I have not come across any specifications being stated by the users I have had experience with.
In my experience there is a large difference between food and pharmacy. The later involving micro polishing etc.
The user will review - surface finish, inclusions or cavities and the basic design.
Sterile enviroments for plasma or potted water and like medias use stainless bodied PTFE Diaphragm valves so that the autoclaving (high temp steam) will reach every part which than contacts the media, if there are areas the steam cannot reach i.e.bearings or inclusions then it is not suitable for this application.
close colaboration with users is a must. Have a look at [b[
[/b] which are butterfly valves which would typically handle powder and the like i.e. no autoclave involved.
Glass valves are used by research facilities developing drugs.
Food applications tend to be a little less stringent. Handling chocolate needs virtually no additional processing except a clean build and many other food applications fall into the same catagory. Again close contact with a user will enable you to gain a better insite.
Hope this helps a little.
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