| Absolute Pressure: |
Air at standard conditions (70 degrees (F) air at sea level with a barometric pressure of 29.92 in. Hg.) exerts a pressure of 14.696 psi. Thjis is the pressure in a system when the pressure gauge reads zero. So the absolute pressure of a system is the gauge pressure in pounds per square inch added to the atmospheric pressure of 14.696 psi (use 14.7 psi in environmental system work). |
| Atmospheric Pressure: |
The pressure exerted in all directions by the atmosphere. At sea level, mean atmospheric pressure is 29.92 inches Hg, 14.7 psi, 407 inches w.g., or 760 mm Hg. |
| barometric Gauge: |
An instrument for measuring atmospheric pressure. See Atmospheric Pressure |
| Standard Ventilation Conditions: |
In industrial and general building ventilation conditions, standard ventilation conditions are 70 F (21.2 C), 50 percent relative humidity, and 29.92 in. Hg (101.3 kPa) atmospheric pressure. |