Is 5000mm waterproof enough?
If you are out for a day in the mountains, you should look for your main waterproof to be rated 5000mm or higher, and most good waterproofs will be around 10,000mm, the highest being around 20,000mm for the wettest conditions. A lower rating means the water will eventually get through if the rain is heavy.
5,000mm or 5 metres (16.4 ft) is how far you could fill the tube before it would start to leak through the fabric. So in theory, you could stand out in the rain until 5,000mm of rain fell before you would start getting wet. The second number relates to how breathable the coat is.
A rating of 5000mm to 10,000mm is suitable for just about all weather conditions but equally at home in lesser ones, great for walking the dog or a serious trek in bad conditions. These higher rated jackets will also be breathable.
Clothing rated between 5,000 mm and 10,000 mm (10k) is a good choice for riders who spend long days out and ski or snowboard in any weather conditions. Avid skiers and snowboarders, especially those in wetter climates, should look for waterproof ratings in the 10,000 mm to 20,000 mm range or better.
We recommend a minimum waterproof rating of 5,000 mm for ski and snowboard outerwear. If you ride primarily in cold and clear conditions and take regular lodge breaks this level of protection could be fine, but anything less and you stand a good chance of getting wet and cold in a storm.
Original GORE-TEX products offer guaranteed waterproof, windproof, and breathable protection. So if your heart rate is going to rise and a strong wind and rain are forecast, some GORE-TEX Invisible Fit footwear and a jacket made with GORE-TEX SHAKEDRY™ product technology could be just what you need.
While the Gore-Tex membrane belongs to the “waterproof” category and is therefore perfectly suited for extreme weather conditions, Gore-Tex-Infinium belongs to the “water-repellent” category. It is therefore very much suitable for everyday use, while Gore-Tex is more suitable for everyday use and everything beyond.
The minimum standard for a jacket to be waterproof is 1,500mm so a jacket with a waterproof rating of 2,000mm would be suitable for moderate rain. See our Waterproof Jacket Guide for more details.
A Hydrostatic Head of 5000mm means that a tent fabric could hold a column of water that is 5000mm tall. 5000mm of water exerts more pressure on the material than a 3000mm of water, so a more accurate description of Hydrostatic Head is the measure of water pressure equivalent to a column of water that is 5000mm tall.
The HH ranges from 1,000mm to 10,000mm; the higher, the more waterproof fabric. 1,000mm is the minimum legal requirement in the UK, but most tents start from 2,000mm. Groundsheets have a higher HH rating from 3,000mm due to the constant contact with the ground and footfall.
What mm is Gore-Tex waterproof?
The higher the number, the more waterproof the item will be. Gore-Tex®, for example, has a waterproof rating of 28,000mm.
In the case of a 10k or 10,000 mm fabric, if you put a cylinder with inner dimensions of 1” x 1” over a piece of said fabric, you could fill it with water to a height of 10,000 mm (10m) before water would begin to leak through.
The tube is filled with water, and the water's height in millimeters when leakage begins becomes the waterproof rating. A piece of fabric that can withstand 20,000mm of water pressure will have a rating of 20,000mm or 20K.
10k waterproofing: A decent rating and the minimum you would want to wear for several hours on the slopes each day. Ski clothing with this rating will keep you dry for a good 2-3 hours in the event of snow.
Water resistant is best. You want a breathable jacket or you will build up moisture from sweat. That's why most jackets use materials such as Goretex or variants, as it's water resistant but breathable. If it doesn't breathe you would get wet and clammy, which would be cold.
Gore-Tex isn't forever
Even powerful Gore-Tex has a lifespan. For people that use their gear daily, this lifetime can range from three to five years while those who use less frequency can get close to 15 years out of their garments.
No airflow through to the shoe to exchange humid internal air with dry external air; and, A soaked exterior fabric that was choking the transmission of internal moisture through the waterproof-breathable membrane.
The best-known such fabric is Gore-Tex, a breathable waterproof fabric invented and trademarked by the Gore family in 1969 that replaced the typical inner layer of waterproof clothing, usually made from polyurethane, with a thin, porous fabric.
In the simplest sense, a waterproof jacket offers the highest level of protection from rain and snow. While a water-resistant jacket offers a good, but lower level of protection. Though there's a little more to it than that.
A waterproof jacket should fit snugly without restricting your movement. When trying one on, move around: jump up and down, wave your arms around, and twist your body. You want to make sure you have full range of movement available to you.
Why is Gore-Tex not waterproof?
Waterproofing a Gore-Tex Jacket will eventually be required because despite the inner layer being a breathable waterproof membrane, the outer layer (shell) of the jacket will lose its waterproofing, soak up water and stay wet, blocking the effect of the Gore Tex.
The most sustainable GORE-TEX alternative fabric is waxed cotton. Waxed cotton is exactly like it sounds: wax (typically beeswax or linseed) is applied to cotton, giving the cloth a hydrophobic coating.
Gore-Tex is a highly breathable waterproof material to keep you from getting too hot. The Gore-tex lining does make them somewhat less breathable (thus a little warmer). I still wear them all year round, and if you are doing any extended hikes where you need dry feet, waterproof is more important than cool.
If a fabric was described as having a 2000mm waterproof coating it means that there would need to a column of water 2,000mm tall sitting on this fabric before would pass through it. In the case of a tent, a 2,000mm waterproof rating would be sufficient to keep you dry in a wide range of conditions.
As an example, a Hydrostatic Head of 1000 is the legal requirement to call a tent 'waterproof' so most start at 2000. 2000-3000 should cope with your standard British rainfall well enough; the higher the hydrostatic head, the better the water protection you have from your tent.
You may notice the letters PU before or after a given waterproof rating. These letters indicate that a polyurethane waterproof coating has been applied to the inside of the tent fabric. Rightline Gear's tent fabric is rated at 2000mm PU, twice the minimum rating.
5,000 mm – If you are looking for a cheap waterproof jacket then this would be the minimum recommended hydrostatic head. 10,000 mm – Many lightweights but high-end jackets will be rated at this level, which is good enough to block heavy rain.
There's no internationally recognised standard of what specific rating 'waterproof' is, but 1500mm is widely accepted as being the minimum to be deemed waterproof and able to handle most rain conditions.
To summarise, and help you choose your new tent, a general rule is that a good quality tent with a 1500 – 3000mm waterhead rating on the tent fly, along with a 6000mm+ rating on the floor or one made from durable polyethylene or PVC, is going to keep you sheltered and dry in all but the absolute worst of conditions.
The level of waterproofing depends on the requirements and design purpose of the jacket. As a rule of thumb guide an hydrostatic head of 3000 is decent waterproofing, however if the jacket is used with a rucksack a much higher value will be needed.
How much rain can a tent withstand?
Beyond 1-inch-per-hour rainfall, the "falling force" of rainfall does not increase substantially, because raindrops break up after reaching a certain size, limiting the force they apply to tent fabric. This force is what can cause water to pass through the fabric and coating.
50m - Water resistant up to 50 meters means it can withstand swimming and cold showers. Hot showers are different as hot water would allow the watch to expand and potentially allow water to get in.
To summarise, and help you choose your new tent, a general rule is that a good quality tent with a 1500 – 3000mm waterhead rating on the tent fly, along with a 6000mm+ rating on the floor or one made from durable polyethylene or PVC, is going to keep you sheltered and dry in all but the absolute worst of conditions.
The minimum standard for a jacket to be waterproof is 1,500mm so a jacket with a waterproof rating of 2,000mm would be suitable for moderate rain.
A Hydrostatic Head of 5000mm means that a tent fabric could hold a column of water that is 5000mm tall. 5000mm of water exerts more pressure on the material than a 3000mm of water, so a more accurate description of Hydrostatic Head is the measure of water pressure equivalent to a column of water that is 5000mm tall.
