Calibration of thermohygrographs and analog hygrometers

GEFRAN LAT 011 laboratory issues calibration certificates of thermohygrographs and analogue hygrometers.
Hair thermohygrographs are instruments capable of measuring temperature and % relative humidity of the environment where they are located.
These values are then traced on graph paper either with a daily or a weekly cycle.
Analogue hygrometers are composed of a graduated dial where a pointer moves to indicate the % relative humidity value in real time.
The measuring ranges accredited by LAT go from 10 to 90% of relative humidity at a 5 to 40°C ambient temperature.
The calibration is carried out in a climatic chamber, using a chilled mirror sensor as reference standard.
To evaluate the hysteresis, LAT accredited procedures require the calibration to be carried out at a pre-fixed temperature (isotherm) on four points by increasing temperature, and on one point by decreasing temperature. It’s up to the customer to decide how many isotherms he needs.
The procedures applied to carry out the calibration, as filed at LAT, are also listed in the certificate.
Furthermore, a LAT certificate is guaranteed to be always traceable (thanks to a filing system granting the certificate to be traced at any time after being issued), and acknowledged world-wide by the other National Metrological Institutes, since LAT is one of the Signatories of the “EA” (European Co-operation for the Accreditation of Laboratories).
For non-accredited measuring ranges and for analogue instruments, the Laboratory provides a TEST REPORT traceable to the relevant national standards.
As far as thermohygrographs are concerred, a TEST REPORT can also be issued for temperature calibrations at the thermohygrograph of different working values. (Calibration to be carried out in a climatic chamber).