3-layer H2No^® fabrics are waterproof and breathable by virtue of an advanced combination of elements: a water-repellent shell fabric, a waterproof H2No barrier and an interior scrim fabric. This fabric package is completely waterproof, windproof, breathable and very durable.

Patagonia's H2No waterproof barrier is porous enough to allow body moisture to escape, without allowing water from the outside in. We apply a laminated scrim on the inside to:

• Quickly disperse built-up water vapor for faster drying
• Protect the waterproof/breathable barrier from abrasion
• Glide easily over the inner layers of the garment while maximizing overall durability and tear strength

Testing and Development

“We reject 93% of the fabrics we evaluate because they don’t perform to our standards. The remaining 7% we subject to further rigorous testing and analysis during product development – and from each production lot – to make sure those standards are continuously met.”
–Randy Harward, Director of Quality

No lab method simulates Mother Nature perfectly, but lab testing can help develop and accurately compare fabrics for specific performance characteristics. At Patagonia, we use the most highly controlled and technology-neutral methods available that most closely simulate actual-use conditions. We test a fabric’s waterproofness by simulating light rain, long-term rain and by forcing water through the face of the fabric. We make sure that a fabric is breathable by measuring its Moisture Vapor Transmission Rate (MVTR).

All products bearing the H2No mark have been vigorously tested for durability in our 24 Killer Wash, a process used to simulate years of use and abuse in a short period of time. This process consists of exposing the fabric to severe thrashing in a modified washing machine for a continuous 24 hours. After the killer wash we test for water permeability, adhering to a standard almost twice that of the U.S. Military.

No approach taken in the lab stands on its own; everything must be confirmed with adequate field testing. For our Field Test Program, a group of trained experts in a variety of climatic bases take prototypes out in to the field and use them in the activities and conditions for which the products are intended. Only a handful of prototypes we test ever make it into the product line. The idea: we endure some misery in the field so our customers don’t have to.

Environmental Impact
To determine the environmental impact, we look at the lifecycle of the product, including end-of-life disposal, and the toxin levels in the manufacturing process. The most environmentally harmful component of a waterproof shell is the waterproof/breathable barrier. It is usually made from three different chemical compounds: polyester (PES, PET), polyurethane (PU) and polytetrafluoroethene (PTFE). As of fall 2008, Patagonia does not use polytetrafluoroethene (PTFE) – the most harmful of the three chemicals – in our waterproof/breathable membrane construction.