Humidity Generator Plus Chilled Mirror Reference is a Winning Combination for Calibration Laboratory

25th October 2019

A leading calibration laboratory in Singapore successfully expanded their accreditation to include humidity and temperature calibrations for pharmaceutical customers utilizing a combination of the HygroGen2-XL and a chilled mirror hygrometer as a reference.

The laboratory in Singapore has SAC-SINGLAS 17025 and they wanted to expand their operations to win business in the pharmaceutical industry with the addition of high-accuracy humidity and temperature calibrations. Their target customer wanted assurance that the laboratory would be able to meet their stringent requirements for their humidity and temperature instrumentation.

After a feasibility study, the HygroGen2-XL humidity generator in combination with a chilled mirror hygrometer as a reference was selected.

Both the HygroGen2-XL and Hygrogen2-S models have a proven track record providing humidity calibrations for the pharmaceutical industry around the world and are universally recognized as leading instruments in their class. The HygroGen2-XL has a 17 litre working volume, which is large enough to calibrate up to 19 probes simultaneously, or to place multiple loggers or even a handheld device directly in the chamber. Both Hygrogen2 models are compact and provide excellent stability and small thermal gradients when compared to other chambers.

A chilled mirror hygrometer can be used can be used to significantly reduce the calibration uncertainties achievable with the HygroGen2 units.

The laboratory used the combination to provide their customer with a fast turnaround for the calibrations. Their willingness to invest in calibration equipment showed a pro-active approach when considering the customer requirement for system accuracy and therefore achievable calibration uncertainty.

Image of the Hygrogen2 XL and S models


The Hygrogen2 Humidity calibrators from Rotronic should be considered by Calibration Laboratories interested in performing humidity and temperature calibrations. The instruments have a relatively small footprint and compare very well with other large temperature and humidity calibration systems. Larger environmental chambers tend to have larger thermal gradients, poor stability and need longer to reach equilibrium after changes in temperature and humidity set point.

As shown in the table below, The HygroGen2-XL is a highly competitive instrument offering a large capacity coupled with excellent stability and fast changes for each calibration point.

HygroGen2 Specifications HG2-S HG2-XL
Chamber volume 2 litres 20 litres
Working volume 1.5 litres 17 litres
Humidity changes
(<±0.1 %rh stability)
5…95 %rh <5 minutes <15 minutes
Temperature changes
(<±0.01 °C stability)
23…50 °C
23…0 °C
<5 minutes
<25 minutes
<15 minutes
<35 minutes
Thermal gradients 15…50 °C <±0.05 °C <±0.05 °C
5…60 °C <±0.1 °C <±0.1 °C
0…5 °C <±0.15 °C <±0.15 °C
Probe mounts Up to 6 probes through door ports Up to 19 probes through door, plus internal shelf racks

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