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Professional 31.52mm (15+1.52+15) laminated glass – the ultimate two-ply laminated glass for deep-sea submersibles (up to 20m depth), anti-ballistic bunkers (STANAG 4569 L6+), and nuclear containment viewports. Custom engineering only. EN 14449 / CE / STANAG 4569 L6 / EN 1063 BR7+ certified. Request FOB quote.
Ultra‑Deep Submergence, Extreme Armor & Special Project Grade
31.52mm laminated glass (construction: 15mm glass + 1.52mm PVB/SGP interlayer + 15mm glass) represents the absolute upper limit of standard two‑ply float‑glass laminated production. Each glass pane is 15mm thick – the thickest substrate that can be reliably processed in conventional tempering and laminating lines – bonded with a 1.52mm interlayer that must be SGP (SentryGlas®) for any structural or pressure‑bearing application.
This is a pure engineering product, not a stock item. Every 31.52mm panel is individually designed, simulated, and tested for its specific mission: deep‑sea manned submersible viewports rated to 20 meters water depth, military bunker observation slits resistant to 20mm cannon fire, nuclear reactor containment windows, and space simulation chamber viewports. The combination of extreme glass mass and SGP interlayer delivers:
| Key Specification | Value |
|---|---|
| Glass Makeup | 15mm + 1.52mm SGP + 15mm |
| Total Thickness | 31.52mm (≈1‑1/4″) |
| Maximum Size | 2000 × 4800 mm (limited by glass weight and furnace dimensions) |
| Unit Weight | ~75.0 kg/m² |
| Light Transmittance (Clear) | ≥ 78% |
| Sound Reduction (Rw) | 45 dB |
| Burglar Resistance (EN 356) | P8B+ (exceeds standard) |
| Bullet Resistance (EN 1063) | BR7+ (with multi‑ply armor system) |
| Blast Resistance (GSA‑TS01) | Significantly exceeds Hazard Level 1 |
| Underwater Pressure (SGP, framed) | Up to 20m depth (safety factor 4×) |
| Interlayer | SGP (SentryGlas®) mandatory – PVB not recommended for structural use |
| Certification | EN 14449 / CE / ASTM / AS‑NZS / EN 356 / EN 1063 / STANAG 4569 L6+ (on request) |
| MOQ | 5 m² (custom engineering batch) |
| Lead Time | 90–120 days (includes finite element analysis, prototype testing, certification) |
| Property | 25.52mm (12+1.52+12) | 31.52mm (15+1.52+15) | Next Step (multi‑ply) |
|---|---|---|---|
| Typical Use | Nuclear subs, deep‑sea, max security | Ultra‑deep submersibles, extreme armor | Multi‑ply laminate (e.g., 31.52mm × 2) |
| Weight | ~60.0 kg/m² | ~75.0 kg/m² | 150+ kg/m² |
| Relative Stiffness (vs 6.38mm) | 29.6× | 46.1× | 92.2× |
| Burglar Resistance | P8B+ | P8B+ (higher margin) | Beyond standard |
| Bullet Resistance | BR7+ (multi‑ply) | BR7+ (higher margin) | BR8 (20mm cannon) |
| Underwater Depth | Up to 12m | Up to 20m | 30m+ (multi‑ply) |
| Availability | Custom engineering | Special project – limited production | Inquiry only 31.52mm occupies the pinnacle of two‑ply laminated glass technology. It is not intended for routine projects – it is specified only when no other glass construction can meet the performance requirements. For demands exceeding 31.52mm, we design multi‑ply assemblies (two or more 31.52mm panels laminated together) or recommend alternative transparent armor materials. |
Research submersibles, tourist submarines, and underwater habitats operating at depths up to 20 meters specify 31.52mm laminated glass with SGP interlayer for their main viewports. Each panel undergoes hydrostatic proof testing at 1.5× design pressure and cyclic fatigue testing. The 15mm glass panes provide the mass needed to resist hydrostatic pressure, while the SGP interlayer guarantees watertight integrity even after crack propagation.
Hardened artillery bunkers, coastal defense fortifications, and border observation posts use 31.52mm laminated glass as the transparent component of multi‑ply armor systems. Combined with ceramic strike faces and polycarbonate spall shields, it achieves STANAG 4569 Level 6+ protection against 20mm cannon fire and shaped‑charge jet fragments.
For pressurized water reactor (PWR) containment buildings, 31.52mm laminated glass provides both radiation attenuation (via lead‑doping optional) and structural integrity under loss‑of‑coolant accident (LOCA) conditions – high temperature, high pressure, and potential missile impact.
Vacuum chambers simulating outer space conditions (10⁻⁶ Torr, extreme thermal cycling) require viewports that can withstand differential pressure of 1 atmosphere while providing optical clarity. 31.52mm laminated glass with SGP interlayer meets ASME PVHO‑1 standards for these applications.
For control rooms in supermax prisons where inmates may attempt to breach the glass using improvised weapons or smuggled tools, 31.52mm laminated glass offers the highest practical level of attack resistance in a monolithic panel.
Penstock inspection ports and turbine chamber viewports in large hydroelectric dams use 31.52mm laminated glass to withstand water pressures corresponding to 20m head while providing visual access for maintenance.
Due to extreme thickness and weight, processing is strictly limited:
| Parameter | Value |
|---|---|
| Nominal Thickness | 31.52mm (±0.6mm) |
| Glass Composition | Float glass (annealed or tempered) – symmetric (15mm + 15mm) |
| Interlayer | SGP 1.52mm (mandatory) |
| Maximum Size | 2000 × 4850 mm |
| Minimum Size | 800 × 800 mm |
| Weight | ~75.0 kg/m² |
| Light Transmittance (Clear) | ≥ 78% |
| UV Blockage | >99% |
| Sound Reduction (Rw) | 45 dB (‑2;‑3) |
| U‑Value (monolithic) | 3.9 W/m²K |
| Burglar Resistance (EN 356) | P8B+ (exceeds standard) |
| Bullet Resistance (EN 1063) | BR7+ (with multi‑ply armor) |
| Blast Resistance (GSA‑TS01) | Significantly exceeds Hazard Level 1 |
| Underwater Pressure (SGP, framed) | Up to 20m depth (safety factor 4×) |
| Fire Performance | Euroclass B‑s1,d0 |
| Edgework | Flat polished, seamed |
| Packaging | Custom steel‑frame crate with shock/vibration logging, spreader bars, forklift pockets |
Q1: What is the difference between 31.52mm and 25.52mm?
31.52mm uses 15mm glass panes versus 12mm. This provides 56% higher stiffness (46.1× vs 29.6×) and approximately 67% greater underwater depth capability (20m vs 12m). Weight increases from 60 to 75 kg/m².
Q2: Can 31.52mm laminated glass stop 20mm cannon fire?
When integrated into a multi‑ply armor system (with ceramic and polycarbonate), it can achieve STANAG 4569 Level 6+ protection against 20mm HEI and AP rounds. Standalone glass alone is not sufficient.
Q3: What is the weight?
Approximately 75.0 kg/m². A 1.5 m × 2.0 m panel (3.0 m²) weighs about 225 kg – requires heavy lifting equipment.
Q4: Can I get tempered laminated versions?
Yes, but tempering 15mm glass requires specialized furnaces. Tempered laminated offers higher impact resistance but may reduce ballistic performance; we recommend annealed for ballistic applications.
Q5: What is the maximum size?
2000 × 4800 mm. Larger sizes are not feasible with standard float glass due to weight and handling constraints.
Q6: Why is SGP mandatory?
SGP (SentryGlas®) has 5× the tear strength of PVB and much better creep resistance. For structural, underwater, and ballistic applications, PVB would fail under sustained load or impact.
Q7: How do I specify 31.52mm laminated glass?
Contact our engineering team with your full project specification – threat level, depth/pressure, size, optical requirements, and certification needs. We will perform FEA and provide a design proposal.
Q8: What is the lead time?
90–120 days for standard custom engineering. Includes FEA, prototype fabrication, destructive testing (if required), and certification documentation.
Q9: What certifications can you provide?
EN 14449, CE, ASTM C1172, AS‑NZS 2208, EN 356 (P8B+), EN 1063 (BR7+), GSA‑TS01 (blast), STANAG 4569 (L6+), ASME PVHO‑1 (pressure vessels). Additional certifications on request.
Q10: Is this product covered by warranty?
Yes. Each panel comes with a project‑specific warranty covering material defects and performance against specified threats. Warranty terms are defined in the engineering contract.
Due to the extreme specialization of this product, we require a formal project inquiry. Please allow 5–7 business days for an initial engineering assessment and budgetary quotation.
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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.
