Bronze Net FR 4mm Reinforced Fire Rated Reflective Foil Insulation
Net-reinforced, fire rated double-sided aluminium foil bubble insulation with heavy-duty 18 micron foil. Reflects 98% of radiant heat, BS 476 Class 1 / Class 0. 4mm, six layers, rolls 1.20 / 1.35 / 1.50 m wide, 12 to 72 m² per roll.
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Description
Bronze Net FR 4mm reinforced fire rated reflective foil insulation
Net-reinforced, double-sided aluminium foil bubble insulation with heavy-duty 18 micron foil. Reflects 98% of radiant heat, BS 476 Class 1 and Class 0.
Bronze Net FR 4mm is the heavy-duty version of our fire rated Bronze insulation. It combines a heavy-duty 18 micron pure aluminium foil and a bi-directional reinforced net with a 4mm sealed FR air-bubble core, for a tough, tear-resistant roof insulation sheet that reflects 98% of radiant heat. With 99% pure aluminium foil on both faces and BS 476 Part 7 Class 1 and Part 6 Class 0 fire classification, it suits warehouses, factories, commercial roofs and homes that need a stronger, fire rated radiant barrier.
Compare with Bronze FR 4mm (without net reinforcement) or the standard Alumix Bronze 4mm Basic / FR insulation.
What is Bronze Net FR 4mm reflective insulation?
Bronze Net FR 4mm (product code AL-SL40-FRN) is a six-layer, double-sided reflective insulation. Its construction is 18 micron foil / reinforced net / film / 4mm FR sealed air bubble / film / foil. The reinforced net adds tear resistance for long purlin runs and busy sites, while the aluminium faces reflect radiant heat and act as a vapour barrier.
Because the core is fire retardant (FR) grade and the product carries EN 13501 B-s1,d0 and BS 476 Class 1 / Class 0 fire performance, Bronze Net FR is a strong choice where both durability and fire safety matter.
Key benefits
- Reflects 98% of radiant heat. The 99% pure aluminium surface has a very low emittance of 0.02 to 0.03, so it reflects heat instead of absorbing it.
- Super FR grade. BS 476 Part 7 Class 1, BS 476 Part 6 Class 0 and EN 13501 B-s1,d0 fire performance.
- Heavy-duty 18 micron foil with bi-directional reinforced net. Stronger and more tear resistant than standard foil insulation.
- Six-layer build, foil on both faces. Reflects heat from either direction.
- Dual action: heat and vapour barrier control. Helps reduce condensation on roof sheets.
- Does not absorb moisture or support mould. Performance does not drop over time.
- No glass fibre, safe to handle. No itching or dust for installers.
- Lightweight and cuts to size on site. No special tools needed.
Technical specifications
| Product type | Double-sided pure aluminium reflective insulation |
|---|---|
| Product code | AL-SL40-FRN |
| Construction | 18 micron foil / reinforced net / film / 4mm FR sealed air bubble / film / foil (six layers) |
| Outer face | 99% pure aluminium foil, both faces |
| Total thickness | 4 mm |
| Roll width | 1.20 m / 1.35 m / 1.50 m |
| Roll length | 10 to 60 m (12 to 72 m² per roll) |
| Radiant heat reflectivity | 98% |
| Surface emittance | 0.02 to 0.03 |
| Core thermal resistance (product alone) | R 0.12 m²K/W |
| High thermal equivalent | R 3.14 m²K/W* |
| Fire performance | EN 13501 B-s1,d0 · BS 476 Class 1 / Class 0 · Super FR grade |
| Fire classification (BS 476 Part 7) | Class 1 |
| Fire classification (BS 476 Part 6) | Class 0 |
| Options | Self-adhesive lap strip |
*Heat flow down, 2 x 50 mm air gaps, ε 0.02 to 0.03.
Thermal performance: R-value by assembly
Reflective insulation works best when installed next to an air gap. The total system R-value depends on how many reflective air cavities are created in the roof, ceiling or wall.
| Assembly / air cavity | Winter (heat flow up) | Summer (heat flow down) |
|---|---|---|
| Roof / ceiling, one 25 mm reflective cavity | R 0.61 | R 1.01 |
| Roof / ceiling, two 25 mm reflective cavities | R 1.10 | R 1.90 |
| Wall assembly, 38 mm cavity, horizontal heat flow | R 0.86 (one cavity) / R 1.60 (two cavities) | |
Values are total system R in m²K/W. Cavity resistance calculated to BS EN ISO 6946 (ref. BS EN 16012) for an unventilated cavity with a low-emissivity surface (ε 0.02 to 0.03). Core product R 0.12 m²K/W applies to the product alone without a reflective air cavity.
Applications
- Roof underlay and metal roofing, over the purlins or under the rafters
- Ceilings and attic spaces
- Walls and partitions
- Warehouses, factories and metal buildings
- Residential and commercial buildings
- New build and renovation projects
How to install Bronze Net FR on a roof or ceiling
- Measure the roof or ceiling area and work out the number of rolls needed for the total m².
- Set the purlins or rafters to the correct spacing.
- Lay Bronze Net FR over the purlins or under the rafters, with the foil face toward the heat source.
- Fix with screws and cut to length, keeping the sheet taut.
- Seal all joints and overlaps with aluminium foil tape.
Air gap tip: keep a 20 to 90 mm air gap on the reflective face for best performance, and maintain at least 75 mm clearance from downlights.
Testing and certification
Bronze Net FR 4mm is tested to BS 476 Part 6 & 7 (Class 1; Class 0 FR grade), ASTM C 1371, ISO 8301 / ASTM C 518 and BS EN ISO 6946. Test reports and certificates are available on request.
Frequently asked questions
What is Bronze Net FR 4mm used for?
It is a net-reinforced, double-sided reflective foil insulation for roofs, ceilings and walls, used in warehouses, factories, homes and commercial buildings to reflect radiant heat and control vapour.
What is the difference between Bronze Net FR and Bronze FR 4mm?
Bronze Net FR adds a heavy-duty 18 micron foil and a bi-directional reinforced net, making it six layers instead of five and more tear resistant. Both have a 4mm FR bubble core and reflect 98% of radiant heat.
Is Bronze Net FR 4mm fire rated?
Yes. It is classified Class 1 under BS 476 Part 7 and Class 0 under BS 476 Part 6, with EN 13501 B-s1,d0 fire performance.
What is the R-value of Bronze Net FR 4mm?
The product alone has a core thermal resistance of R 0.12 m²K/W. Installed with reflective air cavities, total system R-values reach up to R 1.90 m²K/W in a roof with two 25 mm cavities (heat flow down), and a high thermal equivalent of R 3.14 m²K/W with two 50 mm air gaps.
Do I need an air gap when installing?
Yes. Maintain a 20 to 90 mm air gap on the reflective face so the foil can reflect radiant heat.
What roll sizes are available?
Rolls come in 1.20 m, 1.35 m and 1.50 m widths, with lengths from 10 to 60 m, covering 12 to 72 m² per roll. A self-adhesive lap strip is available as an option.
Does it contain glass fibre?
No. Bronze Net FR contains no glass fibre, so it is safe to handle and install.
Get a quote for Bronze Net FR 4mm
Alumix Insulation Global manufactures reflective foil insulation, radiant barriers and vapour barriers for residential, commercial and industrial projects. Contact our team for pricing, bulk orders, technical data or test certificates, or email info@alumixinsulationglobal.com.
Values shown are subject to verification against current test reports. Thermal performance may vary with installation method, air gap and environmental conditions. Specifications subject to change without prior notice.
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