Are You Grounded®? Evaluating Waxed, Solid Dissipative Vinyl Tile vs. Wax-Free, ESD, Conductive Vinyl Tile

Recently we decided to do some spot testing of various “conductive” flooring products in our office in Massachusetts as an exercise to further develop our library of resources available to those who struggle to understand ESD flooring and the underlying principles of static electricity. It is important to note that the day we tested it was very cold outside (and in our office) and that the low relative humidity is the main reason for choosing this particular day to conduct these tests. Static problems are more prevalent when the air is dry. It is well known that many static control products lose effectiveness when it is dry – just when you need them the most.

Hypothesis
The hypothesis that we are looking to test with these evaluations is that static is dissipated least effectively by humidity dependent products like SDT and more effectively by carbon loaded conductive ESD tile. Testing day's super-dry winter conditions eliminate any chance that relative humidity will enhance the discharge properties of any tiles. It is a known phenomenon in the industry that elevated relative humidity can increase the effectiveness of anti-static flooring, one very important reason floors should be tested at low relative humidity and without the aid of waxes or antistatic polishes.

Samples and Testing Methodology

Remembering that the ideal range for ESD flooring systems is 105 to 107, we decided to compare the results of the following flooring samples:

 

 

· SDT VINYL SAMPLE
Armstrong SDT Static Dissipative Tile(figure 1)
Samples that re provided by the manufacturer ‘s distributor

 

· Carbon loaded VINYL SAMPLE
Staticworx Foundation Series ESD Vinyl Tile(figure 2)
This sample was pulled from the Staticworx warehouse of samples

 

· EC RUBBER SAMPLE
Staticworx EC ESD Rubber (figure 3)
This sample was pulled from the Staticworx warehouse of samples

 

 

Armstrong-sdt-sample   (figure 1)  

Ameriworx-svt-sample   (figure 2)    

Presto-ec-esd-rubber-sample  (figure 3)

 

The size of the sample does not influence the effectiveness of the results of this test. These sizes appear as provided by the manufacturer. All samples are shown here, prior to testing, on a standard 8.5” x 11” piece of paper.

 

 

To conduct the test, we used:

·  Prostat, PRS-812 Resistance Meter(figure 4)

· Copper stripping that Staticworx supplies with all ESD flooring orders

· The three flooring samples listed above.

 

 

 

Prostat-OHM-meter

(figure 4)

 

 

 

Any easy way to determine if a flooring material can be grounded effectively is to measure its resistance with a megohm meter (see figure 4.) A good reading is usually below 1,000,000 ohms, that’s 106 in ESD speak and on the meter it’s represented as “1.0 E 06”. An unacceptable reading is any reading above 3.5 E 07-0—it’s critical to understand that the meter’s highest measurement is 10 E 10 and lowest reading is 0 E 00. According to ANSI/ESD S20.20-2007 the system ground should always measure below 3.5 E 07.

 

 

 

Sample Testing

After connecting the meter to the two-weights/conductive cords, we placed each sample with its midline on the copper-grounding strip. Then, we connected the meter—one weight on the copper strip and one on the flooring sample. At this point, we turned on our meter and measured electrical resistance. Here are the results.

 

 

 Sdt-resistance-reading (Figure 5)     

 

Svt-resistance-reading (Figure 6)         

 

Esd-rubber-resistance-reading (Figure 7)

 

In figure 5, the Armstrong SDT Vinyl Tile sample, reads 2.8 E 09, or 2.8 109. In figure 6, the Staticworx Carbon loaded Vinyl Tile sample, reads 8.7 E 05, or 8.7 105. In figure 7, the Staticworx EC Rubber sample, reads 9.8 E 05, or 9.8 105.

 

Test Results

As hypothesized, the tests confirm that SDT is the least effective conductor of static; Carbon loaded ESD tile and EC rubber flooring conduct static most effectively - regardless of the dry conditions.

 

Conclusion: What does this mean?

The main purpose of static control flooring is to prevent discharges between people and static sensitive electronic assemblies. A good static control floor must safely ground static charges away from people regardless of environmental factors. A floor with poor or no conductivity, like Armstrong SDT, cannot effectively ground static charges because the resistance is too high. A high resistance (ohms rating) prevents charges from reaching ground. At low humidity, static charges will actually accumulate on a people as they walk on SDT. Carbon loaded flooring like Staticworx vinyl and EC rubber will perform equally well regardless of relative humidity.

Read more about how Staticworx ESD, Conductive Solid Vinyl Tile (wax-free) compares to Armstrong Static Dissipative Vinyl Tile (requires wax) on the Staticworx website >



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