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6+12A+6 (24mm) and 6+16A+6 (28mm) insulated glass – heavy-duty double glazed units for curtain walls, commercial windows, and high-rise facades. Two 6mm glass panes with 12mm or 16mm air gap. Available with Low-E, tempered, laminated, argon fill. Max size 3300×12000mm. U-value from 1.4 W/m²K. CE / EN 1279 / ISO 9001 certified. Request FOB quote.
6+12A+6 / 6+16A+6 Insulated Glass | 24mm & 28mm Double Glazed IGU for Curtain Walls
24mm & 28mm Double Glazed IGU – The Curtain Wall Standard for Commercial & High‑Rise Architecture
6+12A+6 insulated glass (also written as 6+12A+6 double glazing, 6+12A+6 IGU, or 24mm insulated glass) and 6+16A+6 insulated glass (28mm total thickness) are the two most specified double glazed configurations for commercial curtain walls, office towers, and mid‑to‑high‑rise residential facades worldwide.
Both configurations consist of two 6mm glass panes separated by an aluminum or warm‑edge spacer — either 12mm (12A) or 16mm (16A) — hermetically sealed to form a single insulating glass unit. The 6mm glass thickness provides the structural rigidity required for large‑format curtain wall panels, while the sealed air cavity delivers proven thermal and acoustic insulation.
| Key Specification | 6+12A+6 (24mm) | 6+16A+6 (28mm) |
|---|---|---|
| Configuration | 6mm glass + 12mm gap + 6mm glass | 6mm glass + 16mm gap + 6mm glass |
| Total Thickness | 24mm | 28mm |
| Glass Types Available | Clear, Low‑E, Tempered, Laminated, Tinted, Reflective | Same |
| Spacer Options | Aluminum, Warm Edge (TPE/Swisspacer), Stainless Steel | Same |
| Gas Fill Options | Air (standard), Argon, Krypton | Same |
| Maximum Size | 3300 × 12000 mm (jumbo) | 3300 × 12000 mm (jumbo) |
| Weight (approx., clear/Air) | ~30 kg/m² | ~30 kg/m² |
| U‑Value (Clear/Air) | ~2.6 W/m²K | ~2.5 W/m²K |
| U‑Value (Low‑E/Argon) | ~1.5 W/m²K | ~1.4 W/m²K |
| Sound Reduction (Rw, Clear) | ~31 dB | ~32 dB |
| Sound Reduction (Laminated) | ~37 dB | ~38 dB |
| Certifications | CE, ISO 9001, CCC, SGS, EN 1279 | Same |
| MOQ | 1 × 20′ FCL (~180–280 m²) | 1 × 20′ FCL (~160–250 m²) |
| Lead Time | 2–4 weeks after deposit | 2–4 weeks after deposit |
💡 6+12A+6 is the single most specified IGU configuration for commercial curtain walls globally. It accounts for an estimated 40–45% of all curtain wall glazing units. The 16mm gap variant (6+16A+6) is the preferred upgrade when projects target stricter energy codes or higher acoustic ratings without moving to triple glazing.
The jump from 5mm to 6mm glass panes is the single most important decision in IGU specification. Here's why:
| Property | 5+12A+5 (22mm) | 6+12A+6 (24mm) | Improvement |
|---|---|---|---|
| Glass thickness | 5mm | 6mm | +20% thickness |
| Bending strength | Baseline | +44% | Significantly stiffer |
| Wind load resistance (same span) | Baseline | ~1.7× | Handles taller buildings |
| Weight per m² | ~25 kg | ~30 kg | +20% (manageable) |
| Cost premium | Base | +15–20% | Moderate |
| Typical max floor height | 4–6 stories | 6–15 stories | Higher‑rise capable Bottom line: 6mm panes let you glaze taller buildings, larger panels, and wider spans without switching to costly structural silicone or four‑sided structural glazing systems. |
| Parameter | 12mm Gap (6+12A+6) | 16mm Gap (6+16A+6) | Why It Matters |
|---|---|---|---|
| U‑Value (Clear/Air) | ~2.6 W/m²K | ~2.5 W/m²K | 16A is ~4% better thermally |
| U‑Value (Low‑E/Argon) | ~1.5 W/m²K | ~1.4 W/m²K | 16A squeezes out extra performance |
| Sound Reduction (Rw) | ~31 dB | ~32 dB | 16A adds ~1 dB (modest gain) |
| Argon gas retention | Good | Better | Wider gap = more gas volume = slower leakage |
| Desiccant capacity | Standard | Larger | Longer seal life, less edge condensation |
| Frame pocket depth | 24–27mm | 28–31mm | Check frame compatibility |
| Cost premium | Base | +8–12% | Modest upgrade |
| Best for | Standard curtain walls | Stricter energy codes, wider spans | — Rule of thumb: |
| Configuration | U‑Value (W/m²K) | SHGC | Relative Cost |
|---|---|---|---|
| 6+12A+6 Clear / Air | ~2.6 | ~0.76 | Base |
| 6+12A+6 Low‑E / Air | ~1.8 | ~0.66 | +15–20% |
| 6+12A+6 Low‑E / Argon | ~1.5 | ~0.64 | +25–30% |
| 6+16A+6 Clear / Air | ~2.5 | ~0.76 | +8% |
| 6+16A+6 Low‑E / Air | ~1.7 | ~0.66 | +25–30% |
| 6+16A+6 Low‑E / Argon | ~1.4 | ~0.63 | +35–42% |
| 6+16A+6 Low‑E / Krypton | ~1.2 | ~0.61 | +50–60% With Low‑E coating and argon fill, 6+16A+6 achieves U‑value 1.4 W/m²K — sufficient for Passive House‑certified windows in temperate climates. |
| Glass Combination | Rw (dB) | Traffic Noise Reduction |
|---|---|---|
| 6mm Clear + 12A + 6mm Clear | ~31 dB | Good |
| 6mm Clear + 16A + 6mm Clear | ~32 dB | Good+ |
| 6mm Laminated + 12A + 6mm Clear | ~37 dB | Very Good |
| 6mm Laminated + 16A + 6mm Laminated | ~40 dB | Excellent |
| 6mm Tempered + 12A + 6mm Tempered | ~32 dB | Good For projects near airports, highways, or railways, upgrading to laminated inner pane(s) delivers the best acoustic performance while maintaining the same 24mm or 28mm total thickness. |
The sealed air cavity in both configurations creates an effective thermal break between interior and exterior panes. With Low‑E coating on the #3 surface (inner pane, exterior face), interior surface temperatures stay above the dew point even in cold climates, virtually eliminating condensation on the room‑side glass.
| Glass Combination | UV Blockage |
|---|---|
| 6+12A+6 Clear / Clear | ~72% |
| 6+16A+6 Clear / Clear | ~72% |
| With Low‑E coating | ~85% |
| With laminated pane (PVB) | >99% For museums, galleries, and retail displays, specify one laminated pane to achieve >99% UV blockage. |
The 6mm glass thickness supports the full range of glass types. Mix and match for the outer and inner panes:
| Outer Pane (Exterior) | Inner Pane (Interior) | Best For |
|---|---|---|
| 6mm Clear Float | 6mm Clear Float | Budget commercial, standard curtain walls |
| 6mm Low‑E | 6mm Clear Float | Most popular – optimal thermal performance |
| 6mm Tempered | 6mm Clear Float | Safety glazing (doors, low windows, high traffic) |
| 6mm Tempered | 6mm Tempered | Full safety (balcony doors, public buildings) |
| 6mm Laminated | 6mm Clear Float | Acoustic insulation, security |
| 6mm Laminated | 6mm Laminated | Maximum security + soundproofing |
| 6mm Reflective | 6mm Clear Float | Solar control + privacy |
| 6mm Tinted | 6mm Clear Float | Aesthetics, moderate solar control |
| 6mm Low‑E Tempered | 6mm Tempered Laminated | Premium combo – thermal + safety + acoustic |
| 6mm Ceramic Frit | 6mm Low‑E | Spandrel panels with thermal performance |
💡 The industry‑standard specification for energy‑efficient curtain walls is 6mm Low‑E (outer, #2 surface) + 12A/16A Argon + 6mm Clear Tempered (inner). This achieves U‑value ~1.5/1.4 W/m²K at moderate cost premium and meets most international energy codes.
| Spacer Type | Material | Thermal Performance | Edge Condensation | Relative Cost |
|---|---|---|---|---|
| Aluminum | Extruded aluminum box | Standard (thermal bridge) | Moderate risk | Base |
| Warm Edge (TPE) | Thermoplastic elastomer | Improved (−0.15 U) | Low risk | +10–15% |
| Swisspacer | Reinforced polymer | Best (−0.2 U) | Very low risk | +20–30% |
| Stainless Steel | Box‑section stainless | Good (compromise) | Low risk | +15–20% For projects targeting LEED, BREEAM, or Passive House, warm edge spacers are strongly recommended to minimize thermal bridging at the glass edge. |
| Gas Fill | Thermal Improvement vs. Air | Cost Impact | Best For |
|---|---|---|---|
| Air | Baseline | None | Budget projects, mild climates |
| Argon | ~15% better U‑value | Low (+$1–2/m²) | Most common upgrade – best ROI |
| Krypton | ~25% better U‑value | Moderate (+$5–8/m²) | High performance, thin gaps |
| Xenon | ~30% better U‑value | High (+$15–25/m²) | Specialty applications For both 6+12A+6 and 6+16A+6, argon gas fill is the most cost‑effective upgrade, improving U‑value by approximately 15% versus air fill. |
In a double‑glazed IGU, there are four glass surfaces (numbered from exterior to interior). Coating placement dramatically affects performance:
| Coating Position | Surface | Effect | Best For |
|---|---|---|---|
| #2 surface (outer pane, interior face) | Recommended default | Maximizes solar heat gain in winter, reduces heat loss | Cold climates – retains interior heat |
| #3 surface (inner pane, exterior face) | Alternative | Blocks solar heat gain, keeps heat inside | Mixed climates – balances summer/winter |
| Dual Low‑E (both #2 and #3) | Premium | Maximum thermal performance | Extreme climates – Arctic or desert |
💡 For most commercial curtain walls in temperate zones, #2 surface Low‑E is the standard specification. For hot climates (Dubai, Singapore, Miami), consider #3 surface to block solar heat gain.
| Aspect | 6+12A+6 Limit | 6+16A+6 Limit | Notes |
|---|---|---|---|
| Maximum Width | 3300 mm | 3300 mm | Jumbo width |
| Maximum Height | 12000 mm | 12000 mm | Jumbo length (curtain wall panels) |
| Maximum Area | 12.0 m² | 12.0 m² | Practical limit for handling |
| Minimum Size | 250 × 400 mm | 250 × 400 mm | Smaller sizes possible |
| Weight (Clear/Air) | ~30 kg/m² | ~30 kg/m² | Mechanical assist above 80 kg |
| Recommended Max Panel | 8.0 m² | 8.0 m² | Optimal for curtain wall framing |
⚠️ For units larger than 8.0 m² or weighing over 150 kg, we recommend tempered glass for both panes and consultation with our engineering team for wind load calculations.
| Parameter | 6+12A+6 | 6+16A+6 |
|---|---|---|
| Glass Configuration | 6mm + 12mm gap + 6mm | 6mm + 16mm gap + 6mm |
| Total Thickness | 24mm (±1mm) | 28mm (±1mm) |
| Glass Types | Clear, Low‑E, Tempered, Laminated, Tinted, Reflective | Same |
| Spacer Types | Aluminum, Warm Edge (TPE), Swisspacer, Stainless Steel | Same |
| Desiccant | Molecular sieve (3Å) in spacer | Same |
| Primary Seal | Polyisobutylene (PIB) | Same |
| Secondary Seal | Polysulfide or Silicone (structural) | Same |
| Gas Fill | Air, Argon, Krypton (≥90% initial fill) | Same |
| U‑Value (Clear/Air) | ~2.6 W/m²K (EN 673) | ~2.5 W/m²K (EN 673) |
| U‑Value (Low‑E/Argon) | ~1.5 W/m²K (EN 674) | ~1.4 W/m²K (EN 674) |
| SHGC (Clear/Air) | ~0.79 | ~0.79 |
| SHGC (Low‑E/Argon) | ~0.64 | ~0.63 |
| Sound Reduction (Clear) | Rw 31 dB | Rw 32 dB |
| Sound Reduction (Laminate) | Rw 38 dB | Rw 40 dB |
| Visible Light Transmittance (Clear) | ~80% | ~80% |
| Visible Light Transmittance (Low‑E) | ~70% | ~70% |
| UV Blockage (Clear) | ~72% | ~72% |
| UV Blockage (Laminated) | >99% | >99% |
| Seal Life Expectancy | >20 years (EN 1279‑2/‑3) | >20 years (EN 1279‑2/‑3) |
| Standards | EN 1279, CE, ISO 9001, CCC, SGS | Same |
| Packaging | Vertical A‑frames or horizontal crates | Same |
| MOQ | 1 × 20′ FCL (~180–280 m²) | 1 × 20′ FCL (~160–250 m²) |
| Lead Time | 2–4 weeks | 2–4 weeks |
6+12A+6 is the defining IGU configuration for commercial curtain wall systems worldwide. Office towers, government buildings, hotels, and mixed‑use developments rely on this configuration for its proven performance, structural adequacy, and cost‑effectiveness.
Condominiums, apartments, and penthouse developments from 6 to 40+ stories specify 6+12A+6 or 6+16A+6 for their curtain wall and window wall systems. The 6mm glass handles higher wind loads than 5mm, making it suitable for tall buildings.
Corporate headquarters, business parks, and speculative office developments use 6+12A+6 as the default specification. With Low‑E and argon, it meets ASHRAE 90.1 and EU EPBD requirements.
Hotel chains specify 6+12A+6 for guestroom windows, lobby curtain walls, and restaurant glazing. The 16mm gap variant is preferred for properties near busy streets (acoustic benefit).
Educational and healthcare facilities choose 6+12A+6 with laminated inner pane for acoustic insulation and safety. The 6mm thickness meets safety glazing requirements in most jurisdictions.
Mall facades, storefronts, and shopping center atriums use 6+12A+6 for its combination of safety (tempered), solar control (Low‑E or reflective), and aesthetics.
Embassies, courthouses, and public libraries specify 6+12A+6 with enhanced security options (laminated, tempered) for blast mitigation and forced‑entry resistance.
For skylights up to ~3.0 m², 6+12A+6 with tempered outer pane provides safety and thermal performance. The 6mm thickness handles snow loads better than 5mm.
Our 6+12A+6 and 6+16A+6 insulated glass units are manufactured to EN 1279 standards in our 12,000 m² production facility:
| Standard | Region | Requirement |
|---|---|---|
| EN 1279‑1 | Europe | Terminology and definitions |
| EN 1279‑2 | Europe | Long‑term test method for gas leakage |
| EN 1279‑3 | Europe | Long‑term test method for moisture penetration |
| EN 673 | Europe | U‑value calculation method |
| EN 674 | Europe | U‑value measurement method |
| CE Marking | Europe | Mandatory for EU market |
| ISO 9001 | International | Quality management |
| CCC | China | Mandatory for Chinese market |
| SGS | Global | Third‑party inspection |
| ASTM E2190 | USA | IGU performance standard |
| NFRC | USA/Canada | Energy performance rating |
| Package Type | Orientation | Capacity | Suitable For |
|---|---|---|---|
| Vertical A‑Frame | Edge‑vertical | Up to 35 units/frame | Standard sizes, ≤4.0 m² |
| Horizontal Crate | Face‑horizontal | Up to 15 units/crate | Large jumbo panels |
| Stillage Rack | Edge‑vertical | Up to 50 units/rack | Bulk orders, repeated sizes All packaging includes: |
| Glass Combination | Gas Fill | FOB Indicative Range |
|---|---|---|
| 6mm Clear + 12A + 6mm Clear | Air | $20–30 |
| 6mm Clear + 12A + 6mm Clear | Argon | $22–32 |
| 6mm Low‑E + 12A + 6mm Clear | Air | $24–36 |
| 6mm Low‑E + 12A + 6mm Clear | Argon | $26–38 |
| 6mm Tempered + 12A + 6mm Clear | Air | $24–34 |
| 6mm Tempered + 12A + 6mm Tempered | Air | $28–40 |
| 6mm Laminated + 12A + 6mm Clear | Air | $30–44 |
| 6mm Laminated + 12A + 6mm Laminated | Air | $38–54 |
| 6mm Low‑E Tempered + 12A + 6mm Tempered | Argon | $32–46 |
| Glass Combination | Gas Fill | FOB Indicative Range |
|---|---|---|
| 6mm Clear + 16A + 6mm Clear | Air | $22–32 |
| 6mm Clear + 16A + 6mm Clear | Argon | $24–34 |
| 6mm Low‑E + 16A + 6mm Clear | Air | $26–38 |
| 6mm Low‑E + 16A + 6mm Clear | Argon | $28–40 |
| 6mm Tempered + 16A + 6mm Tempered | Air | $30–42 |
| 6mm Laminated + 16A + 6mm Laminated | Air | $40–56 |
| 6mm Low‑E Tempered + 16A + 6mm Tempered Laminated | Argon | $34–48 |
Final FOB pricing varies with: Glass type combinations (clear, Low‑E, tempered, laminated, reflective, tinted) Spacer type (aluminum vs. warm edge vs. Swisspacer) Gas fill (air vs. argon vs. krypton) Panel dimensions (jumbo sizes incur surcharge) Order volume (FCL vs. LCL) 💡 For a precise project quotation including U‑value calculations, send us your curtain wall elevation drawings or glass schedule.
Q1: What does 6+12A+6 mean?
6mm glass + 12mm air gap + 6mm glass. "A" stands for air gap. Total thickness = 24mm.
Q2: What is the difference between 6+12A+6 and 6+16A+6?
The gap width: 12mm vs. 16mm. The 16mm gap provides ~4% better U‑value, slightly better acoustics (~1 dB), better argon retention, and larger desiccant capacity — at a ~8–12% cost premium.
Q3: What is the U‑value of 6+12A+6 insulated glass?
With clear glass and air fill: ~2.6 W/m²K. With Low‑E coating and argon fill: ~1.5 W/m²K.
Q4: Can 6+12A+6 be tempered?
Yes. One or both panes can be tempered for safety applications. This is standard for curtain walls.
Q5: What is the maximum size?
Up to 3300 × 12000 mm for both configurations. This is the largest standard IGU format in the industry.
Q6: How much does 6+12A+6 weigh?
Approximately 30 kg/m² with clear glass. Laminated glass adds ~2–3 kg/m² per laminated pane.
Q7: What is the difference between 6+12A+6 and 5+12A+5?
6+12A+6 uses 6mm panes vs. 5mm. This provides ~44% higher bending strength, better wind load resistance, and suitability for taller buildings — at ~20% weight increase and ~15–20% cost premium.
Q8: Which spacer should I choose?
Aluminum for budget projects; Warm Edge TPE for improved thermal performance; Swisspacer for Passive House or LEED Platinum projects.
Q9: How long does the seal last?
Properly manufactured IGU seals last 20+ years. Our units pass EN 1279‑2 (gas leakage) and EN 1279‑3 (moisture penetration) accelerated aging tests.
Q10: What certifications do you provide?
CE, ISO 9001, CCC, SGS, EN 1279 (full series). NFRC certification and ASTM E2190 available on request.
Q11: Can I get a sample?
Yes. We provide free samples (typically 300×300mm); customer covers courier freight.
Q12: What is the lead time?
2–4 weeks after deposit for standard FCL orders. Custom configurations or extensive processing may extend to 4–6 weeks.
Q13: Should I choose 12A or 16A for my curtain wall project?
Choose 12A for standard commercial buildings up to 15 stories. Choose 16A for taller buildings, stricter energy codes, or when targeting LEED Gold/Platinum or Passive House certification.
Q14: Can 6+16A+6 be filled with krypton?
Yes. Krypton fill in the 16mm gap achieves U‑value as low as 1.2 W/m²K — suitable for Passive House windows in cold climates.
Tell us your project requirements and we'll respond within 48 hours with a competitive FOB quotation and preliminary U‑value calculations.
Please provide:
•5+9A+5 / 5+12A+5 Insulated Glass – 20mm & 22mm IGU for residential & light commercial
•6+12A+6/6+16A+6 Insulated Glass–24mm/28mm IGU for heavier duty applications
•8+12A+8/8+16A+8 Insulated Glass – 28mm/32mm heavy‑duty IGU
•10+12A+10/10+16A+10 Insulated Glass – 32mm/36mm high‑performance IGU
•Double Glazed Glass – Standard IGU overview
•Triple Glazed Glass – Three‑pane IGU for Passive House
•Low‑E Insulated Glass – Energy‑efficient IGU with Low‑E coating
•Laminated IGU/safety insulated glass – Acoustic & security insulated glass
•Jumbo Insulated Glass – Up to 3300×12000mm oversized IGU
With over 20 years of experience and expertise in glass manufacturing and processing, we are seasoned glass specialists, ready to answer your questions and provide guidance on product selection, installation, and maintenance.
