This video shows why you cant always trust all information on the internet, as well as shows the basics of torque wrenches and a few oddball calculations you might run across when building custom things.
Underground mine ventilation. Underground mine ventilation provides a flow of air to the underground workings of a mine of sufficient volume to dilute and remove dust and noxious gases (typically NOx, SO2, methane, CO2 and CO) and to regulate temperature.
Ventilation refers to the process of air movement into and out of our lungs, and it includes both inspiration and expiration. Inspiration occurs when lung pressure is decreased below atmospheric pressure, and that causes the air to move into the lungs.