zeusfaber,
I have had similar concerns in relation to the different colour codes from different countries. I have not looked at ISO 14726, however had had experience with AS/BS/Petrochem pipe colour coding, and match your experience. Some disturbing different colour/content combinations! When working in different industries and different companies they have all use different colour schemes.
The key to not getting caught out is to ask what colour standard they are working to. As I have stated and reinforced always have a colour/contents chart to decode the system.
Writing the contents name on the pipe is also a good practice, but what language, not everyone speaks English! An excellent example here is; Bahasa Indonesian for “water” is “air”! (Pronounced aieer) Learnt that one as design manager on Pharma plant in Indonesia! Real confusing! In wider industrial sites a line will have an identifier (serial number) and initials for contents e.g. PW for Purified Water lines.
Mark Hutton