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The one that entertained me was the water temp warning icon - an icon that’s at least 50 years old. Its meaning is as well (if not more) established as the floppy disk as save.

Some color blind users can't detect the difference between orange and red. Color is a useful design extra, but you need to take all users into account.

There are lots of ways to do it. You could just include a page in the manual: "These icons indicate emergencies. Those other icons are just warnings," and expect color-blind users to memorize it. It's not optimal, but it's better than nothing.

Emergency icons might be larger, or perhaps flash (gently). You could include a octagonal stop-sign border around icons that indicate emergencies.

Using color as an additional channel for the 90+% of people in the world who can see it. But the remaining set (over 10% of men) are a sizeable audience.

And, these icons adhere to international standards. They are not just "made up" to suit a designer's whim.