I would appreciate some expert advice regarding ESD garment requirements in an electronics manufacturing environment.
In our production facility, we handle exposed printed circuit boards (PCBs) populated with SMD components. At later stages of production, the assemblies are either placed in protective packaging or installed in metal or plastic housings.
Our internal Master Management Manual is based on IEC 61340-5-1 and EN 61340-5-1. It specifies the following requirements for ESD garments:
Panel-to-panel resistance below 1 × 10¹¹ Ω.
Surface resistance below 1 × 10¹¹ Ω.
Garments must be worn closed and cover normal clothing in the upper-body area.
Any caps, headgear and gloves used must meet the applicable ESD requirements.
Management is considering discontinuing ESD T-shirts because another site within the same organization reportedly operates without them, despite both sites being covered by the same global management manual.
I would appreciate your technical opinion on the following questions:
Does IEC 61340-5-1 explicitly require ESD garments for personnel handling exposed PCB assemblies with SMD components, or does this depend on the documented ESD Control Program and risk assessment?
Can ESD garments be eliminated if personnel grounding through wrist straps or ESD footwear and flooring is already implemented?
What measurements, validation tests or documented risk assessments would be necessary to demonstrate that removing ESD garments does not compromise ESD protection?
If an internal management manual explicitly requires ESD garments, can a local site discontinue them without a formally approved change to the procedure?
Under what circumstances could two manufacturing sites handling similar electronic assemblies legitimately have different ESD garment requirements?
I am particularly interested in answers based on the actual requirements of IEC 61340-5-1 and practical ESD audit experience.
IEC61340-5-1 as well as ANSI/ESD S20.20 list ESD Garments in the optional ESD control items. So if an organization includes garments in their ESD control plan, then they are required. If they don’t include them in the ESD control plan, then they are not required. That being said, the question is when should an organization require the use of garments. The main purpose of ESD garments is to reduce the electric field that may emanate from a person’s body. The static control garment system has an additional function to ground the person through a ground cord similar to a wrist strap. I don’t believe you are using the static control garment system so I will continue assuming you are not. The electric field given off by a grounded person is usually small because any built-up charge on a person’s clothing is suppressed from the large capacitance of the person’s body. You can measure the electric field from a person both with and without an ESD garment and compare. If the electric field from a person without an ESD garment is outside the insulator requirements in IEC61340-5-1, then you would need to mitigate this risk by doing something like using ESD garments or ionization. To answer your questions:
Does IEC 61340-5-1 explicitly require ESD garments for personnel handling exposed PCB assemblies with SMD components, or does this depend on the documented ESD Control Program and risk assessment? No, see above
Can ESD garments be eliminated if personnel grounding through wrist straps or ESD footwear and flooring is already implemented? Yes, if the risk of electric fields from personnel is not significant enough to impact the insulator requirements from IEC61340-5-1
What measurements, validation tests or documented risk assessments would be necessary to demonstrate that removing ESD garments does not compromise ESD protection? See above. You may want to consider doing a worst-case experiment using a smaller person (less capacitance) wearing a large, thick insulative shirt or sweater (like polyester).
If an internal management manual explicitly requires ESD garments, can a local site discontinue them without a formally approved change to the procedure? This would be up to your company’s policy for a local site’s ability to change corporate requirements.
Under what circumstances could two manufacturing sites handling similar electronic assemblies legitimately have different ESD garment requirements? If one site has more sensitive ESDS items than others, ESD garments may be needed depending on reduced insulator limits
Greetings of the day from India to all the members on this forum and, a warm welcome to Mr. Michael J. to join our community
Michael Sir,
Already our ESDA expert Andy Sir has given a very descriptive answer. Thank you Andy Sir
Well, first of all ESD Garment is not a mandatory EPE per either of the two Global ESD stds., though it encourages its importance as one of the personal protective aids in a full-fledged EPA.
The very purpose of using the ESD safe garments is to attenuate the charges from our normal synthetic garments worn by the operators. Especially in a clean room/semiconductor /SMT project etc, to avoid the dust particles in microns an unseen enemy again and source for static generation which can be suppressed by wearing these ESD cum clean room garments.
Subject your sensitivity class of the components & devices handled and type of you activities and process, the usage of any additional item can be put in your ESD control plan.
For the same organization each unit’s requirements and applications may differ or could be same with an identical plan/manual.
The requirements mentioned by you in your manual are perfectly ok.
And it looks like that you are using the Static control garment but not Static control garment system where the point to point resistance range will be < 1 x 10^9 ohms and the system resistance shall be at par with wrist strap ie. < 35 x 10^6 ohms. In this case it is hands free operation without the need for wrist strap.
Over all a proper ESD control program and implementation is as good as an insurance policy we take on one’s own life and for assets. You can add as many riders as you prefer for additional safety. Like that, here too, in an ESD Control program plan you can always add on any additional EPEs that you deem it fit for your application. But, maintaining its compliance verification regularly is very important just like the insurance premium payment on time.
Unfortunately; till date even after four decades ( I am referring to Indian industries as I do not have any idea outside my country) I have not seen even a single industry with fool proof ESD protection including the so called ESD Facility Certified units . It is the culture one has to develop and follow it rigorously but it is not unfortunately.
The reason for this continuing lapse in the industry is due to added reasons like; No regular CV and process assessment by the users – inadequate knowledge with the supply chain making the users believe what they say or supply – very limited knowledgeable third party service providers- cost cutting steps everywhere but keeping the Compliance & Quality factors only on documents but not physically -the political and local government guidelines. etc.
This is a section of the company document related to garments in the EPA area:
"The ESD control clothing must feature a panel-to-panel resistance of < 1 x 10^11 Ohm.
The ESD clothing must have a surface resistance of less than 1 x 10^11 Ohm. The ESD clothing must be worn closed and fully cover normal clothing in the upper body area.
If caps, headgear, or similar items are worn, they must meet the ESD requirements. The same requirement applies to gloves."
Greetings of the day from India to all the members on this forum
Thank you Michael Sir for your kind acknowledgment.
It is Sleeve to sleeve ( from one cuff to the other cuff), Right sleeve to left panel and left sleeve to right panel. and it is okay.
For cap and head gear too (as it is from the same apron cloth) it is same range for SR.
If cap a used , please ensure that it will cover the full hair and the cap touching the skin on the ear. The caps should be of right size but it is not just for fashion.
Because it is my observation in many places that people are using the caps very casually without understanding the real purpose behind usage of the caps or head gears.
Gloves needs to be tested per the CAFE test procedure (ANSI ESD STM 15.1 ) for in use resistance test with each finger . The material is not of Apron cloth here. It is mandatory to use the wrist strap when using the gloves and, only gloves usage is not correct. Wrist straps are the primary requirement and is the first line of defense in any ESD control Program .
