Moist and humid air - psychrometric charts, Mollier diagrams, air-condition temperatures and absolute and relative humidity and moisture content.ĭensities of solids, liquids and gases. Ρ ref = density reference at elevation 0 ft and temperature 70 oF - (0.075 lb m/ft 3)į = correction factor from the chart above Example - Density at Elevation 4000 ft and Temperature 300 oFįrom the chart above - at elevation 4000 ft and temperature 300 oF the correction factor is approximate 1.7. Ρ = density at the given temperature and elevation (lb m/ft 3) The density at a given temperature and elevation can then be calculated as The chart above can be used to estimate " temperature vs. The specific volume of standard air at a certain altitude can be calculated by multiplying with the volume correction factor below
Note! - other definitions of STP and NTP are widely used.
STP - Standard Temperature and Pressure is 273.15 K (0 ☌, 32 ☏) and absolute pressure exactly 10 5 Pa (100 kPa, 1 bar) - according IUPAC - International Union of Pure and Applied Chemistry - since 1982.Air density and specific volume as functions of altitude above sea level can be indicated as in the diagrams below: