Rf Health&Safety

Health and Safety (HS-PHS)

HS-PHS
© Copyright 2001 Global Wireless Education Consortium
All rights reserved. This module, comprising presentation slides with notes, exercises, projects and Instructor Guide, may not be duplicated in any way without the express written permission of the Global Wireless Education Consortium. The information contained herein is for the personal use of the reader and may not be incorporated in any commercial training materials or for-profit education programs, books, databases, or any kind of software without the written permission of the Global Wireless Education Consortium. Making copies of this module, or any portion, for any purpose other than your own, is a violation of United States copyright laws.
Trademarked names appear throughout this module. All trademarked names have been used with the permission of their owners .

HS-PHS
Partial support for this curriculum material was provided by the National Science Foundation's Course, Curriculum, and Laboratory Improvement Program under grant DUE-9972380 and Advanced Technological Education Program under grant DUE‑9950039.
GWEC EDUCATION PARTNERS: This material is subject to the legal License Agreement signed by your institution. Please refer to this License Agreement for restrictions of use.

Table of Contents
Overview 5
Learning Objectives 6
Electromagnetic Radiation 7
Site Safety 20
Compliance 34
Summary 39
Contributors 41

Overview
In this module you will learn about radiated power and how it effects the population. You will learn about personal protective equipment and how to work safely at a site that contains electromagnetic radiation. Standards in the U.S. will be discussed along with OSHA requirements.

Learning Objectives
After completing this module, you will be able to:
Explain radiated power and its effects on workers and the general population
Explain OSHA requirements as they relate to RF personal health and safety.

Electromagnetic Radiation

Electromagnetic Energy Samples

Ionizing vs. Non-ionizing Frequencies

EME Mechanism of Injury EME at frequencies above UV Light have enough energy to tear electrons from their atoms. This can cause permanent biological changes to the molecular structure of cells.

RFR Burn vs. Surface Burn A RFR Burn starts at the bone and heats outward towards the skin A surface burn begins at the skin surface and moves inward towards the bone

Whole Body Heating

Whole Body Resonance

Maximum Potential Energy Calculations
Examples:
0% - 100% of MPE* = No time limit
200% of MPE* = 3 minutes, then 3 minutes at 0%
300% of MPS* = 2 minutes, then 4 minutes at 0%
*(MPE = Maximum Potential Energy)

Spatial Averaging versus Metabolic Rate
If measurements were taken at three heights with the following values:
1 foot at 1.0 mW/cm2
3 feet at 2.0 mW.cm2
6 feet at 3.0 mW/cm2
The spatial averaging would be 2.0 MW/cm2

Overexposure Symptoms
Symptoms of overexposure to EME include, nausea, headache, an overall feeling of warmth, perspiration, elevated body temperature, and labored breathing. Severe cases can mimic heat stroke.

General Population Exposure (Uncontrolled)

Occupational Exposure (Controlled)

Site Safety

Common Radio Frequency Antennas
Examples of common radio frequency antennas include the following:
A TV-VHF/UHF antenna has a frequency of 60-600 MHz, power input of 1,000-100,000 watts, a gain of 10 dB, and an ERP of 10,000-1,000,000 watts.
A FM antenna has a frequency of 80-108 MHz, power input of 100-10,000 watts, a gain of 10 dB, and an ERP of 10,000-100,000 watts.
An AM antenna has a frequency of 550-1700 KHz, power input of 100-10,000 watts, a gain output equal to the input, and an ERP of 500-50 kW.

Multiple Signal Sources

Antenna Parameters

Effects of Reflections of RFR Levels

EPA Model for Broadcast and Communication Sites Where ERP = Effective Radiated Power, in watts R = Height of antenna, in meters S = Field strength, in µw/cm 2 (For more information, refer to the GWEC module RT-RF Antenna )

Conducting a Site Survey
The following survey points should be taken into consideration:
Extent of hazardous and potentially hazardous areas, both on and off site.
Control techniques that will effectively reduce potential hazards.
Any other situations that might create a hazardous area (e.g., chemicals, noise, high voltage, or fall hazard).

Final Site Survey Report
When conducting a site survey, the surveyor will prepare a final survey report. This report should document the following:
Adequacy of administrative controls.
Personnel attitudes.
Diagrams or pictures of the site.
Both roof-tops and tower require drawings with dimensions showing position of every antenna.
Results of calculations performed prior to the survey.
Action level radius and height above the ground.
All areas where Occupational Controlled and General Population Uncontrolled levels are exceeded.
Conclusions and recommendations.

RFR Personal Monitors
50 MHz to 2,000 MHz model covers:
Cellular and PCS
Paging systems
Two-way radio systems
SMR systems
FM radio broadcast
VHF and UHF TV
Low Frequency Model covers:
AM radio broadcast
Low band public safety
High frequency model covers:
Satellite uplink
Microwave point-to-point

Basic Work Rules
Certain work rules will help avoid over exposure. These rules are:
Wear RFR personal monitors at all times when:
Working on a roof-top
Working within 30 feet of the base of a tower
When climbing on a tower containing antennas.
The alarm of an RFR personal monitor has priority over another indication of RFR level, even if there is a sign posted stating the RFR level of the area.
Contact the tower owner or management company for special instructions at sites with radio or television broadcast antennas.
Wear RFR personal monitors at all times when working within 500 feet of the base of a tower containing any type of radio or television broadcast antenna system.
Carry two-way radios when working on a tower within 500 feet of broadcast antennas.

Standards in the U.S. Standards in the U.S. Two major standards are used in the U.S.:  IEEE C95.1-1991 (ANSI C95.1-1982)  FCC 1997 Regulations IEEE FCC

Radiation Protection Guide (ANSI C 95.1-1982)

OSHA Standard
State OSHAs support the 1997 FCC regulations and are more aggressive than the federal OSHA.
Consider total exposure levels (regardless of the source or owner).
Has the authority to levy large fines and suspend operations.

Liability for Service Organizations

Compliance

What is Compliance?

Making a Site Compliant
There are two ways to make a site compliant:
Make the site compliant by design
Operate under an RF safety program.

Safety Program
If a site is compliant because it operates under a safety program, the safety program in place must:
Limit the exposure of individuals not covered by the safety program to below the General Population MPE levels.
Limit exposure to workers covered by the safety program to levels below the Occupational/Controlled levels.
Train covered workers to understand RF safety issues and know safe work practices.

Determining Compliance

Summary

Summary
In this module, we have discussed the following topics:
Ionizing versus non-ionizing electromagnetic radiation
The biological effects of EME
Spatial averaging versus metabolic rate
Overexposure symptoms
Uncontrolled exposure
Controlled exposure
Site safety
Standards in the U.S.
OSHA compliance.

Industry Contributors
Telcordia Technologies, Inc ( http://www.telcordia.com )
The following companies provided materials and resource support for this module:

Individual Contributors
The following individuals and their organization or institution provided materials, resources, and development input for this module:
Dr. Cynthia Furse
Utah State University – Department of Electrical and Computer Engineering ( http://www.engineering.usu.edu/ece/faculty/furse/index.html )

Rf Health&Safety

by Deepak Sharma on Jan 24, 2010

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Rf Health&Safety — Presentation Transcript

Rf Health&amp;Safety

by Deepak Sharma on Jan 24, 2010

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Rf Health&amp;Safety — Presentation Transcript

Rf Health&Safety

Rf Health&Safety — Presentation Transcript