1.1 Place the standard dry wet bulb thermometer in the area along with the dry wet bulb thermometer used is to be calibrated.
1.2 Record the wet and dry bulb temperature of the thermometers at various intervals during the course of the day (at least five readings)
1.3 Calculate the percentage relative humidity by taking the difference of dry and wet bulb thermometers by referring to table of wet and dry bulb thermometer readings with corresponding percentages of humidity as read in the standard hygrometer.
1.4 Calculate the percentage variation and check with limits,
1.5 Reference table attached,
Limits : Relative humidity 50 ± 2%
2.0 DOCUMENTATION :
F:Sxxxx/WBR - Dry and Wet bulb Calibration Record.