I can see where Chinski is coming from.
When I first started as a young single Engineer on salary and we got into 24 hr machine shutdowns, I would work straight thru putting in 32 hours at a time, then sleep for 6 hours.
I'm older and wiser now.
You have to think of your own safety, and most, if not all companies have to respect that.
Now when we get into a week long machine shut, I start at 5:am and work till 10:pm for 6 days, so max is 102 hrs a week.