Sound insulation · Stone wool
ROCKWOOL Safe 'n' Silent Pro
- Thickness
- 25–100 mm
- Density
- 40–100 kg/m³
- Sound absorption (NRC)
- 0.90–1.00
What is stone wool and what is it used for?
In short
Stone wool (rock wool, often called Rockwool) is fibre insulation made from molten rock such as basalt, spun into fibres and held together with a binder. It is used for thermal insulation, acoustics in walls, high-temperature industrial work and as a component of fire-protection systems. Stone wool is not asbestos. Actual values such as service temperature or fire-test results must be taken from the documents of the specific product.
- 1Raw material: glass wool uses glass (including recycled glass) and sand; stone wool uses volcanic rock such as basalt — proportions vary by manufacturer
- 2Melted at high temperature and spun into fibres
- 3Formed into rolls, boards or pipe sections — check each product's datasheet for its actual properties; colours here only tell the materials apart
What is stone wool made from?
The main raw material is natural rock such as basalt, together with other materials such as dolomite or industrial slag. It is melted at a very high temperature, spun into fibres, sprayed with binder, then compressed and cured to the required density.
Because it is made from rock, stone wool is an inorganic material. Manufacturers such as ROCKWOOL state that their stone wool is non-combustible with a melting point of around 1,000 °C or higher — but "non-combustible" is a property of the material. It does not mean that a wall or opening containing stone wool has a "fire-resistance rating" of its own. See fire performance terms.
Common forms
| Form | Description | Typical uses |
|---|---|---|
| --- | --- | --- |
| Slab / board | Holds its shape; several densities | Drywall cavities, ceilings, fire-protection systems |
| Roll | Can be rolled; often faced | Under metal roofs |
| Wired mat | Stitched to wire mesh; wraps curved surfaces | Large pipes, boilers, flue ducts |
| Pipe section | Pre-formed to pipe size | Steam and hot process pipes |
What is it used for?
- Acoustics — fitted in drywall cavities or above ceilings to absorb sound in the cavity, e.g. ROCKWOOL Safe'n'Silent Pro. Sound insulation ratings (STC/Rw) belong to the complete wall system, not to the stone-wool slab. See STC and Rw
- High-temperature industry — insulating steam pipes, boilers and hot equipment, e.g. ROCKWOOL ProRox WM, whose grades have different maximum service temperatures in the maker's documents. See choosing high-temperature insulation
- Passive fire protection — as a component in tested systems, such as sealing the gap between a curtain wall and the floor edge. See stone wool in passive fire protection
- Building thermal insulation — roofs and walls, depending on product and thickness
What to know before choosing
- Each stone-wool product is designed for a different job. An acoustic wall slab and a boiler wired mat are not interchangeable
- Check the key values in that product's documents: thermal conductivity (λ) at the relevant temperature, maximum service temperature, density and fire-test results with the standard named
- For stainless-steel pipework, check whether the insulation meets a chloride requirement such as ASTM C795
Is stone wool dangerous?
IARC places insulation "rock (stone) wool" in Group 3, but the fibres can cause temporary irritation during installation, so wear protective equipment. Read more in is stone wool dangerous? and compare with glass wool in stone wool vs glass wool.
Sources
- EURIMA — How is mineral wool insulation made?
- ROCKWOOL — ThermalRock S General Product Information (basalt raw material, non-combustible, melting point)
- ROCKWOOL Technical Insulation — ProRox WM 950SA / 960SA / 970SA Product Data Sheets
- ROCKWOOL — Safe'n'Silent Pro Data Sheet
- IARC Monographs Volume 81: Man-made Vitreous Fibres (2002)
Related products
Categories and example products for this topic
Building thermal insulationSound insulationIndustrial and high-temperature insulationFire protection
- ROCKWOOL Safe 'n' Silent Pro — Slab for buildings: fitted in wall and ceiling cavities of sound-insulating systems
- ROCKWOOL ProRox BL — Blanket for industry: wraps tanks and curved surfaces, rated 350–650 °C by grade
- ROCKWOOL ProRox WM — Wired mat: steam pipes, boiler walls and furnaces, max 650–750 °C by grade
- ROCKWOOL Rocksafe Plus — Fire protection: stone wool safing for the gap between curtain wall and floor edge
Industrial and high-temperature insulation · Stone wool
ROCKWOOL ProRox BL
- Max. temp.
- 350–650 °C
- Density
- 60–100 kg/m³
- Thickness
- 50–100 mm
Industrial and high-temperature insulation · Stone wool
ROCKWOOL ProRox WM
- Max. temp.
- 650–750 °C
- Density
- 80–128 kg/m³
- Thermal conductivity (λ)
- 0.037–0.038 W/m·K (50 °C)
Fire protection · Stone wool
ROCKWOOL Rocksafe Plus
- Thickness
- 135 mm
- Density
- 80 kg/m³
- Thermal conductivity (λ)
- 0.035 W/m·K