Slag wool is one of the most common sound- and heat-insulating materials. Slag is a kind of mineral wool. The main raw material for the production of this material is blast furnace slag, which is processed into microfibers. Further, fibers with the use of a binder are pressed and their forming is performed in plates / sheets. The average length of the fibers of slag wool is 16 mm, diameter from 4 to 12 microns. These indicators are approximately the same for all types of mineral wool.


  1. Specification of
  2. slags Advantages of
  3. Disadvantages of
  4. Harmful substances in slag

Slag wool, most often, non-residential premises or some temporary structures are insulated. Due to its high hygroscopicity, the material can not be used as a heater for facades of buildings or water pipes.

Specification of slag

  1. Thermal conductivity - 0,46-0,48 W /( m * K).
  2. The maximum use temperature is 250 degrees.
  3. The sintering temperature is 250-300 degrees.
  4. The heat capacity is 1000 J /( kg * K).
  5. Binder is 2.5-10%.
  6. The sound absorption coefficient is 0.75-0.82.
  7. Vibration resistance - no.
  8. Class of heat resistance - NG( not lit).
  9. Emission of harmful substances - is.
  10. Sharpness is.

Technical parameters indicate that this material is slightly inferior to other varieties of mineral wool, for example, glass wool or stone wool, by certain indices. This particularly applies to heat conduction and caking.

Here you can see the photos of the slag wool.

Advantages of

The main advantage of slag wool is the possibility of thermal insulation of both straight and curved surfaces. The material is very convenient in mounting on rounded surfaces. Heater serves as a good soundproofing device. When observing the rules of operation, it can last more than 50 years without loss of sound and heat insulation properties. An important advantage of the material is its low cost.

Slag is not a new and well-studied material. Its installation is fairly simple and does not require any additional knowledge. A heater can be laid by one person.

Disadvantages of

For all its advantages, slag wool has several drawbacks. The material does not tolerate sharp changes in temperature.

Blast furnace slag from which this material is produced has high acidity. If you get on the material, even slightly, the amount of moisture, acid is formed, which has a destructive effect on the metal. Therefore, it is not recommended to apply slag on metal surfaces where there is a risk of moisture ingress.

During installation, small fiber particles are peeled from the material. Therefore, it is necessary to work with a slag in a respirator and overalls.

Harmful substances in slag

Phenol-formaldehyde resins, which are part of slag, adversely affect human health. Some experts believe that such substances are very dangerous for humans. However, manufacturers assure that the concentration of harmful substances is very small and can not carry any danger. In order not to risk your health, it is better to buy material only from well-known and trusted manufacturers.

According to the builders who use this heater, they say that the slag is a practical and inexpensive material with a long service life. The main thing is to observe all technical conditions and safety measures during installation.

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