Temperature Range and Barometric Pressure. ASHRAE’s psychrometric charts are constructed for various temperature ranges and altitudes. In Appendix B only the one for normal temperature, that is, 32 to 120°F (0 to 50°C), and a standard barometric pressure at sea level, 29.92 in. Hg (760 mm Hg), is shown. The skeleton of ASHRAE’s chart is shown in Fig. 2.8.