What is the first step in the process for using a psychrometer?

The first step in using a psychrometer involves ensuring that the wick is wet and clean. The psychrometer functions by measuring the temperature of the air through two thermometers: one with a dry bulb and one with a wet bulb where a wick is saturated with water. For the wet bulb thermometer to provide an accurate reading of humidity, the wick must be functioning correctly—this means it should be wet enough to facilitate evaporation, which is essential for determining the depression of the wet bulb temperature. A dirty or dry wick would render the measurements invalid, leading to incorrect humidity assessments.

This step is foundational, as the integrity of the wet bulb's reading directly influences the calculations for relative humidity. Ensuring the wick's cleanliness and moisture level is crucial for obtaining reliable data. Properly preparing the psychrometer sets the stage for effective readings of temperature and humidity, which is vital in various applications, particularly in coatings inspection where environmental conditions are critical for successful application and curing of coatings.