the period of time, the sidereal day, during which the earth makes one complete revolution on its axis relative to a particular star. The mean sidereal day lasts 23 hours 56 minutes 4.1 seconds of the mean solar day.
In this corner: a vent stack is series of vertical pipe vents that passes through at least two stories and is meant to maintain atmospheric pressure in the drainage system. The vent stack usually runs parallel with the soil/waste stack and may either extend up through the roof or connect to a stack vent. And in this corner: a stack vent is the uppermost portion of a soil/waste stack that continues the pipe from above the highest connected fixture out the roof.
The roof exhaust fan or Rooftop Exhauster Fans and ventilators mounted on exterior roof of building, generally utilizing a roof curb for proper seating. Whether using a wall mount fan or roof exhaust fans, they are installed for the sole purpose of removing stale, hot, moisture laden, hazardous or dirty air out of the building. When ventilation is done properly, the HVAC design of a building will also allow fresh air to be pulled into the building through wall shutters, dampers, a supply air fan or intake fans at the same rate as the air removed.