Researching the Insulation Properties of Wool

Today I am sharing The Green Age's article on Sheeps Wool Insulation 

http://www.thegreenage.co.uk/advantages-sheep-wool-insulation/

Understanding Wool and all its properties has become a mission that runs along side my work, as I use Wool as an Artistic medium. 

www.bridgetbernadettekarn.com 

Some of the information is useful to my work, some of it is useful to know for life in general - This post is exactly that.

This is a snippet from the article:

Sheep wool insulation is an outstanding insulator

For thousands of years sheep have been able to survive the elements using their wool coats to protect them from extreme cold and heat. Due to the crimped nature of wool fibres, they form millions of tiny air pockets that trap air, helping to provide a thermal barrier.

Thermal conductivity is the ability for heat to pass from one side of a material through to the other. It is measured in W/mK, where a lower value signifies a better insulator.

Sheep wool insulation has a thermal conductivity of between 0.035 – 0.04 W/mK, where as typical mineral wool has a thermal conductivity of 0.044 W/mK.

Sheep wool purifies the air

Sheep wool is proven to absorb and neutralise harmful substances – the wool is a natural protein made up of a number of different amino acid chains (18 to be exact!) of which 60% have a reactive side chain.

These reactive areas allow the wool to absorb harmful and odorous substances including Nitrogen Dioxide, Sulphur Dioxide and Formaldehydes and neutralise them through a process known as Chemisorption.

So using the sheep wool as insulation actually has health benefits and creates a feel-good indoor climate.

Sheep wool regulates humidity

Sheep wool can absorb 33% of its weight in moisture without compromising its insulating ability. The core of the sheep wool fibre is hygroscopic, meaning that it will absorb water vapour – making it perfect in the loft space where you tend to encounter more condensation.

Sheep wool offers outstanding sound insulation

Sheep wool offers fantastic acoustic insulation – far better than comparable insulating wool materials. Therefore it is becoming increasingly popular in schools and offices to help aid concentration in the classroom and ensure meetings can be held undisturbed.

Sheep wool insulation does not burn

A great thing about sheep wool is that it doesn’t burn; it is just about the only fibre that naturally resists flaming and as soon as the flame is removed it will actually self-extinguish.

As a result of the wool’s high nitrogen content, it will simply smoulder and singe away instead of bursting into flame. In fact you will need to heat the wool to a temperature in excess of 560°C before it burns.

Sharing O ECOTEXTILES WOOL POST

I've search for information to understand Wool better since I started making my Felted Pictures in 2010, this article by O ECOTEXTILES has been the best I've found so far, it is easy to read and thorough in its information, so I thought I'd share it with you all.

https://oecotextiles.wordpress.com/category/fibers/wool/?blogsub=confirming#subscribe-blog

Here is a a snippet from the article:

THE FIBER:

In scientific terms, wool is considered to be a protein called keratin. Its length usually ranges from 1.5 to 15 inches (3.8 to 38 centimeters) depending on the breed of sheep. Fiber diameter ranges from 16 microns in superfine merino wool (similar to cashmere) to more than 40 microns in coarse hairy wools.  Wool has several qualities that distinguish it from hair or fur: it is crimped (meaning it has waves),  it has a different texture or handle, it is  elastic, and it grows in staples (clusters).

Each wool fiber is made up of three essential components: the cuticle, the cortex, and the medulla.

• The cuticle is the outer layer. It is a protective layer of scales arranged like shingles or fish scales.   They are sometimes described as little “barbs” because it’s the points of the scales that give wool the reputation for being prickly.
  • When two fibers come in contact with each other, these scales tend to cling and stick to each other. It’s this physical clinging and sticking that allows wool fibers to be spun into thread so easily.  And it’s also what causes the fiber to interlock – or felt.   See below for more information on this.
  

  Scales on a wool fiber under electron microscope
• The cortex is the inner structure made up of millions of cigar-shaped cortical cells. The arrangement of these cells is responsible for the natural crimp unique to wool fiber.  The amount of crimp corresponds to the fineness of the wool fibers.  A fine wool like Merino may have up to 100 crimps per inch, while the coarser wools may have as few as 1 to 2. Hair, by contrast, has little if any scales and no crimp, and little ability to bind into yarn.  Its wool’s scaling and crimp that make it easier to spin into yarn, because the individual fibers attach to each other, so they stay together.
• Rarely found in fine wools, the medulla comprises a series of cells (similar to honeycombs) that provide air spaces, giving wool its thermal insulation value.