CALIBRATION OF THERMOHYGROMETERS

What is a Thermohygrometer?

A thermohygrometer is an environmental measurement device that measures the outdoor temperature and the relative humidity of the air: the ratio between absolute humidity and saturation humidity, both expressed as the weight of water vapor per unit weight of dry air. Using this instrument is crucial to maintaining a healthy and comfortable environment.
High humidity can increase the risk of diseases, fungi, or mold development as bacteria and pathogens multiply more. Similarly, low humidity can cause coughing, allergies, and congestion.

In specific, temperature-controlled environments such as museums or food storage facilities, where special production processes take place, constant monitoring of air parameters ensures the correct preservation of goods and prevents spoilage.

When should you use a Thermohygrometer?

Thermohygrometers are used in all production areas requiring a controlled environment. They are employed in research and development laboratories, in the pharmaceutical and food industries, for the control and maintenance of ventilation and air conditioning systems, and in drying and storage processes. They are also used in work environments to ensure a healthier environment in accordance with legal requirements that include specified parameters, as well as in meteorology to measure humidity and temperature in various climate zones.

When is the calibration of a Thermohygrometer necessary?

To ensure the correct functioning of a thermohygrometer, the device should be calibrated at least once a year. However, the frequency may vary depending on the intensity of use, the requirements of relevant standards, and the maintenance condition of the device.

How is the calibration of Thermohygrometers carried out?

At TECHNE, the instrument to be calibrated is first analyzed to identify potential problems, registered, and then passed on to the internal calibration laboratory for humidity, LAT 263, which has been certified by ACCREDIA since 2021.

The instrument is placed in a WEISS climate chamber, where temperature and humidity are controlled and can be measured by a reference thermometer or a mirror hygrometer. Two direct reference measurements are performed: air temperature and dew point. These are then compared with the thermohygrometer to be calibrated. Thanks to a unique system in our industry, which allows air to be extracted from the chamber, high measurement accuracy is ensured.

The process is repeated several times with different temperature and humidity values, documenting the instrument's error and measurement uncertainty.

A management software system automatically brings the climate chamber into measurement mode, the collected data from the reference measurements are precisely downloaded and entered into the management system. If it is a hygrometer chain with a display, photos of the instrument are taken when stable measurement points are reached and inserted into the recording system.

These measurements are then stored and automatically imported into the system for managing and creating the ACCREDIA certificate.