Contrary to popular belief Air conditioned offices with false ceilings under metal or Asbestos roof sheets also require ventilation. The roof tops become hot during the summers and transfer the latent heat due to thermal convection towards the false ceiling and structural members like columns and beams. Thus heat enters indirectly into the air conditioned space.
These ventilators keeps the space in between the false ceiling and roofing sheet cool and help in reducing air conditioning cost. This intermediate space between the roofing sheet and false ceiling is also a potential store house of moisture and humidity. Moisture and humidity slowly but surely start damaging the POP ceilings and plaster and also paint on the wall surface. The Ventilators forcefully remove all moisture and keep the intermediate area dry.