Our EPA area requires trash bins made of anti-static material with lids. However, insulating garbage bags will be placed inside the bins. Since our floor is grounded, I have assessed that this method is acceptable as long as a 25 cm distance is maintained.
The auditor believes that insulated garbage bags should not be used in the EPA area. Please, everyone, help me evaluate this.
These can be considered as process required insulators. In this case, accourding to ANSI/ESD S20.20 or IEC 61340-5-1, if the insulator is greater than 300 mm away from an ESDS item, then it is acceptable. If it is closer, then it simply has to be determined if it is a threat.
There are two methods to determin a threat.
- If the field where the ESDS item is less than 5000 v/m or 125 v/in, there is no threat.
- Measure the insulator directly. Since it is 25 cm away, the insulator must be less than 2000 v.
Hope this helps.
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Though we have ESD waste bins in our EPA’s, we also have low charging bags in them (ESD symbol on them & tested when first introduced), as it is when they are exchanged for new bags that there is a high risk, as normal bags charge to such a high extent.
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Thank you very much, Johnk! I completely agree with your point of view.
Hello, Susan! Thank you for bringing up the matter of changing the bags. Let me add that all our staff are wearing anti-static clothing and shoes, and the workshop is equipped with anti-static flooring. Although replacing the bags would generate a significant friction voltage, the static electricity would be transmitted to the floor through the anti-static shoes when it is generated. It is not clear whether there would still be any threat.
Greetings of the day from India to all on the ESD Forum platform and welcome to Mr Huichen to our platform 
Our ESD Guru JK Sir has clearly mentioned what is acceptable and not acceptable per the two global standards .
Just for exchange of each one’s thoughts I would wish to pen down few lines as under .
1.I have seen in many places users using the ESD safe dust bins and putting all the insulative garbage into it and the bins kept sufficiently at a safe distance from the work tops or the area where ESD safe preventive steps required to be taken care of.
2.I do agree with you and Susan Madam’s observations and, indeed it is a true fact that while replacing the garbage bags it would give room for generation of a significant voltage level not desired to be in an EPA or nearby any sensitive devices.
3.In general as per my observation and the usual practice every where, is to carry the dust bins away from the EPA in lid closed position or in case of open lid cases without disturbing the position of the garbage unload them outside the EPA hanger and put in a new waste bag there only and bring back the dust bin to its original place in the respective EPA.
4. In most of the places it is done once a day or once between the shifts when all the activities are stand still and especially the sensitive jobs are either not at the work station or safely covered using static safe enclosures.
- Basically , as is known to all, the generation of charge is due to two main factors Friction & Separationand, Static inertia(inertia of rest) is the natural tendency of an object to resist any change to its current state of rest. According to Newton’s law a stationary object will remain perfectly stationary unless an external, unbalanced force acts upon it.
Thank you
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If the waste bags are insulative, then they will be able to charge up and will not lose the charge through a grounded person (an ioniser can neutralise it, mostly if it is a stationary insulator). That’s the issue with insulators.
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Susan,Thank you very much! I have corrected my wrong ideas. Thank you all for the valuable suggestions provided.
Thank you very much for your valuable suggestions.