News
	March 2008:  Latitude introduces a new electric power tool to cut wool insulation. This will make the install process much faster, simpler and more effective. For more information see the installation section.

Wool Fibre

Wool is an extremely complex protein, evolved by nature over millions of years for the protection sheep through the world in a great variety of climates and conditions as shown in the map below. 

Global distribution of sheep

Unsuitable for Ruminants				Sheep
		Unsuitable		<1		20-50
				1-5		50-100
				5-10		100-250
				10-20		250+
All densities are in heads per km2

 

 

 

 

 

Natures design

The qualities that make wool so useful are genetically built into every fibre on the sheep.

Strong and resilient

Wool fibre is so resilient and elastic that it can be bent 30,000 times without danger of breaking or damage.  Every wool fibre has a natural elasticity and wave or crimp that allows it to be stretched as much as one third and then spring back into place. Wool fibres are resistant to abrasion and can be bent and twisted many times without damage, making it an ideal choice for heavy duty needs such as carpets in hotels and banks. Inside every fibre is an inner core of long spindle shaped cells which are responsible for making the wool stretchy and strong.  A wool fibre when dry can be extended by about 30 percent.  This resilience and natural elasticity makes it excellent for insulation as the wool fibre enadeavours to mainatin is loft and elasticity. 

Wool “breathes”

In cross section , each wool fibre consists of a two part outer layer and an absorbent core.  It is this outer layer that regulates wool’s dual ability to repel liquid yet absorb moisture. If you could look at a single wool fibre under a microscope you would see that it has a thin porous sheath covering overlapping scales that act like tiny roof tiles. These “scales” cause liquid to bead and roll off the surface of the wool fabric, repelling moderate rain and spills.  But wool absorbs moisture vapour ( such as air humidity or perspiration) through the porous coating over the “scales”. Through this unique arrangement, wool can absorb up to 30 percent of its own weight in moisture – without feeling clammy. Damp wool fabric remains absorbent and comfortable inside because its outer surface releases this moisture through evaporation. Although shorn wool is no longer “alive” and growing, it does retain the unique lifelike action of its thirsty centre cells and always striving to stay in balance with the surrounding moisture conditions.  This is why wool is said to “breathe” as it absorbs and evaporates moisture.

Bundles of fibres

If you marked off an area one centimetre square on the back of a Romney sheep and counted the wool fibres on it, you would find about 5,600.  On a Merino sheep, which has fine wool, you would find about 24,000 fibres per square centimetre.  In total, a sheep’s fleece contains between 10 and 50 million fibres depending on the breed. These fibres grow in tufts called staples.  A staple is a bundle of some thousand fibres, each bundle separate from its neighbour. The shape and size of the staple varies between sheep.  In Merinos it is blunt ended, while coarser-wool sheep have a tapering staple.  Within an individual fleece there is also a considerable variation amongst staples. All these staples are kinked from end to end in a regular wave pattern, commonly referred to as crimp.  Generally speaking, the finer the wool, the smaller and tighter the crimp.  Because of this crimp. The true fibre length within the staple is greater than the actual staple length.

Insulation

The crimp in the fibres makes them stand apart from each other, as a result little pockets of still air are trapped between the fibres.  This lining of air trapped inside the fabric acts as an insulator – still air is one of the best insulators found in Nature.

 

It is not surprising then that no man made fibre has ever been able to copy everything in Nature’s original design of wool.

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