Curtain Wall Glass Types & Selection
The glass is the performance engine of every curtain wall. Hanart specifies, sources and processes the right glass for every project — insulating, tempered, laminated, Low-E, fritted, fire-rated and acoustic — matched to your climate, orientation and code.
Glass types used in modern curtain walls
Each glass type solves a specific problem. Most building facades combine several of them in a single insulating glass unit.
Insulating Glass Units (IGU)
The default glass for any double glazed curtain wall: two or three panes separated by a warm-edge spacer and filled with argon or krypton. An IGU is what actually delivers the U-value and condensation resistance on your facade.
- 6–12 mm panes, 12–20 mm cavities
- Argon fill standard, krypton for triple glazing
- Warm-edge spacers to cut edge condensation
- U-value 1.0–1.4 W/m²·K typical
Tempered & Heat-Strengthened
Heat-treated glass is mandatory for overhead glazing, hurricane zones and any location where a broken pane could fall on people. Tempered glass is code-required in most facade locations; heat-strengthened is preferred for the outer pane of large IGUs to avoid optical distortion.
- Tempered: ~4–5× annealed strength, granule break
- Heat-strengthened: ~2× strength, lower distortion
- Both available up to 19 mm and large sizes
- Ceramic frit can be fused during tempering
Low-E & Solar Control Coating
A microscopically thin metal-oxide coating reflects infrared heat while transmitting daylight. It is the single most important choice for energy performance, and its position inside the IGU cavity determines whether the U-value or the solar heat gain dominates.
- Soft-coat Low-E for U-value, hard-coat for durability
- SHGC from 0.18 (strong solar control) to 0.60 (passive solar)
- Visible light transmittance 35–70%
- Color-neutral, silver or bronze tones available
Laminated Glass
Two panes bonded with a PVB or SentryGlas interlayer. It holds together when broken, which is why it is used for safety glazing, acoustic walls, blast resistance and overhead canopies. Combined with tempered glass it becomes the strongest standard configuration.
- PVB 0.76–3.04 mm interlayers
- Acoustic PVB reduces noise up to Rw 46 dB
- Meets EN 356 and blast standards on request
- Ideal for glass fins and structural glazing
Special-purpose facade glass
Beyond the five core types, Hanart supplies specialist glass formats for demanding building programmes.
| Glass Type | Key Property | Typical Application |
|---|---|---|
| Fritted / ceramic printed | Pattern fused in tempering; privacy, glare and solar control, bird-friendly | Spandrels, feature facades, atria |
| Fire-rated glass | EI 60/120 integrity and insulation | Firewalls, compartment floors, escape routes |
| Acoustic laminated | Rw up to 46 dB with acoustic PVB | Hotels, hospitals, airports, mixed-use towers |
| Tinted & reflective | Body-tinted or reflective coating, solar control | Warm climates, aesthetic bronze/grey/green facades |
| Heat-strengthened spandrel glass | Opaque back-panelled glass at slab edges | Hiding structure between floors |
| Smart / electrochromic (option) | Electrically tintable, dynamic solar control | Premium offices, curtain wall research buildings |
| Triple glazing | U-value to 0.9 W/m²·K | Cold climates, passive house envelopes |
| Bird-friendly patterned | Frit or UV coating visible to birds | Atria, low-rise podium glass walls |
How Hanart selects glass for your curtain wall
Glass selection starts with the building, not the catalogue. Hanart runs a four-step specification process on every project so the glazed curtain wall meets its energy, comfort and budget targets together.
- Climate & code — local U-value mandate, condensation criteria and wind load determine the base IGU configuration.
- Orientation & daylight — east-west facades get higher solar control; north-facing and atrium glazing gets higher light transmission.
- Interior comfort — acoustic zones, glare control and occupant proximity adjust the coating and lamination build-up.
- Structural & safety — tempered and laminated configurations are locked by code, blast or impact requirements.
Every recommended glass build-up is validated by optical simulation and, on large projects, a full-scale mock-up before mass fabrication. We document the glass schedule, thicknesses and coating positions in the shop drawings so there is no ambiguity on site.
Glass meets the facade system
Glass in structural glazing
Structural silicone glazing (SSG) and point-supported facades place far higher demands on glass — edge quality, lamination and coating position all change. Hanart coordinates glass processing with the framing system so the two perform as one assembly.
- Edge work with strict tolerances
- Coated and laminated glass for SSG
- Temperature and humidity control in bonding
Glass for curved facades
Curved and free-form envelopes need curved tempered glass, cold-bent lamination and precise frit registration. Hanart's curved glass partners process units that hold geometry within the facade tolerance.
- Curved tempered glass on request
- Cold-bent IGU technology
- Frit patterns registered to panel geometry
Windows, doors & entrances
The same glass specification logic extends to the window wall, storefronts and entrance systems on the same building envelope — so the whole facade reads as one consistent performance story.
- One glass schedule across systems
- Consistent coating tones per facade
- Coordinated mock-up for mixed envelopes
Curtain wall glass questions, answered
Most glazed curtain walls use insulating glass units (IGU) made of two or three panes — typically tempered or heat-strengthened glass with a Low-E coating — filled with argon for thermal performance. Laminated glass is added where safety, acoustic or blast performance matters.
Tempered glass is heat-treated to about 4-5 times the strength of annealed glass and breaks into small granules on failure, which is why building codes require it in overhead and high-risk glazing. Heat-strengthened glass is about twice as strong as annealed glass and breaks into larger pieces, but remains the preferred outer pane for IGUs because it has less optical distortion and lower spontaneous breakage risk.
Low-E (low-emissivity) glass carries a microscopic metallic coating that reflects long-wave infrared heat while letting daylight pass. It is the most important single component for U-value and solar control: with argon fill, a double-glazed Low-E unit achieves U 1.2 W/m²·K, and a triple-glazed unit can reach 0.9 W/m²·K.
Fritted glass has a ceramic pattern fused onto the surface during tempering. It reduces solar heat gain and glare, provides privacy and visual rhythm, and is commonly used on spandrel panels and feature facades. It also helps with bird-friendly design when the frit pattern is dense enough.
Yes. Hanart supplies fire-rated insulated glass and wired or ceramic glass systems rated up to EI 60/120, combined with intumescent perimeter barriers, tested to local fire codes and delivered with certification.
Get a glass specification for your curtain wall
Send your drawings, climate data and performance targets. Hanart will prepare a glass build-up recommendation and budget within 24 hours.