What Is Spandrel Glass? Uses, Types and Specification
What Is Spandrel Glass? Types, Applications, Benefits, and Specifications
Commercial building designs rely on modern glass solutions to achieve attractive architecture, enhanced energy efficiency, and durability. One of the materials used for contemporary building facades is spandrel glass.
In case you are developing a commercial office tower, improving your apartment building, or changing a curtain wall system, it is worth finding out how spandrel glass works.
Spandrel glass is extensively used in commercial buildings, high-rises, and institutional facilities in New Jersey and New York. It allows creating a continuous glass facade and hiding structural elements, insulation, and mechanical systems.
However, choosing spandrel glass means more than selecting its color or finish. Architects, building owners, contractors, and facade consultants should take into consideration thermal stress, fire safety, insulation, and compatibility with vision glass.
The following guide describes what spandrel glass is, the types of spandrel glass, applications, installation, and essential specifications for commercial glazing projects.
What Is Spandrel Glass?
Spandrel glass is an opaque or non-vision architectural glass used in curtain wall systems for concealing structural components between building floors. It creates a visually consistent facade while hiding such building components as concrete floor slabs, columns, insulation, ductwork, and others.
As opposed to transparent vision glass that admits natural light to interior spaces, spandrel glass is meant to prevent visibility into non-occupied spaces that contain structural and mechanical elements.
It is typically installed between the rows of windows in commercial curtain wall and window wall systems.
The main goal of spandrel glass is to create a visually continuous facade without exposing building structural systems.
How Does Spandrel Glass Work?
Spandrel glass works due to application of an opaque coating, ceramic frit, or special backing system that prevents visibility through the glass.
The typical spandrel glass assembly includes:
– Heat-strengthened or tempered architectural glass
– Ceramic frit or opaque coating
– Insulation materials
– Metal back pans
– Sealants and glazing components
– Perimeter fire containment materials if necessary
The exact assembly is determined based on architectural design, performance needs, and construction standards.
Proper spandrel glass specification allows complementing adjacent vision glass and maintaining building exterior.
What Is Spandrel Glass Used For?
Spandrel glass fulfills several roles in the design of modern commercial and residential buildings.
Apart from its primary function of concealing building components, it also plays the role of aesthetic element and, as part of the properly constructed assembly, it is the element of building facade performance.
1. Commercial Curtain Wall Systems
One of the most widespread applications of spandrel glass is to cover areas between floors in curtain wall systems.
Commercial towers commonly combine transparent vision glazing with opaque spandrel glass panels for creation of a uniform facade.
They allow hiding floor slabs, structural supports, and insulation while maintaining the continuous glass facade appearance.
2. High-Rise Residential Buildings
Spandrel glass is often incorporated in apartment buildings, condominiums, and other multifamily developments.
It is used to hide floor edges and structural components while maintaining architectural continuity between residential floors.
For property owners who are considering facade improvements or commercial window replacement projects, matching existing spandrel glass is often an important design consideration.
3. Office Buildings and Corporate Properties
Modern office buildings commonly feature large glass elevations.
Spandrel glass allows combining transparent windows with opaque facade segments without creating any visual discontinuity.
4. Mechanical Equipment Screening
Some facade designs incorporate spandrel glass for hiding mechanical equipment, service areas, and utility components.
Opaque glass allows creating a visually clean facade while transparent glass would expose equipment behind the facade.
5. Building Renovation and Facade Replacement
Facade renovation projects often require replacing the existing spandrel glass panels when they are deteriorated, damaged, or visually inconsistent.
Spandrel glass replacement may involve matching the color, coating, thickness, and thermal performance of the existing glass.
A detailed facade survey is required before selecting new spandrel glass panels.
Ceramic Frit Spandrel Glass
Ceramic frit spandrel glass is produced by applying ceramic enamel coating to the glass surface and firing it during heat treatment.
The resulting surface ensures opacity and provides color durability.
Ceramic frit coatings are available in various colors and patterns and allow coordinating the spandrel areas with other parts of the facade.
Advantages of ceramic frit spandrel glass include:
– Durable ceramic coating
– Various colors and patterns options
– Strong architectural flexibility
– Compatibility with commercial glazing systems
However, ceramic frit spandrel glass may look different from adjacent vision glass because opaque and transparent surfaces reflect light in different ways.
Full-size samples are recommended to be viewed before making the final decision.
Opacified Spandrel Glass
Opacified spandrel glass uses opaque coating applied to the surface of the glass.
Dependent on the manufacturer, the coatings may use silicone-based or other material for the coatings.
Such coatings prevent visibility through the glass and provide architectural flexibility.
Opacified spandrel glass is commonly considered for commercial buildings when architects require consistency of opaque facade panels.
Coating compatibility, adhesion, durability, and warranty conditions should be verified with the manufacturer.
Insulated Spandrel Glass
Insulated spandrel glass combines opaque glazing with insulating glass unit or another insulated assembly.
Such glass may be used in case the design requires alignment with insulated vision glazing.
It may include several glass lites, sealed cavities, coatings, and other elements.
Insulated spandrel glass specifications should consider:
– Thermal stress
– Glass heat treatment
– Insulation
– Edge seals
– Moisture management
– Performance of the whole system
Due to ability of opaque glazing to absorb considerable amount of solar energy, thermal stress and glass durability should be carefully evaluated.
Shadow Box Spandrel Glass
Shadow box spandrel system commonly uses vision glass placed in front of the backing assembly.
The space behind the glass creates visual depth and makes the spandrel area visually aligned with adjacent transparent glazing.
Shadow box spandrel glass is commonly used for architectural designs where facade appearance is the priority.
However, shadow box assemblies should be carefully designed to manage moisture, condensation, ventilation, thermal performance, and durability.
Laminated Spandrel Glass
Laminated spandrel glass is a glass assembly that consists of multiple glass lites combined with the interlayer.
The interlayers may be opaque or colored to provide the non-vision appearance.
Depending on the selected assembly, laminated spandrel glass can also support certain requirements for safety glass or soundproofing.
Spandrel Glass vs. Vision Glass: What’s the Difference?
Despite being similar in appearance, spandrel glass and vision glass are meant for different purposes.
Vision glass is transparent or translucent glazing used for creation of views, admission of daylight, and providing contribution to the building facade.
Spandrel glass is opaque glazing used for concealing building components.
Item
What to state
Section reference
Typically with glazed aluminum curtain walls (MasterFormat 08 44 13) and glazing (08 80 00); confirm with the project spec
Glass type and thickness
Lite configuration, heat-strengthened or tempered, applicable ASTM standard
Opacifying method
Ceramic frit, opacifier or shadow box, with color and reflectance
Insulation and back pan
R-value, material, fire rating, and whether it is part of an NFPA 285 assembly
Fire containment
Perimeter safing system and tested assembly
Performance
U-factor, solar heat gain, thermal stress and wind load criteria
Appearance
Mockup, approval process and tolerances
Warranty
Glass, coating and sealant terms and duration
One of the biggest architectural challenges is the coordination of spandrel glass with vision glass in order to achieve consistent appearance of the facade.
Because spandrel glass and vision glass reflect and absorb light differently, even identical colors or coatings do not necessarily provide the same exterior appearance.
Why Does Spandrel Glass Require Heat Treatment?
Thermal stress is one of the important considerations for specification of spandrel glass.
Opaque glass panels absorb a lot of solar energy, especially when installed in front of insulated back pans or other materials that hinder heat dissipation.
During the exposure to sunlight, the center of the glass becomes substantially hotter than its edges.
Such temperature difference creates thermal stress.
Exceeding of glass stress may cause breaking or fracturing of the glass.
Heat-Strengthened Spandrel Glass
Heat-strengthened glass undergoes controlled heating and cooling in order to increase its resistance to thermal and mechanical stresses compared with the annealed glass.
It is often used in spandrel applications requiring thermal stress resistance improvement.
Tempered Spandrel Glass
Tempered glass undergoes more complex heat treatment process.
It provides increased strength compared with annealed glass and breaks into relatively small fragments upon fracture.
Tempered glass may be required in case of the applicable safety glazing requirements.
Which Option Is Better?
The choice of heat-strengthened or tempered spandrel glass depends on several factors:
– Dimensions and thickness of the glass
– Solar exposure
– Coating features
– Calculations of the thermal stress
– Wind load requirements
– Safety glazing regulations
– Engineering recommendations of the project
ASTM C1048 is one of the important standards concerning heat-treated flat glass.
Professional facade consultant or glazing specialist should determine the best glass configuration for each project.
Spandrel Glass Fire Safety Requirements
Fire safety is one of the key elements of commercial curtain wall design.
Spandrel glass panels are often located at the point of intersection of facade walls and floor slabs.
Such locations require fire-containment assembly to hinder spread of fire and smoke between floors.
- Perimeter Fire Containment
Perimeter fire containment system addresses the junction of floor assembly and the exterior curtain wall.
Depending on the approved design, it may include mineral wool insulation, smoke sealants, and other tested materials.
ASTM E2307 is one of the important test standards for perimeter fire-containment systems.
Spandrel area should be coordinated with the tested assembly in order to provide fire safety.
- NFPA 285 Considerations
NFPA 285 evaluates fire propagation characteristics of certain exterior wall assemblies containing combustible materials.
Depending on the type of the building, wall construction materials, and adopted construction code, an exterior wall assembly should comply with this test.
Fire safety requirements should be evaluated for the complete wall assembly and not just for the spandrel glass.
Why Fire Safety Coordination Matters
Incorrect specification of facade components may jeopardize the performance of the tested wall assembly.
Architects, facade consultants, contractors, and glazing professionals should coordinate glass selection, insulation, back pans, and fire containment during design and installation processes.
How Does Spandrel Glass Affect Building Energy Efficiency?
Spandrel glass can contribute to the thermal performance of commercial building envelopes when it is incorporated into the properly insulated wall system.
However, the energy performance of a spandrel area depends on more than spandrel glass itself.
It is determined by the complete assembly consisting of opaque coatings, insulating materials, metal back pans, framing, and thermal breaks.
- Insulation Behind Spandrel Glass
Insulation installed behind the spandrel panel reduces heat transfer through the non-vision segment of a curtain wall.
The performance of the assembly is dependent on the properties of insulation, its continuity, thermal bridging, and installation quality.
- Thermal Performance of the Assembly
Depending on adopted energy code, the spandrel area may be classified in different ways.
The insulated opaque spandrel assembly may be evaluated as an opaque wall, while other assemblies may be evaluated as fenestration.
Requirements for spandrel glass are dependent on the adopted version of the International Energy Conservation Code (IECC), ASHRAE 90.1, and other local building codes.
- Moisture and Condensation Management
Inadequately designed spandrel glass assembly can suffer from moisture entrapment or condensation.
Designers should evaluate:
– Movement of vapor
– Air leaks
– Drainage
– Cavity ventilation
– Location of the insulation
– Differences in interior and exterior temperatures
Proper moisture management provides protection for the glazing assembly and adjacent building materials.
How to Match Spandrel Glass with Existing Curtain Wall Systems
Achieving consistency of appearance is one of the most difficult tasks during installation and replacement of spandrel glass.
Even if two glass products have identical color specifications, they may differ under varying lighting conditions.
- Review Full-Sized Samples
Glass samples that are small in size may not properly illustrate the appearance of the entire facade.
Full-sized mockups allow evaluation of the color, reflectivity, and visual consistency.
- Compare Glass in Natural Light
Spandrel glass should be viewed together with the adjacent vision glass under natural daylight conditions.
Appearance of glass will vary under different lighting conditions, viewing angles, and reflections.
- Consider Glass Coatings and Tint
Coatings and glass tints affect reflection and absorption of light by the glass.
Where possible, it is better to use coordinated products from the same manufacturer to ensure consistency of appearance.
- Define the Appearance Requirements
Project specifications should include clear requirements regarding the evaluation of the appearance.
They can include the viewing distance, lighting conditions, sample approval, and acceptable variations.
- Evaluate Shadow Box Systems
In cases when appearance consistency is highly important, a shadow box system may be used as an alternative to conventional opaque coating.
However, additional complexity of the shadow box system should be taken into consideration during the design process.
Spandrel Glass Specifications: What Architects Should Include
Spandrel glass specification ensures successful procurement and installation of the product.
Important specification requirements are:
Item
What to state
Section reference
Typically with glazed aluminum curtain walls (MasterFormat 08 44 13) and glazing (08 80 00); confirm with the project spec
Glass type and thickness
Lite configuration, heat-strengthened or tempered, applicable ASTM standard
Opacifying method
Ceramic frit, opacifier or shadow box, with color and reflectance
Insulation and back pan
R-value, material, fire rating, and whether it is part of an NFPA 285 assembly
Fire containment
Perimeter safing system and tested assembly
Performance
U-factor, solar heat gain, thermal stress and wind load criteria
Appearance
Mockup, approval process and tolerances
Warranty
Glass, coating and sealant terms and duration
Spandrel glass is typically included into architectural glazing and curtain wall specifications in accordance with MasterFormat 08 44 13 and 08 80 00.
- Spandrel Glass Installation Considerations
The proper spandrel glass installation requires coordination between glazing contractor, facade consultant, and various other construction trades.
Even the correct production of glass doesn’t ensure proper installation as other components might not be compatible.
Ensure Compatibility with Curtain Wall System
The selected spandrel glass needs to be compatible with the frame and movement of the curtain wall system.
- Confirm Glass Dimensions
Correct measurements of the glass are very important for the proper installation of the glass panel.
The dimensions, edge clearances, and tolerance of the frame need to comply with the approved glazing design.
- Review Back Pan and Insulation
The insulation and back pan need to be properly installed according to the specified assembly.
Wrong installation might affect thermal performance, drainage, or fire containment.
- Comply with Manufacturer Guidelines
Glazing materials, setting blocks, gaskets, and sealants have to be compatible with the selected glass and framing system.
- Inspections after Completion of Work
Quality inspection needs to cover appearance, installation conditions, and compliance with approved drawings.
Spandrel Glass Replacement in New Jersey and New York
Commercial buildings in New Jersey and New York are usually equipped with old curtain wall systems with glazing products that aren’t produced anymore.
The replacement of such panels might require a detailed analysis of the existing facade.
It is necessary for a contractor to review original glass configuration, coating appearance, framing compatibility, back pan, insulation, and fire-containment details.
How to Select Spandrel Glass for Commercial Building
Selecting the right spandrel glazing system is quite challenging and requires a combination of appearance, performance, and requirements of the project.
Before finalizing the glass choice, consider the following:
– What type of curtain wall or window wall system will be used?
– Should spandrel glass match vision glass?
– Which kind is more appropriate – ceramic frit or opacified glass?
– What thermal stress conditions are expected?
– Are insulated spandrel panels required?
– What fire-containment provisions are required?
– How is moisture and condensation managed?
– Are heat-strengthened or tempered glass required?
– What are the structural and energy performance criteria?
– Warranties and replacement materials are available?
Discussing these questions at the beginning can help to prevent specification and procurement issues, and modifications during the installation process.
FAQ About Spandrel Glass
Spandrel Glass Usage in Commercial Buildings
Spandrel glass is used in commercial buildings to hide floor slabs, structural columns, insulation, mechanical equipment, and other non-vision areas of the building. It helps to create a uniform look of the building facade despite hidden building components.
Types of Spandrel Glass
The main types of spandrel glass are ceramic frit spandrel glass, opacified spandrel glass, insulated spandrel glass, shadow box systems, and laminated spandrel glass.
Is Spandrel Glass Tempered?
Spandrel glass can be heat-strengthened or fully tempered to be resistant to thermal stress.
Spandrel Glass vs Regular Glass
Spandrel glass is opaque and used to cover non-vision areas of the building, while vision glass is transparent.
Also, spandrel glass requires additional attention to thermal stress and installation assembly.
Spandrel Glass in Residential Buildings
Yes. Spandrel glass is quite popular in high-rise apartment buildings, condominiums, and other multi-family buildings with glazed facade. Spandrel glass helps to cover structural floor edges.
Spandrel Glass Insulation
Spandrel glass itself doesn’t provide any insulation. Its thermal performance is provided by the whole assembly, which includes insulating materials, back pan, glass configuration, and other framing components.
Shadow Box Spandrel Glass System
Shadow box spandrel system uses glass installed in front of the recessed backing assembly. Usually, it incorporates insulation and metal back pan. This design provides visual depth and better appearance match with vision glass.
Why Does Spandrel Glass Look Different from Vision Glass?
Spandrel glass is opaque and vision glass is transparent. There can be differences in appearance due to different coatings, reflectivity, lighting conditions, and background.
Spandrel Glass Replacement
Yes. Damaged spandrel glass panels can be easily replaced by using compatible glazing solution.
Factors Affecting Spandrel Glass Replacement Costs
Spandrel glass replacement cost is determined by panel dimension, glass configuration, coating requirements, building height, access equipment, labor, and condition of existing glazing components.
Consult Your Spandrel Glass and Commercial Glazing Project with AAWD Inc.
Planning commercial curtain wall installation, facade renovation, or spandrel glass replacement project?
AAWD Inc. is your point of contact for consulting about commercial glazing and architectural facade projects.
Whether you need to select spandrel glass options for new construction or match existing glazing during renovation – share your project drawings and building requirements to discuss suitable solution.
Contact AAWD Inc. today to consult your spandrel glass, curtain wall, or commercial glazing project in New Jersey and New York.
What Is Spandrel Glass? Types, Applications, Benefits, and Specifications
Commercial building designs rely on modern glass solutions to achieve attractive architecture, enhanced energy efficiency, and durability. One of the materials used for contemporary building facades is spandrel glass.
In case you are developing a commercial office tower, improving your apartment building, or changing a curtain wall system, it is worth finding out how spandrel glass works.
Spandrel glass is extensively used in commercial buildings, high-rises, and institutional facilities in New Jersey and New York. It allows creating a continuous glass facade and hiding structural elements, insulation, and mechanical systems.
However, choosing spandrel glass means more than selecting its color or finish. Architects, building owners, contractors, and facade consultants should take into consideration thermal stress, fire safety, insulation, and compatibility with vision glass.
The following guide describes what spandrel glass is, the types of spandrel glass, applications, installation, and essential specifications for commercial glazing projects.
What Is Spandrel Glass?
Spandrel glass is an opaque or non-vision architectural glass used in curtain wall systems for concealing structural components between building floors. It creates a visually consistent facade while hiding such building components as concrete floor slabs, columns, insulation, ductwork, and others.
As opposed to transparent vision glass that admits natural light to interior spaces, spandrel glass is meant to prevent visibility into non-occupied spaces that contain structural and mechanical elements.
It is typically installed between the rows of windows in commercial curtain wall and window wall systems.
The main goal of spandrel glass is to create a visually continuous facade without exposing building structural systems.
How Does Spandrel Glass Work?
Spandrel glass works due to application of an opaque coating, ceramic frit, or special backing system that prevents visibility through the glass.
The typical spandrel glass assembly includes:
– Heat-strengthened or tempered architectural glass
– Ceramic frit or opaque coating
– Insulation materials
– Metal back pans
– Sealants and glazing components
– Perimeter fire containment materials if necessary
The exact assembly is determined based on architectural design, performance needs, and construction standards.
Proper spandrel glass specification allows complementing adjacent vision glass and maintaining building exterior.
What Is Spandrel Glass Used For?
Spandrel glass fulfills several roles in the design of modern commercial and residential buildings.
Apart from its primary function of concealing building components, it also plays the role of aesthetic element and, as part of the properly constructed assembly, it is the element of building facade performance.
1. Commercial Curtain Wall Systems
One of the most widespread applications of spandrel glass is to cover areas between floors in curtain wall systems.
Commercial towers commonly combine transparent vision glazing with opaque spandrel glass panels for creation of a uniform facade.
They allow hiding floor slabs, structural supports, and insulation while maintaining the continuous glass facade appearance.
2. High-Rise Residential Buildings
Spandrel glass is often incorporated in apartment buildings, condominiums, and other multifamily developments.
It is used to hide floor edges and structural components while maintaining architectural continuity between residential floors.
For property owners who are considering facade improvements or commercial window replacement projects, matching existing spandrel glass is often an important design consideration.
3. Office Buildings and Corporate Properties
Modern office buildings commonly feature large glass elevations.
Spandrel glass allows combining transparent windows with opaque facade segments without creating any visual discontinuity.
4. Mechanical Equipment Screening
Some facade designs incorporate spandrel glass for hiding mechanical equipment, service areas, and utility components.
Opaque glass allows creating a visually clean facade while transparent glass would expose equipment behind the facade.
5. Building Renovation and Facade Replacement
Facade renovation projects often require replacing the existing spandrel glass panels when they are deteriorated, damaged, or visually inconsistent.
Spandrel glass replacement may involve matching the color, coating, thickness, and thermal performance of the existing glass.
A detailed facade survey is required before selecting new spandrel glass panels.
Ceramic Frit Spandrel Glass
Ceramic frit spandrel glass is produced by applying ceramic enamel coating to the glass surface and firing it during heat treatment.
The resulting surface ensures opacity and provides color durability.
Ceramic frit coatings are available in various colors and patterns and allow coordinating the spandrel areas with other parts of the facade.
Advantages of ceramic frit spandrel glass include:
– Durable ceramic coating
– Various colors and patterns options
– Strong architectural flexibility
– Compatibility with commercial glazing systems
However, ceramic frit spandrel glass may look different from adjacent vision glass because opaque and transparent surfaces reflect light in different ways.
Full-size samples are recommended to be viewed before making the final decision.
Opacified Spandrel Glass
Opacified spandrel glass uses opaque coating applied to the surface of the glass.
Dependent on the manufacturer, the coatings may use silicone-based or other material for the coatings.
Such coatings prevent visibility through the glass and provide architectural flexibility.
Opacified spandrel glass is commonly considered for commercial buildings when architects require consistency of opaque facade panels.
Coating compatibility, adhesion, durability, and warranty conditions should be verified with the manufacturer.
Insulated Spandrel Glass
Insulated spandrel glass combines opaque glazing with insulating glass unit or another insulated assembly.
Such glass may be used in case the design requires alignment with insulated vision glazing.
It may include several glass lites, sealed cavities, coatings, and other elements.
Insulated spandrel glass specifications should consider:
– Thermal stress
– Glass heat treatment
– Insulation
– Edge seals
– Moisture management
– Performance of the whole system
Due to ability of opaque glazing to absorb considerable amount of solar energy, thermal stress and glass durability should be carefully evaluated.
Shadow Box Spandrel Glass
Shadow box spandrel system commonly uses vision glass placed in front of the backing assembly.
The space behind the glass creates visual depth and makes the spandrel area visually aligned with adjacent transparent glazing.
Shadow box spandrel glass is commonly used for architectural designs where facade appearance is the priority.
However, shadow box assemblies should be carefully designed to manage moisture, condensation, ventilation, thermal performance, and durability.
Laminated Spandrel Glass
Laminated spandrel glass is a glass assembly that consists of multiple glass lites combined with the interlayer.
The interlayers may be opaque or colored to provide the non-vision appearance.
Depending on the selected assembly, laminated spandrel glass can also support certain requirements for safety glass or soundproofing.
Spandrel Glass vs. Vision Glass: What’s the Difference?
Despite being similar in appearance, spandrel glass and vision glass are meant for different purposes.
Vision glass is transparent or translucent glazing used for creation of views, admission of daylight, and providing contribution to the building facade.
Spandrel glass is opaque glazing used for concealing building components.
| Item | What to state |
|---|---|
| Section reference | Typically with glazed aluminum curtain walls (MasterFormat 08 44 13) and glazing (08 80 00); confirm with the project spec |
| Glass type and thickness | Lite configuration, heat-strengthened or tempered, applicable ASTM standard |
| Opacifying method | Ceramic frit, opacifier or shadow box, with color and reflectance |
| Insulation and back pan | R-value, material, fire rating, and whether it is part of an NFPA 285 assembly |
| Fire containment | Perimeter safing system and tested assembly |
| Performance | U-factor, solar heat gain, thermal stress and wind load criteria |
| Appearance | Mockup, approval process and tolerances |
| Warranty | Glass, coating and sealant terms and duration |
One of the biggest architectural challenges is the coordination of spandrel glass with vision glass in order to achieve consistent appearance of the facade.
Because spandrel glass and vision glass reflect and absorb light differently, even identical colors or coatings do not necessarily provide the same exterior appearance.
Why Does Spandrel Glass Require Heat Treatment?
Thermal stress is one of the important considerations for specification of spandrel glass.
Opaque glass panels absorb a lot of solar energy, especially when installed in front of insulated back pans or other materials that hinder heat dissipation.
During the exposure to sunlight, the center of the glass becomes substantially hotter than its edges.
Such temperature difference creates thermal stress.
Exceeding of glass stress may cause breaking or fracturing of the glass.
Heat-Strengthened Spandrel Glass
Heat-strengthened glass undergoes controlled heating and cooling in order to increase its resistance to thermal and mechanical stresses compared with the annealed glass.
It is often used in spandrel applications requiring thermal stress resistance improvement.
Tempered Spandrel Glass
Tempered glass undergoes more complex heat treatment process.
It provides increased strength compared with annealed glass and breaks into relatively small fragments upon fracture.
Tempered glass may be required in case of the applicable safety glazing requirements.
Which Option Is Better?
The choice of heat-strengthened or tempered spandrel glass depends on several factors:
– Dimensions and thickness of the glass
– Solar exposure
– Coating features
– Calculations of the thermal stress
– Wind load requirements
– Safety glazing regulations
– Engineering recommendations of the project
ASTM C1048 is one of the important standards concerning heat-treated flat glass.
Professional facade consultant or glazing specialist should determine the best glass configuration for each project.
Spandrel Glass Fire Safety Requirements
Fire safety is one of the key elements of commercial curtain wall design.
Spandrel glass panels are often located at the point of intersection of facade walls and floor slabs.
Such locations require fire-containment assembly to hinder spread of fire and smoke between floors.
- Perimeter Fire Containment
Perimeter fire containment system addresses the junction of floor assembly and the exterior curtain wall.
Depending on the approved design, it may include mineral wool insulation, smoke sealants, and other tested materials.
ASTM E2307 is one of the important test standards for perimeter fire-containment systems.
Spandrel area should be coordinated with the tested assembly in order to provide fire safety.
- NFPA 285 Considerations
NFPA 285 evaluates fire propagation characteristics of certain exterior wall assemblies containing combustible materials.
Depending on the type of the building, wall construction materials, and adopted construction code, an exterior wall assembly should comply with this test.
Fire safety requirements should be evaluated for the complete wall assembly and not just for the spandrel glass.
Why Fire Safety Coordination Matters
Incorrect specification of facade components may jeopardize the performance of the tested wall assembly.
Architects, facade consultants, contractors, and glazing professionals should coordinate glass selection, insulation, back pans, and fire containment during design and installation processes.
How Does Spandrel Glass Affect Building Energy Efficiency?
Spandrel glass can contribute to the thermal performance of commercial building envelopes when it is incorporated into the properly insulated wall system.
However, the energy performance of a spandrel area depends on more than spandrel glass itself.
It is determined by the complete assembly consisting of opaque coatings, insulating materials, metal back pans, framing, and thermal breaks.
- Insulation Behind Spandrel Glass
Insulation installed behind the spandrel panel reduces heat transfer through the non-vision segment of a curtain wall.
The performance of the assembly is dependent on the properties of insulation, its continuity, thermal bridging, and installation quality.
- Thermal Performance of the Assembly
Depending on adopted energy code, the spandrel area may be classified in different ways.
The insulated opaque spandrel assembly may be evaluated as an opaque wall, while other assemblies may be evaluated as fenestration.
Requirements for spandrel glass are dependent on the adopted version of the International Energy Conservation Code (IECC), ASHRAE 90.1, and other local building codes.
- Moisture and Condensation Management
Inadequately designed spandrel glass assembly can suffer from moisture entrapment or condensation.
Designers should evaluate:
– Movement of vapor
– Air leaks
– Drainage
– Cavity ventilation
– Location of the insulation
– Differences in interior and exterior temperatures
Proper moisture management provides protection for the glazing assembly and adjacent building materials.
How to Match Spandrel Glass with Existing Curtain Wall Systems
Achieving consistency of appearance is one of the most difficult tasks during installation and replacement of spandrel glass.
Even if two glass products have identical color specifications, they may differ under varying lighting conditions.
- Review Full-Sized Samples
Glass samples that are small in size may not properly illustrate the appearance of the entire facade.
Full-sized mockups allow evaluation of the color, reflectivity, and visual consistency.
- Compare Glass in Natural Light
Spandrel glass should be viewed together with the adjacent vision glass under natural daylight conditions.
Appearance of glass will vary under different lighting conditions, viewing angles, and reflections.
- Consider Glass Coatings and Tint
Coatings and glass tints affect reflection and absorption of light by the glass.
Where possible, it is better to use coordinated products from the same manufacturer to ensure consistency of appearance.
- Define the Appearance Requirements
Project specifications should include clear requirements regarding the evaluation of the appearance.
They can include the viewing distance, lighting conditions, sample approval, and acceptable variations.
- Evaluate Shadow Box Systems
In cases when appearance consistency is highly important, a shadow box system may be used as an alternative to conventional opaque coating.
However, additional complexity of the shadow box system should be taken into consideration during the design process.
Spandrel Glass Specifications: What Architects Should Include
Spandrel glass specification ensures successful procurement and installation of the product.
Important specification requirements are:
| Item | What to state |
|---|---|
| Section reference | Typically with glazed aluminum curtain walls (MasterFormat 08 44 13) and glazing (08 80 00); confirm with the project spec |
| Glass type and thickness | Lite configuration, heat-strengthened or tempered, applicable ASTM standard |
| Opacifying method | Ceramic frit, opacifier or shadow box, with color and reflectance |
| Insulation and back pan | R-value, material, fire rating, and whether it is part of an NFPA 285 assembly |
| Fire containment | Perimeter safing system and tested assembly |
| Performance | U-factor, solar heat gain, thermal stress and wind load criteria |
| Appearance | Mockup, approval process and tolerances |
| Warranty | Glass, coating and sealant terms and duration |
Spandrel glass is typically included into architectural glazing and curtain wall specifications in accordance with MasterFormat 08 44 13 and 08 80 00.
- Spandrel Glass Installation Considerations
The proper spandrel glass installation requires coordination between glazing contractor, facade consultant, and various other construction trades.
Even the correct production of glass doesn’t ensure proper installation as other components might not be compatible.
Ensure Compatibility with Curtain Wall System
The selected spandrel glass needs to be compatible with the frame and movement of the curtain wall system.
- Confirm Glass Dimensions
Correct measurements of the glass are very important for the proper installation of the glass panel.
The dimensions, edge clearances, and tolerance of the frame need to comply with the approved glazing design.
- Review Back Pan and Insulation
The insulation and back pan need to be properly installed according to the specified assembly.
Wrong installation might affect thermal performance, drainage, or fire containment.
- Comply with Manufacturer Guidelines
Glazing materials, setting blocks, gaskets, and sealants have to be compatible with the selected glass and framing system.
- Inspections after Completion of Work
Quality inspection needs to cover appearance, installation conditions, and compliance with approved drawings.
Spandrel Glass Replacement in New Jersey and New York
Commercial buildings in New Jersey and New York are usually equipped with old curtain wall systems with glazing products that aren’t produced anymore.
The replacement of such panels might require a detailed analysis of the existing facade.
It is necessary for a contractor to review original glass configuration, coating appearance, framing compatibility, back pan, insulation, and fire-containment details.
How to Select Spandrel Glass for Commercial Building
Selecting the right spandrel glazing system is quite challenging and requires a combination of appearance, performance, and requirements of the project.
Before finalizing the glass choice, consider the following:
– What type of curtain wall or window wall system will be used?
– Should spandrel glass match vision glass?
– Which kind is more appropriate – ceramic frit or opacified glass?
– What thermal stress conditions are expected?
– Are insulated spandrel panels required?
– What fire-containment provisions are required?
– How is moisture and condensation managed?
– Are heat-strengthened or tempered glass required?
– What are the structural and energy performance criteria?
– Warranties and replacement materials are available?
Discussing these questions at the beginning can help to prevent specification and procurement issues, and modifications during the installation process.
FAQ About Spandrel Glass
Spandrel Glass Usage in Commercial Buildings
Spandrel glass is used in commercial buildings to hide floor slabs, structural columns, insulation, mechanical equipment, and other non-vision areas of the building. It helps to create a uniform look of the building facade despite hidden building components.
Types of Spandrel Glass
The main types of spandrel glass are ceramic frit spandrel glass, opacified spandrel glass, insulated spandrel glass, shadow box systems, and laminated spandrel glass.
Is Spandrel Glass Tempered?
Spandrel glass can be heat-strengthened or fully tempered to be resistant to thermal stress.
Spandrel Glass vs Regular Glass
Spandrel glass is opaque and used to cover non-vision areas of the building, while vision glass is transparent.
Also, spandrel glass requires additional attention to thermal stress and installation assembly.
Spandrel Glass in Residential Buildings
Yes. Spandrel glass is quite popular in high-rise apartment buildings, condominiums, and other multi-family buildings with glazed facade. Spandrel glass helps to cover structural floor edges.
Spandrel Glass Insulation
Spandrel glass itself doesn’t provide any insulation. Its thermal performance is provided by the whole assembly, which includes insulating materials, back pan, glass configuration, and other framing components.
Shadow Box Spandrel Glass System
Shadow box spandrel system uses glass installed in front of the recessed backing assembly. Usually, it incorporates insulation and metal back pan. This design provides visual depth and better appearance match with vision glass.
Why Does Spandrel Glass Look Different from Vision Glass?
Spandrel glass is opaque and vision glass is transparent. There can be differences in appearance due to different coatings, reflectivity, lighting conditions, and background.
Spandrel Glass Replacement
Yes. Damaged spandrel glass panels can be easily replaced by using compatible glazing solution.
Factors Affecting Spandrel Glass Replacement Costs
Spandrel glass replacement cost is determined by panel dimension, glass configuration, coating requirements, building height, access equipment, labor, and condition of existing glazing components.
Consult Your Spandrel Glass and Commercial Glazing Project with AAWD Inc.
Planning commercial curtain wall installation, facade renovation, or spandrel glass replacement project?
AAWD Inc. is your point of contact for consulting about commercial glazing and architectural facade projects.
Whether you need to select spandrel glass options for new construction or match existing glazing during renovation – share your project drawings and building requirements to discuss suitable solution.
Contact AAWD Inc. today to consult your spandrel glass, curtain wall, or commercial glazing project in New Jersey and New York.
