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).

1 Gauss (G)

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.

2 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. 6 Responsibilities

6.1 Managers and Department Radiation Safety Officers (DRSOs)

The users of non-ionising radiation sources must be aware of:

 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:

 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:

 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

3 General safeguards to consider are:

 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.

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 10

7.3 Ultraviolet radiation

4 7.3.1 Sources of UV radiation

Sources of UV radiation include:

 sunlight  high pressure discharge lamps  low pressure gas discharge lamps  germicidal lamps  xenon or mercury arcs  carbon arcs  plasma torches  electric welding arcs.

7.3.2 UV Range

TYPE WAVELENGTH LOCATION ON SCALE UV-C 100 nm - 180 nm Vacuum Ultraviolet UV-C 180 nm - 280 nm Short Wavelength UV-B 280 nm - 315 nm Middle UV or Erythemal UV UV-A 315 nm - 400 nm Long UV or Near UV

7.3.3 UV hazards

UV hazards include:

 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:

 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:

 IR lamps  furnaces  heated objects.

5 7.4.2 IF Range

TYPE NAME WAVELENGTH A Near - IR 700 nm to 1400 nm B Far - IR 1400 nm to 1 mm

7.4.3 IR Hazards

IR hazards include:

 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:

 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:

6  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:

 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

 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.

7 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

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:

 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:

 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:

 interactions in tissue that cause local generation of heat

8  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:

 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. 8 Document Control

Established by: OHSC on 25 May 2004

Authorised by: Associate Director, Health & Safety

Next Review: 22 February 2019

Date: 22 February 2016. Version 2.2 (Updated 29/02/2016)