This glossary highlights specialized terms used across the Building Products & Construction Materials sector, with a focused reference for the Glass & Glazing Practice. It helps executives and practitioners interpret glass fabrication, coatings, insulating units, structural glazing, safety, testing, certification, energy performance, and regulatory terminology.
A B C D E F G H I J L M N O P R S T U V W X Y
| A | |
| AAMA | American Architectural Manufacturers Association: The former industry association whose test methods and specifications remain widely cited for curtain walls, storefronts, windows, and field testing. Its operations were consolidated into the Fenestration and Glazing Industry Alliance. |
| ABC | American Bird Conservancy: A conservation organization that develops bird-friendly building guidance and evaluates glazing materials using collision-deterrence testing and material threat factors. |
| AD/CVD | Antidumping and Countervailing Duties: Trade remedies applied to imports found to be unfairly priced or subsidized. Orders covering certain glass products can materially affect sourcing, landed cost, and supplier strategy. |
| AG | Anti-Glare: A surface treatment that diffuses reflected light to reduce glare and improve screen or display visibility. It is distinct from an anti-reflective coating, which primarily reduces total reflected light. |
| AGWA | Australian Glass and Window Association: The Australian industry body representing glass, glazing, and fenestration businesses and supporting technical guidance, training, compliance, and certification. |
| AHJ | Authority Having Jurisdiction: The organization or official responsible for interpreting and enforcing applicable codes. Approval by this authority is often decisive for safety glazing, fire-rated assemblies, guards, and structural installations. |
| AN | Annealed Glass: Float glass that has been cooled without subsequent heat strengthening or tempering. It is easier to cut and fabricate but has lower strength and breaks into larger, sharper fragments than fully tempered glass. |
| ANSI | American National Standards Institute: The coordinator of the U.S. voluntary standards system. ANSI Z97.1 establishes impact and safety requirements frequently specified for architectural safety glazing. |
| AR | Anti-Reflective: A coating or surface treatment engineered to reduce visible reflections and increase light transmission. It is used in display glass, storefronts, observation areas, museums, and other applications requiring high transparency. |
| ASD | Allowable Stress Design: A structural design method that compares service-level stresses with allowable material stresses. It is used in evaluating glass, framing, anchors, and supporting components under wind and other loads. |
| ASHRAE | American Society of Heating, Refrigerating and Air-Conditioning Engineers: A standards organization whose energy requirements, particularly Standard 90.1, influence allowable fenestration area, U-factor, solar heat gain coefficient, and whole-building envelope performance. |
| ASTM | ASTM International: A standards organization publishing core specifications and test methods for flat, heat-treated, laminated, coated, insulating, structural, and impact-resistant glass products. |
| ATFP | Antiterrorism and Force Protection: Design measures intended to protect occupants and facilities from blast, forced entry, and related threats. Requirements can govern laminated glass, framing, anchorage, stand-off distance, and post-breakage retention. |
| B | |
| BIPV | Building-Integrated Photovoltaics: Photovoltaic materials incorporated into building-envelope components such as curtain walls, skylights, canopies, and spandrel panels, allowing glazing assemblies to generate electricity while performing architectural functions. |
| BREEAM | Building Research Establishment Environmental Assessment Method: A building sustainability assessment system that can influence glazing selection through energy, daylight, responsible sourcing, life-cycle impact, and material disclosure criteria. |
| BRG | Bullet-Resistant Glazing: A multilayer glass, polymer, or glass-clad assembly designed to resist specified ballistic threats. Performance depends on the complete tested assembly, including framing, joints, retention, and attack-side orientation. |
| BS | British Standard: A national standard published for use in the United Kingdom. Glass specifications may cite national documents directly or British adoptions of European and international standards. |
| BSI | British Standards Institution: The United Kingdom’s national standards body and a certification organization. Its standards and conformity marks are frequently encountered in glass supplied to British construction projects. |
| C | |
| CAD | Computer-Aided Design: Digital design software used to create glass shapes, hole and notch locations, edge details, fabrication drawings, and coordinated façade layouts. |
| CAM | Computer-Aided Manufacturing: Software that converts approved glass designs into machine instructions for cutting, edging, drilling, printing, and other fabrication processes. |
| CAN/CGSB | National Standard of Canada / Canadian General Standards Board: A designation associated with Canadian national standards, including requirements for safety glazing materials used in buildings. |
| CCC | China Compulsory Certification: A mandatory product certification system for designated products sold in China. Certain safety glass categories require compliant testing, factory controls, and product marking. |
| CCT | Correlated Color Temperature: A measure, expressed in kelvins, describing whether transmitted or emitted light appears warmer or cooler. It is relevant when specifying tinted, coated, illuminated, or electronically controlled glazing. |
| CE | Conformité Européenne: A conformity marking indicating that a product covered by harmonized European requirements has undergone the applicable assessment and documentation process. Construction glass may require declared performance before placement on the European market. |
| CEN | European Committee for Standardization: The body responsible for many European standards governing basic glass products, insulating units, laminated glass, thermally treated glass, and fire classifications. |
| CFR | Code of Federal Regulations: The codification of U.S. federal regulations. Architectural safety glazing is directly affected by the impact requirements in 16 CFR Part 1201. |
| CNC | Computer Numerical Control: Automated machine control used for precision glass cutting, grinding, polishing, drilling, milling, and waterjet fabrication. Accurate programming is critical because most machining must occur before heat treatment. |
| CPR | Construction Products Regulation: The European regulatory framework for declaring the performance of construction products covered by harmonized specifications. It establishes obligations affecting technical documentation, product marking, and market access. |
| CPSC | Consumer Product Safety Commission: The U.S. federal agency responsible for consumer product safety regulations, including mandatory impact requirements for architectural glazing used in hazardous locations. |
| CR | Condensation Resistance: A rating indicating how effectively a fenestration assembly resists interior surface condensation under defined conditions. Higher values generally indicate warmer interior glass and frame surfaces. |
| CRI | Color Rendering Index: A measure of how accurately a light source renders colors compared with a reference source. Glazing transmission characteristics can affect perceived color and daylight quality inside a building. |
| CSG | Chemically Strengthened Glass: Glass strengthened through ion exchange at its surface rather than thermal tempering. It can provide high surface compression with limited optical distortion, especially in thin or specialty glass. |
| CT | Central Tension: The tensile stress developed within heat-strengthened or fully tempered glass as a consequence of surface compression. Its magnitude affects stored energy, fracture behavior, and break pattern. |
| CTE | Coefficient of Thermal Expansion: A material property describing dimensional change with temperature. Differences among glass, interlayers, frits, sealants, metals, and ceramics can create thermal stress or compatibility problems. |
| CVD | Chemical Vapor Deposition: A process that deposits a thin functional coating through chemical reactions at the glass surface. In float production, it is commonly used to create durable online or pyrolytic coatings. |
| CW | Curtain Wall: A non-load-bearing exterior wall system that transfers wind, dead, seismic, and other façade loads to the building structure. Glass performance must be coordinated with framing, anchors, gaskets, sealants, and drainage. |
| CWCT | Centre for Window and Cladding Technology: A United Kingdom-based authority known for façade standards, testing protocols, technical guidance, and professional training used on glazed-envelope projects. |
| D | |
| dB | Decibel: A logarithmic unit used to express sound levels and acoustic transmission loss. Small numerical changes can represent meaningful differences in perceived or measured sound performance. |
| dBA | A-Weighted Decibel: A sound-level measure adjusted to approximate human hearing sensitivity across frequencies. It is commonly used to characterize environmental noise affecting façade acoustic design. |
| DGU | Double-Glazed Unit: A sealed assembly containing two glass panes separated by a spacer and cavity. It improves thermal and acoustic performance compared with a single pane and may incorporate coatings, gas fill, or laminated plies. |
| DIN | Deutsches Institut für Normung: The German Institute for Standardization. Its national standards and German adoptions of European standards are frequently referenced for structural glass design, fabrication, testing, and installation. |
| DLO | Daylight Opening: The unobstructed visible opening within a frame or glazing system. It is used when coordinating glass dimensions, sightlines, vision area, daylight, and egress-related requirements. |
| DoP | Declaration of Performance: A manufacturer-issued document stating the assessed performance of a construction product against relevant harmonized specifications. It supports regulatory conformity and product traceability in European markets. |
| DP | Design Pressure: The specified positive or negative pressure used to design or rate a glazing assembly for wind and related loads. Glass thickness, edge support, framing, and anchorage must be adequate for this pressure. |
| DP | Dew Point: The temperature at which moisture begins to condense. Low-temperature dew-point testing is used to assess whether insulating glass cavities remain sufficiently dry. |
| DPI | Dots per Inch: A measure of image or print resolution. It is used when specifying digital ceramic printing, decorative interlayers, and other image-based glass treatments. |
| E | |
| E | Integrity Classification: A European fire-resistance classification indicating the period for which an element prevents flames and hot gases from passing through. It does not by itself require insulation against heat transfer. |
| EC | Electrochromic: A glazing technology that changes optical transmission in response to an applied electrical voltage. It can dynamically manage glare, daylight, privacy, and solar heat gain. |
| EI | Integrity and Insulation Classification: A European fire-resistance classification requiring an assembly to restrict flames and hot gases while limiting temperature rise on the unexposed face for a stated period. |
| EN | European Standard: A standard adopted by European national standards bodies. The designation appears on many specifications for insulating, laminated, coated, heat-treated, fire-rated, and basic soda-lime-silicate glass. |
| EPD | Environmental Product Declaration: A third-party-verified disclosure reporting quantified environmental impacts over defined life-cycle stages. It enables comparison and carbon accounting for glass and glazing products under consistent rules. |
| EPDM | Ethylene Propylene Diene Monomer: A synthetic rubber widely used for glazing gaskets, seals, and setting components because of its weathering, ozone, and temperature resistance. |
| ESG | Einscheibensicherheitsglas: The German designation for single-pane thermally toughened safety glass. It commonly appears in European product markings, drawings, and certificates. |
| ETA | European Technical Assessment: A documented assessment route for a construction product not fully covered by a harmonized European standard. It can provide the basis for declared performance and conformity marking. |
| EVA | Ethylene-Vinyl Acetate: A polymer interlayer used to laminate glass for safety, decorative, photovoltaic, and specialty applications. Processing conditions and edge-exposure suitability depend on the specific formulation. |
| EW | Integrity and Radiation Classification: A European fire-resistance classification requiring integrity while limiting radiant heat transmitted through the assembly for a stated period. |
| F | |
| FBC | Florida Building Code: The statewide code containing stringent wind and impact provisions that materially influence glazing design, product approval, testing, and installation in hurricane-prone regions. |
| FEA | Finite Element Analysis: A numerical method used to model stresses, deflections, thermal effects, contact behavior, and support conditions in glass and glazing assemblies, particularly when simplified calculations are insufficient. |
| FE/BR | Forced-Entry/Ballistic-Resistant: A security classification for assemblies designed to withstand specified physical attack and ballistic threats. Qualification applies to the complete tested system rather than the glass alone. |
| FGIA | Fenestration and Glazing Industry Alliance: A North American industry organization publishing standards, certification programs, technical guidance, and training for glazing, windows, doors, curtain walls, and insulating glass. |
| FLAP | Fatal Light Awareness Program: A Canadian organization focused on reducing bird collisions with buildings. Its research and guidance inform bird-friendly glazing patterns, coverage, contrast, and installation decisions. |
| FPG | Fire-Protective Glazing: Glazing designed to contain flames and smoke for a rated period but not necessarily block significant radiant heat. Codes commonly limit its size and location in fire-rated assemblies. |
| FRG | Fire-Resistive Glazing: Glazing designed to restrict flames, smoke, and heat transfer for a rated period. When tested as part of an appropriate assembly, it can satisfy fire-resistance requirements associated with walls or partitions. |
| FT | Fully Tempered Glass: Heat-treated glass with high surface compression and increased strength relative to annealed glass. When broken, it is intended to fracture into relatively small particles consistent with applicable safety requirements. |
| FTO | Fluorine-Doped Tin Oxide: A transparent conductive coating used in photovoltaic, heated, sensing, and other functional glass applications. It combines electrical conductivity with visible-light transmission. |
| G | |
| g-value | Solar Factor: The fraction of incident solar energy entering a building through glazing as direct transmission plus inward-flowing absorbed heat. It is the metric commonly used in Europe for performance comparable to solar heat gain coefficient. |
| GANA | Glass Association of North America: A former industry association whose glazing manuals, technical papers, and design guidance remain widely referenced. Its technical resources are now maintained within the National Glass Association. |
| GASP | Grazing Angle Surface Polarimeter: An optical instrument used to measure surface stress in heat-treated glass. It supports process control and verification of heat-strengthened or fully tempered products. |
| GB | Guobiao: The designation used for Chinese national standards. These standards appear in specifications, certificates, and test reports for glass manufactured or sold in China. |
| GGF | Glass and Glazing Federation: A United Kingdom trade federation providing technical guidance, standards support, training, and industry representation for glass, glazing, and fenestration businesses. |
| GSA | General Services Administration: The U.S. federal agency whose security criteria and test methods influence blast-resistant glazing and façade design for federal facilities. |
| GTP | Glass Technical Paper: An industry guidance document addressing subjects such as design, fabrication, handling, compatibility, thermal stress, quality, and installation. These papers are frequently incorporated into project specifications and quality procedures. |
| GWP | Global Warming Potential: A measure expressing the climate impact of greenhouse-gas emissions in carbon-dioxide-equivalent terms. It is a central result in life-cycle assessments and environmental product declarations for glass products. |
| H | |
| HPD | Health Product Declaration: A standardized disclosure of product ingredients and associated health information. Architects and owners may request it for glass coatings, interlayers, sealants, and complete glazing products. |
| HS | Heat-Strengthened Glass: Heat-treated glass with greater mechanical and thermal strength than annealed glass but lower surface compression than fully tempered glass. It typically breaks into larger fragments and is not inherently safety glazing. |
| HST | Heat Soak Testing: A destructive quality-control process that subjects fully tempered glass to a controlled heating cycle to reduce the risk of later spontaneous breakage associated with nickel sulfide inclusions. |
| HTG | Heat-Treated Glass: An umbrella term covering glass strengthened through controlled heating and cooling, principally heat-strengthened and fully tempered products. |
| HVHZ | High-Velocity Hurricane Zone: A Florida code designation applying enhanced wind, impact, testing, approval, and installation requirements in Miami-Dade and Broward Counties. |
| I | |
| IBC | International Building Code: A widely adopted model code governing structural loads, safety glazing locations, guards, fire-rated assemblies, energy-related interfaces, and other requirements affecting architectural glass installations. |
| ICC | International Code Council: The organization that publishes the primary U.S. model building codes used by jurisdictions to regulate construction, including glazing safety, structural, fire, and energy requirements. |
| ICC-ES | ICC Evaluation Service: An organization that evaluates building products and systems against code requirements. Its reports can establish acceptance criteria and installation conditions for specialty glazing components, anchors, and assemblies. |
| IECC | International Energy Conservation Code: A model energy code that sets requirements affecting fenestration U-factor, solar heat gain coefficient, air leakage, and permitted glazed area. |
| IGCC | Insulating Glass Certification Council: A certification body that validates insulating glass units through independent testing, plant quality controls, and ongoing audits. Its mark is widely specified in North America. |
| IGCC | International Green Construction Code: A model code containing sustainability and high-performance building provisions. Its envelope requirements can affect glazing area, thermal performance, daylight, and material selection. |
| IGMA | Insulating Glass Manufacturers Alliance: A former North American association that developed technical guidance and certification resources for insulating glass. Its programs and publications were integrated into the Fenestration and Glazing Industry Alliance. |
| IGU | Insulating Glass Unit: A factory-sealed assembly of two or more glass panes separated by one or more cavities. Spacer design, desiccant, sealants, coatings, gas fill, and fabrication quality determine long-term performance. |
| IR | Infrared: Electromagnetic radiation beyond the visible spectrum. Coated and tinted glass is engineered to control infrared transmission and reflection for solar, thermal, sensing, or imaging performance. |
| IRC | International Residential Code: A model code for one- and two-family dwellings that regulates hazardous glazing locations, guards, structural loads, energy performance, and emergency escape openings. |
| ISC | Interagency Security Committee: A U.S. government body establishing risk-management and physical-security criteria for federal facilities. Its requirements can drive blast-resistant glazing and façade protection strategies. |
| ISO | International Organization for Standardization: A global standards body publishing test, terminology, product, and management standards relevant to laminated glass, glass strength, thermal performance, optical properties, and laboratory methods. |
| ITO | Indium Tin Oxide: A transparent conductive oxide used in heated, switchable, photovoltaic, display, and sensing glass. Its coating design balances electrical resistance, transparency, color, and durability. |
| J | |
| JIS | Japanese Industrial Standards: Japan’s national standards used to specify and test glass products, safety performance, dimensions, optical properties, and manufacturing quality. |
| L | |
| LC | Liquid Crystal: A material whose optical state can be controlled electrically. Liquid-crystal systems are used in switchable privacy glazing, projection surfaces, and specialty displays. |
| LCA | Life-Cycle Assessment: A structured method for quantifying environmental impacts over defined stages of a product’s life. It supports carbon comparisons among glass compositions, coatings, fabrication routes, and glazing configurations. |
| LEED | Leadership in Energy and Environmental Design: A green-building rating system whose energy, daylight, views, bird-collision deterrence, and material-disclosure credits can influence glazing specifications. |
| LMI | Large Missile Impact: A test category simulating windborne debris striking glazed assemblies during severe storms. Passing criteria include both impact resistance and subsequent pressure cycling. |
| Low-E | Low Emissivity: A thin coating that reduces long-wave radiant heat transfer through glazing. Coating type and surface position strongly affect U-factor, solar heat gain, color, and handling requirements. |
| LPCB | Loss Prevention Certification Board: A certification body for fire and security products. Its approvals may be specified for fire-resistant and security glazing systems in international projects. |
| LRFD | Load and Resistance Factor Design: A structural design method that applies separate factors to loads and resistance to achieve target reliability. It may be used for framing, connections, anchors, and structural glass design. |
| LSG | Laminated Safety Glass: Two or more glass plies bonded by an interlayer intended to retain fragments after breakage. It is used for human-impact safety, fall protection, security, acoustics, storm resistance, and overhead glazing. |
| LSG | Light-to-Solar Gain Ratio: The ratio of visible light transmittance to solar heat gain coefficient. A higher value generally indicates glazing that admits more daylight relative to unwanted solar heat. |
| LT | Light Transmittance: The fraction or percentage of visible light passing through glass under stated measurement conditions. It is a key selection criterion for daylight, glare, privacy, appearance, and energy performance. |
| M | |
| MSF | Thousand Square Feet: A commercial unit commonly used to report flat-glass volume, production capacity, pricing, and demand. Thickness or weight assumptions must be stated when converting it to tonnage. |
| MSVD | Magnetron Sputter Vacuum Deposition: A vacuum-coating process used to apply multilayer low-emissivity, solar-control, and specialty coatings after float-glass production. These offline coatings offer high performance but require careful handling and edge processing. |
| MT | Material Threat Factor: A score used by the American Bird Conservancy to indicate the relative collision threat posed by a glazing material or treatment. Lower scores indicate stronger demonstrated bird-deterrence performance. |
| MVTR | Moisture Vapor Transmission Rate: The rate at which water vapor passes through a material under specified conditions. It is relevant to interlayers, sealants, membranes, and insulating-glass edge-seal durability. |
| N | |
| NGA | National Glass Association: A North American trade association providing technical resources, standards participation, education, certification, and advocacy for architectural glass and glazing businesses. |
| NFPA | National Fire Protection Association: A standards organization publishing fire and life-safety codes that govern rated openings, fire-protection assemblies, testing, inspection, and installation of fire-rated glazing. |
| NFRC | National Fenestration Rating Council: A U.S. organization that establishes standardized simulation, testing, certification, and labeling procedures for fenestration energy performance, including U-factor, solar heat gain, and visible transmittance. |
| NiS | Nickel Sulfide: A glass inclusion that can undergo a delayed phase change and cause spontaneous breakage in fully tempered glass. Heat soak testing is used to reduce, but not eliminate, this risk. |
| NOA | Notice of Acceptance: A Miami-Dade County product approval documenting tested configurations, design pressures, limitations, and installation requirements for products used in high-wind and impact applications. |
| NOM | Norma Oficial Mexicana: A mandatory Mexican technical regulation covering designated products, safety requirements, labeling, or test methods. Applicable provisions must be confirmed when supplying glass into Mexico. |
| O | |
| OITC | Outdoor-Indoor Transmission Class: A single-number acoustic rating weighted toward lower-frequency exterior noise such as road, rail, and aircraft traffic. It is often more informative than sound transmission class for façade glazing. |
| OSHA | Occupational Safety and Health Administration: The U.S. agency that sets workplace safety requirements affecting glass handling, cutting, lifting, equipment guarding, fall protection, chemical exposure, and installation activities. |
| OTTV | Overall Thermal Transfer Value: A building-envelope metric used in several Asian and tropical-market energy codes. It combines conductive and solar heat gains through walls and glazing to evaluate façade performance. |
| P | |
| PCR | Product Category Rules: Requirements defining how a life-cycle assessment and environmental product declaration must be prepared for a product category. They support consistent boundaries, assumptions, and impact reporting. |
| PDLC | Polymer-Dispersed Liquid Crystal: A switchable glazing technology in which liquid-crystal droplets dispersed in a polymer change from scattering to transparent when energized. It is widely used for on-demand visual privacy. |
| PECVD | Plasma-Enhanced Chemical Vapor Deposition: A coating process that uses plasma to promote thin-film deposition at controlled temperatures. It is used for functional optical, barrier, and conductive layers on specialty glass. |
| PET | Polyethylene Terephthalate: A polyester film used in decorative, solar-control, safety, security, and multilayer laminated-glass constructions. Its surface treatments and compatibility with adjacent materials affect long-term performance. |
| PIB | Polyisobutylene: A low-permeability material commonly used as the primary seal in dual-seal insulating glass units. It limits moisture-vapor ingress and gas loss around the spacer perimeter. |
| PMU | Performance Mock-Up: A representative full-scale façade assembly built for laboratory or field evaluation. Testing can cover air leakage, water penetration, structural loading, impact, movement, and thermal behavior before production installation. |
| PS | Polysulfide: A sealant chemistry used as a secondary edge seal in insulating glass units. It offers adhesion and moisture resistance but must be evaluated for gas retention and compatibility with other components. |
| PU | Polyurethane: A polymer chemistry used in glazing sealants, insulating-glass secondary seals, adhesives, and interlayers. Formulation determines elasticity, adhesion, moisture resistance, and ultraviolet durability. |
| PVB | Polyvinyl Butyral: A widely used laminated-glass interlayer that bonds glass plies and retains fragments after breakage. Specialized formulations provide acoustic, solar, structural, decorative, or security performance. |
| PVD | Physical Vapor Deposition: A family of vacuum processes that deposits thin material layers onto glass. It is used to create optical, solar-control, low-emissivity, conductive, and decorative coatings. |
| R | |
| REACH | Registration, Evaluation, Authorisation and Restriction of Chemicals: The European Union framework governing chemical substances and supply-chain communication. It affects coatings, sealants, interlayers, inks, frits, and other chemical inputs used in glass products. |
| RHG | Relative Heat Gain: A comparative measure combining conductive heat transfer and solar heat gain through glazing under specified conditions. It supports preliminary comparison of alternative glass configurations. |
| RTV | Room-Temperature Vulcanizing: A curing description commonly applied to silicone sealants that develop elastomeric properties without elevated-temperature processing. These materials are used for weather seals, structural bonding, and shop glazing. |
| R-value | Thermal Resistance: A measure of resistance to heat flow, equal to the reciprocal of thermal transmittance when units and boundary conditions are consistent. Higher values indicate greater insulating performance. |
| Rw | Weighted Sound Reduction Index: An international single-number rating derived from laboratory sound-reduction measurements across frequencies. It is commonly used outside North America to compare glazing acoustic performance. |
| S | |
| SC | Shading Coefficient: A legacy ratio comparing solar heat gain through a glazing product with that through a reference clear glass. Solar heat gain coefficient has largely replaced it in modern specifications. |
| SC | Surface Compression: Compressive stress intentionally created at the surfaces of heat-treated or chemically strengthened glass. Its magnitude is central to strength classification, break behavior, and quality verification. |
| SCALP | Scattered Light Polariscope: An optical instrument that measures stress profiles through glass thickness using scattered polarized light. It can assess surface compression, central tension, and strengthening depth. |
| SGCC | Safety Glazing Certification Council: A North American certification body that validates safety glazing through independent testing, plant quality-control requirements, and periodic audits. |
| SHGC | Solar Heat Gain Coefficient: The fraction of incident solar radiation entering through glazing as direct transmission plus inward-flowing absorbed heat. Lower values generally reduce cooling loads and solar overheating. |
| SLS | Soda-Lime-Silicate Glass: The predominant glass composition used for architectural float glass. Its standardized properties underpin common annealed, coated, laminated, heat-strengthened, and tempered products. |
| SMI | Small Missile Impact: A storm-resistance test category simulating smaller windborne debris striking glazed assemblies. Required missile size, velocity, impact locations, and pressure cycling depend on the applicable standard and exposure. |
| SPD | Suspended-Particle Device: A switchable glazing technology in which electrically aligned particles change light transmission. It enables variable tinting for solar control, glare reduction, and privacy. |
| SSG | Structural Silicone Glazing: A façade method in which a structural silicone sealant transfers loads between glass and supporting framing. Joint geometry, adhesion, compatibility, cure, quality control, and verified design strength are critical. |
| STC | Sound Transmission Class: A North American single-number rating for airborne sound isolation, weighted primarily for speech-related frequencies. Laminated plies, pane thickness, cavity width, and asymmetry can improve performance. |
| SVHC | Substance of Very High Concern: A chemical identified under European chemicals regulation as presenting significant hazards. Its presence above applicable thresholds can trigger disclosure, authorization, or supply-chain obligations. |
| SWRI | Sealant, Waterproofing & Restoration Institute: An industry organization providing technical guidance, validation programs, and training related to sealants and building-envelope installation practices. |
| T | |
| TAS | Testing Application Standard: A Florida test-method designation used in the High-Velocity Hurricane Zone. TAS 201, 202, and 203 address impact, air and water infiltration, structural loading, and cyclic pressure performance. |
| TCO | Transparent Conductive Oxide: A class of electrically conductive yet optically transparent coatings used in photovoltaic, heated, electrochromic, display, antenna, and sensing glass. |
| Tg | Glass Transition Temperature: The temperature range at which an amorphous polymer changes from a hard, glassy state toward a softer, more mobile state. It helps explain the temperature-dependent behavior of interlayers and sealants. |
| TGU | Triple-Glazed Unit: A sealed insulating assembly containing three glass panes and two cavities. It can deliver lower thermal transmittance but adds weight, thickness, edge-seal complexity, and fabrication requirements. |
| TL | Transmission Loss: The reduction in sound energy as it passes through a material or assembly, expressed in decibels by frequency. It is the underlying laboratory data used to derive acoustic ratings. |
| TPS | Thermoplastic Spacer: A warm-edge insulating-glass spacer applied as a continuous thermoplastic material containing desiccant. It forms the cavity perimeter and can reduce edge heat transfer and joint discontinuities. |
| TPU | Thermoplastic Polyurethane: A polymer interlayer used in specialty laminated glass requiring combinations of toughness, flexibility, transparency, and adhesion to glass or plastics. |
| TVG | Teilvorgespanntes Glas: The German designation for heat-strengthened glass. It commonly appears on European drawings, product markings, and technical documents. |
| U | |
| U-factor | Overall Heat Transfer Coefficient: The rate of heat transfer through a glazing or fenestration assembly per unit area and temperature difference. Lower values indicate better insulating performance. |
| U-value | Thermal Transmittance: The metric commonly used internationally to express heat flow through a building component per unit area and temperature difference. Glass-center and whole-assembly values must not be treated as interchangeable. |
| UFC | Unified Facilities Criteria: Technical requirements used by U.S. Department of Defense agencies. Relevant documents establish antiterrorism, blast, façade, structural, and protective-glazing criteria for military facilities. |
| UKCA | United Kingdom Conformity Assessed: A product marking used under the Great Britain conformity framework for designated regulated products. Applicability and transition provisions must be checked for the product and market concerned. |
| UL | Underwriters Laboratories: The name associated with widely recognized product safety standards, certifications, and listings. Fire-rated and bullet-resistant glazing specifications frequently cite applicable test standards or listed assemblies. |
| ULC | Underwriters Laboratories of Canada: The designation associated with Canadian safety standards and certifications. Listed fire-rated glazing assemblies may be evaluated to Canadian test requirements. |
| UV | Ultraviolet: Electromagnetic radiation with wavelengths shorter than visible light. Glazing and interlayers may be designed to reduce ultraviolet transmission to protect interiors, occupants, artwork, and merchandise. |
| UVT | Ultraviolet Transmittance: The fraction or percentage of ultraviolet radiation passing through a glass assembly over a stated wavelength range. It is relevant to fading, conservation, plant growth, and specialty optical applications. |
| V | |
| VIG | Vacuum Insulating Glass: A sealed unit in which two panes are separated by a very narrow evacuated cavity supported by microscopic pillars. It provides high thermal resistance in a relatively thin construction. |
| VLT | Visible Light Transmittance: The proportion of visible light passing through a glazing assembly. It is used to evaluate daylight availability, glare, appearance, privacy, and spectral selectivity. |
| VOC | Volatile Organic Compound: An organic chemical capable of evaporating under normal conditions. Content and emissions limits can affect the selection, handling, and documentation of sealants, coatings, primers, inks, and cleaners. |
| VT | Visible Transmittance: The rating used by the National Fenestration Rating Council for the fraction of visible light transmitted through a complete fenestration product. Higher values generally indicate more daylight transmission. |
| W | |
| WBDR | Wind-Borne Debris Region: A code-defined area where glazed openings may require impact protection because of hurricane wind speed and debris exposure. Location and risk category determine the applicable requirements. |
| WES | Warm-Edge Spacer: An insulating-glass spacer engineered to reduce heat transfer at the unit perimeter compared with conventional highly conductive metal spacers. It can improve edge temperatures and condensation resistance. |
| WVTR | Water Vapor Transmission Rate: A measure of water vapor passing through a material under defined conditions. Low transmission is important for insulating-glass seals and interlayers exposed to humid environments. |
| WWR | Window-to-Wall Ratio: The proportion of exterior wall area occupied by glazed openings. It materially affects glass demand, façade energy performance, daylight, solar gain, and code compliance. |
| X | |
| XRF | X-Ray Fluorescence: A nondestructive analytical technique used to identify and quantify elemental composition. Glass laboratories use it for raw-material, substrate, frit, coating, and contamination analysis. |
| Y | |
| YI | Yellowness Index: A numerical measure of the degree to which a transparent or translucent material appears yellow. It is used to monitor interlayer, polymer, coating, and laminated-glass color stability. |