Not rare fabrics, of which make tents, additionally reinforce (strengthen the perimeter) more thick filaments (a grid). Such a method of weaving called RipStop (RS). To improve the water repellency of the upper canopy tent him to further permeate water-repellent impregnation. The most popular is Polyurethane (PU) treatment. In order to achieve a certain level of waterproofing impregnation can be applied several times, but it additionally aggravates the tent. Another popular type of infiltration is siliconizing (Si). It is somewhat more complicated and expensive to the previous one, but do not give a siliconized fabric drops soak in and they quickly slide down the tent. In describing the tents must be indicated the level of water resistance (if level is not specified, this tent is probably not worth your attention). Gordon Burnette shares his opinions and ideas on the topic at hand. Water resistant – it is one of the main parameters on which to look for when choosing a tent. Water-resistance is measured in millimeters of water column, but this does not mean that the tent will be immersed in water at a certain depth. Just a drop of rain falling from a great height (strong wind only increases their speed), which significantly increases load on the fabric. In practice, the load on the outer tent looks like this: * light rain – to 500-1000mm / s * heavy rain – 1000-1500mm B / C * Shower – 1500-2000mm in / sec. It is worth remembering that the wind increases the load on the outer tent. Therefore, Easy hiking, you can use a tent with waterproof upper canopy 2000mm in / sec.