BS EN 12150-1BS EN 14179 (Heat Soaked)CWCT Standard for Systemised Building EnvelopesApproved Document BReviewed Technical Specification

Decorative Ceramic Frit & Spandrel Glass

Opaque ceramic enamelled panels engineered to conceal floor slabs and structural building services while harmonising facade aesthetics.

Engineering Definition: Thermally toughened glass coated on Surface #2 or #4 with ceramic frit enamel paint that is permanently fired and fused into the glass surface during the 620°C toughening process (BS EN 12150-1, BS EN 14179, and CWCT Standard).

Precision Specification

Composite Architectural Glass Assembly

Multi-Ply Safety Specification

Accessible Static View

Schematic exploded horizontal cross-section showing sequential structural placement.

Outer Structural Ply(Thermally Toughened Glass)

10.0mmExternal impact and wind barrier

Engineered Interlayer Core(Structural SentryGlas / Acoustic PVB)

1.52mmViscoelastic damping & residual load support

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 1C1 (BS EN 12600)

Bending Strength:High mechanical strength (fb,k = 75 to 90 N/mm² for enamelled toughened glass vs 45 N/mm² annealed float)

Thermal Shock Resistance:High thermal endurance (up to 200°C) essential for dark opaque solar heat absorption

Fracture Behaviour:Small granular safety dice; typically backed with insulation tray or laminated to prevent fragment fallout

Typical U-Value (Ug):Engineered as part of insulated back-pan assembly (overall U-value 0.15 to 0.25 W/m²K with non-combustible mineral wool)

Acoustic Reduction (Rw):Rw 32 dB to 45 dB in spandrel cassette assembly

Max Sheet Dimension:Up to 3210mm × 6000mm

Density & Mass:2.50 kg/m² per mm glass thickness

Key Architectural Advantages

•Flawless exterior facade continuity: harmonises colour and reflectivity between vision glass and slab-edge zones
•Inorganic mineral ceramic enamel: 100% UV-resistant, scratch-proof, and will not peel, blister, or fade over building lifespan
•Provides code-compliant non-combustible cladding integration (European Class A1/A2 reaction to fire per Approved Document B)

Critical Engineering Constraints

•High solar absorption in dark colours causes extreme internal cavity temperatures; requires ventilation or heat-soaking to prevent NiS spontaneous fracture
•Must avoid "shadowbox" condensation issues by ensuring vapor-tight sealing of interior insulation trays
•Ceramic frit weakens the base glass bending strength by approximately 15–25% compared to clear toughened glass

Fabrication & Edge Processing Tolerances

Cut After Toughening:PROHIBITED (Catastrophic Fracture)

Heat Soak Testing (HST):Recommended to BS EN 14179

Dimensional Tolerance:Panes <= 2000mm: ±1.5mm; panes > 2000mm: ±2.5mm

Thickness Tolerance:6mm: ±0.2mm; 8mm: ±0.3mm; 10mm: ±0.3mm

Flatness & Roller Wave:Overall bow max 3.0mm/m; local roller wave max 0.15mm/300mm to avoid visual reflection distortion across facade slab bands

Hole & Cutout Geometry Rules:All cutouts, notches, and fixing holes must be processed prior to enamel application and furnace firing

All ceramic frit application and CNC processing must occur prior to the toughening and firing furnace.

Structural Design Basis (Eurocodes / BS EN 16612)CEN / BSI Harmonised

Characteristic Strength:fb,k = 75 to 90 N/mm² (ceramic frit reduces base glass strength by 15–25% per EN 12150-1 Annex A)

Elastic Modulus (E):70,000 MPa

Poisson's Ratio (ν):0.22

Linear Expansion (α):9.0 × 10⁻⁶ K⁻¹

Design Bending Stress Formula (BS EN 16612):BS EN 16612 with thermal stress check factoring high absorption (alpha > 0.85) in dark colours

Architectural Specifier Checklist

Verify these technical criteria prior to contract documentation:

1Mandate Heat Soak Testing (HST) to BS EN 14179 for all opaque spandrels due to extreme solar heat absorption.

2Specify RAL or NCS colour reference and check appearance against vision glass under both transmitted and reflected natural light.

3Confirm whether spandrel is monolithic with back insulation tray or part of a double-glazed shadowbox unit.

4Verify non-combustibility certification under Approved Document B Regulation 7(2) for buildings over 18m (or 11m in Scotland).

Frequent Commercial Applications

Curtain Wall Slab Edge Concealment

Opaque spandrel panels hiding intermediate concrete slabs and ductwork.

Commercial Kitchen & Retail Cladding

Hygienic, easily cleaned back-painted glass wall panels and splashbacks.

Architectural Privacy Screen Fritting

Gradient dot or line ceramic fritting for visual manifestation and glare control.

Network Procurement Routing

BuyGlass.co

Commercial cut-to-size glass manufacturing, direct supply, and transactional quoting platform.

Recommended Action: Request physical coated glass samples under natural daylight and consult facade processor.

Proceed to BuyGlass.co

Reviewed by: Commercial Envelope Consultant, BuyGlass Editorial Panel

Last Standard Verification: 2026-10-30