BS EN 14449BS EN 12600 (Class 1B1 / 2B2)BS EN 356 (P1A to P8B security)BS EN 16613 (Effective Thickness)Reviewed Technical Specification
Laminated Safety & Security Glass
High-integrity polymer interlayers providing mandatory post-breakage retention, fall prevention, and acoustic damping.
Engineering Definition: An assembly of two or more panes of glass permanently bonded under heat and pressure (typically 12–14 bar at 135–145°C in an autoclave) using one or more polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), or structural ionoplast interlayers (BS EN 14449).
Precision Specification
Composite Architectural Glass Assembly
Multi-Ply Safety Specification
Accessible Static View
Schematic exploded horizontal cross-section showing sequential structural placement.
01
Outer Structural Ply(Thermally Toughened Glass)
10.0mmExternal impact and wind barrier
02
Engineered Interlayer Core(Structural SentryGlas / Acoustic PVB)
1.52mmViscoelastic damping & residual load support
03
Inner Structural Ply(Thermally Toughened Glass)
10.0mmInterior barrier and post-breakage integrity
BS EN 12150 / BS EN 14449 Architectural ReferenceIllustrative diagram — project structural verification required
Physical & Mechanical Performance Characteristics
Safety Class:Class 1B1 or 2B2 (BS EN 12600); Class P1A to P5A (BS EN 356 manual attack)
Bending Strength:Equivalent to constituent panes; structural ionoplast interlayers achieve post-yield structural retention and full shear transfer
Thermal Shock Resistance:Dependent on base glass: Annealed laminate ~40°C differential; Toughened laminate up to 200°C
Fracture Behaviour:Glass panes crack upon high impact but fragments adhere tenaciously to the elastomeric interlayer; aperture remains sealed, preventing human fall-through or falling debris
Typical U-Value (Ug):5.4 to 5.6 W/m²K monolithic; 1.0 to 1.3 W/m²K in sealed insulating units
Acoustic Reduction (Rw):Rw 33 dB to Rw 42 dB (acoustic PVB achieves +3 to +5 dB reduction over monolithic glass of equivalent mass)
Max Sheet Dimension:Up to 3210mm × 6000mm (standard autoclave); jumbo structural laminates up to 3300mm × 9000mm
Density & Mass:2.50 kg/m² per 1mm glass + ~0.81 kg/m² per 0.76mm PVB interlayer (density ~1070 kg/m³) / 1.44 kg/m² per 1.52mm Ionoplast
Key Architectural Advantages
- •Post-breakage retention: remains in frame after breakage, preventing fall from height, burglary penetration, or weather ingress
- •Superior acoustic damping: viscoelastic polymer core interrupts sound wave resonance coincidence dip
- •Blocks >99% of UV radiation (280–380nm), protecting commercial merchandise, flooring, and furnishings from photodegradation
- •Mandatory containment specification for BS 6180 freestanding glass balustrades and overhead glazed canopies
Critical Engineering Constraints
- •Annealed laminated glass (e.g. 6.4mm, 8.8mm) can be cold-cut on automatic cutting tables, but toughened laminated glass MUST have all plies cut, edged, and tempered prior to lamination
- •Open edge exposure in damp or marine environments requires neutral-cure silicone edge seals; acid-cure (acetoxy) silicones degrade PVB edges, causing edge delamination or moisture haze
- •Substantial dead weight requires structural verification of framing brackets, hinges, and handling equipment
Fabrication & Edge Processing Tolerances
Cut After Toughening:PROHIBITED (Catastrophic Fracture)
Heat Soak Testing (HST):Recommended to BS EN 14179
Dimensional Tolerance:Panes <= 2000mm: ±2.0mm; panes > 2000mm: ±3.0mm (BS EN 14449 / BS EN ISO 12543-5)
Thickness Tolerance:Sum of glass tolerances + ±0.1mm per interlayer ply
Flatness & Roller Wave:Toughened laminated glass: max displacement (ply mismatch) <= 2.0mm for panes <= 1000mm, <= 3.0mm for panes <= 2000mm, <= 4.0mm for panes > 2000mm; stepped edges require CNC arris
Hole & Cutout Geometry Rules:Holes must be drilled in individual plies prior to tempering and lamination; hole mismatch between plies max ±1.5mm
Toughened laminated assemblies must have individual glass plies fully CNC processed, arrissed, and heat-treated prior to autoclave lamination.
Structural Design Basis (Eurocodes / BS EN 16612)CEN / BSI Harmonised
Characteristic Strength:Determined by plies: fg,k = 45 N/mm² (annealed plies) / fb,k = 120 N/mm² (toughened plies)
Elastic Modulus (E):70,000 MPa (glass plies); Interlayer G(t,T): standard PVB G = 0.1 to 1.0 MPa at 30°C; Structural Ionoplast G > 10 MPa at 50°C
Poisson's Ratio (ν):0.22 (glass plies) / 0.45 to 0.49 (polymer interlayer)
Linear Expansion (α):9.0 × 10⁻⁶ K⁻¹ (glass)
Design Bending Stress Formula (BS EN 16612):Effective thickness calculation per BS EN 16613 (Wölfel-Bennison): hef,w = [sum(hi^3) + 12 · omega · sum(hi · di^2)]^(1/3), where omega is interlayer shear coupling factor
Architectural Specifier Checklist
Verify these technical criteria prior to contract documentation:
1State interlayer type explicitly: Standard PVB vs Acoustic PVB vs Structural Ionoplast (SentryGlas).
2For wet-glazed or exterior exposed edges, specify compatible neutral-cure 100% silicone sealants; avoid acidic or plasticizer-rich sealants.
3Ensure balustrade calculations evaluate cantilever top-edge deflection under design service line-loads (max 25mm per BS 6180).
4For structural glass floors, require triple-ply construction with a sacrificial top ply and structural redundancy.
Frequent Commercial Applications
Network Procurement Routing
GlassSuppliers.co.uk
Intended public marketplace destination for discovering regional glass processors, independent glaziers, and commercial installation contractors across the UK.
Recommended Action: Specify interlayer performance requirements and reach qualified regional architectural laminators.
Proceed to GlassSuppliers.co.ukReviewed by: Senior Glass Materials Technologist, BuyGlass Technical Panel
Last Standard Verification: 2026-10-30