The psychrometric chart (Figure 108-2) is a tool for understanding the relationships between the various parameters of supply air and the relative humidity.This template allows a designer or operator to “work backwards” from a desired room relative humidity to the desired condition of the air as it enters the supply duct. Properties of atmospheric air such as, the dry-bulb temperature, the wet-bulb temperature, the dew-point temperature, the specific humidity, the relative humidity, specific enthalpy and specific volume are discussed in relation to the psychrometric chart below.. Two independent intensive properties are required to completely specify the state of air in the psychrometric chart. Display a fully customizable psychrometric chart in both landscape and portrait modes. Customize the graph in many different ways, including specifying the psychrometric chart line colors, chart background color, hide/display status of chart lines, point colors, process line colors, units of graph values, and the min/max limits of the chart.