Acoustic Performance of Mineral fiber Boards
1. Key Performance Indicators
NRC (Noise Reduction Coefficient): Measures how much sound a surface absorbs within a room to reduce echo and reverberation.
Range: 0.00 (Total reflection) to 1.00+ (Total absorption).
Standard: Typical mineral fiber tiles range from 0.55 to 0.95, while high-density boards can reach 1.05+.
CAC (Ceiling Attenuation Class): Measures a ceiling system's ability to block sound from traveling through a shared plenum (the space above the ceiling) to adjacent rooms.
Performance: A CAC of 35+ is considered high performance for speech privacy.
𝛼 (Absorption Coefficient): The fraction of incident sound energy absorbed at specific frequencies (125Hz to 4kHz).
2. Technical Mechanisms
Porous Absorption: The dense fiber matrix of mineral fiber traps sound waves, converting acoustic energy into microscopic heat energy rather than letting it pass through or bounce back.
Density & Thickness:
Medium density (40–80 kg/m³) is ideal for absorbing mid-to-high frequencies.
Thicker boards (e.g., 2-inch / 50mm) provide better low-frequency (bass) control.
Fiberglass vs. Mineral Fiber: Mineral fiber panels are typically denser and heavier than fiberglass, offering higher CAC (sound blocking) but sometimes lower NRC (sound absorption) compared to lightweight fiberglass tiles.
3. Industry Standards
ASTM E84: Standard for surface burning characteristics (Flame Spread and Smoke Developed).
ASTM C423: Standard test method for sound absorption and sound absorption coefficients by the reverberation room method.
EN ISO 11654: International standard for classifying sound absorbers (Classes A to E).
