Introduction
Conventional wisdom suggests that the fibers used to construct a base layer are a key factor in drying performance. Here, I examine the drying performance of eight fabric samples produced using four different fibers in fabrics that cover a range of thicknesses and complexities. The short take on these tests is that, as we shall see, conventional wisdom does not reflect reality.
Thanks to the community for asking good questions about my previous two drying articles: Why is my wicking layer soaked? and What’s the best base layer fabric? Wool vs. Alpaca vs. Polyester. These questions made me want to investigate the subject of drying further.
Here is what I found:
- It’s Not Just About the Fiber: Modern fiber, yarn, and fabric technologies have developed so that end products can be chemically treated, spun, knit, or woven to provide a wide range of drying characteristics. In this study, a 60 gram/square meter (gsm) Alpha Direct sample took 40 minutes longer to dry than a 100% merino base layer sample. Who would predict that? What is clear is that you cannot assume one garment will dry faster or slower than another based on what fiber is used in the garment.
- Water Content is Key: A fabric’s drying time is determined predominantly by the amount of water it contains when saturated. Fabric thickness is the key factor that predicts saturation water content in the eight fabrics studied. Fabric thickness accounted for 90% of the variance in drying time in this study. While fiber type also plays a role – particularly for hygroscopic fibers like wool and cotton that bind water at a molecular level – our results suggest that the dominant factor in drying speed is how much water the fabric can physically trap, which is largely determined by thickness.
- Natural vs. Synthetic: Hygroscopic fibers, like wool and cotton, can incur drying energy penalties that do not exist for synthetic fibers, resulting in slower drying times for these natural fibers. The drying penalties are relatively small for the eight test samples. I have included test results of two highly non-standard fabrics where fiber type substantially impacts water retention and drying rate. The circumstances under which fiber type plays a significant role in drying time are still to be determined. (See Appendix 1.)
- What Consumers Should Know: Fiber content can impact the drying performance of fabrics. However, The consumer will often not be able to determine when the fiber in a garment will significantly influence its drying time. The best strategy is to layer properly to avoid trapping moisture in your garments.
- What To Avoid for Faster Drying: If you want your fabrics to dry quickly, avoid fabrics with the following features: (a) thicker fabrics tend to trap more water and dry more slowly; (b) hygroscopic fibers inherently require extra energy to dry; (c) fabrics with increased fiber complexity, increased texture, or chemical treatment to increase wicking will tend to hold more moisture and take longer to dry.
Choose wisely – Giving up some of these features may cause the loss of other desirable features.
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Home › Forums › By the Numbers: Another Look at Fabric Drying Performance – How can an Alpha Direct Base Layer take Longer to Dry than a Wool Base Layer?