When I have to install a water heater on the second floor I pipe the T&P relief to the floor drain if the drain is installed where it wont leak down to the next level. If that is not the case I ask the inspector if I can discharge it into the drip pan.

Well , best way to handle this is to call the city's plumbing inspector. He will tell you the way he interrupts the code as well what he would allow and disallow. As a plumber here in Illinois I have called and checked with the local inspectors due to each city and township modifies the Illinois plumbing code. Just always keep in mind they can make the code stricter but can not violate the Illinois plumbing code. In other words the Illinois plumbing code is the bare minimum to be allowed.