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.
How to Install a Roof Vent. Roof vents are devices that allow the moisture in a house to escape, which prevents the growth of mold and mildew. Roof vents also help to keep wood rot, which is a form of fungal decay, from developing in the house. Roof vents are made of plastic or metal, and are also known as turbine vents.