NOTE This standard does not establish independent chamber tests for the glass; the glazing is verified as part of the framing system test under the applicable framing standard. (10.2.3)

10.3 Insulating Glass Unit Verification

NOTE The IGU fabricator's IGCC or IGMA certification and ASTM E2190 durability qualification serve as the basis for accepting the units; no field durability test is required. (10.3.1)

10.3.2 Units delivered with a broken seal, visible internal condensation or fog, or a damaged edge seal shall be rejected and replaced before glazing.

11 Cleaning and Protection

11.1 Construction Protection

11.1.1 Glass shall be protected from damage by adjacent construction operations from delivery through substantial completion.

11.1.2 Welding, cutting, and grinding shall not be performed near installed glass without sacrificial shields; weld spatter and grinding sparks fuse into the glass surface and create inclusions that cannot be removed without replacing the lite.

11.1.3 Glass shall not be marked with adhesive labels, paint, or tape applied directly to a coated surface, and protective films shall be removed within the film manufacturer's exposure limit so they do not bond permanently.

11.2 Final Cleaning

11.2.1 At substantial completion the glass shall be cleaned with a non-abrasive glass cleaner approved by the glass and coating manufacturers.

11.2.2 Abrasive pads, scrapers, and razor blades shall not be used on coated glass surfaces, because they scratch and remove the coating.

11.2.3 Acidic and alkaline construction-residue cleaners (masonry and concrete cleaners) shall not be allowed to contact the glass, coatings, or IGU edge seals.

11.2.4 Glass Cleaning Restrictions Datasheet

Glass Cleaning Restrictionsselect

Mild detergent or approved glass cleaner only — no abrasives, scrapers, or acids

Per glass and coating manufacturers' written cleaning procedures

Per drawings — cleaning specifications

12 Warranty

12.1 The insulating glass unit fabricator shall provide a written warranty against IGU seal failure — visible obstruction, fogging, or moisture between the lites and, where applicable, loss of gas fill below the warranted threshold — for a minimum of 10 years from substantial completion.

12.2 The laminated glass fabricator shall provide a written warranty against interlayer defects (delamination, edge separation, and discoloration beyond published limits) for a minimum of 5 years from substantial completion.

12.3 The coated glass fabricator shall provide a written warranty against coating defects (peeling, cracking, deterioration, and, for exposed coatings, durability failure) for a minimum of 5 years, and for exterior durable coatings for a minimum of 10 years, from substantial completion.

12.4 Where structural silicone glazing or wet glazing is used, the sealant manufacturer shall provide a written warranty against adhesive and cohesive sealant failure for a minimum of 10 years for ASTM C920 Class 50 or 100 and ASTM C1184 structural silicone sealants.

12.5 Warranty Term Datasheets

Warranty Term — IGU Sealrange

years

51015

Warranty Term — Laminated Glass (Interlayer)range

years

510

Warranty Term — Coated Glassrange

years

510

Warranty Term — Glazing / Structural Silicone Sealantrange

years

51020

12.6 Warranties shall be written in the name of the Owner, shall be transferable for the warranty term, and shall not exclude lites replaced under the field quality-control corrections required by this standard.

12.7 Blanket exclusions for spontaneous breakage of tempered glass shall not be accepted where heat-soak treatment was required and performed; the warranty shall cover spontaneous breakage of heat-soaked tempered glass attributable to nickel-sulfide inclusions for the warranted term.