Funny you should mention this, as I was reading a thread on a similar topic a few days ago (sorry, I can't provide a link, but I think it might have been on the
www.eng-tips.com board).
Much of the discussion was about status indicators in industrial systems of various types, and it sounds as though there are a variety of in-house standards.
Status indicators for circuit-breakers in power plants were mentioned, with some using red=closed, green=open, others vice versa. Somebody else mentioned similar differences to show valve status on pipelines, with systems that used one common color for closed and a different color to show open depending upon the pipeline contents.
