rf safety at wireless sites bob johnson, l-3 communications narda safety test solutions
TRANSCRIPT
RF Safety at Wireless Sites
Bob Johnson, L-3 Communications
Narda Safety Test Solutions
Presentation Overview
FCC Limits
Rooftops and Towers
RF Safety Compliance
AT&T vs. Orchitt and other legal happenings
The Golden Two Rules
Questions and Answers
Graphical Limits
1 3 10 30 100 300 1 3 10 30 100 300 3 10 30 100 300
= Controlled/Occupational Environments= Uncontrolled/General Public Environments
0.1
1.0
10
100
1000
47 CFR 1.1310 Radio-frequency exposure limits (in terms of equivalent power density)
kHz
mW/cm2
H
E
S
MHz GHz
Important Points About Compliance
Note that limits are specified in “Controlled/Occupational” and “Uncontrolled/General Population”. A fence does not make your facility “Controlled/Occupational”.
Your property is an “Uncontrolled” environment without an RF safety plan.
IEEE C95.7 recommends that you initiate an RF safety program, and appoint an RFSO, if you exceed similar “Action” level.
Engineering Controls
Elevate Antennas
Reduce power
Relocate Antennas
Increase distance between antennas
Administrative Controls
Posting Signage
Installing Barriers
Employing Personal Monitors
Specific Site Safety Rules
Barriers
An attempt to comply was made, however restricted areas must be maintained!
Note, status of plastic chain fencing
EME Action Thresholds
GeneralPublic
SiteWorker
RFQualified
And TrainedWorker
OnlyFools
Allowed
20%
100%
300%
1000%
No Procedures Required
Post Notice Sign, EMEGuidelines. General EME Awareness
EME Protective ClothingHigh Level Site Specific
AwarenessPost Caution Sign
Post Warning Signs
Performing Surveys
Many have purchased “broadband equipment”. This system reads out directly in terms of “% of Std.”.
In this case, that is % of FCC limits for Occupational/Controlled” environments.
Therefore, any readings above 20% means a safety plan is required, with additional controls above 100%.
Performing Surveys
At Multiple emitter sites, broadband equipment cannot adequately measure 5% contributors.
Narrowband equipment such as the SRM-3000 can measure all emitters individually without turning any emitters off.
This type of a system is being trialed by the FCC Enforcement Bureau, now.
Personal RF Monitors
Wearable monitors are available for qualified person use in areas where high levels are known to exist, like on towers.
Models can be supplied with climbing pouches and higher alarm levels for use with suits.
Always worn on outside!
Review
Find out what the field levels are at your site.
Get proper signs, and install them in the right place.
Remember to spatially average readings, don’t overly restrict your emissions.
Remember 5% rule.
Follow-up with readings when antennas are changed or anything that could alter your action areas.
Recent Litigation
August 20, 2007 - Decision of The Supreme Court of the State of Alaska No. 6139 - July 6, 2007 AT&T Alascom and Ward North America, Inc., v. John Orchitt; and The State of Alaska, Department of Labor and Workforce Development, Division of Workers' Compensation. Alaska Supreme Court Upholds Award for RF Radiation Injury Below Thermal Exposure Level.
The Golden Rules
In order to comply with FCC RF Exposure regulations, you only need to do two things:
Insure your employees cannot be over-exposed by any entities emitters
Insure no person is over-exposed by your emitters
Safety programs must be in place for areas where the action (“Uncontrolled/ General Public”) level is exceeded.
Questions?
World leaders in RF safety programs, products and support for FCC licensees.
For help with your program, (even if your not buying anything!) give us a call at (631) 231-1700 Extensions 230 or 434.
www.narda-sts.us