Humidification and ESD mitigation in low RH zones

We have an issue where we have a lab with humidification but need to expand with proper ESD controls external to a non humidified area. I have heard in some facilities where humidification in hot dry climates are discouraged that additional Ionization is used as a mitigation. Has anyone used curtains plastic to seal off areas where a humidity portable unit could be installed.

Hi Larry and welcome to the forum.

This is a great question to ask but the answer is really, “it depends”. It really depends on the type of ESD control program you have and how well you understand the controls. First of all, if you have ESD control items that have been qualified to ANSI/ESD Standard Test Methods (STM), they are suppose to use an environment of 12% Rh. This is to ensure that the controls are humidity independent.

The items that will need to be evaluated are the insulators. They can vary due to humidity and should be evaluated to see if they pose a theat. You can used ANSI/ESD S20.20 for the requirements for insulators.

If the two conditions above are met, then you are done. Your process will be humidity independent. If not, then you either need to evaluate your ESD controls at the lowest humidity that is experienced in your facility or in the case of process insulators that are a threat, do something. This is how to determine if ionization is needed in a any situation at any humidity level.

Please feel free to append this entry if you have any further questions.

I concurr with Jonk K but would add that beware of materials like pink polythene and antistats. These often need humidity about 30% rh to work properly.