The term Vapex is used in several different areas, but in the present text this is about the tent materials. This is a very breathable yet water repellent material.
The meaning of the word Vapex
If you search for this term, you will see it written as VAPEX and the meaning of this abbreviation is ‘vapor extraction’, you can see more about this here.
But in the context of tent materials, the word is used as Vapex, and the meaning is the following – this is a special high-precision membrane created by hydrophilic polyurethane. So you have it attached to the fabric and it allows for the molecules of water vapor to go out, while at the same time the liquid water from outside cannot pass in the opposite direction.
So from this description, you realize that you have something similar to a Gore-Tex membrane which works on the same principle.
Why does it work as described
This is because of the difference in size between the water vapor molecules and the water droplets. On the other hand, the Vapex membrane has pores of a certain size – how big seems to be a business secret. In the Gore-Tex membrane, you have pores that are roughly 20000 times smaller than a water droplet yet 700 times larger than a water vapor molecule. So you get the idea.
But Vapex is not used for rain flies so there must be differences in the size of pores. My guess is that the pores are not small enough and the material isn’t waterproof.
So where is it used
The Vapex film apparently creates a very consistent and quality laminate with a great durability. Here are some data I found about its permeability performance, dependent on the fabric used in the combination:
- Polyester Fleece/Vapex/Polyester Fleece: 1050 g/m²/24h.
- Woven Nylon/Vapex/Nylon Tricot: 850 g/m²/24h.
So as you realize, in these examples, the Vapex membrane is sandwiched between two other fabrics, but there are other ways of using it. In general, this is an extremely breathable and lightweight material.
In the tent industry, the only example currently known to me is the Arctic Oven 12 tent which you see in the picture below, and in some other tents from the same brand. Note, the number 12 is the size in feet, not the number of users of this tent.
So here you have the inner tent wall made of the Vapex and the orange fly is something else (a urethane coated oxford nylon).
You will hardly find anything better for Arctic use, but this tent has been used everywhere and it has performed well even in California. No doubt this is due to its Vapex material in the inner tent. Please see more in this nice video.
So, thank you for reading. If you have some questions regarding tents, please check on my FAQ page above. Otherwise, please use the comment box below. Have a nice day.