The single-wall tent as a starting point
The majority of tents are designed with double walls, i.e. two fabrics separating the tent's interior from its external environment. Samaya was born of the conviction that the evolution of the single-wall tent was the key to revolutionizing bivouac equipment for a wide range of uses. Offering single-wall tents optimized for waterproofing, breathability and air permeability became an obsession for the Samaya R&D team.
With the right materials, this single-wall design offers the advantage of a significant reduction in weight and folded volume, since single-wall tents by definition require less fabric than double-wall tents. Single-wall tents also offer better resistance to wind and weather, thanks to the greater solidarity between the various tent elements and the balloon effect observed in windy conditions, which increases the pressure on certain parts of the tent. Depending on the conditions, ease of erection and dismantling can prove invaluable.
Waterproofing
Waterproofing requirements are different for a jacket than for a tent.
Unlike a jacket, there is no friction or pressure exerted directly on the walls of a tent. The equivalent water column generated by a very heavy rainfall without friction is 2,000 to 3,000 mm[1]. An impermeability of 10,000 mm is therefore more than sufficient for the wall. On the other hand, high impermeability is essential for the floor, due to the pressure exerted by the weight of the individual. That's why most of the floors in our 4-season tents have a waterproof rating of 20,000 mm.
[1] The millimeter of water column, also known as Schmerber, is a unit for measuring the water impermeability of textiles. The value associated with mm of water column is obtained by carrying out a waterproofness test in accordance with ISO811. This test involves continuously increasing the pressure exerted by water (in other words, increasing the intensity of the rain) on a textile. When the water passes through the textile, the pressure value is recorded and the associated millimeters of water column calculated. This value corresponds to a fabric's impermeability limit.
Air permeability
We distinguish between two phenomena:
Pressure-driven air renewal: this corresponds to the flow of air through the fabric under a certain pressure. For example, if it's windy, a slight, imperceptible flow of air enters the tent. This outside air, normally composed of oxygen, replaces the air inside the tent, which has been depleted of oxygen by the user's breathing.
Air renewal through diffusion: diffusion is a natural phenomenon in which particles and materials spread out, become uniform and homogenize. It occurs either when there is a change in temperature or material concentration, or when two different levels of temperature or material concentration meet. Diffusion can occur when there are no obstacles to the transport of particles from one medium to another. Users breathing inside their tent inevitably reduce O2 concentration and increase CO2 levels. Only a tent with air-permeable walls enables air renewal through diffusion, continuously balancing the O2 concentration inside the tent.
Breathability
Breathability refers to a fabric's ability to evacuate water vapor. Water vapor is generated by breathing, since we produce 800 mL of water in 24 hours. What's more, as the temperature drops, the relative humidity of the air rises: fewer H2O molecules are stored in the same volume of air (Mollier diagram)[1].
When relative humidity reaches 100%, the air is totally saturated. Water vapor from breathing condenses and forms droplets. The breathability of a fabric helps to evacuate water vapor, thus limiting condensation. The rise in temperature in the tent due to the presence of humans, and the conservation of this heat, also enable more humidity to be conserved in gaseous form, facilitating its evacuation to the outside.
[1] If we compare the size of an air/water molecule in the nanometer range with that of liquid water in the millimeter range, liquid water is 100,000 times larger than the air/water molecule.
Samaya technology developed for the tent
Nanovent®
Designed to provide waterproofing, breathability and air permeability in the tent, the Nanovent® membrane consists of a random interweaving of polyurethane filaments whose size is nanometric (1 billion times smaller than 1 meter). By managing the density of the electrospun interlacing, the membrane's pores are dimensioned to be too small to let drops of water through, but large enough to let air through. Nanovent® technology ensures unprecedented waterproofing.
This electrospun membrane is combined with two layers of nylon. The inner layer is a hydrophilic nylon which, when condensation occurs, diffuses water over a large surface area, enabling it to dry more rapidly. The outer layer is a water-repellent nylon (water-repellent treatment), allowing water to flow smoothly over its surface. These layers ensure the fabric's mechanical strength and the protection of the electrospun membrane. This 3-layer laminate is used on the walls of ALPINE and 8K range tents.
The role of the membrane and the three main membrane families
Membrane fabrics bring together these three characteristics, which are essential for the efficiency of a single-wall tent. A membrane is a thin structure, relative to its size, which separates two media, preventing all or part of the material from passing from one to the other, depending on the width of its pores and its thickness. The membrane acts as a filter to guarantee the waterproofing, air permeability and breathability of the single-wall tent.
There are three main families of membranes with specific properties:
To optimize the use of single-wall fabric, Samaya relies on its Nanovent® technology, developed specifically for tents, to meet the challenges of waterproofing, air permeability and breathability.
