BOMI Air Handling, Water Treatment & Plumbing Systems Practice Test

In psychrometrics, the state of moist air is described by a set of properties used on the psychrometric chart to relate temperature, moisture, and energy. The seven commonly listed properties are dry-bulb temperature, wet-bulb temperature, dew point, relative humidity, humidity ratio (mass of water vapor per mass of dry air), enthalpy, and specific volume. Absolute humidity—mass of water per volume of air—looks related but isn’t treated as one of the standard independent psychrometric properties. It depends on pressure and temperature and isn’t used as a primary coordinate on the chart, so it isn’t included among the seven. The other properties cited (dew point, enthalpy, humidity ratio) are core elements of the psychrometric framework, describing condensation conditions, energy content, and moisture content per unit of dry air, respectively.