Non-ionising radiation risk management procedure

Non-ionising radiation risk management procedure
1 Purpose
To ensure awareness and compliance with its legal obligations by informing Departments and
users of requirements when using equipment that produces non-ionising radiation.
2 Scope
The procedure applies to any member of the University of Melbourne using or associated
with equipment that produces non ionising radiation.
3 Legislation
Health Act 1958 (Vic)
Occupational Health and Safety Act 2004 (Vic)
4 References
AS 2243.5: Safety in laboratories. Non-ionizing radiations
AS/NZS 2772.2: Radiofrequency fields - Principles and methods of measurement and
computation - 3 kHz to 300 GHz
AS/NZS 2211.10: Safety of laser products - Application guidelines and explanatory notes to
AS/NZS2211.1
AS/NZS IEC 60825.1: Safety of laser products. Equipment classification and requirements
ARPANSA, Radiation protection standard for maximum exposure levels to radiofrequency
fields – 3 kHz to 300 GHz, RPS 3
ARPANSA, Radiation protection standard for occupational exposure to ultraviolet radiation,
RPS 12
5 Definitions
Ampere (A)
A unit of electric current
Extremely Low Frequency Electric Fields (ELFEF)
Low frequency radiation is the portion of the electromagnetic spectrum with frequencies
between 0 - 300 Hertz. The Unit for electric field strength is Volts Per Metre (Kv/m). The
unit for Magnetic Flux Density is the Tesla (T) or the Gauss (G).
Gauss (G)
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A unit of magnetic induction
Infrared radiation (IR)
Infra Red Radiation is electromagnetic non-ionising radiation transmitted to the body in the
form of radiant heat. Infrared radiation occurs in wavelengths from 700 nm to 1 mm.
Lasers
Lasers differ from other sources of light due to differences in the mechanism of operation,
and the quality of light produced. Lasers emit light either as a continuous wave (CW) or
pulsed wave (PW). Laser light can be of high optical power, and range from the infra red to
the ultraviolet section of the EMS. Generally the beam is monochromatic with low
divergence.
Non-ionising electromagnetic radiation
Radiation where the wavelength is greater than 100 nanometres and the energy does not
exceed 1 electron volt (1 eV).
Radiofrequency radiation (RF)
Radiofrequency (RF) radiation is considered to be that portion of the electromagnetic
spectrum with frequencies between 100 kHz and 300 GHz. The frequencies in the GHz range
are also commonly referred to as microwave radiation.
Tesla (T)
A unit of magnetic flux density
Ultrasonic radiation
Ultrasonic Radiation, or ultrasound refers to the electro/mechanical vibrations at frequencies
above 16kHz.
Ultraviolet radiation (UV)
Exposure range from 290 nm to 4 μm. About 10% of all light reaching the earth from the sun
is in the ultraviolet range. The most hazardous is the range below 325 nm which is
responsible for sunburn and the formation of skin cancers.
Energy concentrations found in artificial sources of radiation may be substantially more than
what is emitted from the sun.
Visible light
The visible light spectrum extends in colour from violet, at a wavelength of 380 nm to red at
a wavelength of 760 nm. The maximum sensitivity of the human eye occurs in the green
region around 555 nm.
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6 Responsibilities
6.1 Managers and Department Radiation Safety Officers (DRSOs)
The users of non-ionising radiation sources must be aware of:
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the nature of any associated hazard and methods to assess and minimise that hazard;
the level of risk posed to staff/students and property/environment by the equipment
prior to use;
the controls required to reduce risks to acceptable levels using the hierarchy of control
in accordance with the OHS risk management procedure;
the University and local area emergency procedures in accordance with the
Emergency preparedness and response procedure; and
the OHS incident, injury and hazard reporting and investigation procedure.
6.2 Head of Department/School
The Head of Department/School must ensure that users of equipment that emits non-ionising
electromagnetic radiation:
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adopt safe work practices;
comply with all University procedures; and
document plant risk assessments in accordance with the Regulated plant risk
management procedure;
undertake adequate training (and licensing if applicable) in accordance with the OHS
training procedure. Training must include:
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the safe storage and handling of equipment;
emergency procedures;
personal protective equipment; and
emergency procedures and first aid.
6.3 Staff/Students
Staff and students must comply with all safe working procedures when using equipment that
emits non-ionising radiation.
7 Procedure
7.1 Ultrasonic Radiation
7.1.1 Safe Guarding Requirements
General safeguards to consider are:
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shielding the sources thus protecting individuals from direct or indirect exposure to
radiation;
maximizing the distance between the source and the operator;
minimizing the exposure time;
PPE (proper eye shields.
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7.2 Extremely low frequency electric field (ELFEF)
7.2.1 Hazards
ELFEF act directly on the surface of the body as well as internally. At a cellular level some
frequencies can cause direct stimulation of excitable cells and accounts for persons being able
to perceive an external electric field, and experience electric shock. An external field strength
of 10 000 volts per metre can induce a current density (<1 A per m2) high enough to stimulate
excitable cells.
ELF Magnetic fields induce electric fields in the body which result in current flow through
biological tissue. Normal biological processes produce current densities of 1 mA per m2. To
induce a current flow, an external flux density of 65 μT or 650 mG would be required.
7.2.2 Protection
ELFEF is easily shielded by any properly earthed conducting enclosures. In addition, the
earthing of any metallic object in any electric field will reduce the possibility of induced
charges.
ELF magnetic fields are not as easy to shield, so exposure levels must be considered at the
design stage where equipment is likely to emit these fields. Alternatively, distance from the
source will greatly reduce exposure.
7.2.3 Exposure limits
The National Health and Medical Research Council guidelines on limits of exposure to 50/60
electric and magnetic fields are:
EXPOSURE TYPE
TESLA (mT) GAUSS (G)
Occupational 24 hours
0.5
5.0
Occupational short term
5.0
50
Non-occupational 24 hours
0.1
1
Non-occupational short term
1.0
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7.3 Ultraviolet radiation
7.3.1 Sources of UV radiation
Sources of UV radiation include:
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sunlight
high pressure discharge lamps
low pressure gas discharge lamps
germicidal lamps
xenon or mercury arcs
carbon arcs
plasma torches
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electric welding arcs.
7.3.2 UV Range
TYPE
UV-C
UV-C
UV-B
UV-A
WAVELENGTH
100 nm - 180 nm
180 nm - 280 nm
280 nm - 315 nm
315 nm - 400 nm
LOCATION ON SCALE
Vacuum Ultraviolet
Short Wavelength
Middle UV or Erythemal UV
Long UV or Near UV
7.3.3 UV hazards
UV hazards include:
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a sensitivity to acute response in skin occurs between a wavelength of 290nm to
300nm.
a sensitivity to a response in the cornea and conjunctiva occurs at a wavelength of
about 270nm.
7.3.4 UV recommended exposure limits
The maximum permissible exposure limits recommended by the International Radiation
Protection Association are:
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UVA < 10Wm-2(1mWcm-2) for periods greater than 15 minutes.
UVB and UVC exposure duration determined using Table 2.2 in AS 2243.5
7.4 Infrared radiation
7.4.1 Sources of IR
Sources of IR include:
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IR lamps
furnaces
heated objects.
7.4.2 IF Range
TYPE
A
B
NAME
Near - IR
Far - IR
WAVELENGTH
700 nm to 1400 nm
1400 nm to 1 mm
7.4.3 IR Hazards
IR hazards include:
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damage to tissues in the eye, or contribute to heat stress. Absorption of IR in the
tissues of the eye is wavelength dependent.
near IR will be absorbed in the lens of the eye and may contribute to the development
of cataracts.
far IR is absorbed at the surface of the eye and does not cause deep tissue damage,
however superficial burns may occur.
heat stress (from radiant heat) can cause adverse health effects.
7.4.4 IR recommended exposure limits
To avoid possible delayed effects upon the lens of the eye, the irradiance of IR must be
limited to 100 W/m2.
Care must be taken when using an IR heat lamp or any near IR source where a strong visual
stimulus is absent.
7.5 Radio frequency radiation (including microwave radiation)
7.5.1 Sources of RF
Sources of RF exposure include:
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AM/FM broadcast transmitters
VHF/UFH TV transmitters
portable communication transceivers
military and civilian radar
communication equipment (mobile phones)
RF welders
medical diathermy units
microwave ovens
7.5.2 RF Range
The electromagnetic range for RF radiation is 100 kHz to 300 GHz.
7.5.3 RF Hazards
RF radiation can interact with human tissue in a number of ways:
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thermal absorption of RF energy resulting in an increase of temperature in bological
tissue
non-thermal or athermal interaction at lower frequencies resulting in excitation of
nerve or muscle cells
electric shock and burns, at low frequencies electrical charges can result in electric
shock or burns
7.5.4 RF protection
RF radiation protection can be achieved by:
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restricting access to areas where the permissible levels are exceeded by barriers and
warning signs
adequately shielding microwave equipment such as ovens and generators
7.5.5 RF Exposure limits
Exposure Levels for RF Radiation are as summarised in Tables 5.1 & 5.2 in AS 2772.1
7.6 Visible light
7.6.1 Sources of visible light
Sources of visible light include
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the Sun
electric arcs
welding arcs
incandescent lamps
high intensity discharge lamps
tungsten halogen (quartz halogen / quartz iodine) lamps
high intensity pulsed light sources (flashtubes)
7.6.2 Visible light range
The electromagnetic range for invisible light is380 nm to 760 nm.
7.6.3 Visible light hazards
The eye has the ability to focus concentrated light onto very fine points on the retina,
cataracts can result from photochemical damage, particularly in the blue and ultraviolet
region of the spectrum.
7.6.4 Visible light exposure limits
No single safe exposure limit can be given for the amount of light reaching the eye, as the
hazard depends on the physical size and intensity of the source, and the duration of exposure.
Where possible intense light must be completely enclosed from the observer.
Viewing windows must be fitted with darkened glass to attenuate prominent wavelengths,
both visible and invisible.
7.7 Lasers
7.7.1 Classes of lasers
Classes of lasers include; 1, 1M, 2, 2M, 3R, 3B and 4.
7.7.2 Laser hazards
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Lasers are capable of inflicting biological damage to the eye and skin, Lasers are particularly
hazardous to sight. The power density of the laser beam image on the retina is in the order of
100 000 times the power density at the front surface of the cornea.
7.7.3 Laser exposure limits
Refer to AS/NZS IEC 60825.1 for information on classification of lasers and for additional
information for the use of high powered lasers.
7.7.4 Laser controls
Ensure the following:
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training for all operators of Class 3 and 4 lasers is undertaken
the power density of the beam is kept as low as practicable
shields are used to prevent reflections, and to stop the direct beam from going beyond
the area
reflected beams from shiny objects are avoided
baffles are placed near lenses or other shiny objects
laser warning signs is displayed
the laser beam is terminated in a shutter when not in use
7.8 Ultrasonic radiation
7.8.1 Ultrasonic sources
Ultrasonic sources of exposure include:
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medical diagnosis and therapy
non-destructive testing
ultrasonic cleaning.
7.8.2 Ultrasonic hazards
Ultrasonic radiation hazards can arise from both airborne and liquid coupled sources resulting
in:
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interactions in tissue that cause local generation of heat
cellular destruction associated with cavitation in tissue causing alterations in
membrane function
ultrasonic vibrations affecting the diffusion of chemicals through cell walls
7.8.3 Ultrasonic controls
General ultrasonic safeguards to consider are:
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shielding the sources thus protecting individuals from direct or indirect exposure to
radiation;
maximising the distance between the source and the operator;
minimising the exposure time.
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8 Document Control
Established by: OHSC on 25 May
2004
Authorised by: Director, OHS and Injury Management
Date: 26 June 2012. Version 2.0
Next Review: 26 June 2015
(c) The University of Melbourne - uncontrolled when
printed.
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