Open space for revised corridor door (option 2) is approx. 0.25 m2. Open space shall be 0.4 m2. But AIA not remove existing transfer air grille, it have enough opening space.
In option “AIA will be additional FAD work and connect with existing FA riser”. We not recommend it because it shall be effected to main building (Fresh air flow form FA riser do not include for this option).
In option “add the fan to carry air from outside area to fill toilet”. Fan for male toilet can be reduced open space but female cannot because air intake from toilet corridor.