Guide to Choosing Glass Used in Building Construction: Types, Properties, and Code Considerations

Choosing the right glass used in building construction affects safety, energy efficiency, daylighting, and long-term maintenance. This guide summarizes common glass types, key performance criteria, relevant codes and standards, and practical selection tips for designers, builders, and building managers.

Glass used in building construction: common types and where they are used

Different projects and locations call for different glass products. Common types include:

Annealed glass

Basic float glass produced by controlled cooling. It is economical and used where breakage does not pose a serious hazard. Annealed glass breaks into large, sharp shards and is therefore rarely used where safety glazing is required.

Tempered (toughened) glass

Heat-treated to increase strength; breaks into small, granular fragments that are less likely to cause serious injury. Used for doors, sidelights, shower enclosures, and other safety glazing locations required by codes.

Laminated glass

Two or more glass plies bonded with an interlayer (usually polyvinyl butyral or ionoplast). Holds together when broken, providing post-breakage security, pedestrian protection, and sound reduction. Common in skylights, façades, and areas requiring burglary or hurricane resistance.

Insulated glass units (IGUs)

Two or more glass lites separated by a spacer and sealed to create an air- or gas-filled cavity. Improves thermal performance and reduces condensation. Often combined with low-E coatings for energy efficiency.

Coated and specialty glass

Low-E coatings reduce thermal emissivity; solar control coatings lower solar heat gain coefficient (SHGC); reflective and tinted glass manage glare and solar heat. Fire-rated, wired, and acoustic laminates address specific safety or performance needs.

Performance criteria to consider when selecting glass

Selection depends on multiple performance metrics rather than a single “best” product. Important criteria include:

Safety and impact resistance

Codes identify locations where safety glazing is mandatory (doors, side lights, low glazing near stairs, and shower doors). Tempered and laminated glass typically meet these requirements. Refer to code provisions in the International Building Code (IBC) and regional regulations.

Thermal performance and energy efficiency

U-value (heat transfer), Solar Heat Gain Coefficient (SHGC), and visible transmittance (VT) are key metrics. IGUs with low-E coatings and inert gas fills (argon, krypton) deliver better insulation and can help meet energy codes like the International Energy Conservation Code (IECC).

Acoustic control

Laminated glass and thicker IGUs improve sound insulation—important near highways, airports, and noisy urban environments. Acoustic performance is measured using sound transmission class (STC) or weighted sound reduction indices.

Structural and wind-load considerations

Glass exposed to wind pressure, blast loads, or heavy snow loads must meet structural design requirements and testing standards. Glass edge quality, framing, and anchorage influence in-service safety and longevity.

Fire resistance

Fire-rated glazing assemblies are tested to provide limited integrity and/or insulation under fire conditions. These products are used in vertical and horizontal fire barriers where required by code.

Code, standards, and testing references

Building codes and technical standards set minimum requirements for safety, energy efficiency, and performance. Key references include the International Building Code (IBC), the International Energy Conservation Code (IECC), and product testing and designation standards from national testing organizations. For glass testing methods and material specifications, see ASTM International.

Other relevant standards include safety glazing criteria (ANSI/ICC standards), impact resistance tests, and regional product certification programs. Local jurisdictions may adopt versions of national codes and may require specific labeling or certification for used products.

How to choose the right glass for a project

Selection is a balance of performance, cost, aesthetics, and code compliance. Consider the following process:

• Identify required functions (safety glazing, thermal control, acoustic isolation, fire rating).
• Consult applicable codes and project specifications early in design to confirm mandatory requirements.
• Evaluate climate and orientation: higher solar exposure increases the value of low-SHGC coatings; cold climates prioritize low U-values.
• Match glass type to framing and structural conditions; ensure proper edge protection, sealants, and spacer selection for IGUs.
• Assess maintenance, cleaning access, and long-term durability (resistance to seal failure, abrasion, and environmental exposure).
• Factor lifecycle cost rather than only first cost—better-performing glass can reduce HVAC loads and glare-related retrofit costs.

Sustainability and lifecycle considerations

Energy-efficient glazing contributes to reduced heating and cooling energy use. Consider glazing designed to meet or exceed local energy code requirements and pursue validated performance data. Recyclability, embodied carbon of glass products, and supplier transparency on manufacturing processes are increasingly relevant for green building certifications and procurement policies.

Frequently asked questions

Which glass used in building construction meets safety and energy requirements?

Tempered and laminated glass commonly satisfy safety glazing mandates; insulated glass units with low-E coatings and gas fills address energy performance. Combining laminated safety glass in an IGU can meet both requirements where needed.

When is laminated glass preferred over tempered glass?

Laminated glass is preferred when post-breakage integrity, security, or acoustic performance is important, such as in overhead glazing, façades, and windows in hurricane-prone areas. Tempered glass is used where impact protection with rapid fragmentation is acceptable.

What role do coatings and gas fills play in IGUs?

Coatings such as low-E reduce radiative heat transfer and SHGC; gas fills like argon or krypton reduce conduction across the cavity, both improving U-value. Selection depends on climate, orientation, and energy targets.

Are there special requirements for fire-rated glass?

Fire-rated glazing must be tested and labeled for specific fire-resistance ratings. Only products listed in tested assemblies should be used where codes require fire-resistance-rated openings.

How can compliance and product performance be verified?

Verify manufacturer documentation, third-party test reports, and labeling for conformity with referenced standards. For laboratory methods and material standards, consult national standards organizations and local code authorities before specifying or installing glazing systems.