Is the requirements intent to place the air handler and ductwork in a closet that does not communicate with the garage?

Placing an air handler in a closet with a door that opens into the garage will eventually allow air from the garage to be draw in.  Also, over time the weather-stripping around the doors will degrade and allow for the negative pressure of the return air side of the system to draw air from the garage into the mechanical closet.

If the door can open to the garage, does this door need to meet a fire rating to maintain the fire-rated envelope?