IB7 Flashcards

1
Q

Nurses working in a radiotherapy treatment facility use a liquid to treat patients that contain an ionizing radioactive material. The liquid is prepared by the nurses before they administer it to the patients. After the treatment, they clean the area and equipment before disposing of any remaining liquid.

(a) Outline how nurses could be exposed to the radioactive material while carrying out this work AND, in EACH case, identify the corresponding route of entry.
(b) Outline practical control measures to help reduce the nurses’ exposure to the radioactive material while they are carrying out this work.

A

(a)
Liquid splashes onto the skin of the nurse i.e. Absorption - on the skin/eyes

Liquid splashes onto the skin and the nurse lick fingers or eat something that becomes contaminated i.e. Ingestion - drinking/eating

The liquid becomes airborne particulates i.e. Inhalation - breathing in [not sure how this would happen

A nurse accidentally injects his/herself or gets needle stick injury i.e. Injection - through the skin

(b)

  • Dedicated room to prepare the liquid which should be away from generally accessible areas.
  • warning sign
  • walls and ceilings should be coated with a smooth finish to ensure ease of cleaning. Floors covered impervious surface, all gaps and joints sealed to avoid contamination traps.
  • Genral dilution ventilation should be provided in the workroom and LEV should be provided where the material is handheld (Fumes cupboards and glove box)
  • Radioactive waste disposal sinks (with splashback )should be dedicated to radioactive materials to ensure that radioactive liquids can be safely disposed of, without contaminating other equipment.
  • Prohibiting eating and drinking in areas where unsealed radioactive sources are
  • a high standard of personal hygiene to prevent spread and
  • Hand wash sinks should be provided in the lobby area before entry into the workroom with elbow- or knee-operated taps
  • The covering of wounds with waterproof dressing.
  • Use of speceil PPE
  • Monitoring facilities for hand and feet contamination should be provided on both sides of an overshoe barrier (to prevent contamination spreading by foot).
  • Hand wash sinks should be provided in the lobby area before entry into the workroom
  • Secure shielded containers for transport and storage of radioactive materials - secure.
  • Secure storage for waster material.
  • The provision, use and, where applicable, laundering of personal protective equipment such as gloves, lab coats and over shoes; the availability of competent advice
  • Personal monitoring by means of film badges
  • spill kits available
  • The provision of trainingand information to workers on the health risks involved and the control measures to be applied;
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2
Q

(a) Identify possible health effects from exposure to ionisingradiation.(5)
(b) Outline control measures that could minimise workers’ exposure to ionisingradiation.(15)

A
(a) 
•Acute effects of exposure to ionising radiation (radiation sickness) include:
–Nausea.
–Vomiting.
–Diarrhoea.
–Fever.
–Death.

These effects are non-stochastic; they do not occur below a particular dose threshold.

•Chronic effects of exposure to ionising radiation are increased risk of:
–Cancer.
–Genetic damage.

These effects are stochastic; there is no known threshold below which the effects cannot occur and the greater the dose, the greater the risk

(b)

  • Limiting the time of exposure with the exclusion of particularly vulnerable groups such as young persons and pregnant women;
  • The use of sealed sources whenever possible;
  • Increasing the distance between the radiation source and those at risk to reduce the level of exposure;
  • Using shielding between the radiation source and those likely to be exposed with the amount of shielding required dependent on the energy of the source;
  • Containment for example by the use of glove boxes;
  • Prohibiting eating and drinking in areas where unsealed radioactive sources are used together with the need for a high standard of personal hygiene to prevent spread and
  • The covering of all breaks in the skin with protective material;
  • The provision, use and, where applicable, laundering of personal protective equipment such as gloves, lab coats and over shoes; the availability of competent advice;
  • The provision of training and information to workers on the health risks involved and the control measures to be applied;
  • Personal monitoring by means of film badges;
  • Regular monitoring of the work area for example by means of a geiger counter and ensuring the safe disposal of all contaminated materials.
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3
Q

An organization that provides sports facilities for employees and their families is about to install ultraviolet sunbeds and lamps.

Identify the risks associated with the use of such tanning equipment and the precautions that should be taken.

A

The risks associated with the UV radiation given off by the tanning equipment are:

ƒSkin cancer or melanoma, which can prove fatal.

ƒBurns to the skin (same condition as sun-burn).

ƒEye damage such as cataracts or conjunctivitis.

ƒWeakened immune system.

ƒPremature aging of the skin, due to breakdown of the elastic collagen in the skin.

ƒPhotosensitisation whereby other chemicals in the body are activated by the UV to produce skin irritation and pigment changes.

The precautions that would be appropriate would include:

ƒPhysical screening of tanning equipment to prevent non-users from any exposure to the UV light.

ƒProvision and enforcement of the use of goggles to protect the eyes.

ƒTraining for all staff in the use of equipment, safety controls, and the importance of exposure times.

ƒHaving safety features, such as timers and emergency alarms, fitted to the equipment to prevent overexposure.

ƒMaintenance of the equipment with special attention given to the correct types of UV tubes fitted to the tanning equipment.

ƒInformation and advice to users on the need to limit or avoid exposure, especially for high-risk individuals such as those with fair skin.

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4
Q

Outline the precautions needed to prevent accidental exposure to a high-power laser used for cutting metals.

A

A risk assessment, focusing on the risks associated with the use of a class 4 laser, would be necessary, as would the development of a safe system of work on the safe use of the laser. The room or area that the laser was in would have to be designated a Laser Protection Area and appropriate warning notices should be displayed. One of the most important precautions that would be taken, to prevent accidental exposure to a high powered laser used for cutting metal, would be the total enclosure of the laser, the beam and the metal item being cut. This would be achieved by the use of metal enclosures (guards) around the machine and its workbench. Any openings into the enclosure, such as access doors, material feed hatches, etc. should be interlocked in such a way that electrical power is isolated from the laser itself until the guards are in place. In some instances this total enclosure is possible. In other instances it is not and then partial enclosure of as much of the laser and work area as possible must be achieved using fixed and interlocked guards. Access to the laser must be restricted to authorised personnel with suitable training to understand the risks and precautions of the device. Eye protection would have to be worn in the vicinity of the laser to prevent damage from UV radiation emitted by the cutting process. With a high power laser, there is also the risk of reflected laser light scattering off rough dark surfaces, so the eye protection should totally enclose the eye so as to protect against this laser scatter. Warning signs should be displayed during the actual operation of the laser, perhaps with a visible warning at the same time. Training for operators and their supervisors would have to be given on the various risks inherent with the device and the precautions necessary to ensure safety.

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5
Q

A pharmaceutical research company is intending to use unsealed radioactive chemicals in small quantities for research purposes. Outline the main preventive and protective measures that would have to be thought about with respect to the radiation risk. Describe the key ionising radiation risk control requirements that would apply.

A

A risk assessment would be necessary. It should be undertaken by a competent person appointed by the employer (the research company). This competent person might be a Radiation Protection Adviser (RPA) or they might be a person with sufficient knowledge, training and experience of this sort of work to be considered competent in their own right. However, they would still work under the scrutiny of an RPA. The design and specification of the laboratory where the experiments would be carried out would have to be considered. Floors and workbenches would have to be of a non-absorbent nature and easy to clean in the event of accidental spillage or contamination.

Suitable lockable storage facilities would have to be provided. This would have to be clearly signed as containing radioactive sources. Containment facilities would have to be provided for the handling of the radioactive sources during experimentation. This might be in the form of fume cupboards (partial enclosures with extraction) to prevent any vapour, mists or aerosols formed during handling from escaping into the laboratory air environment. Total enclosure might be necessary in some instances. Other containment might also have to be provided, for example incubators for the micro-organism once the radioactive source has been added. These would have to be appropriately labelled so as to indicate the radioactive nature of the experiments being carried out.

The laboratory would have to be suitably designated, signed and kept secure against unauthorised access. If significant doses of radiation are anticipated, then the laboratory might have to be classed as a Controlled Area. If doses are anticipated to be lower, then it might be classed as a Supervised Area. In either case, a set of procedures and rules would have to be developed to govern the radiation risk in the lab. This might be done by a designated Radiation Protection Supervisor (RPS) under the control of the RPA. The RPS would be responsible for the day to day running of the radiation protection controls. Handling of radioactive sources would always be done whilst wearing lab gloves, might be done using forceps to maximise finger distance from source and might, in some instances, be done remotely using manipulators.

Workers within the lab might have to be designated as Classified Workers. A classified person is a person who must be over 18 years old, they have been certified as fit for work by a medical practitioner and they are able to enter a “controlled area”. It is possible that they will receive an effective dose of greater than 6 milliSieverts (mSv) per year or an equivalent dose to the relevant tissue or organ of greater than 3/10th of the relevant equivalent dose limit. Dosimetry would have to be carried out for workers in the lab in order to ensure that relevant dose limits were not exceeded. The dose limits under the regulations are an effective dose of greater than 20 milliSieverts (mSv) per year, or an equivalent dose to tissues or organs that varies, depending on the tissue or organ of interest. Dosimetry would usually be carried out using dose badges, worn on the lab coats (or fingers) of workers. These badges are then collected and analysed by an accredited service routinely to give a reliable estimate of exposure. This dosimetry would be organised by the RPS. Radiation detection equipment, such as a Geiger counter, would also be present in the lab as would spill and decontamination equipment. Arrangements would have to be made for the safe storage and disposal of waste materials. General good hygiene rules would apply in the lab, such as no eating, drinking (or smoking) and the requirement to remove gloves and wash hands on finishing work with raioactive materials.

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6
Q

(a) Describe the health effects that might be experienced by people who are over-exposed to ionising radiation.
(b) Outline the range of control measures that should exist when people are exposed to ionising radiation at work.

A

(a) Health Effects:
The acute health effects from exposure to ionising radiation include erythema, skin burns and dermatitis. Radiation sickness is also an acute effect with resultant hair loss, sickness and vomiting. Cataracts may develop in the longer term and exposure to radiation will cause changes to DNA, cell damage and cell death. If the testes or ovaries are exposed then sterility may be a consequence.

Radiation can also cause genetic defects resulting in hereditary damage and harm to the foetus and induce a carcinogenic response. Another health effect may be decreased immunity.

(b) Control Measures

The control measures that should be in place where persons may be exposed to ionising radiation at work begin with designation of controlled and supervised areas with written local rules. Vulnerable groups such as young persons and pregnant women should be excluded from such areas.

Control of exposure time, remote handling to increase the distance from radiation sources and shielding such as lead, concrete or plastic are three key radiation control measures. Use of sealed sources will reduce the possibility of contamination and procedures should be in place to undertake leak tests of such sources. In addition, routine checks and maintenance should be carried out on all equipment generating ionising radiation. Where unsealed sources are used containment will be required in the form of enclosures such as glove boxes and fume cupboards. Signs and notices will need to be posted and enforcement of no eating, drinking and smoking in unsealed radioactive areas. Other measures include personal hygiene to prevent spread of contamination and the requirement to cover cuts and wounds. PPE such as respiratory, hand and eye protection may be needed along with management to ensure its effective use. Persons working with radiation will need training in health risks and control measures and will need exposure monitoring and supervision as well as health surveillance. Personnel monitoring of radiation exposure can be carried out by using film badges and area monitoring using a Geiger counter). Radioactive materials should have suitable storage and arrangements for safe disposal of contaminated materials. Finally there should be emergency plans in place and access to competent advice.

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7
Q

Staff working in a dental practice are exposed to x-rays.

a) Outline the properties of x-rays. (4
(b) Outline how the dental practice can monitor the staff exposure. (6)

A

(a) X-rays are a form of electromagnetic radiation artificially produced when an x-ray machine is switched on. They are generated by bombarding a metal target with high energy electrons and are very penetrating. They can shine through many types of material such as paper, aluminium and human tissues. Consequently, they present an external radiation hazard but can be shielded by lead.
(b) Thermo-Luminescent Dosimeters (TLDs) can be used to monitor radiation exposure. They are personal dosimeters which can be worn on the body to monitor exposure over a fixed period of time and give a measurement of dose. Following exposure to x-rays, the dosimeters are processed to determine the level of exposure. The TLD is heated and the amount of light emitted indicates the degree of exposure. An approved dosimetry service should be used to determine the radiation dose from the TLDs

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8
Q

A new health club is planning to install ultraviolet (UV) tanning equipment. The equipment uses UV sources with a higher intensity than normal sunlight to accelerate tanning.

(a) Identify effects that could result from exposure to UV radiation.
(b) Outline control measures that could be put in place for workers. and customers for the safe operation of this equipment at the health club. (12)
(c) Identify TWO other workplaces where sources of UV radiation are found AND identify how exposure to UV radiation occurs in the EACH workplace. (4)

A

(a)

ƒSkin cancer or melanoma, which can prove fatal.

ƒBurns to the skin (same condition as sun-burn).

ƒEye damage such as cataracts or conjunctivitis.

ƒWeakened immune system.

ƒPremature aging of the skin, due to breakdown of the elastic collagen in the skin.

ƒPhotosensitisation whereby other chemicals in the body are activated by the UV to produce skin irritation and pigment changes.

The precautions that would be appropriate would include:

■ Physical screening of tanning equipment to prevent non-users from any exposure to the UV light.

■ Provision and enforcement of the use of goggles to protect the eyes.

■ Training for all staff in the use of equipment, safety controls, and the importance of exposure times.

■ Having safety features, such as timers and emergency alarms, fitted to the equipment to prevent overexposure.

■ Maintenance of the equipment with special attention given to the correct types of UV tubes fitted to the tanning equipment.

■ Information and advice to users on the need to limit or avoid exposure, especially for high-risk individuals such as those with fair skin.

■ It is good practice that you make sure the equipment is cleaned and sanitised
between customers.

■ You should have received information from the manufacturer or supplier on the correct operation of your UV tanning equipment, and should have familiarised yourself and any employees with it, and be following it. This information should include the correct lamps to use and the maintenance regime.

■ When you are replacing UV tubes make sure the right type are fitted and reassess the exposure requirements of your customers when subsequently
using the equipment.

(c) two sources of UV radiation: science lab equipment; ink and adhesive curing
(3)
■ arc-welding: Welding arcs can exceed the UV
radiation guidelines in seconds within a
few meters of the arc. artificial sources exposure from arc be direct exposure as well as radiation that is reflected from metal surfaces, walls, and ceilings.

■ The Sun ; UV from the sun is highest in summer; when working out doors.

■ ink and adhesive curing.

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9
Q

A training organization wants to introduce hand-held laser pointers for use by their trainers when presenting courses to students.

Recent media reports suggest that some hand-held laser pointers can contain Class 3B or Class 4 lasers.

(a) Identify potential eye damage that could result from exposure to lasers with these classifications.
(b) Outline control measures that could help reduce the potential for eye damage to the trainers and students.

A

(a)
• Class 3B : can cause retinal damage
• Class 4 : cause burns to the retina, temporary or permanent loss of visual acuity or blindness

(b)

  • The need to use lower power lasers or lower class lasers
  • not pointing lasers directly at students

-avoidance of reflective surfaces, , which could redirect the beam (e.g., glossy TV screens/computer
monitors, mirrors, polished metal surfaces)

  • the importance of securing lasers from student use
  • to enusre Keep laser pointer off while talking, especially that during training the trainer will use hand gesture when talking to explain
  • Choose a laser pointer that stays on only when the button is pressed. That way you can never leave the beam on by accident.
  • – Training for users of Classes 3R, 3B and 4 lasers (and possibly even for lower classes, such as 1M and 2M, because of the risks associated with magnifying lenses).

– Signs warning of the laser hazard inside a particular enclosure or in a room/area.

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10
Q

(a) Identify FIVE workplace sources of ionizing radiation.

b) Outline control measures that should be in place when persons may be exposed to ionizing radiation at work. (15

A

(a)
-The use of non-destructive testing (NDT) equipment; the medical/dental use of x-rays;

  • Re-processing nuclear fuels and the presence of radio-active isotopes in nuclear power stations;
  • The presence of ionizing radiation albeit in small quantities for instance in smoke detectors and luminous articles;
  • The use of ionizing radiation for process measurement and control and in laboratories for research projects.

(b)
limiting the time of exposure with the exclusion of particularly vulnerable groups such as young persons and pregnant women; the use of sealed sources or those of lower intensity whenever possible; increasing the distance between the radiation source and those at risk to reduce the level of exposure; using shielding such as lead, concrete or plastic between the radiation source and those likely to be exposed with the amount of shielding required dependent on the energy of the source; by containment and enclosure such as with the use of glove boxes; prohibiting eating and drinking in areas in unsealed radioactive areas together with the need for a high standard of personal hygiene to prevent spread and the covering of all
breaks in the skin with protective material; the provision, use, and laundering of personal protective equipment such as gloves, lab coats, and overshoes; the availability of competent advice from a Radiation Protection Adviser or Supervisor and the provision of training and information to workers on the health risks involved and the control measures to be applied; the preparation of plans to cope with any emergency; personal monitoring by means of film badges; regular monitoring of the work area for example by means of a Geiger counter and ensuring the safe disposal of
all contaminated materials

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11
Q

Forestry workers are required to wear personal protective equipment (PPE) to protect them from hazards associated with the machinery they
use. This PPE includes eye and head protection, gloves, and protective clothing.

The workers are outdoors and being exposed to high levels of ultra-violet (UV), non-ionizing radiation from the sun. This situation can lead to heat-related illnesses and health effects from exposure to the sun.

(a) Explain the importance of maintaining heat balance in the body. (4)
(b) Identify possible effects of heat-related illness. (4)
(c) Outline control measures to help reduce the risks from exposure to heat and non-ionizing radiation hazards for the forestry workers. (12)

A

(a)
The body must maintain a stable temperature for the efficient functioning of the central nervous system and body organs and the chemical reaction within the body

maintenance of temperature is essential to survive and accidents can occur if workers get too hot or too
cold.

(b)
• Inability to concentrate.
• Muscle cramps (due to salt loss through sweating).
• Heat rash (sometimes called ‘prickly heat’).
• Severe thirst (due to dehydration) - a late symptom.
• Fainting (sometimes called ‘heat syncope’).
• Heat exhaustion - fatigue, giddiness, nausea, headache, moist skin.
• Heatstroke - hot dry skin, confusion, convulsions, loss of consciousness. it can lead to coma and death

(c)
■ Sun Shield Shade Cover Hard, appropriate clothing should be used to avoid excessive thermal
insulation and allow respiration, encourage the removal of personal protective equipment when resting to help encourage heat loss

■ Reschedule work which exposed workers to the sun to cooler times of the day, early morning

■ Control the duration of each work period and ensure that sufficient rest breaks are incorporated into work routines so that workers can cool down. Heat stress indices, such as the WBGT index, can be used to make calculations of the maximum allowable work period and the rest period required to achieve heat balance.

■ provide free access to cool drinking water, water station that should be installed near to work location, and promote drinking water.

■ introduce shading in areas where individuals are working whenever it is practical

■ Use a high-factor sunscreen (at least SPF15)

■ Educate workers about recognizing the early symptoms of heat stress.

■ training on the hazards and risk associated with heat stress, dehydration and heat stroke.

■ first-aid provision to tackling the hazards of hypothermia and heatstroke.

■ Supervision is necessary to ensure that the work regimes are followed and that potential heat stress is
detected at an early stage.

■ Acclimatisation is important to enable workers to become used to the more extreme thermal environments.

■ Health Surveillance The regular monitoring of workers is important for those who work in extreme temperatures. The testing of kidney, respiratory and cardiovascular functions, together with general health, are relevant.

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12
Q

Glassblowers use furnaces to produce molten glass that they then blow into shapes to make glasses and vases. During their work, they are exposed to different types of non-ionizing optical radiation.

(a) Identify the possible ill-health effects to the glassblowers from exposure to the non-ionizing optical radiation.
(b) Describe the specific requirements of the personal protective equipment that would be required to protect the glassblowers from the non-ionizing optical radiation.
(c) Other than ill-health effects and control measures, outline what should be considered in a radiation risk assessment.

A
(a) 
Such as skin reddening and burns
skin cancers eye damage in the form of cataracts and photo conjunctivitis
retinal damage and ashen cataract
cornea damage after prolonged exposure.

(b)
-Long-sleeved clothing to protect against ultraviolet radiation.
-Leather gloves or gauntlets to protect the skin from infrared radiation would be required.
-Appropriate shaded goggles with
optical density based on individual
beam parameters
-long pants, long skirt or equivalent leg covering (no shorts)

(c)
- Information should be sought from suppliers about the potential emissions and any controls required during installation and use.

  • Any activities that are likely to give rise to a risk of exposure.
  • Comparison of measured exposure levels with exposure limits obtained from the competent authority (established in national or international law or national standards).

-The potential for the misuse or misunderstanding of safety precautions. Examples of misuse would include
violations of safety rules such as access restrictions.

-The duration of exposure and how to protect particularly vulnerable groups.

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13
Q

Lasers are often used by the entertainment industry during displays and music concerts attended by members of the public. The lasers used are
of very high power and are given a hazard classification.

(a) Outline the hazard classification system used for lasers.
(b) Outline how exposure to lasers can cause damage to the eyes.
(c) Outline control measures that could be used to reduce the risks to the public at such displays.

A

(a) four classes

ƒ Class 1 considered safe under reasonably foreseeable use.
ƒ Class 1M similar to Class 1 but beam is not safe if viewed with the aid of magnifying
optical instruments.
ƒ Class 2 (for lasers emitting in the visible range):
– Low-power devices.
– Eye protection is normally afforded by the aversion response and the blink reflex
of the eye.
ƒ Class 2M similar to Class 2 but beam is not safe if viewed with the aid of magnifying
optical instruments.
ƒ Class 3R laser products limited to maximum output power of 5mW - these can
potentially cause eye injury.
ƒ Class 3B laser products limited to a maximum output power of 500mW - these are
considered hazardous to the eye, both directly and reflections.
ƒ Class 4 high-powered devices (> 500mW) - they are hazardous to eyes and skin and
can cause fires.

(b)

exposure route for laser light is direct exposure where the light beam hits the eye, or less obvious exposure route is indirect exposure where the laser light reflects off shiny surfaces and then strikes the eye

either way when the light , enters the eye and blinking response is not quick enough to protect the eye.

IR wavelengths and UV lasers can cause damage to the tissues at the front of the eye, such as the cornea and lens

High power laser beams can cause permanent blindness in very short exposure times

the eye may focus the laser beam through the cornea and lens to a very small spot on the retina, so concentrating the light intensity. (and causing a heating effect.)

The severity of any injury from exposure to the laser light depends on a number of factors including wavelength, duration and angle of exposure.

(c)
- use of the laser system’s lowest power setting possible for alignment and zoning, must also be set.

  • eliminate the needs to use laser
  • avoidance of reflective surfaces, , which could redirect the beam into the adience
  • interlock switches to prevent lasers from firing if the projector housing is opened
  • Each projector must have proper labeling, such as a warning label at the aperture to warn against looking into the aperture
  • Once laser systems are mounted properly, the beams must be tuned to where they will be propagated during the show, avoiding areas that could directly hit audience members.
  • using the lowest class of laser,
  • directing the laser beams away from the public, removing reflective surfaces,
  • using competent operators,
  • Operational controls such as crowd barriers/warning signs and stewards to keep people away from no-go areas, use of competent operators and an appropriate level of supervision to ensure safe systems of work are followed, well-practiced emergency shutdown procedures;
  • Suitable handover arrangements between a supplier/installer and display operator (if different) including information about safe operation, checks & maintenance;
  • seeking advice from a laser safety officer and -restricting access to hazardous areas by displaying warning signs.
  • To ensure that beams are projected away from airports, flight paths
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14
Q

(a) Identify the way in which lasers are classified according to their hazard.
(b) Low power lasers are widely used to read barcode labeled products at checkouts in retail premises.

Outline:

(i) the design features;
(ii) the procedural controls;

that should be in place for the safe operation and maintenance of the equipment.

A

(a) lasers are classified according to BS EN 60825 which contains seven different classifications( 1, 1M, 2, 2M, 3B, 3R and 4), which class 1 being the lowest powered type - found in, for example, CD players and supermarket checkout scanners - through to class 4.
(i) Design features should include:

■ Using class 1, lasers which are the lowest powered.
■ Ensuring that the lasers are enclosed or embedded in the scanning unit and can’t be accessed.
■ Enclosing the scanning device in a protective housing or enclosure
■ where handheld scanning guns are used, providing a trigger to operate these devices.
■ Providing a key control with interlock to the power source to prevent unauthorized access
■ positioning the laser device to avoid eye level contact
■Using suitable warning signs

(ii)
■ Following the manufacturer’s guidance
■ Training operator to not look directly into the beam or, in the case of hand-held systems, not to direct the beam at a person.
■ Providing a safe system of work for the maintenance of the equipment
■ Ensuring maintenance is carried out by a competent person.
■ Ensuring that the housing can only be removd by a competent person with the correct tools and that the beam is controlled.
■Implementing a defect reporting procedure.

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15
Q

A contractor has been hired to examine the quality of a weld repair to a metal pipe on a chemical plant. It has been decided that on-site radiography, using either gamma or X-ray sources, is the only practical
option in this case.

Outline suitable measures to control the risk of exposure to radiation from the examination work.

A

■ using competent advice (Radiation Protection Officers), competent contracts, proper planning of the job, safe systems of work

■ Minimizing the exposure time reduces a worker’s dose from the radiation source.

■ Maximize distance from the source(s) of radiation. A worker’s radiation dose decreases as the worker’s distance from the source increases. For gamma rays and X-rays, (i.e., the inverse square law).

■ Radioactive sources shall be effectively shielded.

The following materials can be used to
provide shielding of ionizing radiation sources;
■ High mass materials for x-ray, gamma.

■ Barriers are placed at access points above and below the location of the work. Notices are displayed at the barriers to explain access restrictions and the meaning of warning signals.

■ The radiographer should confirm that people are excluded from the areas where there is a radiation hazard, a different signal, often a beacon, indicate x-ray, gamma-ray generated.

■ Radioactive sources should be kept in a secure, fire-resistant and adequately shielded storage location when not in use, and should be kept separate from other materials. The storage location for X-ray machines that are not in use is not required to be shielded, Removal and return of sources to a storage location must be recorded

■Maintaining the equipment in a good state of repair

■ Give advance notice to the local managers, foremen, and workers. site notification for the people to be affected by the radiation

■ Monitoring (dose monitoring of the radiographers,
area monitoring, activity monitoring of equipment) and making sure the monitoring
the equipment itself was calibrated and well-maintained.

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