A Comparison of IEEE C95.7
Radio Frequency (RF) Safety
Program Elements with
Elements Recommended for
Laser Safety
in the ANSI Z136.1 Standard
Stephen W. Hemperly, CIH, CSP, CLSO
Hitachi Global Storage Technologies
San Jose, CA
AIHCE 2006 – Roundtable 217
Presentation Outline
Background on nonionizing radiation (NIR)
safety program-related guidelines &
standards
Radio frequency (RF) & laser radiation
sources
RF and laser safety program elements
Summary
Background
“Nonionizing radiation safety programs
exclusive of laser safety programs, are rare.
This is likely because the ANSI Z136.1
Standard for Safe Use of Lasers (ANSI
1993) addresses the complete laser safety
program.”
R.T. Hitchcock and R.M. Patterson: Radiation Control
Program. In Radio-Frequency and ELF Electromagnetic
Energies. New York: Van Nostrand Reinhold, 1995. p. 475.
Nonionizing Radiation Protection
Program Elements
Program responsibility
Inventory of sources
Pre-purchase approval of
sources
Hazard assessment
Accident / incident
investigation
Control measures
Information and training
Hazard communication
Medical surveillance
Instrument calibration
Self-checks and audits
Documentation
Recordkeeping
R.T. Hitchcock, C.E. Moss, W.E. Murray, R.M. Patterson, and R.
James Rockwell: Chapter 22, Nonionizing Radiation in The
Occupational Environment: Its Evaluation, Control, and Management,
2nd Edition. Fairfax, VA: AIHA, 2003. p. 547.
Elements of a Comprehensive RF
Protection Program:
RF source equipment
meeting RF or other
safety standards
RF hazard ID & periodic
surveillance by
competent person
RF hazard area ID/control
Control RF exposures to
applicable guidelines
RF safety & health
training
Employee involvement in
program structure and
operation
Implementation of
appropriate medical
surveillance
Periodic review of program
effectiveness
Responsibility, authority, &
resources to implement &
enforce program aspects
R.A. Curtis (Director USDOL/OSHA Health Response Team:
Presentation to National Assoc. of Broadcasters at Broadcast
Engineers Conference; Las Vegas, NV; April 12, 1995
Nonionizing Radiation Protection
Program Elements
Program responsibility
Inventory of sources
Pre-purchase approval of
sources
Hazard assessment
Accident / incident
investigation
Control measures
Information and training
Hazard communication
Medical surveillance
Instrument calibration
Self-checks and audits
Documentation
Recordkeeping
R.T. Hitchcock, C.E. Moss, W.E. Murray, R.M. Patterson, and R.
James Rockwell: Chapter 22, Nonionizing Radiation in The
Occupational Environment: Its Evaluation, Control, and Management,
2nd Edition. Fairfax, VA: AIHA, 2003. p. 547.
Radio Frequency (RF) Safety
Standards
Institute of Electrical and Electronics Engineers,
Inc. (IEEE) ANSI– approved voluntary standards
– C95.1-- “Safety Levels with Respect to Human
Exposure to Radio Frequency Electromagnetic Fields,
3 kHz to 300 GHz”
– C95.2 – RF energy and current flow symbols
– C95.3 -- Measurements & computations of RF fields
– C95.4 – Safe distances between RF antennas and
blasting caps
– C95.6 – Safety Levels for 0-3 kHz (sub-RF) fields
– C95.7 – “Recommended Practice for Radio
Frequency Safety Programs, 3 kHz to 300 GHz”
IEEE C95.7 – 2005 Recommended
Practice for RF Safety Programs
1. Overview (Scope, Purpose, Application)
2. References
3. Definitions, abbreviations, etc.
4. RF safety program elements
Plus Nine Appendices (Informative)
Laser Safety Standards
Most current Z136.1 version published in 2000
Updated version (2006?)
Z136.1 – “Mother” of laser safety standard family
–
–
–
–
–
–
Z136.2 – Optical fiber communication systems
Z136.3 – Health Care Facilities
Z136.4 – Measurements and Instrumentation
Z136.5 – Educational Institutions
Z136.6 – Outdoor Use
Z136.7 – Protective Devices (draft)
Europe’s International Electrotechnical
Commission (IEC) – additional set of standards
ANSI Z136.1 -2000
Safe Use of Lasers
1.
2.
3.
4.
5.
6.
7.
General (Scope,
Application, LSO)
Definitions
Hazard Evaluation and
Classification
Control Measures
Laser Safety Programs
& Employee Training
Medical Surveillance
Non-beam Hazards
Criteria for Exposure to
Skin and Eyes
9. Measurements
10. Revision of Standards
Referred to in This
Document
Tables & Figures (part of
standard)
Eight Appendices (for
Information only)
8.
Scope
IEEE C95.7-2005
Guidelines/procedures for RF
safety program
Frequency range:
300 GHz – 3 kHz
Microwave (MW) subset:
300 GHz to 300 MHz
ACGIH: 30 kHz to 3 kHz is
sub-radiofrequency
Wavelength range:
1 meter (m) to 105 m
ANSI Z136.1-2000
Recommendations for safe
laser use
Frequency range:
(generally not used a laser
source descriptor)
Wavelength range:
180 nm to 1 mm
Purpose and Application
IEEE C95.7-2005
• Assist in RF safety program
ANSI Z136.1-2000
Provide reasonable and
adequate guidance for safe
development
use of lasers and laser
• Control potentially hazardous
systems
exposure to worker or public
Based on characterizing areas Based on placement of
subject to RF energies into one lasers/laser systems into a
of four exposure categories
hazard class
References other standards in References other special
IEEE C95 series
laser application standards
in Z136 series
RF Exposure Categories
RFSP
Category
Exposure Condition
Control Actions
Required
1
Action level not
exceeded
None; except when
action level exceeded
2
Possible action level,
but not exposure
limit, exceedance
Exposure limit
exceedance w/o
mitigating controls
Exposure limit
exceeded in
accessible areas
Some program
elements, signage,
time averaging
More program
elements, RFSO,
more training,
Restrict source
output or prevent
personnel access
3
4
RF Exposure Sources
Dielectric heaters (10-100 MHz, many at 27 MHz)
Induction furnaces (<10 kHz) and
heaters (3.9 kHz – 1.25 MHz)
Microwave heaters (915 and 2450 MHz)
Plasma processors (100 kHz – 2450 MHz, typically
13.56 MHz)
Broadcasting (535 kHz – 890 MHz)
Communications (3 – 2000 MHz, 43-45 & 94 GHz)
Radar (primarily 1-35 GHz)
VDTs and Televisions (10-75 kHz w/ higher harmonics)
Medical devices (500 KHz – 100MHz)
Sputtering Device
Laser Hazard Classes
Class
Exposure Condition
Control Actions Required
1
Eye safe, even with
optical aids
None – except for
enclosed Class 3B or 4
1M
Class 1, except with
optical aids
No optical aids; or aids
adequately attenuated
2
(visible)
Safe for momentary
viewing
0.25 sec. aversion
response protective
2M
(visible)
Class 2, except with
optical aids
No optical aids; or aids
adequately attenuated
3R
Marginally unsafe for
intrabeam viewing
Limited controls (e.g.
labels and training)
3B
Unsafe for intrabeam LSO; harmful access
viewing
preventing controls
4
Eye and skin hazard
Restrict source output or
prevent personnel access
Laser Exposure Sources
Material processing lasers (Nd:YAG, CO2, excimer,
Nd:glass)
Research & medical lasers (CO2, argon, excimer,
krypton, HeNe, Nd:YAG & freq.-doubled Nd:YAG)
Laser pointers (HeNe, diodes, and freq.-doubled
Nd:YAG lasers)
Telecommunication lasers (diodes in fiber optics;
VCSELs in free space optical communication systems)
Military lasers (Nd:YAG & visible diode)
Alignment lasers (HeNe & visible diode
Bar code-reading lasers (HeNe & diode)
While this can not really happen, one CAN get a thermal
lesion on one's retina by staring long enough down the axis
of a laser pointer's beam. Please remember that laser
pointers are tools not toys!
Lasers in Research Lab
Laser Research Laboratory
Free Space Optical Communication
with RF Backup
Linkhead with
Class IM
RF output
5.4 to 5.8 GHz
output from
multiple (4)
100 mW
850 nm
Vertical Cavity
Surface
Emitting Lasers
(VCSELs)
Laser-Containing Tool
RF - Excessive Exposure Effects
Frequency (thus, wavelength) dependent
Thermal effects
• Behavioral/other nervous
system effect (reversible)
• Reproductive &
developmental effects
(animal data only)
• Cancer (animal data only –
inconclusive)
•Ocular effects (restrained
animals only)
• Skin burns (delayed &
similar to sunburn)
• MW clicking – cochlear
thermal elastic expansion &
contraction
Note: Specific non-thermal effect mechanism not
identified – no effects clearly linked to non-thermal
exposures
Lasers - Excessive Exposure
Effects
Laser Effects -- Wavelength dependent
(e.g., 400-1400 nm – retinal hazard region)
Eye injury
• Retinal thermal burns, acoustic damage,
photochemical injury
• Lens-related damage
• Corneal damage
• Skin damage (thermal & photochemical)
Viewing Conditions
LASER
Intrabeam Direct (primary)
Beam
LASER
Curved
mirror
Intrabeam - Curved
Surface Specular
Reflection
LASER
LASER
visual angle
Intrabeam - Flat
Surface Specular
Reflection
Point Source Diffusion Reflection
(Extended Source Viewing When Apparent
Visual Angle Exceeds Some Minimum)
Optical Gain of the Eye
Lens
Cornea
Iris
Retina
Pigment Epithelium
Fovea Centralis
Macula Lutea
Optic Nerve
Aqueous
Optic Disk
Ciliary Muscle
Sclera
Choroid
For wavelengths that focus on the retina, the optical gain of
the eye is ~ 100,000 times: if irradiance at cornea is
1 mW / cm², then irradiance at the retina will be 100 W /cm².
Radio Frequency Safety Program
(RFSP) Elements per IEEE C95.7
Administrative (includes designation of
Radio Frequency Safety Officer [RFSO])
Identification of Potential RF Hazards
Controls
Personal Protective Equipment (PPE)
Training
RFSP Audit
Ancillary Hazards
Laser Safety Program Elements
per ANSI Z136.1 (Sec. 5 & App. D)
Designated Laser Safety Officer (LSO)
Education and Training
Hazard Control Measures
Incident Investigations
Appropriate Medical Surveillance
Program Elements Comparison
RF Safety (IEEE C95.7)
Designation of RFSO
Potential RF hazard ID
Controls
– Engineering
– Administrative
Education & Training
PPE
RFSP Audits
RF Safety Committee
Medical Surveillance
Laser Safety (ANSI Z136.1)
Designation of LSO
Potential laser hazard ID
Control Measures
– Engineering
– Administrative
Education & Training
PPE
Surveys / Inspections
Incident Investigation
Laser Safety Committee
Medical surveillance
LSO Responsibilities
Conducting or verifying
laser classification
Evaluating laser hazards
Assuring control measure
implementation
Approving procedures
Recommending/approving
protective equipment
Approving signs & labels
Approving laser facilities &
equipment
Auditing safety features
Assuring provision of
training
Determining medical
surveillance
Providing or ensuring the
provision of laser safety
consultation services
Establishing/maintaining
laser hazard control
policies/procedures
Suspending, restricting, or
terminating laser operations
deemed unsafe
Ensuring maintenance of
necessary records
Conducting surveys
inspections/accident
investigations
RFSO Duties
Initially evaluating RF sources
Maintaining RF source
inventory
Evaluating safety procedures
Evaluating existing RF
exposure safety program
documentation
Disseminating RF safety policy
Providing authoritative advice
Reviewing/authorizing RF
surveys & control measures
Authorizing designated RF
safety personnel
Coordinating RF safety
awareness
Conducting/arranging
regular site audits
Conducting annual RF
hazard survey policies &
procedures review
Managing policy &
procedure breaches,
including accidental overexposure incidents
Developing/approving RF
hazard assessment tools
Arranging for regular
survey/monitoring
equipment calibration
Ensuring proper
documentation control and
central archiving
RF Safety Training
General awareness training for “all persons” with access to
areas where RF exposure may exceed applicable limits.
Commensurate with exposure situation include:
– Introduction to RF sources & RF safety (RF generation,
propagation, transmission, antennas, etc.)
– Discussion of biological effects/hazards
– Explanation of standards/regulations and basis for them
– Information about potential excessive exposure situations
& their control
– RF safety program elements
– Instruction on how to respond to over-exposure incidents
– Information about potential RF susceptibility of medical
devices/implants & electro-explosive devices at field
strengths substantially less than human exposure limits
– Additional information sources
Exposure Guidelines
Radio-frequency (RF)
Radiation
Maximum Permissible
Exposure (MPE) values for
controlled and uncontrolled
environment
Per IEEE Std. C95.1
Action Levels
• C95.1 Lower tier limits
• Gen. public guidelines
(FCC & ICNIRP)
• One-fifth of ACGIH TLVs
Laser Radiation
MPE values
Per ANSI
Z136.1depending on
emission characteristics
and viewing conditions
Laser Safety Training
Laser safety training for “each employee working routinely
with or around lasers above Class 3a…” Commensurate
with the greatest potential hazards include:
– Fundamentals of laser operation
– Bioeffects of laser radiation
– Specular vs. diffuse reflections
– Non-beam (ancillary) hazards of lasers
– Laser and laser system classes
– Control measures
– Management & employee responsibilities
– Medical surveillance practices
– Electrical safety and CPR training, as applicable
Ancillary Hazards – RF Sources
– Electric shock
– Ionizing radiation
– Mechanical
– Eye hazards
– Heat exchange
systems
– Fall from heights
and/or through
openings
– Confined space
entry
– Trip hazards
– Welding/cutting
operations
– Heat stress
– Toxic chemicals/gases
– Cooling refrigerants
– Optical radiation
sources, coherent
(lasers) and noncoherent sources
Per IEEE C95.7, Section 4.7
Ancillary Hazards - Lasers
– Electrical
– Laser-generated air
contaminants
– Collateral radiation
(X-ray, UV, visible, RF,
plasma radiation)
– Fire
– Explosion
– Compressed gases
– Laser dyes and
solvents
– Robotic mechanical
– Noise
– Waste disposal
– Limited work space
– Ergonomics
Per ANSI Z136.1-2000, Section 7
Elements Common to RF and
Laser Safety Programs
Identification and inventorying of exposure
sources (as well as potential exposure
populations)
Characterization of sources -- placement into:
– RFSP category based on exposure condition
assessment (instrument selection & measurements)
– Laser class by classifying or verifying laser
manufacturer’s classification
Ancillary hazards consideration / evaluation
Suitable control application
Training for potentially exposed individuals as
well as for RFSOs & LSOs
Thank you for your kind attention!!!
Should you have an interest in joining the
AIHA Nonionizing Radiation Committee –
or if you have questions after the conference,
I may be contacted at:
steve.hemperly@hitachigst.com