April 22, 2020
Butterfly Valve Liners and Hydrocarbons
From time to time, a problem comes in to the Milwaukee Valve product managers or application engineers that serves as a reminder of the importance of liner selection in relation to the medium. But sometimes, visual evidence really drives the point home. Here are a few examples:

This first photo shows an iron butterfly valve with an EDPM liner. This valve was installed on a Purge Oil line. The Purge Oil is used to preserve fuel tanks of jet aircraft when not in use for extended periods of time. 
The second example shows a butterfly valve with EPDM liner installed in a ULSD (Ultra Low Sulfur Diesel) Fuel line. 
For the last example, we were told this valve was on Jet A Fuel or Purge Oil line. These are different media, so it’s unclear which one did the damage, but we wouldn’t recommend EPDM for either.
And as a point of reference, here’s what an intact EDPM-lined butterfly valve should look like.
EDPM is NEVER to be used with hydrocarbon medias , such as Gasoline, Kerosene, Diesel Fuel, Jet Fuel, Natural Gas, Propane, Petroleum-based oils and lubricants, or Asphalt. For these applications, and depending on the media and pressure temperature requirements of the installation, an Elastomer Guide for rubber-lined butterflies ( https://www.milwaukeevalve.com/data/files/EngineeringSpecs.pdf ) recommends Buna or Viton. Buna is also recommended for compressed air lines, as they could contain compressor oils and lubricants not compatible with EPDM.
Application engineer Sydney Green recently developed a one-page Technical Bulletin on this topic, which can be found at https://www.milwaukeevalve.com/data/files/BFVLinerHydrocarbonService.pdf . As always, if unsure of a specific application, consult your regional manager for guidance. 
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