Humidity calibration stabilises the humidity of the sample gas and measures it against a suitable base reference.

 A humidity calibration system consists of

• Dry air source,

• A moisture generator that provides the required moisture content,

• A reference instrument that is more accurate than the device under test to provide reliable measurements

• A manifold that supplies calibration gas to the sensor/instrument under test.

When calibrating for relative humidity and temperature, the manifold should be temperature controlled or placed in a temperature-controlled environment to determine the relative humidity dew point value with temperature.