Editing Mineral wool

{{short description|Fiber made from spun molten minerals}}
{{Redirect|Rockwool|a manufacturer|Rockwool International}}
{{Multiple issues|{{inadequate lead|date=August 2018}} {{sources|date=August 2018}}}}
[[File:Rockwool 4lbs per ft3 fibrex5.jpg|thumb|Mineral wool close-up]]
[[File:Rochwool pipe covering wh fire test.jpg|thumb|upright|Mineral wool pipe covering applied to a steel pipe for a [[fire test]]]]

'''Mineral wool''' is any [[fiber|fibrous]] material formed by [[spinning (polymers)#Melt spinning|spinning]] or [[drawing (manufacturing)#Plastic drawing|drawing]] molten [[mineral]] or rock materials such as [[slag]] and [[ceramic material|ceramics]].<ref>"Man-made mineral fibre (MMMF) is a generic name used to describe an inorganic fibrous material manufactured primarily from glass, rock, minerals, slag and processed inorganic. The MMMF produced are non-crystalline (glassy, vitreous, amorphous)." [http://ec.europa.eu/social/BlobServlet?docId=7722&langId=en] Recommendation from the Scientific Committee on Occupational Exposure Limits for man made-mineral fibres (MMMF) with no indication for carcinogenicity and not specified elsewhere</ref>

Applications of mineral wool include [[thermal insulation]] (as both [[building insulation|structural insulation]] and [[pipe insulation]]), [[filtration]], [[soundproofing]], and [[hydroponics|hydroponic]] growth medium.

== Naming ==
Mineral wool is also known as '''rock wool''', mineral cotton, mineral fiber, man-made mineral fiber (MMMF), and man-made vitreous fiber (MMVF).

Specific mineral wool products are stone wool and slag wool. Europe{{who|date=May 2020}} also includes [[glass wool]] which, together with [[ceramic]] fiber, are entirely artificial fibers that can be made into different shapes and are spiky to touch.

== History ==
Slag wool was first made in 1840 in [[Wales]] by Edward Parry, "but no effort appears to have been made to confine the wool after production; consequently it floated about the works with the slightest breeze, and became so injurious to the men that the process had to be abandoned".<ref>Spon, Ernest. [http://hdl.handle.net/2027/mdp.39015063827573?urlappend=%3Bseq=449 ''Workshop Receipts''] ... London: E. & F. N. Spon, 18831892. Page 439</ref> A method of making mineral wool was patented in the United States in 1870 by John Player<ref name="Appleton">"Mineral Wool or Mineral Cotton", ''Appleton's Annual Cyclopedia and Register of Important Events of the Year 1891''. New Series vol. 16. New York: 1892. 528. Print.</ref> and first produced commercially in 1871 at [[Georgsmarienhütte]] in [[Osnabrück]] [[Germany]]. The process involved blowing a strong stream of air across a falling flow of liquid iron slag which was similar to the natural occurrence of fine strands of volcanic slag from [[Kilauea]] called [[Pele's hair]] created by strong winds blowing apart the slag during an eruption.<ref name="Appleton" /> 

[[File:Hallway insulation.jpg|thumb|Common insulation applications in an [[apartment building]]]]

According to a mineral wool manufacturer, the first mineral wool intended for high-temperature applications was invented in the United States in 1942 but was not commercially viable until approximately 1953. More forms of mineral wool became available in the 1970s and 1980s.<ref name=":1">{{Cite web|url=https://www.htiwcoalition.org/producthistory.html|title=HISTORY OF HTIW PRODUCTS|access-date=2018-08-08|archive-url=https://web.archive.org/web/20180819150513/http://htiwcoalition.org/producthistory.html|archive-date=2018-08-19|url-status=dead}}</ref>

== High-temperature mineral wool {{Anchor|HTMW}} ==
[[Image:Industrial furnace equipped with HTIW modules.jpg|thumb|Industrial furnace equipped with high-temperature mineral wool modules|alt=]]
[[Image:Industrial furnace.jpg|thumb|upright|Industrial furnace in operation, equipped with high-temperature mineral wool|alt=]]

High-temperature mineral wool is a type of mineral wool created for use as high-temperature insulation and generally defined as being resistant to temperatures above 1,000&nbsp;°C.  This type of insulation is usually used in industrial furnaces and foundries. Because high-temperature mineral wool is costly to produce and has limited availability, it is almost exclusively used in high-temperature industrial applications and processes.{{Citation needed|date=January 2019}}

=== Definitions ===

Classification temperature is the temperature at which a certain amount of linear contraction (usually two to four percent) is not exceeded after a 24-hour heat treatment in an electrically heated [[laboratory oven]] in a neutral atmosphere. Depending on the type of product, the value may not exceed two percent for boards and shaped products and four percent for mats and papers.

The classification temperature is specified in 50&nbsp;°C steps starting at 850&nbsp;°C and up to 1600&nbsp;°C. The classification temperature does not mean that the product can be used continuously at this temperature. In the field, the continuous application temperature of [[Amorphous solid|amorphous]] high-temperature mineral wool ([[#Alkaline earth silicate wool (AES wool)|AES]] and [[#Alumino silicate wool (ASW)|ASW]]) is typically 100&nbsp;°C to 150&nbsp;°C below the classification temperature. Products made of polycrystalline wool can generally be used up to the classification temperature.{{Citation needed|date=June 2018}}

=== Types ===

There are several types of high-temperature mineral wool made from different types of minerals. The mineral chosen results in different material properties and classification temperatures. 

==== Alkaline earth silicate wool (AES wool) ====

AES wool consists of amorphous glass fibers that are produced by melting a combination of calcium oxide (CaO−), magnesium oxide (MgO−), and silicon dioxide (SiO<sub>2</sub>). Products made from AES wool are generally used in equipment that continuously operates and in domestic appliances. Some formulations of AES wool are bio-soluble, meaning they dissolve in bodily fluids within a few weeks and are quickly cleared from the lungs.<ref name=":0">{{Cite news|url=http://insulationet.com/en/materials/high-temperature-wool/|title=High temperature insulation wool - Production, Properties, Classification|work=insulatioNet.com|access-date=2018-06-24|language=en-US}}</ref><ref>{{Cite web|url=http://icanz.org.au/health-and-safety/biosolubility-faqs/|title=Biosolubility FAQ's|website=ICANZ|language=en-US|access-date=2019-01-19}}</ref>

==== Alumino silicate wool (ASW) ====

Alumino silicate wool, also known as refractory ceramic fiber (RCF), consists of amorphous fibers produced by melting a combination of aluminum oxide (Al<sub>2</sub>O<sub>3</sub>) and silicon dioxide (SiO<sub>2</sub>), usually in a weight ratio 50:50 (see also VDI 3469 Parts 1 and 5,<ref name="VDI">VDI Guideline: VDI 3469 Part 1 - Overview  Part 5 – High-Temperature Insulation Wool</ref> as well as TRGS 521). Products made of alumino silicate wool are generally used at application temperatures of greater than 900&nbsp;°C for equipment that operates intermittently and in critical application conditions (see Technical Rules TRGS 619).{{Citation needed|date=January 2019}}

==== Polycrystalline wool (PCW) ====

Polycrystalline wool consists of fibers that contain aluminum oxide (Al<sub>2</sub>O<sub>3</sub>) at greater than 70 percent of the total materials and is produced by [[Sol–gel process|sol–gel method]] from aqueous spinning solutions. The water-soluble green fibers obtained as a precursor are crystallized by means of heat treatment.<ref name="VDI" /> Polycrystalline wool is generally used at application temperatures greater than 1300&nbsp;°C and in critical chemical and physical application conditions.

==== Kaowool ====

Kaowool is a type of high-temperature mineral wool made from the mineral [[kaolin]]. It was one of the first types of high-temperature mineral wool invented and has been used into the 21st century.<ref name=":1" /> It can withstand temperatures close to {{convert|1650|C|F}}.<ref>{{Cite web|url=https://www.fabricationspecialties.com/pdf/hightemp.pdf|title=Thermal Ceramics}}</ref>

== Manufacture ==
Stone wool is a furnace product of [[lava|molten rock]] at a temperature of about 1600&nbsp;°C through which a stream of air or steam is blown. More advanced production techniques are based on spinning molten rock in high-speed spinning heads somewhat like the process used to produce [[cotton candy]]. The final product is a mass of fine, intertwined fibers with a typical diameter of 2 to 6 [[micrometer (unit)|micrometers]]. Mineral wool may contain a [[binder (material)|binder]], often a [[terpolymer]], and an [[mineral oil|oil]] to reduce dusting.

== Use ==

Though the individual fibers [[heat conduction|conduct heat]] very well, when pressed into rolls and sheets, their ability to partition air makes them excellent insulators and [[sound absorption|sound absorbers]].<ref>Weiner, Ethan. Acoustic Treatment and Design for
Recording Studios and Listening Rooms. "Without question, the most effective absorber for midrange and high frequencies is rigid fiberglass."http://www.ethanwiner.com/acoustics.html#rigid%20fiberglass.</ref><ref>Houghton, Matt. Sound On Sound. "What is the best density for a good, fairly wide-spectrum absorber? . . .try looking for mineral wool in the region of 45-75kg/m3." http://www.soundonsound.com/sos/oct10/articles/qa-1010-2.htm</ref> Though not immune to the effects of a sufficiently hot fire, the fire resistance of [[glass wool|fiberglass]], stone wool, and [[ceramic]] fibers makes them common [[building material]]s when [[passive fire protection]] is required, being used as spray [[fireproofing]], in [[wall stud|stud]] cavities in [[drywall]] assemblies and as [[packing (firestopping)|packing]] materials in [[firestop]]s.

Other uses are in [[resin bonded panel]]s, as filler in compounds for [[gasket]]s, in [[brake pad]]s, in [[plastic]]s in the [[automotive]] industry, as a [[filtration|filtering]] medium, and as a growth medium in [[hydroponics]].

Mineral fibers are produced in the same way, without binder. The fiber as such is used as a raw material for its reinforcing purposes in various applications, such as friction materials, gaskets, plastics, and [[coating]]s.

{| class="wikitable"
|+ '''Heat resistance of mineral wool'''<ref name="competition-commission_org_uk-glass_wool_report">{{cite web | url=https://www.amazon.co.uk/SuperFOIL-SFBA-600mm-Wide-Long/dp/B07NS4MHNT/ref=sr_1_5?keywords=superfoil+insulation&qid=1648067276&sr=8-5 | title=SuperFOIL Foil Insulation Roll 0.6m x 25m - Energy Saving DIY Bubble Foil Sheet - 3-in-1 Sustainable Thermal Insulation Reflective Radiant Barrier & Vapour Barrier - Multi Purpose for Home & Auto : Amazon.co.uk: DIY & Tools | website=Amazon UK }}</ref>
|-
! Material !! Temperature
|-
| Glass wool         || 230–260&nbsp;°C
|-
| Stone wool         || 700–850&nbsp;°C
|-
| [[High-temperature insulation wool|Ceramic fiber wool]] || 1200&nbsp;°C
|}

=== Hydroponics ===

Mineral wool products can be engineered to hold large quantities of water and air that aid root growth and nutrient uptake in [[hydroponics]]; their fibrous nature also provides a good mechanical structure to hold the plant stable. The naturally high [[pH]] of mineral wool makes them initially unsuitable to plant growth and requires "conditioning" to produce a wool with an appropriate, stable pH.<ref name="Alexander 1994">{{cite book |url = https://books.google.com/books?id=cHT3bMm3njsC&q=rockwool |title = The Best of Growing Edge |author = Tom Alexander |author2=Don Parker |date = 1994 |publisher = New Moon Publishing, Inc. |isbn = 978-0-944557-01-3}}</ref>{{rp|16}} [https://www.futuregarden.co.uk/expert-advice/six-top-tip-for-growing-plants-in-rockwool/ Conditioning methods include pre-soaking mineral wool in a nutrient solution adjusted to pH 5.5 until it stops bubbling].

=== High-temperature mineral wool ===

High-temperature mineral wool is used primarily for insulation and lining of industrial furnaces and foundries to improve efficiency and safety. It is also used to prevent the spread of fire.<ref name=":0" />

The use of high-temperature mineral wool enables a more lightweight construction of [[industrial furnaces]] and other technical equipment as compared to other methods such as fire bricks, due to its high heat resistance capabilities per weight, but has the disadvantage of being more expensive than other methods.

== Safety of material ==
[[File:Rockwool close up 3.jpg|thumb|left|Mineral wool under microscope]]

The [[International Agency for Research on Cancer]] (IARC) reviewed the [[carcinogenicity]] of man-made mineral fibers in October 2002.<ref>[http://monographs.iarc.fr/ENG/Monographs/vol81/index.php IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 81 (2002), Man-made Vitreous Fibres] (PLEASE NOTE: Some manufacturers of insulation products{{Who|date=December 2011}} have cited this volume while making erroneous claims that "IARC scientists confirm safety of mineral wool insulation". These claims are just false. The findings in this volume are not a determination of non-carcinogenicity or overall safety.)</ref> The IARC Monograph's working group concluded only the more [[biopersistent]] materials remain classified by IARC as "possibly carcinogenic to humans" ([[List of IARC Group 2B carcinogens|Group 2B]]). These include refractory ceramic fibers, which are used industrially as insulation in high-temperature environments such as [[blast furnace]]s, and certain special-purpose [[glass wool]]s not used as insulating materials. In contrast, the more commonly used vitreous fiber wools produced since 2000, including insulation glass wool, stone wool, and slag wool, are considered "not classifiable as to carcinogenicity in humans" ([[List of IARC Group 3 carcinogens|Group 3]]).

High bio soluble fibers are produced that do not cause damage to the human cell. These newer materials have been tested for carcinogenicity and most are found to be noncarcinogenic. IARC elected not to make an overall evaluation of the newly developed fibers designed to be less bio persistent such as the alkaline earth silicate or high-alumina, low-silica wools. This decision was made in part because no human data were available, although such fibers that have been tested appear to have low carcinogenic potential in experimental animals, and because the Working Group had difficulty in categorizing these fibers into meaningful groups based on chemical composition.<ref>[http://monographs.iarc.fr/ENG/Monographs/vol81/mono81.pdf IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 81 (2002), Man-made Vitreous Fibres], Overall evaluation, p. 339</ref>

The European Regulation (CE) n° 1272/2008 on classification, labelling and packaging of substances and mixtures updated by the Regulation (CE) n°790/2009 does not classify mineral wool fibers as a dangerous substance if they fulfil criteria defined in its Note Q.

The European Certification Board for mineral wool products, EUCEB, certify mineral wool products made of fibers fulfilling Note Q ensuring that they have a low bio persistence and so that they are quickly removed from the lung. The certification is based on independent experts' advice and regular control of the chemical composition.

Due to the mechanical effect of fibers, mineral wool products may cause temporary skin itching. To diminish this and to avoid unnecessary exposure to mineral wool dust, information on good practices is available on the packaging of mineral wool products with pictograms or sentences. Safe Use Instruction Sheets similar to Safety data sheet are also available from each producer.

People can be exposed to mineral wool fibers in the workplace by breathing them in, skin contact, and eye contact. The [[Occupational Safety and Health Administration]] (OSHA) has set the legal limit ([[permissible exposure limit]]) for mineral wool fiber exposure in the workplace as 15 mg/m<sup>3</sup> total exposure and 5 mg/m<sup>3</sup> respiratory exposure over an 8-hour workday. The [[National Institute for Occupational Safety and Health]] (NIOSH) has set a [[recommended exposure limit]] (REL) of 5 mg/m<sup>3</sup> total exposure and 3 fibers per cm<sup>3</sup> over an 8-hour workday.<ref>{{Cite web|title= CDC – NIOSH Pocket Guide to Chemical Hazards – Mineral wool fiber |url = https://www.cdc.gov/niosh/npg/npgd0432.html |website= www.cdc.gov |access-date= 2015-11-27}}</ref>

[[Registration, Evaluation, Authorisation and Restriction of Chemicals]] (REACH) is a European Union regulation of 18 December 2006. REACH addresses the production and use of chemical substances, and their potential impacts on both human health and the environment. A Substance Information Exchange Forum (SIEF) has been set up for several types of mineral wool. AES, ASW and PCW have been registered before the first deadline of 1 December 2010 and can, therefore, be used on the European market.

*ASW/RCF is classified as carcinogen category 1B.
*AES is exempted from carcinogen classification based on short-term in vitro study result.
*PCW wools are not classified; self-classification led to the conclusion that PCW are not hazardous.

On 13 January 2010, some of the aluminosilicate refractory ceramic fibers and zirconia aluminosilicate refractory ceramic fibers have been included in the candidate list of [[Substances of Very High Concern]]. In response to concerns raised with the definition and the dossier two additional dossiers were posted on the ECHA website for consultation and resulted in two additional entries on the candidate list. This actual (having four entries for one substance/group of substances) situation is contrary to the REACH procedure intended. Aside from this situation, concerns raised during the two consultation periods remain valid.

Regardless of the concerns raised, the inclusion of a substance in the candidate list triggers immediately the following legal obligations of manufacturers, importers and suppliers of articles containing that substance in a concentration above 0.1% (w/w):

* Notification to ECHA -REACH Regulation Art. 7
* Provision of Safety Data Sheet- REACH Regulation Art. 31.1
*Duty to communicate safe use information or responding to customer requests -REACH Regulation Art. 33

=== Crystalline silica ===

Amorphous high-temperature mineral wool (AES and ASW) is produced from a molten glass stream which is aerosolized by a jet of high-pressure air or by letting the stream impinge onto spinning wheels. The droplets are drawn into fibers; the mass of both fibers and remaining droplets cool very rapidly so that no crystalline phases may form.

When amorphous high-temperature mineral wool is installed and used in high-temperature applications such as industrial furnaces, at least one face may be exposed to conditions causing the fibers to partially devitrify. Depending on the chemical composition of the glassy fiber and the time and temperature to which the materials are exposed, different stable crystalline phases may form.

In after-use high-temperature mineral wool [[crystalline silica]] crystals are embedded in a matrix composed of other crystals and glasses. Experimental results on the biological activity of after-use high-temperature mineral wool have not demonstrated any hazardous activity that could be related to any form of silica they may contain.

== Substitutes for mineral wool in construction ==
Due to the mineral wool non-degradability and potential health risks, substitute materials are being developed: [[hemp]], [[flax]], [[wool]], [[wood]], and [[cork_(material)|cork]] insulations are the most prominent. [[Biodegradability]] and health profile are the main advantages of those materials. Their drawbacks when compared to mineral wool are their substantially lower mold resistance, higher [[combustibility]], and slightly higher [[thermal conductivity]] (hemp insulation: 0.040 Wm{{sup|-1}}k{{sup|-1}}, mineral wool insulation: 0.030-0.045 Wm{{sup|-1}}k{{sup|-1}}).<ref>{{Cite journal| doi = 10.1515/lpts-2015-0004| issn = 0868-8257| volume = 52| issue = 1| pages = 38–51| last1 = Lekavicius| first1 = V.| last2 = Shipkovs| first2 = P.| last3 = Ivanovs| first3 = S.| last4 = Rucins| first4 = A.| title = Thermo-Insulation Properties Of Hemp-Based Products| journal = Latvian Journal of Physics and Technical Sciences| date = 2015-02-01| bibcode = 2015LatJP..52a..38L| doi-access = free}}</ref>

== See also ==
* [[Asbestos]], a mineral that is naturally fibrous
* [[Basalt fiber]], a mineral fiber having high tensile strength
* [[Glass wool]]
* [[Pele's hair]]
* [[Risk and Safety Statements]]

== References ==
{{Reflist|30em}}

== External links ==
{{Commons category|Mineral wool}}
{{NIE Poster|Wool, Mineral|{{PAGENAME}}}}
* [http://dsp-psd.pwgsc.gc.ca/Collection-R/Statcan/44-004-XIB/44-004-XIB-e.html Statistics Canada documents on shipments of mineral wool in Canada]
* [https://web.archive.org/web/20110726130818/http://www.iom-world.org/pubs/IOM_TM1101.pdf Review of published data on exposure to mineral wool during installation work] by A Jones and A Sanchez Jimenez, [[Institute of Occupational Medicine]] Research Report TM/11/01
* [http://www.iom-world.org/pubs/IOM_TM8718.pdf Assessment of airborne mineral wool fibres in domestic houses] by J Dodgson and others. [[Institute of Occupational Medicine]] Research Report TM/87/18

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[[Category:Building insulation materials]]
[[Category:Materials]]