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Fire and Heat

One of the most important advantages conferred by wool clothing relative to synthetic garments is wool's greater relative resistance to fire and heat.

Wool does not melt, and although it does burn, it is classified as non-flammable because it requires more oxygen than is present in the atmosphere to ignite.  Wool will only burn at a much higher temperature than the temperature that will melt synthetics, which are infamous for melting onto skin and into wounds.

“Wool burns with a self-extinguishing flame and produces a soft ash that dissipates and will not lodge in open wounds,” says Jeanette M. Cardamone, a chemist at the United States Department of Agriculture Agricultural Research Service Eastern Regional Research Center (ERRC) in Wyndmoor, Pennsylvania. “Synthetic materials, on the other hand, form hot, molten beads that can drip into a wound and cause trauma.”

The following summary is shamelessly copied and pasted from the "Flame Resistance" page of the website of the International Wool Textile Organization.  

Because of the way the wool fibre is structured, wool requires more oxygen than is available in the air to become flammable. Wool is accordingly an excellent fibre when it comes to fire safety. Furthermore, it does not melt, drip or stick to the skin when it burns. 
Of the commonly used textile fibres (cotton, rayon, polyester, acrylic and nylon), wool is widely recognised as the most flame resistant. Wool’s fire resistant attributes include:
  • A very high ignition temperature of 570-600° C
  • A high Limiting Oxygen Index (LOI) (the measure of the oxygen level needed to sustain combustion)
  • A low heat of combustion (the measure of the amount of heat energy released in the burning process)
  • Does not melt or stick
  • Self-extinguishing
Wool’s inherent fire resistance comes from its naturally high nitrogen and water content. Because of these, wool requires higher levels of oxygen in the surrounding environment in order to burn. Wool may be ignited if subjected to a significantly powerful heat source, but does not normally support flame, and will instead smoulder – usually only for a short time. In addition, wool’s cross-linked cell membrane structure will swell when heated to the point of combustion, forming an insulating layer that prevents the spread of flame. This also means that wool produces less smoke and toxic gas than synthetic fibres.

 

GREAT THANKS TO THE IWTO for the preceding information.

This study by the United States Forest Service explains why fire fighters are prohibited from wearing synthetic base layers ... Only natural fibers are allowed because of the burns caused by melting of synthetics.  As of mid-September, 2018, a firefighter and film maker for the US Government has begun wearing and testing WeatherWool (he chose an Anorak) and we are really looking forward to his feedback and I am guessing he will become an Advisor after he's been out in the wool for a couple of months.

Another one of our customers is a hobby blacksmith. He surprised me saying he wears WeatherWool in his foundry ... but it shouldn't have ... the wool is indifferent to sparks, it won't melt, it won't burn under shop conditions, it handles embers far better than synthetics, and it insulates him from the radiant heat of the hot metal.

14 September 2018