The pipes on the roof in the car park are for the sewerage from the apartments. Legally they cannot be below a certain level, as it needs to be above the minimum roof height. The pipes are on angles to control the flow of the sewerage so that it flows to drainage areas and can be removed from the building.
The image above shows a pipe running into an air-conditioning duct. This is a mistake from the plans and needs to be adjusted on site. The mistake arises due to the different plans not being overlaid to determine if the layouts will fit. When working out how to fix the problem the workers must consider many factors such as: maintaining minimum roof height, not having the pipe flow upwards and not having sharp turns in the air condition duct which causes a loud whistling sound.