ALL ABOUT WATERPROOF FABRICS

Long gone are the days of Burberry, Ventile and Gabardine. Where once these fabrics were de rigeur, now the name Gore-Tex reigns supreme in the world of waterproof outdoor clothing – or does it?

Elsewhere on the Paddy Pallin Blog we talked about Choosing a Waterproof Jacket. In this article we’re embracing our inner ‘tech nerd’ and exploring how and why these fabrics keep you dry and outdoors longer.

The last 10 or so years, have seen a number of outstanding new fabric technologies emerge to compete with or even out do Gore-Tex, as the “best” solution to keeping us dry and comfortable in the outdoors. Fabrics such as eVent, Polartec Neoshell, HyVent from The North Face, and Marmot’s Membrain are just a few of the more popular options. What sets apart all of these fabrics from each other is their differing ability to keep us dry and comfortable in a wide variation of activities, from light drizzle through to driving monsoonal rain.

The main purpose of a waterproof jacket (or what we often call Hardshell/Shell in the outdoor industry) is to protect us from those nasty outside elements – water and wind, but at the same time allow us to remain comfortable whilst wearing them. This comfort is heavily dependent on the shells’  “breathability” (the ability of the garment to allow our sweat to escape). All of today’s good jackets will keep out wind and water, however, the best jackets will not only stop water and wind, but will also transport our sweat outside of the jacket efficiently. But how do they manage to do this?

Basically modern waterproof/ breathable jacket (WPB ) fabrics are broken down into a few types:

Micropourous Coatings or Membranes: ( PTFE ) polytetrafluoroethylene and (PU ) Polyurethane. These materials are constructed as such that the fabric contains  billions of holes per square cm and act as a filter, using surface tension, they inhibit water penetration but allow water vapour through. Think of it as being similar to stretched Teflon. Because oils from our body, sunscreen, funk, etc have low surface tension, they will invade the membrane and inhibit the pores from keeping out water, so most PTFE membranes ( such as Gore-Tex ) are now coated to stop these contaminants. However it reduces the breathability to a degree, but increases the overall durability of the membrane. The original Gore -Tex is the most widely recognised type of this fabric technology.  This original Gore-Tex without the protective coating was extremely breathable however over time tended to leak. Other examples of these types of membranes are: eVent and Polartec NeoShell.

How the layers of Gore-Tex, eVent & NeoShell function. Source: Outside Online.

Continuous Hydrophillic Coating or Membrane: These fabrics contain a microporous structure and are manufactured by using a hydrophilic ( water loving ) coating. They manage to move vapour away by a process called molecular wicking, which works by absorbing water molecules to the surface of the hydrophilic material and then passing along to the next molecule, which keeps going along throughout the thickness of the film. Garments made from these fabrics tend to be slightly less breathable than PTFE style fabrics ( Gore Tex and eVent ) and their breathability is heavily dependent on temperature.  Where they excel is in cold conditions hovering just above 0c. Examples of this fabric can be seen in Marmot’s Precip and NanoPro style garments, and also The North Face’s HYvent series. These style of garments also tend to be lighter and more packable.

Bicomponent Micropourous and Hydrophilic Laminates: Modern Gore Tex is made from this. It is PTFE , and the pores are filled with hydrophilic polyurethane. This results in a much greater durability, and very hydrophilic polyurethane can be used.

There are a few other construction methods, however the above represent the majority utilised in the high end brands of jackets.

Factors influencing a jackets performance:

DWR: Durable Water Repellancy

The DWR is perhaps one of the most important factors of a garments continued breathability and capacity to keep you dry and comfortable. Basically a DWR is a coating that is applied to the outside of the fabric (either fluropolymers, silicones or hydrocarbons), that increases the contact angle or surface tension of the fabric when water comes in contact with it. This causes the water to bead and to simply roll off your garment, instead of allowing it to flatten and seep into the fabric. All jackets are treated with this DWR layer when made, however over time with use it will wear away. Abrasion, oils and dirt will all degrade the DWR, and as such it will need to be re-applied at intervals all determined by how often you use your garment and how well you care for it. Once the DWR has been worn away, the garment will be less breathable and also may “wet out” – a term that basically means that the face fabric will absorb water. This will severely hamper the fabrics ability to transfer away moisture from the jacket.

Even though your garment will still be waterproof, its ability to remove your sweat will be diminished significantly and you may think that the jacket isn’t waterproof anymore, or that it is leaking. What actually is happening is that the water vapour is condensing back into liquid when it hits a wet face fabric.  Products such as Nikwax  TX-Direct and McNett Revivex are examples of reproofing DWR products. A more in-depth article on how to care for your Rain Jacket will come next week.

An example of two very similar Gore-Tex Active Shell Jackets – On the left a brand new jacket with robust and effective DWR, on the right a jacket that’s been heavily used for several months with a face fabric that is starting to wet-out slightly.

Waterproof Ratings

Every waterproof jacket you buy, will most likely come with some sort of waterproof rating, which simply put is a guide to how well and long the jacket will keep out the water. Fabrics are tested using a Hydrostatic Head ( HH ) tester – a machine that determines the resistance of fabrics to water penetration under pressure. The fabric is placed around the bottom of a cylinder, then water is added until it leaks through the fabric. The machine measures the “head” (pressure) of water that can be applied to a fabric before water penetration is observed. The minimum standard to call a fabric “waterproof” is 1000 mm HH, and over a period of 24hrs. There are many figures and claims made by companies and the outdoor academia as to what HH is required to keep all water out in normal conditions, however there is no definitive answer. 10,000 mm HH will certainly be sufficient!. Waterproof rating should be used only as a guide between  similar styled and brand garments. Many other factors such as the design, features and construction of the garment factor heavily in the overall ability to keep you dry.

Breathability

This term is probably the most often discussed feature or quality of today’s modern waterproof jacket.

When humans are active, we perspire or sweat and create a moist atmosphere inside the garment we are wearing, and as exertion/activity increases, moisture from sweat builds up inside the garment. This moisture is a problem as not only does it make us more uncomfortable, it also increases the potential to overheat whilst active, and at rest can cause us to get cold. Being wet in very cold conditions can lead to hypothermia.

So how is breathability measured? – Great question!

There are many different scientific tests carried out by various companies to measure breathability, yet unfortunately there is no universally accepted standard.  There is the RET (Hohenstein Method), the Inverted Cup Method and a few others. Hence mentioned that, one of the most commonly seen and used tests, measures the amount of water vapour in grams that can pass through a m2 of the chosen fabric in a 24hr period, simply known as MVTR ( Moisture Vapour Transmission Rate ).  The higher the MVTR, the better the breathability right?! – Unfortunately not quite always!

A garments breathability is heavily dependent on the environment. In order to breath and transfer moisture to the outside of your jacket, there must be a humidity differential between the 2 sides of the fabric. If it is more humid inside a garment , than the outside air, then naturally the water vapour will want to pass through to the outside, however if the opposite exists ( as exists in very temperate climates ), then the  breathability will be less and at times feel like it isn’t working at all. Hiking in say Tully Northern Queensland, Or in Litchfield south of Darwin or PNG Jungles (Kokoda) – will significantly slow the noticeable breathability of a garment, whereas if you are at the ski fields of the Snowy Mountains, or deep in the Wolgan Valley of the Blue Mountains during August or scrambling up to Mt Ossa in September, then your shell will breathe a lot better. The truth is that in some climates – no matter how good your jacket is, there are some conditions where it just plain won’t breathe!

Other factors than can affect the breathability of a fabric are how clean the garment is. If your jacket is dirty, and contaminated with dirt, grime, oils, etc. Then the pores that the vapour is trying to escape through will be blocked. Also, one of the most important aspects of breathability is how good the DWR (Durable Water Repellent) coating is on a garment.

Below is a list of waterproof and breathability ratings of various fabrics:

So based on the above table, what do these mean, in relation to outdoor activities?

Waterproofness Ratings:

• 5,000mm: This is where a rainproof jacket begins, however in a really horrendous downpour you’ll eventually get wet.
• 10,000mm – 15,000mm: This is where a waterproof garment becomes practical for real-world use. These jackets will withstand some pretty serious downpours of rain and well as some heavy, wet snow. However, if you subject them to pressure (like crashing in wet snow, kneeling or sitting down in the case of pants, or the pressure of a heavy packs shoulder straps & hip belt) then they’ll soak through over time.
• 20,000mm and Up: Driving rain in the tropics or the south west of Tasmania? Not an issue. Wet slushy snow in Perisher? Yep! This is the jacket you want if you’re planning on being out in all conditions, carrying a heavy load and what to know you will stay dry.

Breathability Ratings:

• 5,000 – 10,000g/m²: This jacket would work fine for resort skiing, urban travel or hanging out in camp while it’s pouring rain. However you would get pretty clammy if you had to do much hiking.

• 10,000 – 15,000g/m²: This jacket would be ok for more adventurous travel, hiking, and back country skiing. Again if your bush-bashing straight uphill, breaking trail through snow or travelling in highly humid locations you may feel a bit clammy.

• 15,000 – 20,000g/m² & above: You definitely want something in this range if you’re heading out into the hills for an extended trip, travelling through South East Asia with a plan to trek or any other trip where you can see yourself working hard and perspiring heavily.

Conclusions

Breathability is heavily influenced by the environment, activity levels, cleanliness of the garment and its DWR. Ratings are only a guide and should not be the sole factor in choosing which garment to buy. In order to maintain breathability, the garment must be cleaned and reproofed regularly. A jackets breathability has limitations: nothing will work in extremely humid, wet environments. Lighter fabrics will normally breath better than heavier ones, however won’t have the same durability long term.

TYPES OF WATERPROOF FABRICS AND BRANDS

There are many types of waterproof breathable jackets on the market. Some claim to be better than others, and some are more popular than others because of the “cool” factor and marketing hype.

The following are just a few types available. Each have their own merit, and will perform depending on the conditions the garment is used in and for.

GORE PRODUCTS (Gore-Tex) Introduced in 1978, Gore Tex led the way in the WPB market for many years with its award winning ePTFE membrane. The original Gore Tex was extremely breathable, however was quite susceptible to being degraded by oils from our body, sunscreen, grime and general funk, and it wasn’t until they bonded a PU coating to it, to stop the oils invading the membrane that then made it the leader for many years in the overall outdoor wet weather market for the qualities of waterproof/breathable plus durability. Gore has continued to pave the way as a market leader and now produces a number of different fabrics to cater to the outdoor market. Even though Gore is the most well known of the WPB manufacturers, what continues to be seen in the outdoor market is that the absolute top brands in outdoor garments continue to use Gore products as their mainstay of WPB garments.

3-layer GORE-TEX fabric with GORE C-KNIT: Uses backer technology that optimizes comfort while providing durable, waterproof and windproof protection. The reliable and proven bi-component GORE-TEX® membrane system is bonded to an extremely thin, dense yet lightweight circular knit to form a patent-pending laminate. Weighing up to 10 percent less than previous 3-layer GORE-TEX® fabric, this new laminate improves breathability by as much as 15 percent in a less bulky, more robust 3-layer construction. The smooth texture of the knit backing is soft to the touch, and makes the garment easier to slide on and off over other layers. The Arc’teryx Men’s Zeta AR and Women’s Zeta AR jackets use this technology.

GORE-TEX PRO: This laminate is used in the higher end jackets of the best leading outdoor gear brands. Designed for sustained use in severe environments and for those that abuse their jackets. It is made up of multiple layers of ePTFE bonded to the face fabric –  ( usually a high abrasion resistant denier fabric ) and a gridded backing textile. This new fabric has no oleophobic PU layer and is over 25% more breathable than the previous Pro Shell fabric. Jackets made from this fabric are ultimately very durable and reliable in the most severe conditions. The top tier offerings from Arc’teryx and Patagonia; such as the Men’s Theta AR , Men’s Pluma GTX and Women’s Pluma GTX all use Gore Tex Pro fabric in their best outerwear.

GORE-TEX: This is available in both 2 layer and 3 layer versions. The 2 layer fabric has a separate mesh style liner which drapes nice against the body and breathes well. The 3 layer is similar to the older well known XCR fabric that was around for a few years.  This version is the tried and tested laminate. It is used in everyday outdoor garments and is usually found in the more affordable range of Gore shellwear. The most used laminate in the Gore range, it still offers the same combination of waterproof and breathable attributes but at a more reasonable price than Pro. The Women’s Arcteryx Codetta Coat , Patagonia Women’s Triolet GTX and Men’s Triolet GTX jackets all use a 3-layer Gore fabric. Whilst the TNF Women’s Hyperair GTX Trail jacket and Men’s Hyperair  GTX Trail jacket use a lighter 2-layer fabric.

GORE-TEX Paclite: Pacite is ideal for exactly what the name suggests, packing light. This fabric is a 2.5 layer construction and whilst it’s waterproof ratings are solid, it’s more suited to travel and urban wet-weather gear than strenuous rough outdoor activities. The Marmot Minimalist jacket/pant and Arc’teryx Women’s Beta SL jacket all employ Paclite & are perfect for your next trip enjoying the sights, sounds and flavours of Europe for example.

Non GORE-TEX fabrics

eVENT: This 3 layer membrane is by far the biggest competitor to W.L Gore’s fabric. Similar to GORE-TEX in that it is a ePTFE, however the pores of the membrane are lined with an oleophobic and hydrophobic (oil and water hating) chemical. By doing this eVent remains air permeable. Rather than moving moisture out of the garment by means of diffusion, eVent fabric vents moisture directly to the outside of the fabric.

Some scientific tests have stated that eVent in a 30% humidity scenario is almost 200% more breathable than the best Gore-Tex fabric, and over the years since its inception, this is something many users of this fabric will attest to, however the downside to this fabric is that the membrane isn’t protected as well as GORE-TEX and requires more regular washing to maintain its high performance. If the user can look past this, eVent fabric has for many years been used in some of the best made garments from the very best brands such as RAB.

eVENT DVstorm: eVent have recently moved into offering different versions of their membrane, with varying performance specifications suitable for different types of activity or garment. An example of this is DVstorm. This 3-layer membrane is designed to be lightweight, maintain a solid waterproof rating, but offer exceptional levels of breathability. Of course a lightweight garment using DVstorm will likely be less durable compared to a traditional tougher eVent alternative. The Men’s Muztag jacket from Rab for example is an excellent full-featured but lightweight DVstorm equipped hard shell.

THE NORTH FACE HyVENT: Another proprietary branded fabric, HyVent is a hydrophilic polyurethane coated fabric. Using diffusion, your moisture /sweat is moved from your warm/moist environment inside your jacket to the cooler/drier environment outside. Made in 2, 2.5 and 3 layer fabrics. The 2 layer version uses a hanging liner to protect the PU film, whereas the 2.5 layer incorporates their own “Dry Touch ” texture which raises the coating away from the skin which gives the fabric better durability and comfort. The 3 layer is similar to most other tri-layer WPB fabrics on the market, however unlike GORE-TEX which uses ePTFE for the membrane, The North Face uses a PU coating. The 2 and 2.5 layer fabrics are seen in their ever popular 3 in 1 style Triclimate range of jackets.

Helly Tech^® PERFORMANCE: Is designed for any outdoor activity where performance is key and time in the rain is inevitable. This 2.5 layer waterproof and breathable fabric moves water away from the body efficiently, thus keeping you dry and allowing you to perform your best. The Helly Hansen Loke is perfect as an ‘occasional use’ layer for outdoor activities like climbing, skiing, adventure travel and hiking. The Men’s: Dubliner and Squamish jackets, and Women’s: Welsey Trench , Aden Long Coat and Squamish jacket , are the perfect accomplice for any urban or colder weather travel.

Patagonia H2No: The 2.5-layer H2No Performance Standard shell fabrics are completely waterproof, windproof, breathable and highly packable. Because 2.5-layer H2No Performance Standard shell fabrics are so lightweight and compressible, they’re excellent choices for backpacking, alpine climbing and backcountry skiing and snowboarding. They combine a water-repellent shell fabric with a waterproof/breathable membrane and protective top coat barrier without the need for a protective lining fabric, which makes it light weight and highly packable. Additionally a distinctive raised print layer is applied for decreased surface tension when layering and increased moisture management. 2.5-layer H2No Performance Standard shell fabrics are coated with DWR
 (durable water repellent) fabric finish that repels light rain and snow. In conjunction with a waterproof/breathable barrier, the DWR finish keeps the outer fabric from becoming saturated so that the breathable barrier can do its job. The classic Patagonia Torrentshell range uses the 2.5 layer H2No fabric.

MARMOT NanoPro: This is Marmots own 2.5 layer Micro-porous coated fabric. Another of the air permeable fabrics, Marmot’s new technology claims it to be up to 43% more breathable than their previous coating technology. Performance wise, it is similar to both Patagonia H2NO and North Face HyVent. Garments using this fabric are usually aimed towards the value conscious customer who wants a light, breathable waterproof jacket at a reasonable price. Their Precip jacket is a fantastic example of a mid-priced, well-functioning WPB jacket for everyday use.

MONT Hydronaute & Hydronaut Pro: Mont have been a stalwart for Durable, bomb-proof wet weather clothing in Australia for some time. In the past they have used other companies fabrics, but their greatest success has been won using their in-house membrane based 3L Hydronaute fabrics. Hydronaut Pro takes the already bomber foundation of the original Hydronaute & adds increased breathability for those high-output pursuits. A big part of what makes Mont outerwear so ideal for rough conditions is the face fabrics that demonstrate excellent abrasion resistance, tear strength and pinhole resistance. The Men’s Mont Austral Jacket / Pants & Womens Siena Jacket / Pants use Hydronaute. Whilst the Odyssey jacket’s use the higher performing Hydronaute Pro.

PERTEX Shield+: Pertex have been making tp quality outdoor fabrics for quite some time. Whilst they are Better known for their super light & durable face fabrics for garments like down jackets & sleeping bags, in recent years Pertex have produced a range of high performance wateproof/breathable options.Using a PU film construction, alongside fabrics with a soft hand and increased stretch the Shield+ 2.5L fabric heralds comfortable, solidly performing layers.

PROFLEX by Rab: This is something quite a bit different than all of the above options. Developed by Rab, Proflex is a new 3-layer membrane fabric that is essentially a hard-soft-shell. So what that mean’s is it’s a soft supple,highly stretchy and super breathable fabric (akin to a soft-shell right). But, it’s also got a 10,000mm HH rating. Constructed using a new propitiatory membrane sandwiched between a face fabric and lining that are knitted, not woven as is the norm. Durability, and the ability to resist wetting-out are the two obvious trade-offs.

SO WHICH JACKET IS THE ONE I SHOULD BUY?

In this day and age, realistically – there are no really bad and good fabrics. If you are purchasing from one of the top tier outdoor shops, no matter what you buy, you are going to get a garment that will keep you dry. However, as this article shows, there is a huge difference in durability, breathability and long term waterproofness. What is essential is that you choose a jacket/garment that is designed well. A poorly designed and ill-fitting jacket will never perform or be comfortable, no matter its fabric qualities.

Last week on the Paddy Pallin blog we talked about Choosing a Waterproof Jacket – If you’re now all clued up on fabric technologies but still not sure what Jacket will serve you best – check that out.

Just remember that sure, there is marketing hype, and the coolness factor, but pretty much just like buying a good car – you get what you pay for. Remember that if you look after your jacket, then you will get many, many years of fantastic use from it, and as clothing goes – the outer most “shell” layer is perhaps the most important part of anyone’s clothing system.

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