In 2019, the waterproof, breathable textiles market was valued at US$1.7 billion, according to a market analysis report. It further estimates a compound annual growth rate of 6.6% over the following 6 years for that particular market. This trend is being driven by a growing awareness of the health benefits of sports and the increased necessity to exercise outdoors. Within this space, water repellent garments have become key performers.
Water repellency describes water beading on the surface of a material, preventing the water from penetrating, which is often achieved through combining membranes or coatings with tightly woven fabrics. The benefit of water repellent garments is their breathability. The fabric remains porous making them permeable to air, water vapor, and liquid water, which makes them more comfortable to the wearer. Ultimately, a water repellent garment should offer comfortable protection from intermittent rain.
Largely because a change in consumer behavior makes it so.
We have seen an increase in athleisure for many years now. The sportswear industry has influenced mainstream fashion, and innovations in technology has led to improvements in functionality.
For outdoor wear in particular, the onset of a global pandemic has increased demand even further. With the long-term closure of gyms, swimming pools, and exercise classes, more and more of us are heading outdoors to exercise. More people are vacationing in their home country as well, which for a lot of us means swapping swimwear for raincoats and walking trousers. With this increase in demand comes more rigorous performance testing to ensure these garments perform as they should when exposed to the elements.
It is also becoming more common to select accessories, such as backpacks, for their water repellent or waterproof qualities. Another consideration for brands and manufacturers can often involve more feature specific testing to establish, for example, what role seams, zippers, and pockets play.
Consumers expect comfort from their garments. Comfort is influenced by fit factors as well as fabric properties such as stretch and recovery, and thermal and moisture management properties. But for outdoor wear in particular, comfort is about finding a balance between keeping water out and letting sweat escape.
&/news2021-11b/8216;There are risks involved with getting the breathability of water repellent fabrics wrong’
Safety is arguably the most important feature that users can expect from their performance garments. There are risks involved with getting the breathability of water repellent fabrics wrong, mainly that they can trap sweat and cause the wearer to overheat. This might not seem like an issue for a quick walk around the park, but for wearers on long hikes this could cause serious health risks.
To understand the testing we need to undertake, it is important to understand the make-up of a garment, and the role that layers play.
In sportswear, and especially outdoor wear, a three-layer clothing system is often advocated, with each layer in the system performing a different function that complements the whole for maximum comfort.
A layering system typically includes:
An effective outer layer should have a high level of water resistance as well as a high level of water vapor permeability (‘breathability’). How this layer is constructed plays a significant part in this.
This is where the challenge of the outer layer comes in—creating a fabric which provides good water resistance is relatively simple, but doing this while maintaining breathability is a more complex process, as these two properties have an inverse relationship in typical textiles. A thorough testing regime can prove the balance between these properties have been met.
Water repellency is tested by spray methods, using instruments such as the , where water is run over the surface of the fabric and the repellency is visually graded.
For the Bundesmann method, in particular testing to ISO 9865, the test instrument generates artificial rainfall to simulate the real life conditions the end garment will be used in. Here three aspects of water repellency are measured:
As with any testing, there are certain parts of the process to look out for, which can have an impact on your results.
Pro Tips in testing:
Traditionally the Bundesmann test requires a lot of water, which can be an issue for apparel brands and manufacturers who are tackling issues of sustainability.
The UN Partnership on Sustainable Fashion found that fashion is responsible for nearly 20% of the world&/news2021-11b/8217;s wastewater, and 10% of global carbon emissions, so there is a lot of pressure to be cleaner, more efficient, and ultimately sustainable. Although testing plays a small part in the process, there are significant savings to be made in water usage during testing.
recently conducted a small research project into the efficacy of water recirculation on our Bundesmann testing instrument.
A typical Bundesmann water repellency tester that runs for 8 hours per day, five days per week, is consuming 3360 liters (888 gallons) of water. It is plumbed into the mains and drained directly after a single fall onto the specimen. Recirculating the water would reduce usage, but we had to establish there would be no detrimental effects to testing when doing this.
Concerns:
We conducted significant testing, in-house and using an external laboratory, to verify that the results would be accurate regardless. The test results concluded that there was consistency from start to end, and by confirming this, we were able to calculate the savings our recirculation unit could offer.
 ‘99% less water is used during testing alone’
We also found that by using the recirculation unit, we were able to maintain the temperature of the water much easier. The percentage of water absorbed by fabrics can increase as the temperature increases, so this is important to control for consistency of results.
With an increase in demand for water repellent clothing, and the subsequent increase in the popularity of Bundesmann testing, understanding and implementing repeatable testing is crucial to substantiate any claims made about a garment. The challenge for retailers and manufacturers is to meet and exceed consumer’s expectations for comfort and performance, and water repellency is one part of the puzzle for achieving this.
Author: Paul Montalto, Technical Knowledge Manager,
BEST VIEWED IN CHROME AND FIREFOX BROWSERS. We use cookies to ensure that we give you the best experience on our website. By using our services, you agree to our use of cookies.
Okay