RF Safety at Wireless Sites

1
RF Safety at Wireless Sites

• Bob Johnson, L-3 Communications
• Narda Safety Test Solutions

2
Presentation Overview

• FCC Limits
• Rooftops and Towers
• RF Safety Compliance
• ATT vs. Orchitt and other legal happenings
• The Golden Two Rules
• Questions and Answers

3
Graphical Limits
47 CFR 1.1310 Radio-frequency exposure limits (in
terms of equivalent power density)
1000
Controlled/Occupational Environments
Uncontrolled/General Public Environments
H
100
E
10
S
1.0
0.1
3 10 30 100 300
1 3 10 30 100 300
1 3 10 30 100 300
mW/cm2
GHz
kHz
MHz
4
Important Points About Compliance

• Note that limits are specified in
  Controlled/Occupational and Uncontrolled/Genera
  l 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.

5
Engineering Controls

• Elevate Antennas
• Reduce power
• Relocate Antennas
• Increase distance between antennas

6
Administrative Controls

• Posting Signage
• Installing Barriers
• Employing Personal Monitors
• Specific Site Safety Rules

7
Barriers
An attempt to comply was made, however restricted
areas must be maintained!
Note, status of plastic chain fencing
8
EME Action Thresholds
Only Fools Allowed
Post Warning Signs
1000
RF Qualified And Trained Worker
EME Protective Clothing High Level Site
Specific Awareness Post Caution Sign
300
100
Site Worker
Post Notice Sign, EME Guidelines. General EME
Awareness
20
General Public
No Procedures Required
9
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.

10
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.

11
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!

12
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, dont
  overly restrict your emissions.
• Remember 5 rule.
• Follow-up with readings when antennas are changed
  or anything that could alter your action areas.

13
Recent Litigation

• August 20, 2007 - Decision of The Supreme Court
  of the State of Alaska No. 6139 - July 6, 2007
  ATT 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.

14
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.

15
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
• Nardasts_at_L-3com.com