Nafion™ ionomer tolerates relatively high temperatures; its melting point is over 200°C. The Chemours Company, the manufacturer of the ionomer, lists a maximum operating temperature for its membranes of 190°C. When Perma Pure produces tubing from this material, we list a maximum operating temperature of 125°C. This lower temperature is conservatively assigned because The Chemours Company membranes are bonded to reinforcing materials and are used with liquids while Perma Pure gas dryers are used with gases and are not reinforced. We are concerned about pressure tolerance at higher temperatures due to softening of the material, but Nafion™ will presumably tolerate temperatures in excess of this specification. However, the rate of water transfer rapidly declines above 90°C so for most applications this is where we set a recommended limit. In cases where hotter gases are led directly into the dryer, this shows that the material can operate in that condition well.