IB -7 Phusical Agents 2 - Radiation Flashcards
how are lasers classified under BS EN 60825 standard
class 1 - safe for foreseeable use - laser is low power or totally enclosed
class 1m - same as 1 however can not be viewed through a magnifying lense
class 2 - lasers which emit a visible range only, low power devices, can cause eye damage scanners
class 2m - similar to class to but can not be viewed through a magnifying lens
class 3R - limited to a maximum power of 5mw can cause eye damage after short exposure - pointer pens
class 3B - maximum power 500mw hazardous to eyes both directly and indirectly - laser reserach
class 4 - high powered devices over 500mw hazardous to eyes and skin and can cause fire - laser display and laser cutter
identify the risks associated with ultra violet sun beds and the precautions needed
risks = skin cancer or melanoma / burns to skin / eye damage - cataracts / weakened immune system / premature ageing due to breakdown of collagen / phtosenitization - other chemicals activated by UV to skin irritation and pigment changes
precautions = physical screening of equipment to prevent non users from UV rays / provision and enforcement of goggles / training of staff in use and safety controls / prevent over exposure - alarms and timers / maintainance - correct type of UV tubes fitted / info and advice to users - limit and avoid exposure especially for fair skin / training on risks and operation of equipment
outline the design features of low powered lasers used to read bar code labels
- no greater power than class 1
- embedded or enclosed systems
- protective housing
- trigger operation for hand held users
- key controlled with interlocks for power source
- positioning to avoid eye exposure
outline the procedural controls for low powered lasers used for bar code scanners
- manufactures guidance
- training in safe use
- ssow for maintenance and repair
- removal of case requires special key/tool
- produce for reporting defects
- competent person to maintain
- signage
outline the precautions needed to prevent exposure to high powered lasers used for cutting metals
- risk assessment for class 4 laser
- ssow
- laser protection area with signage
- total enclosure of beam and the item being cut (metal enclosure)
- any gaps interlocked around the enclosure so power is isolated until all guards are in place
- if total enclosure is not possible - then part enclose
- access restricted to trained personnel
- eye protection must totally enclose eye to prevent from light scatter and reflections
describe the key risk control measures when using unsealed radioactive chemicals
- risk assessment by competent person -RPA radiation protection advisor who will also advice employees or correct working methods
- floors and surfaces - non absorbent and easy to clean
- suitable lockable storage facilities to be provided - clearly signed
- containment facilities - fume cupboards with extraction appropriately labeled
- kept secure and restrict access
- controlled or supervised area
- handling - correct PPE and forceps or remotely
- dosimetery for workers to ensure limits are not exceeded
- arrangement for safe storage and disposal of waste
- general good hygiene rules
- emergency procedures
- notification to the HSE
describe the possible effects from exposure to ionising radiation
effects become more marked as the exposure increases
acute effects - nausea & vomiting / hair loss / diarrhoea / headache / fever / central nervous system impairment / skin burns and ulceration / death= radiation sickness erythema / burns
low doses 24 -48 hr high does minutes
chronic effects
- cataracts
- cell damage / cell death
- sterility
- genetic defects
- increased risk of cancer
- decreased immunity
what are the control measures that should be put in place when a person is exposed to ionising at work
- controlled areas
- local rules
- exclusion of vulnerable groups
- use of sealed sources
- leak tests / routine checks / maintainance of equipment
- control exposure time
- distance
- shielding
- containment & enclosure
- signs & notices
- no eating / drinking / smoking
- personal hygiene
- PPE
- training
- exposure monitoring and controls
- storage
- health surveillance
- disposal
- emergency plans
- competent advice
- dose monitoring - Geiger counter
- area monitoring
outline the properties of x rays
electromagnetic radiation / artificially produced / generated by bombarding a metal target with high energy electrons / very penetrating / shine through most types of material (human tissue) / external radiation hazard / shielded by lead
how do you measure the personal exposure to radiation
film badges & dosimeters (TLD) / personal worn on body of user / fixed period of time / provide the dose / dosimeters are are processed and film badges developed (blackening of photographic film indicates degree of exposure) / TLD are heated and the amount of light emitted indicates the level of exposure /approved dosimetry service used for testing
what are the types of ionising radiation and what do they penertrate
alpha particles - have little penetrating power can be stopped by skin or paper and only travel a few centimetres (smoke detectors)
Beta particles - more penetrating then alpha particles but less then gamma rays / can travel meters in the air through paper and the horney layer of the skin. they can not pass through aluminium or thick lead (medical and biological research / radioactive isotopes in nuclear power station)
x rays and gamma rays- very penetrating / shines in straight lines at the speed of light / through aluminium & human tissue / unlikely to penetrate through 50mm thick (medical & dental equipment)
ionising radiation can also be used in process measurement and control in laboratories for research projects
identify types of non ionising radiation and the workplaces they would be found
- UV - Sunlamps in tanning salons / arc welding / science laboratory equipment / ink & adhesive curing - outside work
- Visible - general lighting / cutting & welding / theatre & photographic lights / visible light lasers
- IR - metal furnaces / glass furnaces / fire / heat lamp
- Microwaves - microwave ovens / mobile phone masts / mobile phone antennae
- radio waves - communication equipment
