Dowtherm™ and High Temperature Seals

Seal Stability & Dowtherm™

Daniel Cohen 
Market Developer - Dow Glycol Heat Transfer Fluids 
September 2020

Dowtherm™ & High Temperature Systems  

2020 has been stuffed full of challenges and change and your heat transfer equipment has been the most consistent performer amidst all the volatility. One of the trends that we have seen recently is that when facilities are coming back online or conducting maintenance, some of the seals have shrunk or have begun leaking.  This is a direct result of taking a continuous, hot system that has been accustomed to running 24/7 and subjecting components to an abrupt cool down during jurisdictional shutdowns. It is very important to make sure that as you restart a system, there is enough safety stock of Dowtherm™ on hand to fulfill the system requirements. The shelf life is indefinite, and the risk of running out is very real and very probable if a seal unexpectedly leaks.  

Seal Thermal Ranges  

When evaluating seals & elastomers, the recommended materials & their optimum service temperature ranges are listed below; 


-100°F to 350°F
-73°C to 177°C

Perfluoro Rubber

5°F to 500°F
-15°C to 260°C

Tetrafluoroethylene-Propylene (AFLAS®)

23°F to 338°F
-5°C to 170°C

Expanded PTFE (Gore-Tex®)

-450°F to 550°F
-268°C to 288°C

Graphite (Grafoil®)

-400°F to 1600°F
-200°C to 870°C

Fluorocarbon Rubber (Viton®)

-20°F to 450°F
-29°C to 232°C

Avoid the shrinking and hardening that occurs from using incorrect elastomers. Whether the seal is hardening due to a leaching of plasticizer or disintegrating at an elevated temperature, leaks simply cannot occur.  It is critical to avoid the needless costs incurred from leaking a premium long-life heat transfer oil like Dowtherm™ due to something as preventable as proper seal selection. Trust that ChemPoint has seen it all and we are ready and standing by to support your turnaround needs this fall. When you need Dowtherm™, call ChemPoint! 

Get a Sample

PHONE  425.372.9464


Hi, let us know if you have any questions as you visit our website.

ChemPoint reps are here to assist you