Melamine foam is a lightweight, open-cell foam known for its exceptional fire resistance, sound absorption, and thermal insulation properties. In commercial aviation, it is primarily used as a cabin insulation material and acoustic damping layer, contributing to both passenger comfort and safety compliance with flammability regulations.

Background and Evolution

Melamine foam was developed in the 1990s from melamine-formaldehyde resin, a thermosetting polymer known for its high crosslink density and thermal stability. Its introduction into aviation followed a broader industry push to adopt fire-safe and lightweight materials after several high-profile cabin fires in the late 1980s and early 1990s.

As aircraft interior materials became subject to stricter flammability, smoke, and toxicity (FST) standards (e.g., FAR 25.853), melamine foam quickly gained favor due to its self-extinguishing properties and ability to meet burn-through requirements without toxic emissions. It has since become a standard for cabin insulation in aircraft such as the Airbus A320 series, Boeing 737, and Bombardier CRJ family.

How Melamine Foam Is Used

• Thermal Insulation: Installed between the aircraft fuselage and interior panels to stabilize cabin temperature.
• Acoustic Damping: Reduces cabin noise from engines, airflow, and systems through its porous structure.
• Duct Liners and Housings: Used inside air conditioning and avionics systems to dampen sound and minimize heat transfer.
• Seat Cushions (Occasionally): In some cases, laminated in thinner layers beneath upholstery for fire resistance.
• Cabin Wall and Ceiling Panels: Sandwiched between decorative panels to meet safety and comfort standards.

Why Melamine Foam Is Used

• Fire Resistance: Classified as self-extinguishing; does not melt or drip when exposed to flame.
• Low Smoke and Toxicity: Produces significantly less smoke and fewer toxic gases than polyurethane or polyethylene foams.
• Lightweight: Very low density (~9–11 kg/m³), which helps reduce aircraft weight and improve fuel efficiency.
• Acoustic Performance: High NRC (Noise Reduction Coefficient) due to open-cell structure, dampening sound across a broad frequency range.
• Formability: Easily cut or shaped to fit complex aircraft contours and insulation blankets.

Technical Specifications

• Base Material: Melamine-formaldehyde resin.
• Density: Typically 9–11 kg/m³ (0.56–0.69 lb/ft³).
• Thermal Conductivity: ~0.035 W/m·K (good for insulation).
• Flame Spread Index: <25 (ASTM E84).
• Smoke Developed Index: <50.
• Operating Temperature Range: −180°C to +240°C (−292°F to +464°F).
• Color: Usually white or light gray in raw form, but may be laminated or covered.

Comparison to Alternative Materials