keratin protein
ChemistryWool is specified as keratin protein. Density band ~1.31 g/cm³.
Darker cells mean a higher score for this topic on that metric.
Strength32
Heat resistance38
Fire performance48
Insulation72
Workability70
Circularity58
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Last reviewed Sources & creditsMedia creditsMethodology
Quick answers
Is Wool non-combustible?
Declared reaction class in this atlas: better than commodity synthetics in many apparel tests. Assemblies still need resistance tests.
Does Wool insulate?
Thermal mark 72/100 versus the atlas. Conductivity note: low when lofted.
What is the density band?
~1.31 g/cm³
How is it made?
Origin story: Neolithic sheep; merino Spain; industrial Yorkshire (Near East → Spain → Australia).
Can it be recycled?
Circularity mark 58/100 — editorial, route-specific.
Typical melting or failure heat?
chars; does not melt-drip like PE
heat 38 · fire 48
What holds Wool together is not the nickname. Formula keratin protein, density ~1.31 g/cm³.
Meters are atlas-relative. Grades are the SKUs buyers write.
Phases
Microstructure
OrderProcessing sets grain, crystallinity or fibre orientation — the reason two lots of Wool can test differently.
Interfaces
SurfacesCoatings, oxide films, sizings or paper faces often decide weather and fire behaviour more than the bulk brochure.
Defects
FlawsInclusions, voids, knots, pinholes or residual stress start the failures that mill certificates do not list.
Grades
VariantsWool is a family. Grade names below are the ones buyers actually write on RFQs.
Ageing
TimeMoisture, UV, creep, hydrogen or carbonation shift properties in service. Design to the aged state.
Relative meters
Strength32
Strength is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Heat envelope38
Heat envelope is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Fire behaviour48
Fire behaviour is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Insulation72
Insulation is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Workability70
Workability is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Circularity58
Circularity is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Grades
Fine merino <18 µm
Next-to-skin.Next-to-skin.
Medium 21–24 µm
Suiting.Suiting.
Crossbred
Carpets, knit outer.Carpets, knit outer.
Lambswool
First clip softness.First clip softness.
Recycled wool
Shoddy / mungo tradition.Shoddy / mungo tradition.
Bonds
Primary bonding
Wool holds together by covalent chain chemistry.
Secondary forces
Hydrogen bonds, van der Waals stacks or grain-boundary cohesion set toughness and moisture uptake.
Composites & fills
Fillers, fibres, plasticisers or aggregates are part of the real product, not impurities.
Environment film
Oxides, chars, sizings or paints are the layer the world actually meets.
Change the grade, the coating or the moisture and you have a different material with the same English name.
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