d) Plumbing shafts in the core of the building shall have minimum 30minutes fire rating, if it is 
in wet area or naturally ventilated or external walls, the doors may not require any specified 
rating. e) Separation between floors shall be with 120minutes fire stop
3.4.5.5 - Refuse chutes opening provided in the building shall have minimum 120minutes fire 
rating wall and 60minutes door. General requirement of fire doors in individual  occupancies