B7 Ollie Flashcards
Radiation
Form of energy
Natural (minerals,radon gas,UV)
Man-made (x-rays , microwaves )
The amount of energy will determine if it is ionis ing or non-ionis ing radiation
Radio activity is the term us ually applied to ionis ing radiation emissions
Electromagnetic waves or particulate
Electromagnetic Spectrum
All move at same speed (3 x 108 ms -1)
Different wavelengths
Shorter the wavelength, higher the energy
Gamma Rays and X-rays:
Ionising
UV/Visible/InfraRed/Microwaves/Radio-waves :
Non-ionising
Ionising radiation also includes particulate forms
Ultra-Violet Radiation - Basic Information
UV- A - 400 t o 315 nm
UV- B ( most hazardous ) - 315 t o 280 nm
UV- C - 280 t o 100 nm Intensity(irradiance) also important:
Welding arc at 1m - 1700 W/m2
Summers un at noon - 170 W/m2
Ultra-Violet Radiation - Sources & Effects
Sources:
Arc-welding, sunlight, tanning studios , UV water treatment, curing of resins
Effects:
Burns , erythema (reddening of s kin), keratoconjunctivitis (arc-eye), premature ageing, cataract, skin cancer
Infra Red Radiation - Basic Information
Electromagnetic radiation 700nm to 1mm
Does not penetrate deeply, so skin and eyes at risk Sources:
Emitted by any hot body
Furnaces , foundries , glas s blowing, hotwork
Effects:
Cataract, burns , erythema, heat effects
(e.g. heat-stroke)
Microwaves - Basic Information
Electromagnetic radiation 1mm to 1m
Cause water molecules to rotate and vibrant: heating
Radiated power (irradiance) important
Sources:
Microwave ovens , drying and curing processes , radar, communication systems
Effects:
Burns , localised heating, cataract, links with cancer
Radio frequency - Basic Information
Wave lengths 1 mm to 10 Km
1 mm to 1 m referred to as microwaves
All have heating effect, but particularly microwaves
Strength of field depends on irradiance (radiated power) and distance from antenna/source
Sources:
Radio transmitters , radar
Effects: Heating, burns, potentially cancer
Controls for Non Ionising Radiation
Reduce source strength
Reduce time of exposure
Increas e distance (note: inverse square rule applies ) Shielding
PPE (including suncream)
Controls for Non Ionising Radiation -Specific Measured
Design Siting Direction control Reduction of s tray fields Screening Enclosures Distance Safe systems of work Instructions Training
Sunbeds (Regulation)Act 2010
Persons in control of sunbeds
Must ensure not used(or offered for use)to persons under 18
Enforced by Local Authority
Fine on conviction
Control of Artificial Optical Radiation at Work Regulations (CAORR) 2010
Light emitted from all artificial sources i.e. light in all its forms such as ultraviolet, infrared and laser beams , but excluding sunlight
CAORWR -No Action (List1)
Ceiling-mounted and task lighting Photocopiers Computers and PDAs Remote control devices Photographic flash lamps – when used singly Gas -fired overhead heaters Vehicle lights Class 1 lasers e.g. laser printers and bar code scanners
CAORWR - Action Required (List 2)
Welding (both arc and oxy-fuel) and plasma cutting
UV fluorescence and sterilisation systems
Furnaces
UV curing of inks , paints and welding
Laser surgery, blue light and
UV therapies
Class 3 Band Class 4 lasers
Search lights and professional projection systems
Risk Assessment to Consider
The level, wavelength and duration of exposure
Employees particularly at risk
Interactions between radiation and photos ensitising chemical substances , and from multiple sources of exposure Information from health surveillance
Manufacturers and published information
The availability of alternative equipment
The Exposure Limit Values
CAORWR -ELV
Exposure Limit Values (differ for different wavelengths )
If RA suggests levels to exceed these limits , employer must produce action plan
Demarcation, restrict access and signage
Information, instruction and training
Health surveillance
Ionising Radiation - Basic Information
Sufficient energy to cause ionisation
Ion:
Atom or molecule that has gained or lost an electron Cause production of ions in body tissues
Subsequently cause damage to biological molecules
Types of Ionis ing Radiation
Particulate: Alpha particles Beta particles Neutrons Electromagnetic radiation: X rays Gamma rays
Radionuclides
Chemicals that emit radiation Unstable
Electromagnetic or particulate Occurs spontaneously
Us ually identified by name and
mas s no. e.g. radon-222
An atom changes identity as it decays (e.g. radon-222/polonium-218) U n i t o f d e c a y ; t h e B e c q u e r e l (B q ) = 1 trans formation per s ec
Alpha Particles
2 neutrons + 2 protons Releas ed by radionuclides Alpha emitters: Americium-241, Plutonium-236, Uranium-238, Polonium-210 Uses: Smoke alarms , s tatic eliminators Penetration: L o w, a b s o r b e d b y p a p e r
Beta Particles
High s peed electrons Releas ed by radionuclides Beta emitters: Carbon-14, Tritium, Iodine-131 Uses: Thickness gauges,medical Penetration: Medium, abs orbed by pers pex/aluminium
Free Neutrons
Neutron:
Sub atomic particle with neutral charge
Emitted by radionuclides e.g. Californium-252 and by nuclear reactors Uses:
Crystallography
Caus es materials (e.g. containers ) to become radioactive and have ionising effects
Very penetrative
Abs orbed by hydrogen rich material e.g. water, concrete
Gamma Rays
Electromagnetic radiation: High energy Produced by radionuclides Gamma emitters: Cobalt-60, Caes ium-137 Uses: Cancer treatment, fill level, NDT, thicknes s gauges Penetration: Highly penetrative - s topped only by dens e metals e.g. Lead
X-Rays
Electromagnetic radiation:
High energy (les s than gamma)
Generated electronically us ing high voltage electricity High s peed electrons interact with s olid materials
Uses:
Radiography, crys tallography
Penetration:
Highly penetrative - s topped only by dens e metals e.g. Lead
Half-life
Time taken for an atom to
dis integrate to half of its original energy
Units of Radiation
Becquerel (Bq) - no. dis integrations per s econd (amount of radioactivity at source)
Gray (Gy) - unit of abs orbed dos e (dos e of 1 Gray when 1 Joule of energy is absorbed by 1 Kg of tissue)
Sievert (Sv) - dos e equivalent; gives relative harmful effects (Grays x Quality Factor) (biological ris k of expos ure)
Sieverts
Sievert (Sv) - dos e equivalent, gives relative harmful effects (Grays x Quality Factor)
Gamma, X-rays x1
Thermal neutrons x5
Beta x1
Fas t neutrons x20
Alpha particles x20
This means alpha particles are 20x more ionis ing/harmful than gamma and X-rays
Doserates -Sieverts perunittime
Ionis ing Radiation Regulations - dos erates in milis ieverts (mSv)per year
Biological Effects
Erythema, burns Naus ea, vomiting, fatigue Weight los s , haemorrhage, hair los s Radiation s icknes s Cancer Cataract
Stochas tic Effects
Probability of effect is proportional to the initiating caus e (dos e received)
Increas ing dos e will increas e likelihood but not s everity Cancer induction
Hereditary effects
Non-stochastic Effects
Do not occur until a thres hold is reached Then effect proportional to dos e Erythema (s kin reddening)
Depilation (hair loss)
Radiation s icknes s Blood count changes
Factors that Determine Effects
Dos e (frequency/duration/intens ity of expos ure)
Type of radiation
Dos e effect relations hip (s tochas tic/non-s tochas tic)
Dos e dis tribution and part of body irradiated
Individual s us ceptibility (e.g. pregnant women)
External expos ure or internal pos ition (e.g. alpha particles )
Radiation Doses
Background - 1.9 mSv/yr
Average uk inhabitant - 2.6 mSv/yr Average radiation worker - 4 mSv/yr Max permitted dos e - 20 mSv/yr Ches t X ray - 0.3 mSv
Radiation s icknes s - 100 mSv Death - 300mSv
Radon
Radioactive gas , naturally produced
Res pons ible for half individual expos ure in UK
HPA Target Level 100 Bqm-3
Us ually 20, higher in s ome areas
Radon detectors from HPA for hous eholders and workplaces Controls ; s umps , ventilation, s eals
Buildings Regulations - reas onable precautions
Ionis ing Radiation Regulations (IRR) 1999 - Regulation 5& 6
Re g 5 & 6 :
Notification and authoris ation required from HSE for lis ted tas ks e.g. X-rays/medical
Some exemptions Reg 7:
Ris k as s es s ment required to es tablis h controls
Mustconsider (ACOP):
Nature of s ource, dos e rate, res ults of dos imetry Manufacturers information, controls in place
Accident and emergency s ituations , potential failure of controls
IRR - Regulation 8 & 9
Reg 8:
Employer tocontrol exposuretoemployees and others AFARP
ACOP:
Expos ure s hould be res tricted to as far below dos e limits as
reas onably practicable
Usuallytakentobeas as lowas reasonablyachievable(ALARA)as recommended by the ICRP
Hie rarchy o f co ntro l:
Engineering controls , s afe s ys tems of work and PPE
Reg 9:
Maintenance of controls : tes ted at s uitable intervals
IRR - Regulation 11 & 12
Reg 11-Dose limits:
18yrs and above 20 mSv/yr
I f i m p r a c t i c a b l e 50 m S v / y r ( m a x 1 0 0 / 5 y r s )
Under18 yrs 6 mSv/yr
Specific values for parts of the body - lens of the eye 150, hands 500 mSv per year
Reg 12:
Contingency plans where accident reas onably fores eeable
IRR - Regulation 13 & 14
Reg 13:
Radiation employers to appoint Radiation Protection Advis or in writing - s ome exemptions
Reg 14:
Employer to provide s uitable information, ins truction and training: i)therisks tohealthcreatedbyexposure
ii) the precautions which s hould be taken
iii) the importance of complying with the medical, technical and adminis trative requirements of the Regulations
IRR - Regulation 16
Requirements and designationforControlled Areas and Supervised Areas:
Controlled Areas - where dos e levels are likely to exceed 6mSv per year or exceed 3/10 of any otherdos e limit
Supervis ed Areas - where dos e levels likely to exceed 1mSv per year or exceed more than 1/10 of anyother dos e limit
IRR - Regulation 17 & 19
Reg 17:
Employers mus t draw up Local Rules for Controlled Areas and Supervised Areas
Employers mus t appoint Radiation Protection Supervis ors to ens ure compliance with Local Rules and legal requirements
Reg19:
Employers mus t ens ure that des ignated areas are monitored with appropriate equipment
Monitoring equipment mus t be maintained and tes ted (ACOP - at leas t annually, and calibrated beforefirs t us e)
Monitoring records mus t be kept for 2 years
IRR - Regulation 20
nyone likely to receive 6 mSv per year, or more than 3/10 any dos e mus t be des ignated as a Clas s ified Pers on
Clas s ifiedPers ons mus t be over 18 yrs old, and mus tbe certified by an appropriate medical practitioner as being fit for work
IRR - Regulation 27 to 33
Reg 27 to 33-controlofradioactive substances:
Thes e include:
Using sealed sources SFARP
Keeping records of quantity and location (2 years )
Suitable s torage
HSEtobenotifiedofreleases ofradioactivematerials (subjectto certain quantities )
Suppliers and manufacturers mus t ens ure equipment is s afe
IRR - Regulation 34
Employees duties:
Not to expos e thems elves to ionis ing radiation SFARP PPE- full and proper us e/return to accommodation Pres ent thems elves for medical examinations
Radiation Protection Advis or (RPA)
Us ually external cons ultant
Needed by almos t all radiation employers
To be appointed in writing
Cons ulted regarding controlled and s upervis ed areas , radiation controls , monitoring, drawing up of local rules etc
Competence
Radiation Protection Supervis or (RPS)
Needed when the employer needs to des ignate controlled/s upervis ed ar eas
To help employer ens ure compliance with local rules /regulations Employee with knowledge of work
Numbers depend on as s es s ment/type ofwork/number of s ources number of Clas s ified Pers ons
Level of competence required determined by employer
Names to be included in local ru
Controlled Areas
Needed where does likely to exceed 6mSv yr or 3/10 of any dos e If s pecial procedures neces s ary
Segregation and s igns indicating ris k
Monitoring required
Entry limited to Clas s ified Pers ons Local rules required
Control of contamination e.g. hygiene
Supervised Areas
Des ignated where dos e received likely to be 1 mSv or 1/10 of any dos e Signage required
Monitoring required
Local rules
Radiation Protection Supervis or required Nophysical demarcation
Nomonitoring of staff
Classified Persons
Anyone likely to receive 6mSv yr or 3/10 of any dos e
Mus t be over 18 yrs and certified by medical practitioner as fit for work (within past 12 months)
Adequate medical s urveillance
Employer mus t meas ure dos e received
Approved dos imetry s ervice
R e c o r d s k e p t 50 y r s
Clas s ified worker mus t be informed
Principles of Radiological Protection
Us e s malles t pos s ible s ource
Reduce expos ure time to minimum Maintain greates t dis tance pos s ible Provide adequate s hielding
Dos e monitoring/limits
PPE
Procedures to prevent internal haz ard Sealed sources
Internal Radiation Haz ard - Control (1)
Eliminate the ris k through the choice of lower activity s ources Containment in glove boxes or fume cupboards
Strict control on food cons umption/good hygiene practice Workplace des ign e.g. impervious s urfaces and provis ion of fume cupboards or glove boxes .
Internal Radiation Haz ard - Control (2)
Appropriate PPE s uch as gloves and lab coats
Extens ive training and information
Emergency plans and procedures to be inplace in cas e of s pillage Monitoring/dos imetry
Decontamination meas ures for equipment and clothing that may come in contact with the radioactive s ource.
IRR - Medical Expos ure
Aim protect medical patients from unintended, exces s ive or incorrect expos ure to radiation
Als o volunteers in medical res earch programmes
Require that the ris k from expos ure is as s es s ed agains t the clinical benefit
Should ens ure that patients receive no more expos ure than is neces s ary to achieve the des ired benefit
Radiation Detectors
Io nis atio n Chamb e rs :
Chamber containing gas Ions produced when bombarded with radiation
Current flows and is meas ured Ge ige r-Mulle r Tube s:
Type of ionis ation chamber
High voltage between electrodes in chamber
Accelerates ions - can be us ed to give “click”
Meas uring Radiation
c i nti l l a ti o n C o unte r s :
Contain crys tal (e.g. s odiumiodide) that gives out light when irradiated
Liquid ScintillationCounters:
Sample mixed with a liquid which fluores ces when irradiated
Choice of Detector
Type of radiation Level of activity Level of accuracy Vis ual/audible Conditions ofuse Cos t
Pers onal Monitoring - Why?
To maintain a pers onal his tory of expos ure
To highlight need for further medical examination
Confirm control meas ures are effective
Usetodefend claims
Provide employees a degree of individual comfort that they are s afe Legal requirement for Clas s ified Pers ons or if reas onable caus e to believe neces s ary to ens ure health and s afety of any employee
Pers onal Monitoring - Types
Filmbadge:
Thermolumines cent dos emeters (TLDs ) Directreading/warning ins truments
All dos imetry s ervices mus t be approved by HSE (Reg 35IRR)
Film Badge
Badge containing photographic film Worn on lapel/top pocket
Windows allow pas s age of different types of radiation
Film developed-blackening directly proportional to expos ure
Optical dens ity of film meas ured Typically is s ued monthly
Thermolumines cent Dos imeters (TLDs )
Contain crys tals e.g. Sodium/lithiumfluoride – s tore energy of ionis ing radiation Ifcrystals heatedatalaterstage, light is emitted - proportional to exposure
Worn on lapel/top pocket
Worn for 2 weeks up to 2 years – can be re-us ed
Largely replaced film badges , les s likelyto be damaged
Als o extremity dos e (finger/wris t)
Direct Reading Dosimeters
Small lightweight - incorporating ionis ation chambers or Geiger Muller tubes
Can be linked to alarms
Need to be calibrated
Switched on Battery check
Us e of Dos imeters
Avoid damage
Do not leave clos e to radiation s ources when not worn Switch on/zero
Do not open/damage cas e
Donotwearotherpeople’s dosimeters
Avoid expos ure to heat/humidity/chemicalvapours
Do not s hield in us e
Proces s films /devices as s oon as pos s ible after return
Lasers
A device for concentrating vis iblelight, IR or UV into an intens e narrow beam of high energy
Light Amplification by the Stimulated Emis s ion of Radiation
Eye s urgery, compact dis c players , las erlight s hows , s upermarket
s canners , cutting, welding, meas uring devices
Lasers -Associated Hazards (1)
Burns , es pecially retina of eye – direct and reflected beams Lacerations with high power las ers
Electricity – high voltages
Chemicals and fume – s ample preparations , us e of dyes and s olvents , fumes produced by cutting and engraving
Lasers -Associated Hazards (2)
Mechanical – manual handling materials and gas cylinders , falls when acces s ing high parts of the equipment, s lips and trips on cables , cryogenic liquids , nois e, vibration
Fire – high power, direct and reflected beams , ignition of cut materials
Laser Classification -1,1M,2 &2M
IEC/BS/EN 6085-1 Standard
Class 1:
I n h e r e n t l y s a f e (N o s k i n o r e y e h a z a r d )
Class 1M:
Safe unles s pas s ed through magnifying optics
Class 2:
Low power devices emitting vis ible radiation not inherently s afe but eyes protected by avers ion res pons e
Noskin hazard
Class 2M:
As 2 unles s pas s ed through magnifying optics
Las er Clas s ification - 3R, 3B & 4
Class 3R:
When output viewed directly may exceed recommended levels Low risk of injury
Haz ard with optical devices
Class 3B:
Output invis ible, or beam caus es damage fas ter than blink res pons e May als o caus e s kin burns
Class 4:
Mos t haz ardous
Highes t powered devices
Immediate eye and s kin injury
Expos ure to diffus e reflections may be haz ardous
Las er Safety Officer
IEC/BS/EN60825-1LaserSafetyStandard recommendation:
To be appointed for Clas s 3B las ers and above Aware of s afety is s ues
Overs ee us e
Ins tallation in s mall bus ines s es
Training depends on degree of ris k
Las er Protection Advis er
Dept. Health Guidance to NHS/healthcare s ector
Class 3B and 4 lase rs:
Mus t cons ult or appointa Las er Protection Advis er
Competence and role to be defined by employer
Certification s chemes for LPSs e.g. HPA and the As s ociation of Las er Safety Profes s ionals
Las er Protection Advis er - Roles
Undertake ris k as s es s ments
Identification of the Las er Controlled Area
Overs ee the commis s ioning of the las er i.e. pos t ins tallation
Ens ure that s uitable local rules and working practices are drafted Provide training to Las er Protection Supervis ors and us ers Undertake regular equipment and pers onnels afety reviews
Inves tigate and report as appropriate any advers e events
Las er Protection Supervis ors
Dept. Health Guidance
Supervis e the work of pers onnel who operate equipment
Supervis e any local rules and ens ure that they are followed on a day-to- d ay b as i s
Competence to be determined by LPA
Lasers -Controls
Enclos ure of working area
Des ign e.g. direction control, reduce reflective s urfaces , beam attenuator, s creens , warning s ignals e.g. lights
Las er warning s igns
Interlocks , key control, s ys tems of work
Las er control areas
Training of pers onnel
Eye/Face protection
Lasers -Legislation(1)
The ControlofArtificialOpticalRadiation(AOR)atWork Regulations 2010:
Clas s 3B and 4 las ers Lis t 2 (action required)
Ris k as s es s ment - reduce expos ure ALARP
Ins truction and training
Health s urveillance
IfExposure LimitValues (AnnexIIcoherentradiation) likelyto be exceeded:
Action plan
Demarcate areas
Res trict acces s
Post signs
Lasers -Legislation(2)
Health and Safety at Work Act 1974
Management of Health and Safety at Work Regulations 1999:
Provision and Use of Work Equipment Regulations 1998
Electricity at Work Regulations 1989
