Transcript Class 3b - UALR: Graduate Institute of Technology

Radiation Safety Program: Regulations and Practical
Considerations for Safe Use of Radioactivity
Radiation Safety Office
ETAS-239
501-569 8210
Graduate Institute of Technology, UALR
University of Arkansas at Little Rock
Ionizing and Non-ionizing radiation?
•
Radiation carries a range of energy forming an electromagnetic spectrum.
•
Radiation that does not have enough energy to break chemical bonds but
can vibrate atom is referred to as “Non-ionizing Radiations” e.g.
radiowaves, microwaves, infrared, visible light etc.
•
Radiation that has enough energy to break chemical bonds is referred to
as 'ionizing radiation, e.g. alpha particles, beta particles, gamma rays etc.
Ionizing Radiation
How to know if there is a radiation
source or radiation area- Symbols?
How to know if there is a radiation
source or radiation area- Symbols?
"CAUTION RADIATION
AREA"
“CAUTION RADIOACTIVE
MATERIALS"
Radiation Package
Symbols
Radiation Protection Procedures
•External Radiation Protection
•Internal Radiation Protection
•Survey Procedures or Monitoring
•Radiation Spills
•Waste Disposal Guidelines
Radiation Dose Limit
A-L-A-R-A
ALARA is an acronym meaning As Low As
Reasonably Achievable. It is a requirement of
the agreement state (ADH) that all facilities
possessing radioactive materials licenses to
have a formal ALARA program. It is the policy of
University of Arkansas at Little Rock to keep this
exposure as low as reasonably achievable
(ALARA).
General Handling Precautions
•Protective Clothing:
lab coats, gloves, masks, eye protection, sealing tapes etc
•The Work Place
Designate Clean area, Hood, Absorbent paper, drip trays,
locks, no food items
•Manipulations of Radioactive Materials
plan ahead, pippetting, use minimum amounts, sealing
tubes, reduce volatilization, proper monitoring, shielding,
dosimeter, public perception
External Radiation Protection:
The Three Basic Rules
•Time:
Dose = Dose Rate x Time
•Distance:
The Inverse Square Law
ER2 = ER2 x (D1/D2)^2
•Shielding:
Radiation Energy
Shield Density
Shield Thickness
Bremsstrahlung
HVL & TVL
Concerns
Internal Radiation Protection
Mode of Entry into Body
Inhalation
Ingestion
Absorption
Injection
Individuals Requiring Radiation
Safety Training
Three general categories of UALR employees with respect
to their exposure to radiation:
•
Radiation Workers: Those workers whose major
responsibilities involve working with sources of ionizing
radiation or radioactive material.
•
Ancillary Workers: All personnel who may come in contact
with or enter an area that contains radioactive material or
sources of ionizing radiation e.g. janitorial staff.
•
Non-Radiation Workers: personnel who would not normally
be expected to encounter radioactive material or radiation
sources in the course of their employment at UALR. This
group does not require radiation training.
Emergency Contacts
Radiation Safety Officer
501-569-8210
Assistant Radiation Safety Officer
501-569-8003
After Hours: Public Safety
501-569-3550
Also check “NRC Notice to Employees” posted in
the radiation use and storage areas
Part 1:
Fundamentals of Laser
Operation
Laser Output
Pulsed Output (P)
Energy (Watts)
Energy (Joules)
Continuous Output (CW)
Time
Time
watt (W) - Unit of power or radiant flux (1 watt = 1 joule per second).
Joule (J) - A unit of energy
Energy (Q) The capacity for doing work. Energy content is commonly used to characterize the output
from pulsed lasers and is generally expressed in Joules (J).
Irradiance (E) - Power per unit area, expressed in watts per square centimeter.
Types of Laser Hazards
1.
2.
3.
4.
5.
Eye : Acute exposure of the eye to lasers of certain
wavelengths and power can cause corneal or retinal burns
(or both). Chronic exposure to excessive levels may cause
corneal or lenticular opacities (cataracts) or retinal injury.
Skin : Acute exposure to high levels of optical radiation
may cause skin burns; while carcinogenesis may occur for
ultraviolet wavelengths (290-320 nm).
Chemical : Some lasers require hazardous or toxic
substances to operate (i.e., chemical dye, Excimer lasers).
Electrical : Most lasers utilize high voltages that can be
lethal.
Fire : The solvents used in dye lasers are flammable. High
voltage pulse or flash lamps may cause ignition.
Flammable materials may be ignited by direct beams or
specular reflections from high power continuous wave
(CW) infrared lasers.
Lasers and Eyes
• What are the effects of laser energy on the eye?
– Laser light in the visible to near infrared spectrum (i.e., 400 1400 nm) can cause damage to the retina resulting in
scotoma (blind spot in the fovea). This wave band is also
know as the "retinal hazard region".
– Laser light in the ultraviolet (290 - 400 nm) or far infrared
(1400 - 10,600 nm) spectrum can cause damage to the
cornea and/or to the lens.
• Photoacoustic retinal damage may be associated
with an audible "pop" at the time of exposure. Visual
disorientation due to retinal damage may not be
apparent to the operator until considerable thermal
damage has occurred.
MULTIPLE PULSE RETINAL INJURY
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EYE INJURY BY Q-SWITCHED LASER
Retinal Injury produced by four pulses from a Nd:YAG laser range finder.
Photo courtesy of U S Army Center for Health Promotion and Preventive Medicine
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Skin Hazards
• Exposure of the skin to high power laser beams (1
or more watts) can cause burns. At the under five
watt level, the heat from the laser beam will cause a
flinch reaction before any serious damage occurs.
The sensation is similar to touching any hot object,
you tend to pull your hand away or drop it before
any major damage occurs.
• With higher power lasers, a burn can occur even
though the flinch reaction may rapidly pull the
affected skin out of the beam. These burns can be
quite painful as the affected skin can be cooked,
and forms a hard lesion that takes considerable
time to heal.
• Ultraviolet laser wavelengths may also lead to skin
carcinogenesis.
SKIN BURN FROM CO2 LASER EXPOSURE
Accidental exposure to partial reflection of 2000 W CO2 laser beam
from metal surface during cutting
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Other Hazards Associated with Lasers
Chemical Hazards
Some materials used in lasers (i.e., excimer, dye and chemical
lasers) may be hazardous and/or contain toxic substances. In
addition, laser induced reactions can release hazardous particulate
and gaseous products.
(Fluorine gas tanks)
Electrical Hazards
Lethal electrical hazards may be
present in all lasers, particularly
in high-power laser systems.
Secondary Hazards including:
•cryogenic coolant hazards
•excessive noise from very high energy lasers
•X radiation from faulty high-voltage (>15kV) power supplies
•explosions from faulty optical pumps and lamps
•fire hazards
Laser Class
The following criteria are used to classify lasers:
1. Wavelength. If the laser is designed to emit
multiple wavelengths the classification is based on
the most hazardous wavelength.
2. For continuous wave (CW) or repetitively pulsed
lasers the average power output (Watts) and
limiting exposure time inherent in the design are
considered.
3. For pulsed lasers the total energy per pulse
(Joule), pulse duration, pulse repetition
frequency and emergent beam radiant
exposure are considered.
CLASS 1
• Safe during normal use
• Incapable of causing injury
• Low power or enclosed beam
CLASS I Laser Product
Label not required
May be higher class during
maintenance or service
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Nd:YAG Laser Marker
CLASS 2
•
•
•
•
Staring into beam is eye hazard
Eye protected by aversion response
Visible lasers only
CW maximum power 1 mW
Laser Scanners
Laser Radiation
Do Not Stare Into Beam
Helium Neon Laser
1 milliwatt max/cw
CLASS II LASER PRODUCT
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CLASS 3a
• Aversion response may not provide
adequate eye protection
• CDRH includes visible lasers only
• ANSI includes invisible lasers
• CW maximum power (visible) 5 mW
Expanded Beam
Laser Pointers
Laser RadiationDo Not Stare Into Beam or View
Directly With Optical Instruments
Helium Neon Laser
5 milliwatt max/cw
CLASS IIIa LASER PRODUCT
LASER RADIATIONAVOID DIRECT EYE EXPOSURE
ND:YAG 532nm
5 milliwatts max/CW
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CLASS IIIa Laser Product
Small Beam
CLASS 3b
DPSS Laser with cover removed
• Direct exposure to beam is eye hazard
• Visible or invisible
• CW maximum power 500 mW
LASER RADIATIONAVOID DIRECT EXPOSURE TO BEAM
2w ND:YAG Wavelength: 532 nm
Output Power 80 mW
CLASS IIIb Laser Product
Courtesy of Sam’s Laser FAQ, www.repairfaq.org/sam/lasersam.htm, © 1994-2004
Laser-Professionals.com
CLASS 4
• Exposure to direct beam and scattered
light is eye and skin hazard
• Visible or invisible
• CW power >0.5 W
• Fire hazard
VISIBLE LASER RADIATIONAVOID EYE OR SKIN EXPOSURE TO
DIRECT OR SCATTERED RADIATION
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Photo: Keith Hunt - www.keithhunt.co.uk
Copyright: University of Sussex, Brighton (UK)
2w Nd:YAG
Wavelength: 532 nm
Output Power 20 W
CLASS IV Laser Product
ANSI Classifications
•Class 1 denotes laser or laser systems that do not,
under normal operating conditions, pose a hazard.
Class 2 denotes low-power visible lasers or laser
system which, because of the normal human aversion
response (i.e., blinking, eye movement, etc.), do not
normally present a hazard, but may present some
potential for hazard if viewed directly for extended
periods of time (like many conventional light sources).
ANSI Classifications (cont’d)
• Class 3a denotes some lasers or laser systems having a CAUTION label
that normally would not injure the eye if viewed for only momentary
periods (within the aversion response period) with the unaided eye, but
may present a greater hazard if viewed using collecting optics. Class 3a
lasers have DANGER labels and are capable of exceeding permissible
exposure levels. If operated with care Class 3a lasers pose a low risk of
injury.
• Class 3b denotes lasers or laser systems that can produce a hazard it
viewed directly. This includes intrabeam viewing of specular reflections.
Normally, Class 3b lasers will not produce a hazardous diffuse reflection.
• Class 4 denotes lasers and laser systems that produce a hazard not only
from direct or specular reflections, but may also produce significant skin
hazards as well as fire hazards.
Reflection Hazards (cont’d)
Specular
Reflection
Diffuse
Reflection
CONTROL MEASURES
Engineering Controls
 Interlocks
 Enclosed beam
Administrative Controls
 Standard Operating Procedures (SOPs)
 Training
Personnel Protective Equipment (PPE)
 Eye protection
Common Laser Signs and Labels
LASER SAFETY EYEWEAR
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LASER PROTECTIVE BARRIER
Photo courtesy of
Laser-Professionals.com
WHO HAS PRIMARY RESPONSIBLITY
FOR LASER SAFETY ANY TIME A
CLASS 4 LASER IS OPERATED?
The person operating the laser
always has the primary
responsibility for all hazards
associated with laser use.
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SAFE BEAM ALIGNMENT
•
Most beam injuries occur during alignment.
•
Only trained personnel may align class 3B or
class 4 lasers (NO EXCEPTIONS!)
•
Laser safety eyewear is required for class 3B and
class 4 beam alignment.
•
ANSI REQUIRES approved, written alignment
procedures for ALL class 4 laser alignment
activities and recommends them for class 3B.
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INTRODUCTION
Compressed gases present a unique hazard. Depending on the
particular gas, there is a potential for simultaneous exposure to both
mechanical and chemical hazards. Gases may be:
•Flammable or combustible
•Explosive
•Corrosive
•Poisonous
•Inert
•or a combination of hazards
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INTRODUCTION
Careful procedures are necessary for handling the various
compressed gases, the cylinders containing the compressed
gases, regulators or valves used to control gas flow, and the
piping used to confine gases during flow.
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IDENTIFICATION
The contents of any compressed gas cylinder must be clearly
identified. Such identification should be stenciled or stamped
on the cylinder or a label. Commercially available three-part
tag systems may also be used for identification and inventory.
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HANDLING & USE
Cylinders may be attached to a bench top, individually to the
wall, placed in a holding cage, or have a non-tip base
attached. Chains or sturdy straps may be used to secure
them.
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HANDLING & USE
Standard cylinder-valve outlet connections have been
devised by the Compressed Gas Association (CGA) to
prevent mixing of incompatible gases.
The outlet threads used vary in diameter; some are
internal, some are external; some are right-handed,
some are left-handed.
In general, right-handed threads are used for non-fuel and
water-pumped gases, while left-handed threads are used for
fuel and oil-pump gases.
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HANDLING & USE
Cylinders should be placed with the valve accessible at all
times. The main cylinder valve should be closed as soon as it
is no longer necessary that it be open (i.e., it should never be
left open when the equipment is unattended or not operating).
This is necessary not only for safety when the cylinder
is under pressure, but also to prevent the corrosion and
contamination resulting from diffusion of air and
moisture into the cylinder after it has been emptied.
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HANDLING & USE
Cylinders are equipped with either a hand wheel or stem
valve. For cylinders equipped with a stem valve, the valve
spindle key should remain on the stem while the cylinder is in
service.
Only wrenches or tools provided by the cylinder
supplier should be used to open or close a valve. At no
time should pliers be used to open a cylinder valve.
Some valves may require washers; this should be checked
before the regulator is fitted.
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HANDLING & USE
Cylinder valves should be opened slowly. Oxygen cylinder valves
should be opened all the way.
Open up the oxygen cylinder valve stem just a crack. Once
the needle on the high pressure gauge has stopped, open up
the valve all the way. This back-seats the valve.
Oxygen cylinders must have the valve opened up all the way
because of the high pressure in the cylinder. There is a backseating valve on the oxygen cylinder. This prevents the highpressure gas from leaking out through the threaded stem.
When opening the valve on a cylinder containing an irritating or
toxic gas, the user should position the cylinder with the valve
pointing away from them and warn those working nearby.
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HANDLING & USE
Cylinders containing flammable gases such as hydrogen or
acetylene must not be stored in close proximity to open
flames, areas where electrical sparks are generated, or where
other sources of ignition may be present.
Cylinders containing acetylene shall never be stored on
their side.
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HANDLING & USE
Oxygen cylinders, full or empty, shall not be stored in the
same vicinity as flammable gases.
The proper storage for oxygen cylinders requires that a
minimum of 20 feet be maintained between flammable gas
cylinders and oxygen cylinders or the storage areas be
separated, at a minimum, by a fire wall five feet high with a
fire rating of 0.5 hours.
Greasy and oily materials shall never
be stored around oxygen; nor should
oil or grease be applied to fittings.
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HANDLING & USE
After the regulator is attached, the
cylinder valve should be opened
just enough to indicate pressure
on the regulator gauge (no more
than one full turn) and all the
connections checked with a soap
solution for leaks.
Never use oil or grease on
the regulator of a cylinder
valve.
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HANDLING & USE
The following rules should always be followed in regards to
piping:
 Plastic piping shall not be used for any portion of a
high pressure system.
 Do not use cast iron pipe for chlorine.
 Do not conceal distribution lines where a high
concentration of a leaking hazardous gas can build up
and cause an accident.
 Copper piping shall not be used for acetylene.
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HANDLING & USE
A cylinder should never be emptied to a pressure lower than
172 kPa (25 psi/in2) (the residual contents may become
contaminated if the valve is left open).
When work involving a compressed gas is completed, the
cylinder must be turned off, and if possible, the lines bled.
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HANDLING & USE
When the cylinder needs to be removed or is empty, all
valves shall be closed, the system bled, and the regulator
removed.
The valve cap shall be replaced, the cylinder clearly
marked as "empty," and returned to a storage area for
pickup by the supplier.
Empty and full cylinders should be stored in separate areas.
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HANDLING & USE
Where the possibility of flow reversal exists, the cylinder
discharge lines should be equipped with approved check
valves to prevent inadvertent contamination of cylinders
connected to a closed system.
"Sucking back" is particularly troublesome where gases
are used as reactants in a closed system.
A cylinder in such a system should be shut off and removed
from the system when the pressure remaining in the cylinder
is at least 172 kPa (25 psi/in2).
If there is a possibility that the container has been
contaminated, it should be so labeled and returned to the
supplier.
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HANDLING & USE
Liquid bulk cylinders may be used in laboratories where a
high volume of gas is needed.
These cylinders usually have a number of valves on the
top of the cylinder.
All valves should be clearly marked as to their function.
These cylinders will also vent their contents when a preset
internal pressure is reached, therefore, they should be
stored or placed in service where there is adequate
ventilation.
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TRANSPORTATION OF
CYLINDERS
1. To protect the valve during transportation, the cover cap
should be screwed on hand tight and remain on until the
cylinder is in place and ready for use.
2. Cylinders should never be rolled or dragged.
3. When moving large cylinders, they should be strapped to
a properly designed wheeled cart to ensure stability.
4. Only one cylinder should be handled (moved) at a time.
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