21mm FPOS composite fire glass in steel-framed partition configuration. Tested to AS1530.4:2005, Report R15E14B.
1. The Compliance Challenge
The developer of a new 14-storey commercial tower in Melbourne's CBD faced a critical compliance hurdle. The National Construction Code (NCC) Section C required fire-resistant construction between tenancy separations on every floor plate, with a mandated FRL of at least -/60/60 for the partition glazing separating individual office suites from common corridors.
The challenge was not merely finding fire-rated glass. The project team needed a complete system — glass, steel framing, intumescent seals and installation methodology — that had been furnace-tested as an assembly. Substituting any component with an untested alternative would void the certification and risk rejection by the building surveyor at final inspection.
Compounding the issue, the architect had specified large vision panels (up to 2.4 m wide) to maintain natural light penetration into the corridor core. This pushed the glazing well beyond standard door vision panel sizes, requiring test evidence that covered the actual panel dimensions.
2. Determining the FRL Requirement
Working with the project's fire engineer, we reviewed the NCC Deemed-to-Satisfy provisions for Class 5 buildings (offices) with a rise in storeys exceeding 12. The relevant clause required:
- Structural adequacy: Not required for non-loadbearing glazing (dash position)
- Integrity: 60 minutes minimum to prevent flame and hot gas passage
- Insulation: 60 minutes minimum to limit radiant heat transfer
The resulting FRL specification was -/60/60, meaning the glazing system needed to maintain both integrity and insulation for a full 60 minutes under AS1530.4 furnace conditions. This immediately ruled out integrity-only (E-rated) products and directed the specification toward composite insulated fire glass.
3. System Solution: Glass + Frame + Seal
PyroSpec specified a fully tested partition system comprising three integrated components:
| Component | Specification | Test Evidence |
|---|---|---|
| Fire Glass | 21mm FPOS composite insulated fire glass | Report R15E14B, NATA-accredited lab |
| Framing | Steel box section, 50mm x 50mm x 3mm, powdercoated | Tested as part of assembly R15E14B |
| Seals | Graphite-based intumescent seal, 4mm x 10mm | Compatible with tested assembly |
| Glazing Method | Wet glaze with fire-rated silicone | Per manufacturer's installation manual |
The 21mm FPOS composite glass was selected because it combines multiple intumescent interlayers between toughened glass plies. Under fire exposure, these interlayers expand to form an opaque ceramic barrier that blocks radiant heat — the critical mechanism for achieving the insulation (I) component of the EI60 rating.
Importantly, the test report covered panel sizes up to 2,700 mm x 2,400 mm, comfortably exceeding the architect's maximum specified panel. This eliminated the risk of the certifier rejecting the system on size grounds.
4. Certification Outcome
The system was submitted to the building surveyor with a complete evidence pack including:
- NATA-accredited test report R15E14B with full furnace data
- Installation instructions referencing the tested assembly configuration
- Compatibility declaration confirming no component substitutions
- Declaration of Performance (DoP) for CE-destined export documentation
The actual furnace performance exceeded the specification requirement:
| Performance Metric | Specification Required | Actual Test Result | Margin |
|---|---|---|---|
| Integrity (E) | 60 minutes | 68 minutes | +13% |
| Insulation (I) | 60 minutes | 68 minutes | +13% |
The building surveyor issued the fire safety certificate without qualification. The 13% performance margin above the rated FRL provided the project team with confidence that minor on-site variations in installation would not compromise compliance.
5. Project Outcomes
The glazing package was installed across all 14 floors over an 8-week programme. Key outcomes:
- Zero certifier non-conformances at final inspection
- All 127 partition panels installed per tested assembly specification
- Full documentary evidence archived for future building audit
- Tenant fit-out commenced on schedule with no fire compliance delays