Hair Hygrometer
2 definitions

An instrument used to monitor relative humidity by measuring the changes in the length of human hair that accompany humidity variations.

FK Reading Ease
8.3

FK Grade Level
Graduate School
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  • A hygrometer that measures relative humidity by means of the variation in length of a strand of human hair.

    The length variation of a properly treated hair is 2%–2.5% when the humidity changes from 0%–100%. The hair hygrometer is considered to be a satisfactory instrument in situations where extreme and very low humidities are seldom or never found. The rate of response is very dependent on air temperature; the lag time increases with decreasing temperature. For air temperatures between 0° and 30°C and relative humidities between 20% and 80%, a good hair hygrometer should indicate 90% of a sudden change in humidity within about three minutes.

    FK Reading Ease
    40.9

    FK Grade Level
    College
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