A brief analysis of mineral fibres for sound-absorption materials

Abstract

The article reviews the role of mineral fibres in noise-reducing materials against the background of growing noise concerns in high-rise residential buildings and green-building policy. It classifies sound-control materials into sound-absorbing, sound-insulating and vibration-damping types, and notes that the mineral fibres used in sound control belong to man-made mineral vitreous fibres (MMVF): glass fibre, glass wool, rock wool, slag wool and aluminium silicate fibre. Rock wool is made from natural basalt, diabase and dolomite/limestone melted in a cupola furnace and fibreised by centrifugal spinning; slag wool from blast-furnace or industrial slag.

It compares the two on appearance (rock wool grey-green from Fe2O3 staining; slag wool white or grey-white), acidity coefficient Mk = (SiO2+Al2O3)/(CaO+MgO) — rock wool generally 1.6–2.5, slag wool 1.0–1.5 — water resistance, and service temperature: rock wool usable above 800°C with a softening point of 900–1000°C, slag wool not above 675°C. Sprayed mineral-fibre products are described as forming a three-dimensional fibre network that attenuates sound, improving low-frequency sound insulation of metal roofs; they are A1 non-combustible per GB 8624-2012 and non-corrosive to steel and concrete bases.

The technical requirements listed are: for granulated wool (sprayed absorption), fibre diameter ≤5 μm, grain size 5–20 mm, shot content ≤6% (60-mesh sieve residue), density <125 kg/m³, thermal conductivity 0.042 W/(m·K), noise reduction coefficient ≥0.7 at 25 mm when required; for short-cut fibres in vibration-damping water-based floor coatings, L/D ≥25, shot content ≤5% (120-mesh sieve residue), hydrophilic dispersion at a low fibre-to-water ratio of 1:1.5, applied at 3 mm thickness for a noise reduction of 15–20 dB.

Key facts

• Scope: mineral fibres in sound-absorption, sound-insulation and vibration-damping materials
• MMVF family: glass fibre, glass wool, rock wool, slag wool, aluminium silicate fibre
• Raw materials: rock wool from basalt, diabase, dolomite/limestone; slag wool from blast-furnace/industrial slag
• Acidity coefficient: Mk = (SiO₂+Al₂O₃)/(CaO+MgO); rock wool 1.6–2.5, slag wool 1.0–1.5
• Service temperature: rock wool up to above 800°C (softening 900–1000°C); slag wool not above 675°C
• Fire rating: A1 non-combustible per GB 8624-2012
• Granulated wool: diameter ≤5 μm; grain size 5–20 mm; shot ≤6% (60-mesh); density <125 kg/m³; 0.042 W/(m·K); NRC ≥0.7 at 25 mm
• Short-cut fibre for damping coatings: L/D ≥25; shot ≤5% (120-mesh); 3 mm coating; noise reduction 15–20 dB

The original article is in Chinese; see the Chinese version for the full text. This page provides the English title, abstract and key facts only — translated and compiled from the original, without full verbatim translation.