Mineral wool

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Mineral wool
Mineral wool mats
Mineral wool mats
raw materials see list on the left
Primary energy consumption (production) Stone wool: 150-400 kWh / m³

Glass wool: 250-500 kWh / m³

Material properties
Thermal conductivity  λ 0.030-0.045 W / (m · K)
Specific heat capacity  c 840–1000 J / (kg · K)
Bulk density ρ Stone wool: 22–200 kg / m³

Glass wool: 20–153 kg / m³

Vapor diffusion resistance  μ 1-2
Building material class A1
Areas of application especially roof insulation and core insulation
material costs 45–150 € / m³
Glass wool production using the blowing process: liquid glass runs into a fiberizing machine (2012)
Glass wool stoves at VEB Trisola (1972)
Carpenters insulating an old building with rock wool between the rafters.

Mineral wool is a soft material made from man-made mineral fibers . Depending on the starting material, a distinction is made between slag wool , glass wool and rock wool .

Mineral wool is mainly used as a non-combustible insulation material for the thermal insulation of houses. In industry, it is used in particular as noise and fire protection, e.g. B. for wrapping tanks, containers, boilers and turbines. Mineral wool is usually produced as a nonwoven or with a higher density than panels. In addition, rock wool is also used as a soil-free substrate for hydroponics in industrial vegetable and ornamental plant cultivation.


There are three basic processes for the production of mineral wool, the drawing process, the blowing process and the centrifugal process. Today, the processes are often combined with the centrifugal drawing process or the centrifugal blow molding process.

In all processes, the raw materials are melted between 1,200 and 1,600 degrees Celsius.

Drawing process

The drawing process is used to produce continuous fibers that are mainly used in the textile sector. Particularly noteworthy here is the rod drum pulling process, which was patented in the 1930s, see glass fiber .

Blow molding

In the blow molding process, the melt is frayed by blowing.

Centrifugal process

The spinning process is similar to making cotton candy . The melt of glass or stone is spun into fibers by hitting a rapidly rotating flywheel drop by drop and being thrown into fibers by the rotation. Binding and impregnating agents are added to the fibers . The result is a fiber fleece that is transported on a chain belt through a curing oven at around 230 ° C. In another process, the melt is passed over rapidly rotating rollers or the melt is shredded using high-pressure burners.

Energy demand

The production of mineral wool requires energy and the like. a. to melt the raw materials. The Gütegemeinschaft Mineralwolle e. V. names the following required quantities of primary energy :

  • Stone wool: 150… 400 kWh / m³
  • Glass wool: 250… 500 kWh / m³

For comparison: The production of polystyrene particle foam (EPS) has a primary energy requirement of 200–760 kWh / m³, that of polystyrene extruder foam (XPS) has a primary energy requirement of 450–1000 kWh / m³. In these materials, however, a large part of the energy is still chemically bound, while mineral wool does not contain any chemical energy.

raw materials

Advertising photo for glass wool fibers, GDR 1958

The rocks are mostly extracted in open-cast mining .


Mineral wool is resistant to mold, rot and vermin.

While stone wool has a high temperature resistance of usually 1000 ° C, it is usually around 700 ° C for conventional glass wool. This property has an impact on the suitability of the insulation material for partitions or for the insulation of supporting structures. For fire protection reasons, it may be necessary to use the higher temperature-resistant rock wool for bulkheads (e.g. for cable penetrations) or for the insulation of non-fire-resistant structures (usually steel or wooden structures).

Stone wool has a higher acoustic insulation capacity and, under oxidizing conditions, also a high thermal stability. Under reducing conditions it sinters together at approx. 800 ° C, which can be prevented by pre-heat treatment. Stone wool is biosoluble in the human lungs and is therefore not a health hazard.

Glass wool is elastic, whereas rock wool is hardly or not at all. Stone wool has a higher bulk density than glass wool - it weighs up to 200 kg / m³. That means:

  • Stone wool has a higher dead weight than glass wool with the same insulation performance.
  • Thermal insulation : Stone wool has a lower thermal conductivity , which is why summer heat radiated in during the day is more delayed than with glass wool.

History of slag wool

It was observed at an early stage in iron production that when the combustion air was forced through, wool-like flakes of slag fibers formed at leaks in the blast furnace wall. The possibility of being able to produce slag wool from blast furnace slag was known from the middle of the 19th century.

The first large quantities of slag wool were produced by Edward Parry in Wales as early as 1840, but the process could not be controlled and was therefore abandoned. According to another source, slag wool was first factory-made in 1864 by George Parry, also in Wales. The first commercial production took place in 1871 in the steelworks of the Georgs-Marien-Bergwerks- und Hüttenverein in Georgsmarienhütte .

Rock wool: A cuboid cut from a rock wool mat is placed on the cut surface and photographed from the front above.  The fibers are yellow to light gray and run in irregular waves predominantly parallel to the uncut areas on the right and left.  At the edge facing the viewer, the mat has loosened up a bit (has it been?) And where the fibers are less firmly attached to one another, narrow spaces have arisen, some of which are criss-crossed with isolated fibers.
Rock wool

In contrast to this type of recycling of the slag , the need for heat-resistant insulation materials for pipe and boiler insulation in industry increased from the middle of the 19th century in order to reduce the heat losses of machines and devices and thus to increase efficiency. At the same time, a cold chain developed in business and trade that required insulation materials that were not sensitive to moisture. The slag wool met these requirements.

History of glass wool

From 1849, Jules de Brunfaut developed glass fibers that were pulled from heated glass rods and wound onto a roll. When they peeled off the roll, they pulled together into spiral fibers. These fibers, known as glass wool, were originally developed for the production of textiles and used, among other things, for textiles and in chemistry as filter material.

In contrast, the industrial production of glass wool became possible from 1931 onwards using the so-called Hager process by Friedrich Rosengarth . It is similar to the production of cotton candy , in which liquid glass melt is thrown into thin threads over a rotating disk, creating a fleece . Rosengarth called the product of this process glass wool. He made this invention in 1928/30. But he lacked the capital to use his invention. On October 15, 1931, he ceded his rights to the Dutch company Naamlooze Vennootschap Maatschappij tot Beheer en Exploitatie van Octoien NV in The Hague for a process for the production of fibers or webs from glass, slag and similar substances that are plastic in heat . The Saint Gobain company was involved in this patent exploitation company . The invention was patented on November 30, 1930 in Germany under number 539738. The patent specification explains, among other things, that:

“The production of threads or webs from molten glass (so-called glass wool) has so far been carried out on spinning machines, on which the threads are pulled from prepared glass rods or through nozzles from the molten mass, while in the production of slag wool the threads are generated by steam or wind blowers. In the present invention, a different approach is taken, namely, according to the new method, the hot liquid glass or slag mass is conducted in a thin stream that is as uniform as possible onto an expediently horizontal, rapidly rotating disk made of suitable material. The liquid mass splatters into the finest drops, which are thrown off by the centrifugal force and at the same time form thin, fine threads that sink down around the rotating disc and can be applied in an even layer. "

- Reich Patent Office, November 26, 1931

The first glass wool products were produced in two factories in Germany around 1936. The long-fiber web was initially also called glass wadding . The date of the announcement of the grant of the patent for dead Beheer was November 26, 1931. The inventor was not mentioned.

A similar process was developed in 1933 by Games Slayter at Owens-Illinois .

History of rock wool

Carl Grünzweig invented the cork insulation board in 1880. Ten years later the Grünzweig & Hartmann company in Ludwigshafen employed 100 people. (See also: ISOVER .)

In 1909, Max Grünzweig, the founder's son, discovered that cork granulate increased its volume several times over when heated without air supply. This enabled the weight of the cork insulation materials to be reduced considerably.

With the invention of glass floss in Bergisch Gladbach, a serious competitor product arose. Therefore one began to intensively develop a fiber material from materials that were permanently available. In addition, the product should be superior to the glass floss.

After many attempts at melting, it was possible in 1939, after four years of research, to produce a new mineral fiber insulation material, rock wool, from the basic components of marl and lime . The new insulation material was manufactured under the product name “Sillan” as uncured wool in loose form, as a sheet on paper backing, as braids and as corrugated mats.

Health aspects

safety instructions

Mineral wool

GHS labeling of hazardous substances
08 - Dangerous to health


H and P phrases H: 351
P: no P-phrases

  • The coarse fibers of the mineral wool (thicker than 3 µm) lead to skin irritation on contact with the skin and to itching in most people. Sensitive skin can react more strongly, with redness, swelling and the like.
  • Fiber dust from older mineral wool is classified as “possibly carcinogenic ”. Mineral wool produced since 1996 is considered harmless due to its lower bio-persistence and the less respirable fibers. However, this is a voluntary commitment. Only from June 2000 is there a ban on the manufacture and use of old KMF.

The health and safety at work assessment of artificial mineral fibers (KMF), which also include glass and rock wool fibers, is regulated in the Technical Rule for Hazardous Substances (TRGS 521) or in the Hazardous Substances Ordinance (GefStoffV).

Mineral wool may only be sold or passed on if it is free from suspected cancer, i.e. if it has at least one of the following properties (exemption criterion):

  • the carcinogenicity index must be Ki ≥ 40
  • the filament diameter must be greater than 3 microns, that is not respirable be
  • since 1998: Proof of a sufficiently high biosolubility (property of fine fibers to be dissolved and broken down in the body by the body's own substances) (generally provided by animal experiments ) must be available; a fiber type is only shown if the half-life of its biosolubility is 40 days or less. The following applies: the higher the biosolubility, the lower the half-life

Proof that a mineral wool meets these criteria is most easily recognized by the RAL quality mark “Products made from mineral wool”, with reference to Directive 97/69 / EC of the Commission.

"Bio-persistent fibers" (with low biosolubility) - this includes glass or rock wool that was manufactured before about 1995 or that was used up to June 1, 2000 ( prohibition of manufacture, marketing and use in Germany) and which do not have the RAL quality mark - may no longer be placed on the market according to the German GefStoffV, i.e. no longer manufactured or sold in Germany. Of course, these materials are used in many old buildings. Before major renovation or demolition work (see TRGS 521), it is therefore always necessary to check how old the built-in material is (or, as a precaution, it is assumed that it is old material). If it was installed before 1995, it is most likely a material of lower biosolubility. The corresponding occupational health and safety measures in accordance with TRGS 521 then apply. If, on the other hand, it is material that was installed at a later date, one can assume (at least for products from major manufacturers) that it is the new generation of biosoluble mineral wool. If in doubt you should ask the manufacturer, because the carcinogenicity index is not the only one of the above exemption criteria.

Due to the irritating effects of fibers and dust on the skin, you should always wear gloves and long-sleeved clothing or protective clothing (e.g. a disposable protective suit) when cutting and installing glass or rock wool . Contaminated skin should be cleaned with cold (instead of warm) water, because otherwise the fibers can get stuck in the pores of the skin.

Delivery forms

  • Loose in sacks (plucked, offcuts) is the most cost-effective option and is used to fill cavities
  • Mineral wool flakes as blown insulation for filling cavities and hollow layers
  • Mineral wool felt mats laminated with bitumen cardboard or with quilted aluminum foil (previously also with paper as the carrier material)
  • Mineral wool felt mats bonded with synthetic resin
  • Mineral wool fleece between bituminous sealing and roofing membranes
  • Mineral wool mats quilted on galvanized or stainless steel wire mesh
  • Mineral wool mats (semi-rigid and rigid) cut as wedges for insulation between the rafters, for example on a cold roof
  • Lamellar mats laminated with quilted aluminum foil
  • Half-shells
  • Mineral wool felt slats coated with mineral paint (for better adhesion when applying plaster)
  • Mineral wool felt panels with fleece coating
  • Mineral wool ball about 300 kg

In the industrial sector, spun fibers are increasingly being replaced by drawn fibers with a controlled geometry, as these usually have better resistance to vibrations in addition to being harmless to health.

Brands and Manufacturers

Major manufacturers of mineral wool are:

Smaller manufacturers:

Environmental aspects, disposal

The rocks are mostly extracted in quarries in open-cast mining . This is associated with interventions in nature and the landscape .

Glass wool and rock wool are not recycled as a rule, but on landfills disposed of . However, individual companies offer systems based on the old-for-new principle for single-origin mineral wool.

The use of rock wool as a growing medium (with hydroponics ) creates large amounts of waste. After a season, rock wool blocks or sacks with roots are deposited. For the Netherlands alone (according to a source from 2008) , around 200,000 cubic meters of rock wool residues are produced annually as waste that has to be disposed of.

According to the AVV , old mineral wool must be disposed of under AVV number 17 06 03 *, while new mineral wool can be disposed of under AVV number 17 06 04.


  • EN 13162 Thermal insulation products for buildings - Factory made mineral wool (MW) products - Specification .

Similar materials

Individual evidence

  1. a b Comparison table glass wool - rock wool In: mineralwolle.de, accessed on October 20, 2013
  2. on polystyrene particle foam (EPS) and polystyrene extruder foam (XPS) , accessed on January 6, 2017
  3. " Newer products that are labeled as" bio-soluble "have a half-life of about 60 days. Old rock wool fibers have a higher bio-persistence (resistance) and a half-life of about 300 days. In: waermedaemmstoffe.com, accessed on 20 . October 2013
  4. a b Herbert M. Ulrich. Handbook of the chemical investigation of textile fibers - second volume: Chemism, properties and use of textile (unchanged) fibers and their testing. Springer-Verlag, Vienna 1956; P. 731
  5. ^ Charles Wood: Utilization and properties of blast furnace slag . in. Van Nostrand`s Engineering Magazine. Volume XXIII. July - December 1880. D. Van Nostrand Publisher, New York 1880, p. 144
  6. Ludwig Darmstaedter (ed.): Handbook for the history of natural sciences and technology . Second, revised and increased edition. Published by Julius Springer, Berlin 1908, p. 637 ( online ).
  7. ^ Swapna Mukherjee: Applied Mineralogy: Applications in Industry and Environment. Springer, Dordrecht (Netherlands) 2012, ISBN 978-94-007-1161-7
  8. ^ Building "Science" timeline
  9. ^ Wener Eicke Hennig: Brief history of insulation materials, first part. wksb magazine for heat protection ∙ cold protection ∙ sound insulation ∙ fire protection, 56th year, issue 65/2011, p. 8
  10. a b Emanuel Herrmann: Miniature pictures from the area of ​​the economy. , Nebert, 1872. pp. 23-29.
  11. So named after the first employer who worked for Rosengarth, see article Friedrich Rosengarth .
  12. Edmund Ruppert : The insulation material front runner ISOVER, at home in Bergisch Gladbach since 1931 , in: Rheinisch-Bergischer Calendar 2010, ISBN 978-3-87314-444-6 , ISSN  0722-7671 , p. 239
  13. Horst Möller: Saint Gobain in Germany, From 1853 to the present, p. 100. Retrieved on October 3, 2014 .
  14. Karl-Hans Garke, Leopold Schneider: History of the glass-silk industry GmbH, later Glaswatte GmbH, Bergisch Gladbach, later Glasfaser GmbH, Bergisch Gladbach or Aachen, today Grümzweig + Hartmann and Glasfaser AG, Bergisch Gladbach plant , Aachen 1978
  15. a b c Patent DE539738 (Scan, pdf)
  16. Werner Eicke-Hennig: Brief History of Insulation Materials, Part One , p. 21, accessed on January 1, 2016
  17. Patent US 2133235 A: Method and apparatus for making glass wool.
  18. Edmund Ruppert : The insulation material frontrunner ISOVER, at home in Bergisch Gladbach since 1931 , in: Rheinisch-Bergischer Calendar 2010, ISBN 978-3-87314-444-6 , ISSN  0722-7671 , p. 241f
  19. a b Entry on mineral wool in the GESTIS material database of the IFA , accessed on July 29, 2017(JavaScript required) .
  20. ^ Statement by the construction trade association
  21. TRGS 521, edition: February 2008
  22. Wendel Wohlleben, Hubert Waindok, Björn Daumann, Kai Werle, Melanie Drum, Heiko Egenolf: Composition, Respirable Fraction and Dissolution Rate of 24 Stone Wool MMVF with their Binder . In: Particle and Fiber Toxicology . 2017. doi : 10.1186 / s12989-017-0210-8 .
  23. Michaela C. Theurl: CO2 balance of tomato production: Analysis of eight different production systems in Austria, Spain and Italy. In: Social Ecology Working Paper. 110, Vienna, December 2008, ISSN  1726-3816 ( aau.at PDF).

Web links

Commons : Mineral Wool  - Collection of pictures, videos and audio files