Basic knowledge of how to deal with rainwear


Basic knowledge of rainwear


Water resistance

The structure of our waterproof products is such that rain is prevented from passing through by coating the back surface of the fabric with water-resistant material. Furthermore, water-resistant tape on the back of seams stops absorption of water. (Some welder products do not need this feature.) The official term for water-resistance is water pressure resistance.
*Waterproof materials prevent water from penetrating clothing, but since the inside of the clothes does not breathe well, it gets humid and steamy as you sweat.

Water repellency

The mechanism of water repellency is that water is repelled by covering each and every fiber with water repellent material (made of silicone resin・fluorine resin) which makes it hydrophobic. Since it has tiny spaces between folds, it is breathable. However, after long-term use, there will be a decrease in efficiency, so please use a waterproof spray sometimes.


If you cover your body with waterproof materials, it gets humid inside due to perspiration. Moisture permeability (breathability) is the ability to prevent rain from penetrating, while at the same time releasing sweat and vapor. It is measured by grams of water permeated per square meter in 24 hours. A standard amout of perspiration per hour is ; for a resting adult, 50g, during light exercise, 500g, and during hard exercise, as much as 1000g.