A Guide to Grounding Standards for 911 Call Centers: Motorola R56 and ATIS-0600321-2010
We recommend watching this video, "How to Choose Anti-Static Carpet for 911 Call Centers and FAA Applications" before reading this archived article about static electricity discharge problems in emergency 911 dispatch call centers. You will learn why it is important to reference compliance with standards like Motorola R56 and ATIS 0600321 before ever installing any static control carpet in any type of call center or command room.
There is a lot of confusion concerning the correct ohms rating for static control flooring used in end user operational equipment environments like E 911 Emergency dispatch communication centers. Most of the confusion is caused by mixing the flooring requirements of an end user with the static prevention standards and strategies used in electronics manufacturing and explosives handling. The purpose of this post is to clear up this confusion and provide you with access to application-appropriate industry resources and standards organizations. Please note: the ESD Association document ANSI/ESD S20.20-2007 is not referenced in this article because S20.20 is intended for practitioners who wish to design and implement a static control process in ESD protected areas as part of a comprehensive program in electronics manufacturing environments. This article strictly deals with end user operational equipment concerns like data centers and dispatch call centers.
During research for an upcoming September 2011 article, we examined FAA, telecommunications and computer industry grounding, lightening and safety standards. The research yielded information that lays to rest outdated assumptions about the proper electrical specifications of floors - particularly carpeting - installed in environments where static sensitive operational equipment is used. Many ESD flooring distributors incorrectly assumed that conductive flooring measuring between 2.5 X 10 E4 and 1.0 X 10 E6 was acceptable and in fact preferred for static sensitive end user environments. This static prevention strategy was borrowed from unrelated requirements involving the mandatory use of conductive flooring when handling explosives and flammable materials. This assumption and the applicability of explosives grade flooring for installation in end user environments - spaces often accessible to the public - is incorrect and poses unnecessary risks. Conductive flooring does not comply with the pertinent grounding standards for electronic end user spaces. According to five different authorities and/or standards organizations, there is consensus in the recommended ohms resistance range for the type of flooring discussed here. The overlap or consensus opinion consists of a range above 1.0 X 10 E6 and below 1.0 X 10 E10 ohms for end user spaces like server rooms, 911 call centers and data centers.
Specifically we looked at standards and recommendations from the following organizations:
IBM site recommendation and physical planning
IBM's Recommended range of flooring 1.5 X 10 E5 - 1.0 X 10 E10 ohms
A common document referenced by data center designers
Motorola R56 Standards and Guidelines for Communication Sites
MEASURES FOR CONTROLLING ELECTROSTATIC DISCHARGE: PROTECTING AGAINST ELECTROSTATIC DISCHARGE IN EQUIPMENT ROOMS AND DISPATCH CENTERS
APPENDIX C: PROTECTING AGAINST ELECTROSTATIC DISCHARGE IN EQUIPMENT ROOMS
AND DISPATCH CENTERS from Appendix C 3.3 of 2005 - 68P81089E50-B
9/1/05 — UP Version:
"Carpeting or floor tiles within an equipment room or dispatch center, including raised flooring, should have a resistance to ground measurement of between 106 and 109 ohms when measured using the test method of ANSI/ESD STM7.1-2001 or later"
A new revision will be coming soon. This information was provided directly to Staticworx by the current working R56 committee.The excerpt from the new version is pasted into the bottom of this post
This standard is often cited for defining grounding parameters in 911 call centers
ATIS-0600321-2010 Protection for Network Operator-Type Equipment Positions
Available for purchase: Digital Edition available from www.engineers.ihs.com
Excerpt: Page 5, Section 4.2 Flooring
"Any carpeting or floor tiles should have a resistance to ground between 10 E6 and 10 E10 ohms when measured using the method of ESD-S7.1."
A telecommunications standard overseen by most telecommunications manufacturers
Applicable to numerous environments
FAA STD 019e Lightning and Surge Protection, Grounding, Bonding and Shielding
Section 184.108.40.206.3.5 Static Dissipative ESD Floor Coverings
Recommended range of flooring 1.0 X 10 E6 - 1.0 X 10 E9 ohms
The 019e document supersedes a previous document (019d) where conductive flooring was considered acceptable.
Requirements for the Design of ICT Rooms - Best Practice Document
Recommended range of flooring 1.0 X 10 E6 - 1.0 X 10 E7 ohms per a European resistive properties test method.
Section 3 - Subsection 9 General Requirements
As you review these organization's recommended parameters keep in mind 3 factors:
- Research has shown that conductive flooring offers no advantage over static dissipative flooring in end user environments.
- When evaluating the ohms ratings, keep in mind that the difference between each ascending exponent is a factor of 10. For example 1.5 X 10 to the 4th = 15,000 ohms --- 1.5 X 10 to the 5th = 150,000 ohms
- A floor measuring between 2.5 X 10 E4 and 1.0 x 10 E6 is defined as a conductive floor. A floor measuring between 1.0 X 10 E6 and 1.0 X 10 E9 is defined as a static dissipative floor.
Addendum: As part of our research we contacted Shane Morrison, a member of the Motorola committee overseeing Motorola R56. The purpose of contact was to determine if Motorola might be expanding their electrical resistance range for acceptable static control carpet. The pre-2011 range was 1.0 X 10 E6 to 1.0 X 10 E9 ohms. There is currently a new draft of R56 in the works. As with other grounding and electrical standards organizations like ATIS, we were told that Motorola's acceptable resistance range will remain in the static dissipative range from 1.0 X 10 E6 to 1.0 X 10 E9.
Below is an excerpt as will appear in the new draft:
Motorola R56 Appendix C
PROTECTING AGAINST ELECTROSTATIC DISCHARGE (ESD) IN EQUIPMENT ROOMS AND DISPATCH CENTERS
Carpeting or floor tiles within an equipment room or dispatch center, including raised flooring, should have a resistance to ground measurement of between 106 and 109 ohms when measured using the test method of ANSI/ESD-S7.1-2005 or later. Existing flooring that does not meet this requirement should be treated with a topical solution such as an antistatic floor wax or spray solution. The effectiveness of antistatic solutions is temporary and varies with floor material and relative humidity. Flooring resistance should be monitored every two weeks minimum to verify conformance to the above requirements. See ATIS-0600321.2010, section 4.2 and ANSI/ESD-S7.1-2005 for more information.
When ESD protective flooring is used, the following should be observed:
- ESD protective flooring shall be installed per the manufacturer's recommendations.
- ESD protective flooring and floor coverings should be installed, grounded, and tested by trained installers.
- Personnel entering the equipment room or dispatch area should wear ESD dissipative footwear or dissipative foot straps. The footwear should provide dissipative resistance values of less than 3.5 ´ 107 ohms as measured according to the measuring requirements within ANSI/ESD STM97.1-2006 or later. The footwear should also provide dissipative resistance values of less than 1.0 ´ 109 ohms as measured according to the measuring requirements of ANSI/ESD STM97.1-2006 or later.
When ESD protective flooring is not installed at a dispatch position or equipment room, an ESD protective floor mat should be installed at the work areas. When ESD protective floor mats are installed, the following should be observed:
- The floor mat should provide dissipative resistance values between 106 and 109 ohms when measured using the test method of ANSI/ESD-S7.1-2005 or later.