Avionics EMF Safety Training_Initial and Annual

1
EMF 101 :
Basics, Terminology, and Applications

2
Overview
Basics
• The Electromagnetic Spectrum
• Nonionizing Radiation
• Terminology
• Applications
• Health Effects
• Common Intentional/Unintentional Sources
• Workplace Specific Sources

3
The Electromagnetic
Spectrum

4
What is EMR?
• Electromagnetic radiation (EMR) consists of waves of
electric and magnetic energy moving together
through space at the speed of light
Need diagram of plane wave

5
Types of EMR
• Ionizing
– Has enough photon energy to
ionize atoms
– Effects can be stochastic or
nonstochastic
• Non-Ionizing
– Not enough photon energy to
ionize atoms
– All nonstochastic (threshold
effects)

6
Non-Ionizing Radiation
• The energy levels associated with nonionizing
photons are not great enough to cause the ionization
of atoms and molecules
• The effects are non-stochastic, threshold effects

9
Terminology
• Complete glossary can be found in AFI 48-109
• Antenna—A device designed for radiating (or
receiving) electromagnetic energy
• Athermal Effect—(nonthermal effect) Any effect of
electromagnetic energy absorption with or not
dependent upon the production of heat or a
measurable rise in temperature.
• Average Power (Pavg)—The time-averaged rate of
energy transfer:

10
Terminology (Cont.)
• Decibel (dB)—The logarithmic unit used to indicate
relative intensities of power or voltage, equal to 10
times for power, and 20 times for voltage, the common
logarithm of the ratio
• Hertz (Hz)—The unit for expressing frequency. One
hertz equals one cycle per second. Commonly used
multiples are kilo-hertz (kHz), megahertz (MHz), and
gigahertz (GHz)
A2
A1
dB = 20 log10 dB = 10 log10
P2
P1
________

11
• Impedance—The total opposition that a circuit or
propagation path presents to an EMF current or wave.
The ratio of the electric field strength to the magnetic
field strength
• Power—A physical quantity describing the rate of
delivery or transmission of energy. In this document,
power will refer to radiofrequency power with units of
watts (W)
• Power Density (S)—Power per unit area normal to the
direction of propagation, usually expressed in watts
per meter squared (W/m2) for hazard assessment, or
mW/cm2. See also Pointing Vector
Terminology (Cont.)

12
Terminology (Cont.)
• Specific Absorption Rate (SAR)—The time rate at
which RFR energy is imparted to an element of
biological body mass. Average SAR in a body is the
time rate of the total energy absorbed divided by the
total mass of the body. SAR is expressed in units of
watts per kilogram (W/kg). Specific absorption (SA)
refers to the amount of energy absorbed over an
exposure time period and is expressed in units of
joules per kilogram (J/kg). The time derivative (rate) of
the incremental energy (dW) absorbed by an
incremental mass (dm) contained in a volume element
(dV) of a given density (r). SAR is expressed in units of
watts per kilogram (W/kg)

13
Upper Tier or Controlled Exposure Standards
• Safety Margin (a factor of 10) is applied to the accepted threshold of effect
(4W/kg)
• SAR Exposure criterion of 0.4 W/kg (0.1 MHz - 6 GHz)
Lower Tier or UnControlled Exposure Standards
• Safety Margin (a factor of 50) is applied to the accepted threshold of effect
(4W/kg)
• SAR Exposure criterion of 0.08 W/kg (0.1 MHz - 6 GHz)
2 Tiered Standard

14
Specific Absorption
Rate (SAR)
• The average value of energy absorbed by the whole body
• Power per unit body weight (watts)/kilogram (W/kg)
• SARs above 4 W/kg have potential for harmful effects
• 4 W/kg has been established as the Working Threshold for Unfavorable
Effects in humans

15
• < 0.1 MHz - Electro-stimulation of tissue
• 0.1 MHz - 6 GHz - Specific Absorption Rate
• 6 GHz - 300 GHz - Surface heating, body is quasi-optical
Spectrum Coverage –
3 kHz-300 GHz

16
Contact Current EMF Burn
• EMF burns can occur when EMF current enters through a small cross-
section of the body
• EMF burns can occur at any EMF frequency
• The conditions for an EMF burn can even exist on systems not subject to
EMF control
• Potential locations for EMF burn are: Antennas, cables, connectors, all
EMF circuits, and microphones – any bare metal

17
Induced Current
• In any environment, currents are limited to a level that prevents EMF
burns due to high current densities
• Below 100 kHz in Upper Tier Environments : Current density is a function
of frequency
• Above 100 kHz, 100 mA threshold applies

18
Induced and Contact
Current > 100kHz
• Perceived as heat
• Threshold for perception depends upon:
- Frequency of the current
- Surface area of contact
- Individual characteristics
• Perception: Just able to detect the stimulus
• Annoyance: Mild irritant if repeated
• Startle: One exposure sufficient to avoid

19
Overexposure Responsibilities
• Individual(s) exposed notify supervisor
• Supervisor notifies unit RPO
– Supervisor ensures hospitalization if obvious
injury
– If not, Flight Surgeon within 72 hours
• Emergency Room notifies PH to initiate an AF Form
190

20
BES Investigation
• Name, rank, & SSAN
• RF emitter information:
– gain, frequency, peak & average power, duty
factors, sweep characteristics, beam
configuration (beam width, sector size)
• Operational description
• Dates, times, exposure duration, & individual
narratives
• Name and rank of the attending physician

21
Overexposure Investigations
• Arrange with unit supervisor to reconstruct the
incident
• Measurements to determine actual exposure levels
• Get photographic support
• All personnel should be present

24
Navigation Aids
AN/TRN-26 Deployable
TACAN Beacon-Transponder
Set
VORTAC
ILS

28
Common Unintentional
Sources

31
Workplace Specific Sources
MODEL AN/ARC - 164
NOMENCLATURE UHF RADIO F-16 ACFT
LOCATION Varies
FREQUENCY CLASSIFIED
UPPER TIER LIMIT CLASSIFIED
LOWER TIER LIMIT CLASSIFIED
HAZARD DISTANCE 2.93 feet

32
MODEL AN/APG-68
NOMENCLATURE FIRE CONTROL RADAR
LOCATION Varies
HAZARD DISTANCE 120 feet

33
MODEL AN/ARC - 186
NOMENCLATURE VHF RADIO F-16 ACFT
LOCATION Varies

34
MODEL ARN-118
NOMENCLATURE TACAN
LOCATION Varies

35
MODEL AN/APX-101
NOMENCLATURE IFF
LOCATION Varies

36
MODEL AN/PLM-4(V3)
NOMENCLATURE RADAR SIMULATOR
LOCATION Varies
HAZARD DISTANCE Non-Hazardous

37
MODEL AN/APN-232
NOMENCLATURE RADAR SIMULATOR
LOCATION Varies

38
MODEL SADL
NOMENCLATURE SADL RADIO F-16 ACFT
LOCATION Varies

39
MODEL TS-4530/USM
NOMENCLATURE IFF T/S (Test Stand)
LOCATION Varies

40
MODEL IFR-4000
NOMENCLATURE ILS T/S (Test Stand)
LOCATION Varies

41
MODEL AN/APX-113
NOMENCLATURE AIFF
LOCATION Varies

42
MODEL AN/ARC-210
NOMENCLATURE RT-1851A COMM 2
LOCATION Varies

43
MODEL AN/ARC-210
NOMENCLATURE RT-1990 COMM 3
LOCATION Varies

Avionics EMF Safety Training_Initial and Annual

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Avionics EMF Safety Training_Initial and Annual

Similar to Avionics EMF Safety Training_Initial and Annual (20)

More from William Perkins

More from William Perkins (20)

Recently uploaded

Recently uploaded (20)

Avionics EMF Safety Training_Initial and Annual