Testing ESD Carpet Tile Resistance: Exposing the Facts
As many have noticed, Staticworx recently generated major industry news with our launch of ShadowFX, the first anti-static carpet tile that meets the latest national safety requirements and provides lifetime static control.
Based on standards and specifications from organizations like NFPA, Motorola, ATIS, FAA, and IBM, carpet that is too conductive is not approved for use in healthcare, telecommunication, electronic equipment, and end-user environments like networked offices, data centers, dispatch centers and hospitals.
The need for a new product was clear, since previous options—like conductive, mission-critical, ESD-grade carpet tiles—are made with excessively conductive yarns and backings. We recognized this need and responded with ShadowFX.
While ShadowFX has been touted as a breakthrough product, it has caused some carpet distributors and manufacturers to feel anxious. They point out that older, conductive carpet lines have been installed in many facilities for many years. This is true, but it misses the point:
If conductive carpet doesn’t comply with the recommended range of electrical resistance required by third-party standards organizations, it exposes workers and the facility owners to risk and unnecessary liability in the event of an accident.
The Facts Speak for Themselves
As part of our due diligence during the development of ShadowFX carpet tile, we reviewed numerous grounding and safety standards. This was essential to the project because grounding standards differ depending on the environment where the floor will be used. Since our goal was to build one product for all applications, we scrutinized standards in great detail. For example, NFPA 99 is well known because it is the key grounding document used for defining flooring in healthcare environments. Many flooring manufacturers cite the NFPA minimum resistance of 25,000 ohms in their specifications for conductive flooring. Some flooring manufacturers and distributors assume this low minimum resistance permits the use of highly conductive flooring.
However, upon closer examination, section E6.6.8.2.7 in NFPA 99 stipulates that resistance testing must be performed using a 500 volts applied test voltage. Understanding the physics surrounding this specific requirement is essential to understanding ESD flooring and electrical safety. As voltage is increased, resistance will decrease. The opposite is also true. As voltage is decreased, resistance increases. How does this relate to an architect or designer? This means that they should always cite the details of the appropriate grounding standard and test method for a particular type of space when they write a specification. Since most marketing collateral for ESD carpet tiles reference an ANSI/ESD test method that tests floors using 10 volts – not 500 volts – it is quite possible that the floor could appear to meet an approved conductivity range when in fact it is not even safe for use in explosives handling environments.
To make the implications of the preceding paragraph more easily understood, we have measured the resistance of three conductive ESD carpet tiles using two applied voltages: 10 volts and 500 volts.
Testing of Conductive Carpet Tiles with Black PVC-free Backing
10 volts 500 volts
ANSI/ESD NFPA 99:
Color 1 7.5 x 10e4 1.6 x 10e4 = 16,000
7.2 X 10E4 1.4 X 10E4 = 14,000
Color 2 7.5 x 10e4 1.4 x 10e4 = 14,000
6.9 X 10E4 1.3 X 10E4 = 13,000
Color 3 5.0 x 10e4 1.4 x 10e4 = 14,000
Please note: A more conductive reading below 25,000 ohms is not an indication of a floor's ability to perform better than the standard requires. To pass NFPA 99, the resistance must measure above 25,000 ohms when tested at 500 volts using the NFPA 99 test method. These tiles would not pass a certification in any ESD application including those specified using: Motorola R56, ATIS 0600321, FAA 019e.
Conclusions:
1. Conductive carpet tiles with black carbon loaded backing do not meet the safety requirements of NFPA 99 when they are tested using the NFPA 99 test method.
2. A floor measuring at or above 25,000 ohms using NFPA test methods would likely measure over 100,000 ohms (10 E5) using ANSI/ESD test methods.
3. 25,000 ohms is an inadequate lower parameter for commercial floor resistance specifications.
4. Conductive carpet tile should not be used in health care or clinical applications.
5. Always require certification to ATIS-0600321 (or equivalent) and NFPA 99 after installation for equipment environments.
Further:
The requirements for ESD carpet tile installed in telecommunications environments, call centers, dispatcher rooms, radio broadcasting areas, FAA flight towers and data centers are more conservative than NFPA 99. The grounding standards for all of these environments require a resistance greater than 1,000,000 (1.0 X 10 E6) ohms.
See this link:http://www.staticworx.com/articles/MotorolaR56-ATIS-0600321_flooring_dissipative_not_conductive.php
Download Chart-Comparison-Staticworx SDC-vs-PVC-free Conductive
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