Footwear SD10 Certification//STM 9.1 Product Qual

#1

Hello,

I’d like to know if we can use footwear with SD10 Static Dissipative certification, or how can we link Footwear Product Qualification for Footwear (STM 9.1) with SD10?

Can it be tailored based on the Footwear/Flooring system internal product qual done at the site maybe?

Thank you!

#2

Santiago,

I am unfamiliar with SD10 so I am unsure how the resistance of the shoe is measured. Certainly someone, like yourself, could come to the working group meetings of the ESDA and propose SD10 be added to STM9.1. Perhaps a tailoring statement could be used to use the SD10 certification if it can be shown to be equivalent.

#3

The ASTM standard F2413 is used to measure the electrical resistance of a shoe. The SD10 designation indicates that the resistance of the shoe is between 1 and 10 Megohms. I am not sure how that test is made and under what conditions so I cannot comment any further without reviewing the document.
A case can be made that the footwear is “qualified” per this standard, but there still needs to be body voltage measurements taken to ensure that there is no charging above 100 volts.

#4

thanks @JohnK,

So just to understand, so i can take this as a “qualified” since it complies with F2413, but I will need to do the 97.2, right?

#5

First, you need to make sure that the F2413 test is equivalent to ANSI/ESD STM 9.1. I don’t have that standard and I can’t comment on it. If it is equivalent, then you just need to do 97.2.

#6

Thanks @JohnK , here some info about it (Based on AI check, let’s assume is real but I’ll check that if your approach is beneficial for us based on this scenario): the conclusion is that they are not 100% equivalent, but ASTM F2413 SD10 has a highest level of ESD protection for sensitive micro-electronics.

My question would be: How do I add this within my program to tailor my 9.1 based on this one?
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1. The Electrode Difference (The “Inner” Contact)

This is the most significant physical difference in how the current is passed through the shoe.

  • ASTM F2412 (SD 10): Uses 3 lbs (1.36 kg) of 3mm stainless steel balls poured inside the shoe. This creates a uniform weight and a massive amount of contact points across the entire insole.
  • ANSI/ESD STM 9.1: Uses a 5 lb (2.27 kg) metal plug (Foot-form) or a human subject’s foot. This mimics the specific pressure points of a human heel and ball of the foot rather than a total “fill” of the shoe.

2. Resistance Thresholds

Even if the “SD 10” shoe is tested under both standards, the “Passing” window changes.

Feature ASTM F2413 (SD 10) ANSI/ESD STM 9.1
Lower Limit $1.0 \times 10^6 \Omega$ ($1 M\Omega$) $1.0 \times 10^5 \Omega$ ($0.1 M\Omega$)
Upper Limit $1.0 \times 10^7 \Omega$ (10 $M\Omega$) $1.0 \times 10^9 \Omega$ (1,000 $M\Omega$)

The Conflict: * A shoe that passes STM 9.1 at $500 M\Omega$ would FAIL an ASTM F2413 “SD 10” test (because it is too resistive).

  • ASTM SD 10 is a much “tighter” and more conductive requirement than the base STM 9.1 standard.

3. Voltage Application Rules

The “stress” put on the material during the test is different:

  • ASTM F2412: You apply a set voltage (usually 50V) and record the resistance.
  • ANSI/ESD STM 9.1: Follows a specific “Switching” rule. You start at 10V.
    • If the resistance is $< 1.0 \times 10^6 \Omega$, you record the 10V result.
    • If it is higher, you must switch to 100V. This is done because some ESD materials are “voltage-dependent”—they only become conductive when “pushed” by higher voltage.

4. Environmental Conditioning

Static electricity is the enemy of dry air. Both standards require “pre-conditioning” the shoes, but the targets differ:

  • ASTM F2413: Generally targets 15% Relative Humidity (RH) at $23^\circ\text{C}$.
  • ANSI/ESD STM 9.1: Requires testing at two distinct environments:
    1. Low Humidity: $12% \pm 3% \text{ RH}$ (The “hard” test).
    2. Moderate Humidity: $50% \pm 5% \text{ RH}$ (The “standard” test).

Summary of Equivalence

They are not 100% equivalent. If you are looking for a shoe that meets the highest level of ESD protection for sensitive micro-electronics, you want a shoe that passes ASTM F2413 SD 10 specifically because its upper limit ($10 M\Omega$) is 100 times more conductive than the maximum allowed by STM 9.1 ($1,000 M\Omega$).

Essentially, SD 10 is a “high-performance” subset of what STM 9.1 allows.

#7

Sound resonable, just keep the documentation in case you are asked about it. Then do the 97.2 testing.

1 Like
#8

Thanks @JohnK, would it be added via tailoring it with this rational? could you confirm?

#9

Just document a tailoring statement in the ESD control program or have a spearate report that you file with your product qualificaiton data.