I recently had a very long, crazy party, where I ended up drinking a lot. Something like 13 shots worth of 90-proof alcohol over the course of the night (about 6 hours). I know that toward the end of the evening, when I was being drunk and particularly stupid, one of my friends convinced me to drink a little bit faster than I had been before, with the result that I had six shots of vodka in a half hour period.
According to the drinking rules I myself helped write for Tournaments, Fairs, & Taverns, each shot of vodka contained 12 alcohol units. You can drink up to your Constitution x5 before you're so drunk you can't talk. I could still talk and walk rather well, so I must've drunk less than that.
By the rules in TFT, before the 6-shot binge, that's still 84 AU, minus 48 AU from being able to metabolize a little bit each hour, for a total of 36 AU. Then add in the extra 72 AU from drinking the six shots quickly, and you get 108 AU.
Divide by 5, and in order for me to do what I did, I would have to have a 22 Constitution. Or possibly an 18 Constitution and the Endurance feat. Since I know I'm human, and the only way to go above 18 Con is with leveling up, I have to be at least 16th level. Go me.