BISCO® A2 Sound Barrier
BISCO® A2 Sound Barrier is a solid VMQ silicone rubber engineered for demanding aircraft and rail acoustic barrier applications, with a density of 1.64 g/cm³ per ISO 2781, Shore A hardness of 62 per ISO 868, tensile strength of 2.8 MPa per ISO 37 Type 2, and temperature stability of -58°F to 356°F. The material demonstrates excellent performance in low-frequency noise reduction and passes FAR/JAR Part 25 flammability, flame propagation resistance, flame penetration resistance (bonded condition), smoke gas components, and smoke density requirements, and meets Airbus ABS5708.
Key Properties
- Hardness, Shore A: 62 (ISO 868)
- Tensile Strength: 2.8 MPa (ISO 37 Type 2)
- Elongation at Break: 220% (ISO 37 Type 2)
- Density: 1.64 g/cm³ (ISO 2781)
- Temperature Stability: -58°F to 356°F
- Flame Propagation Resistance: Pass (FAR, Part 25, App. F Part VI)
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Color | Light Gray | — |
| Polymer Type | VMQ | ISO 1 629 |
| Density | 1.64 g/cm³ | ISO 2781 |
| Hardness, Shore A | 62 | ISO 868 |
| Temperature Stability | -58°F to 356°F | — |
Mechanical Properties
| Property | Value | Test Method |
| Tensile Strength | 2.8 MPa | ISO 37 Type 2 |
| Elongation at Break | 220% | ISO 37 Type 2 |
| Tear Strength | 10.2 N/mm | ISO 34 Method C |
Flame & Fire Performance
| Property | Value | Test Method |
| Flammability | Pass | JAR/FAR, Part 25, App. F Part 1, Para (a) (1) (ii) |
| Flame Propagation Resistance | Pass | FAR, Part 25, App. F Part VI |
| Flame Penetration Resistance in Bonded Condition | Pass | JAR/FAR, Part 25, Change 15/Amdt. 25-60, App. F Part III |
| Smoke Gas Components | Pass | AITM 3.0005 |
| Smoke Density | Pass | JAR/FAR 25, App. F, Part V & AITM 2.0007 |
Compliance
- JAR/FAR Part 25, App. F Part 1, Para (a)(1)(ii) — Compliant (Pass, Flammability)
- FAR Part 25, App. F Part VI — Compliant (Pass, Flame Propagation Resistance)
- JAR/FAR Part 25, Change 15/Amdt. 25-60, App. F Part III — Compliant (Pass, Flame Penetration Resistance in Bonded Condition)
- AITM 3.0005 — Compliant (Pass, Smoke Gas Components)
- JAR/FAR 25, App. F, Part V / AITM 2.0007 — Compliant (Pass, Smoke Density)
- Airbus ABS5708 — Compliant (Meets)
- Aircraft acoustic insulation requiring solid VMQ silicone with the full suite of JAR/FAR Part 25 flame, smoke, and toxicity compliance including flame penetration resistance in bonded condition
- Noise reduction liners for aircraft interior panels where excellent low-frequency sound blocking performance and Airbus ABS5708 compliance are required
- Aircraft flooring noise barriers requiring a high-density solid silicone (1.64 g/cm³) with documented smoke gas components and smoke density pass per AITM 3.0005 and AITM 2.0007
- Rail interior noise blocking applications requiring a flexible, solid silicone sound barrier with aerospace-grade flame performance
- Applications requiring flame penetration resistance in bonded condition per JAR/FAR Part 25, App. F Part III — a compliance not listed on the fiberglass-reinforced A2 TDS
Common industries: Aerospace, rail, defense.
BISCO® A2 Sound Barrier is a solid VMQ silicone rubber specifically engineered to block the transmission of sound with excellent performance in low-frequency noise reduction, while simultaneously meeting the demanding flammability, smoke density, and toxicity requirements of commercial aerospace and rail interior applications.
Innovative filler technology is used to achieve superior flame resistance meeting the radiant panel flammability test FAR 25.856(a). It meets Airbus ABS5708 specification. Typical applications include aircraft acoustic insulation, interior panel noise reduction liners, aircraft flooring noise barriers, and rail interior noise blocking.
The material achieves a density of 1.64 g/cm³ per ISO 2781, Shore A hardness of 62 per ISO 868, tensile strength of 2.8 MPa, and elongation at break of 220% per ISO 37 Type 2. Tear strength is 10.2 N/mm per ISO 34 Method C. The full suite of aerospace flame compliance is passed: flammability per JAR/FAR Part 25, App. F Part 1, Para (a)(1)(ii); flame propagation resistance per FAR Part 25, App.
F Part VI; flame penetration resistance in bonded condition per JAR/FAR Part 25, Change 15/Amdt. 25-60, App. F Part III; smoke gas components per AITM 3.0005; and smoke density per JAR/FAR 25, App. F, Part V and AITM 2.0007.
Compliant with JAR/FAR Part 25, App. F Part 1, Para (a)(1)(ii) (Flammability), FAR Part 25, App. F Part VI (Flame Propagation Resistance), JAR/FAR Part 25, Change 15/Amdt. 25-60, App. F Part III (Flame Penetration Resistance in Bonded Condition), AITM 3.0005 (Smoke Gas Components), JAR/FAR 25, App. F, Part V / AITM 2.0007 (Smoke Density), and Airbus ABS5708.
What differentiates the BISCO® A2 Sound Barrier from the A2 Fiberglass Reinforced Sound Barrier?
The A2 Sound Barrier is a non-reinforced solid VMQ silicone with a measured density of 1.64 g/cm³ and isotropic mechanical properties, providing a single tensile strength value (2.8 MPa) and tear strength (10.2 N/mm) not dependent on direction or areal density. The fiberglass-reinforced grade provides higher tensile and tear strength in specific orientations and is available in three areal densities. The non-reinforced A2 carries a more extensive compliance suite including flame penetration resistance in bonded condition (JAR/FAR Part 25, App. F Part III), smoke gas components (AITM 3.0005), and Airbus ABS5708 — none of which appear on the fiberglass-reinforced TDS.
Why is hardness important for a solid silicone sound barrier used in aircraft and rail applications?
Hardness governs how the solid silicone sound barrier loads the mounting structure, conforms to adjacent components, and transmits or attenuates acoustic energy through its mass-law mechanism. For a sound barrier, a material that is too soft will deflect under structural loads and may not maintain the mass-law mass required for effective low-frequency attenuation; one that is too hard may not conform to irregular panel surfaces during bonded installation, creating acoustic bypass paths. The A2 Sound Barrier's Shore A hardness of 62 per ISO 868 and density of 1.64 g/cm³ define its acoustic mass and structural compliance for aircraft and rail interior applications.
What is the temperature stability range for the BISCO® A2 Sound Barrier?
The temperature stability range is -58°F to 356°F as listed on the TDS.
Is the BISCO® A2 Sound Barrier suitable for regulated aerospace environments?
Yes. The A2 Sound Barrier passes JAR/FAR Part 25, App. F Part 1, Para (a)(1)(ii) (flammability), FAR Part 25, App. F Part VI (flame propagation resistance), JAR/FAR Part 25, Change 15/Amdt. 25-60, App. F Part III (flame penetration resistance in bonded condition), AITM 3.0005 (smoke gas components), and JAR/FAR 25, App. F, Part V / AITM 2.0007 (smoke density), and meets Airbus ABS5708, as listed on the TDS.
How should the BISCO® A2 Sound Barrier be specified?
Specify grade (A2SOUSIL), thickness, color (Light Gray), applicable compliance requirements (JAR/FAR Part 25 App. F Parts I/III/V/VI, AITM 2.0007, AITM 3.0005, Airbus ABS5708), dimensional tolerances, and finished format (sheet, slit roll, or die-cut component).
