Greetings,

Please find the setup, and the datasheet attached with the message to understand the context.

We have recently purchased a pair of EZO-HUM humidity sensors. So, given the present factory calibration, there is a confusion regarding its calibration with air, and whether it needs to be recalibrated for reading relative humidity values in humidified hydrogen.

How is it usually done? Is there any multiplication factor which can be multiplied to the output value of the humidifier to get the accurate RH value for hydrogen? or any factor which can calibrate it? or any process to read accurate humidity values in humidified hydrogen? Is it even needed to calibrate where hydrogen replaces air or can it read RH values for Hydrogen accurately itself?

We haven't done the temperature calibration yet. So to explain a bit, what we understand now is that, given the humidifier is supposed to give accurate results in an atmospheric air environment, we want to know whether it will be giving accurate humidity values if the environment is humidified hydrogen.

Do let me know your thoughts, since we are going to use the sensors in an experiment :)

This is what I received from Atlas Scientific when I asked the same questions on how the sensor functions:

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Efrem (Atlas Scientific)

Aug 1, 2025, 12:16 PM EDT

Hi Sayan,  Any work with Hydrogen is very experimental, we have no data on this.  There is no humidity calibration, there is only temperature calibration. Have you done the temp calibration?  How far off is it?

-Efrem

and this,

Efrem (Atlas Scientific)

Aug 1, 2025, 5:03 PM EDT

The temperature calibration is in the data sheet....  The device runs a few degrees warmer than the actual air, so you want to calibrate that offset out.  I have no idea how humidity of hydrogen works....   the answer it outputs is all that you can get, there is no way to change the output.

-Efrem

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