At the 2025 EOS/ESD Symposium in Riverside, California, Toni Viheriäkoski from Cascade Metrology and our Product Development Manager Pasi Seppälä presented new research challenging long-standing assumptions in ESD control. Their and other co-authors’ study, “Reassessing Material Resistance Requirements for the Control of Charged Device Model-Like Discharges”, offers data-driven insights that could reshape international standards.
Why was this study necessary?
Toni Viheriäkoski
Current ESD standards—such as ANSI/ESD S20.20-2021 and IEC 61340-5-1:2024—recommend resistance limits up to 1 × 10⁶ ohms for surfaces that may contact ESD-sensitive devices. However, there is little data showing that such high resistance levels reduce the risk of CDM-like discharges. We wanted to test this assumption with real-world measurements on common polymer materials used in ESD control.
Pasi Seppälä
Our motivation was simple: overly conservative resistance limits restrict material choice and increase manufacturing costs without adding safety. We wanted to provide experimental evidence to support more balanced, data-based guidance for standardization.
Are electrically conductive materials allowed in ESD-protected environments?
Toni Viheriäkoski
Yes. Both IEC 61340-5-1:2024 and ANSI/ESD S20.20-2021 allow the use of conductive materials when handling ESD-sensitive devices. The key is to ensure there’s no potential difference between the object or surface contacting ESD sensitive item. Metals are commonly used, especially in cleanrooms.
Why do some organizations set a lower resistance limit?
Toni Viheriäkoski
If there’s concern about Charged Device Model (CDM) discharges, some companies raise surface resistance to reduce discharge current. However, our measurements and circuit simulations show that even a few hundred ohms is enough to attenuate peak current by a factor of ten compared with metal. Higher resistance increases safety but raising it to hundreds of thousands or millions of ohms likely results in overkill.
What do the current standards actually state?
Pasi Seppälä
In the relevant standards there is a different recommendation level.
ANSI/ESD S20.20-2021: ’If there is a concern for CDM failures, then a lower limit of 1.0 x 106 ohms for point-to-point and groundable point should be considered".
IEC 61340-5-1:2024: "In situations where charged device model (CDM) damage is a concern, a minimum point-to-point resistance limit of 1 × 104 Ω is recommended.
What were your main findings?
Toni Viheriäkoski
We compared DC resistance with actual ESD resistance across ten polymer samples; materials like PP, PE, PA, and TPU filled with carbon black or carbon fibers.
The key outcomes:
- No linear correlation between DC resistance and ESD resistance.
- ESD resistance decreases with higher voltages.
- With low voltages (250 – 1000 V), even few hundreds of ohms already limit discharge current effectively.
- Setting the lower limit at 10 kΩ provides a sufficient safety margin without over-restricting material choices.
So, is the 1 MΩ limit excessive for general recommendation when CDM risk is a concern ?
Toni Viheriäkoski
In ESD Protected Areas (EPA) voltages over 1000 V should not be present ideally. It was difficult to trigger a CDM-like discharge below 1000 V when the resistance was 10 kΩ or higher. 1 MΩ limit blocks many cost-efficient and environmentally friendlier materials without improving safety. We suggest revisiting it and basing future standards on measured behavior, not legacy assumptions.
What would you say to those who doubt lowering the limit?
Pasi & Toni
We respect organizations’ internal requirements. Safety always comes first, and we invite ESD professionals and standardization bodies to look at the data and join the conversation. If someone disagrees, we welcome peer-reviewed results showing otherwise. Evidence-based discussion is how standards evolve and remain relevant.
How does this research connect to Premix’s broader work?
Pasi Seppälä
At Premix, we constantly explore how conductive plastics can make ESD control more predictable and cost-efficient. This study aligns with our mission to base decisions on science and data. By understanding true ESD behavior, we can design next-generation conductive materials that are both safer and more sustainable, supporting our customers who deal with ESD control.
What happens next?
Toni Viheriäkoski
The findings are being shared with international ESD standardization committees. Our hope is that we will contribute to a more realistic lower resistance limit, one that maintains safety while allowing innovation and flexibility in material selection.
Key Takeaway
Even hundreds of ohms can effectively attenuate uncontrolled static discharge current in carbon-black–based conductive materials. Overly conservative limits add cost without improving safety as the available materials in > 1 MΩ range are often quite expensive. Data-driven updates to ESD standards could make materials selection more efficient while maintaining robust protection.
About the Experts
Toni Viheriäkoski is the founder and CEO of Cascade Metrology Oy, a Finland-based company specializing in ESD metrology and consulting. With over 25 years of experience in ESD control, Toni is an active workgroup member of international standardization committees and has authored multiple papers on ESD phenomena, material testing, and measurement methodologies.
Connect with Toni on LinkedIn →
Pasi Seppälä is a Product Development Manager at Premix Group, focusing on conductive plastics for ESD, EMI shielding, and power cable applications. He has extensive expertise in polymer compounding and electrostatic protection across electronics and automotive industries.
Connect with Pasi on LinkedIn →
👉 Continue the Discussion
Interested in learning more or continuing the conversation?
Reach out to:
Toni Viheriäkoski: Toni.Viheriakoski@ESDcafe.fi
Pasi Seppälä: Pasi.Seppala@premixgroup.com
