Guidance for work with ionising radiation

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					University of Bath. Guidance for work with ionising radiation. March 2009

 This document (for users of both X-rays and radioactive materials)
 should be read in conjunction with
     1. section 4.2.13 of the University Safety Manual (guidance and
        policy on work with ionising radiation [IR]) available at
 If radioactive materials are to be used the following documents are also
 essential reading -
     2. Guidance for users of radioactive materials (available at
     3. the relevant set(s) of Local Rules (available from your RPS).

     Legislative background against which our procedures are based.
     Prior authorisation is needed for some activities.
     Prior risk assessment is needed for all activities involving IR.
     Designation and labelling of radiation areas is required for all areas
      where IR is used.
     Monitoring of radiation areas is needed to demonstrate best practice.
     Designation of IR Workers is required for anyone involved in IR work.
     Female radiation workers have particular dose restrictions.
     Restriction and limiting of radiation doses.
     Minimising external radiation exposures.
     Assessments of radiation exposure are needed in some situations.
     Dosimetry is undertaken both routinely and in emergency situations.

 Legislative Background.
 Contravention of the provisions in any of these (or their amendments) is a
  criminal offence and individuals found guilty could be at risk of fines or
 The Ionising Radiations Regulations 1999 1 (IRR99) place a duty on
  employers to take steps to restrict exposure of people to ionising radiation
  (IR) (in accordance with Regulation 8), i.e. to keep radiation doses as low as
  reasonable practicable (ALARP).
 University policy, irrespective of strict dose limits 2, is to operate the
  ALARP concept.
 The University must appoint an RPA (Reg 13(2)) and departmental RPSs
  (Reg 17(4)).
 These Regulations are administered by the Health and Safety Executive
  (HSE) and supported by an Approved Code of Practice (ACOP) titled Work
  with Ionising Radiation which provides practical guidance to assist in
  implementing IRR99.
 The Ionising Radiations (Medical Exposure) Regulations 2000 3 apply to
  work involving medical (or research) exposures to individuals.
 The Radioactive Substances Act l993 4 (RSA93) regulates the keeping and
  use of radioactive materials, and the accumulation and disposal of

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        University of Bath. Guidance for work with ionising radiation. March 2009

          radioactive wastes. It is administered by the Environment Agency (EA) and
          is primarily concerned with protecting the environment from radioactive
          pollution by controlling the disposal of radioactive waste. Certificates of
          Registration issued under the provisions of RSA93 authorise us to keep and
          use radioactive materials in the form of sealed and unsealed sources.
          Similarly a Certificate of Authorisation regulates the accumulation and
          disposal of radioactive waste. Both types of certificate are accompanied by
          standard conditions and limitations, and copies of the certificates must be
          displayed on the premises where radioactive materials are used. (Copies of
          ours are lodged with departmental Radiation Protection Supervisors –
         Under the RSA93 there are currently a total of 18 Exemption Orders that allow
          certain radioactive sources and practices to be exempt from the Act. These
          include items such as smoke detectors. These are currently (March 2009)
          being reviewed and the review process should be complete by April 2010.
         The registration of some sources is exempted by any one of these Exemption
          Orders 5.
         Periodic inspections of the premises will be made by both the HSE and the
          EA. They have the power to enter premises unannounced to inspect and
          confirm that there is no contravention of the above Acts, and the authority to
          withdraw authorisations and issue prohibition notices and, in severe cases,
          prosecute individuals and/or the University.
         The Justification of Practices Involving Ionising Radiations Regulations 2004 6
          require any radiation work to be justified in that the benefits from the work
          outweigh any potential detriment to human health or the environment from
          the IR used. If a new type or class of activity is planned then a case must
          be submitted to the Justifying Authority for approval.
         The Carriage of Dangerous Goods and Use of Transportable Pressure
          Equipment Regulations 2007 7 govern the packaging, movement and road
          transport of radioactive materials. The URPO must be consulted if
          University members are planning to send radioactive materials off campus
          by any means. A consignment certificate must accompany all such
         The Management of Health and Safety at Work Regulations 1999 8 require a
          risk assessment to be compiled for ANY risk (Reg 3). This includes
          radiation risks and also an assessment of risk from radon (a naturally-
          occurring radioactive gas) as the Claverton Down campus and University
          properties in Bath are all in Radon Affected Areas.
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         Prior authorisation is required (from the Health and Safety Executive for
          compliance with Regulation 5 of IRR99) for the use of X-ray sets in
          research. This is covered by a generic authorisation (as long as the
          conditions in the generic authorisation are met). HSE has developed two
          certificates of generic authorisation;
             For the use of electrical equipment intended to produce X-rays and
             For the use of accelerators (other than electron microscopes).


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        University of Bath. Guidance for work with ionising radiation. March 2009

          Each certificate contains conditions which are basic requirements for that
          use of ionising radiation; compliance with the conditions alone will not be
          sufficient to achieve full compliance with IRR99.
         The following practices (and some others) do not need authorisation under
          IRR99. The use of;
             electron microscopes,
             X-ray sets for routine analytical, diagnostic or investigation purposes
             X-ray gauging and detection systems in measurement processes.
         Proposals for research X-ray exposures to humans must be vetted by the
          Bath Research Ethics Committee 9 (e.g. DXA exposures).
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         Prior risk assessment.
         Before commencing a new activity involving work with IR a suitable and
          sufficient assessment of the risk (to anyone) must be made by the person in
          control of the work for the purpose of identifying the measures needed to
          restrict exposure to IR. This is to demonstrate that -
            (a) all hazards with the potential to cause a radiation accident have been
                identified; and
            (b) the nature and magnitude of the risks arising from those hazards have
                been evaluated.
          Where the assessment shows that a radiation risk exists from an identifiable
          radiation accident, then all reasonably practicable steps must be taken to -
            (a) prevent any such accident;
            (b) limit the consequences of any such accident which does occur; and
            (c) provide employees with the information, instruction and training, and
                with the equipment necessary, to restrict their exposure to ionising
         For radioactive materials the prior risk assessment is incorporated into the
          scheme of work which must be completed, and accepted by the RPS and
          URPO, before the material can be ordered. The scheme of work (and risk
          assessment) will be reviewed every year.
         For X-ray sources the Local Rules provide an estimate of risk.
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         Designation and labelling of Radiation Areas.
         Work areas where ionising radiation is to be used must be classified as
          Controlled or Supervised and labelled accordingly (IRR99 Reg 16). The
          URPO (in consultation with the RPA) will keep these areas under review in
          order to keep the classification up-to-date. Designated storage facilities and
          disposal sinks in these areas must be suitably labelled.
         Controlled areas must be designated where there is;
             an external dose rate, averaged over a working day, > 7.5 μSv / hour
             a dose rate to the hands, averaged over a working day, > 75 μSv / hour
             a significant risk of spreading radioactive contamination outside that
             a need to prevent, or closely supervise, access to the area by workers
               unconnected with the work involving IR (e.g. maintenance workers)


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University of Bath. Guidance for work with ionising radiation. March 2009

        an assessment that workers could receive an effective dose > 6 mSv /
 Each Controlled area must be physically demarcated, or, if this is not
   reasonably practicable, delineated by some other suitable means and all
   access points to Controlled areas must be labelled with suitable radiation
   warning signs.
 Access to Controlled areas is restricted to Classified persons or persons
   (workers or visitors) following an approved written system of work which
   will ensure that they are most unlikely to receive more than three-tenths of
   any dose limit. Entry into a Controlled area must be solely for the purpose
   of carrying out approved duties or procedures and all involved must have
   received adequate training. Except for the RPS, URPO, RPA or Inspectors
   exercising a statutory power, or in cases of fire or other serious emergency,
   no-one else may enter a Controlled area without following a written system
   of work.
 If a visitor who is a Classified worker at another establishment requires
   access to a Controlled area, the URPO must be consulted in order to ensure
   that the employer cooperation requirements of IRR99 Reg 15 may be met.
 At present the University has Controlled Areas in the Radiation store room,
   4W infill lab, 5W 2.35 and the machine enclosures in the X-ray
   Crystallography Suites in buildings 1S, 3W and 4W. There are currently no
   classified workers in the University.
 A Controlled area can equally be designated if the work being carried out
   could give rise to an internal contamination hazard and not an external
   hazard. For assessment of these areas, the table below gives the activities
   for selected radionuclides that, if exceeded as a storage level, necessitate
   the laboratory concerned being designated as a Controlled Area. For
   completion the table also includes the Annual Limits for Intake (ALI) for
   occupationally exposed workers.
 It must again be stressed that dose limits and annual limits for intake
   are maximum levels and all efforts must be made to ensure that doses
   are as low as reasonably practicable.

                                         Stored activity (Bq) for
                                                                     ALI (Bq)
        Isotope           Half-life         Controlled Area
      TRITIUM           12.35 years             1 x 1010              1 x 109
   CARBON-14            5730 years               9 x 108              4 X 107
    SODIUM-22            2.6 years               2 x108               7 X 106
    SODIUM-24            15 hours                1 x 104              5 x107
 PHOSPHORUS-32           14.3 days               1 x 108              8 x 106
   SULPHUR-35            87.4 days               8 x108               3 x108
   CALCIUM-45            163 days                3x 108               2 x 107
      ZINC-65            244 days                1x 108               5 x 106
    IODINE-125            60 days                1 x107               1 x 107
    IODINE-131             8 days                1 x 107              8 x105

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        University of Bath. Guidance for work with ionising radiation. March 2009

         Supervised areas must be designated if
            any person is likely to receive an
            effective dose greater than 1mSv a
            year (or an equivalent dose greater
            that 1/10 of any relevant limit) or if it is
            necessary to keep the conditions of the
            area under review to determine
            whether the area may require
            designation as a controlled area.
         In practice this requirement is extended
            to cover all areas used for handling
            radioactive materials which are not              Lab door label (RAMs).
            designated as Controlled areas.
            Supervised areas need not occupy an
            entire room but will cover workstations
            or storage locations where radioactive
            materials are present. All such areas
            must be identified by means of suitable
            radiation warning signs
         There are no special restrictions on
            access to supervised areas, but
            radioactive materials, X-ray equipment,
            and equipment/ workstations marked
            with the radiation hazard trefoil
            (because of potential contamination)              Lab door label (X-rays)
            should only be used by registered radiation workers or undergraduate
            students under close supervision.
         Labs containing Supervised (and Classified) areas are identified by a label on
            the outer door (as top picture on the right) but the actual designated area is
            usually confined to demarcated workstations and storage facilities (e.g.
            fridges or freezers). The URPO will alert the Estates department to identify
            designated sinks and associated pipework on building plans.
            Maintenance work on designated sinks and associated pipework may only
            be carried out with the written approval of the URPO under a permit to
            work (PTW).
         If radiation work is discontinued in an area which was previously designated
            as a Controlled or Supervised area, or if a designated sink is no longer
            required for disposal of aqueous radioactive waste, a thorough check must
            be made by the RPS to ensure that no contamination remains. Results of
            the monitoring must be recorded and a copy sent to the URPO. All radiation
            hazard signage must then be removed and building plans amended
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         Monitoring of radiation areas.
         Any controlled or supervised area must be adequately monitored by the users
          either for contamination of RAMs or leakage of X-rays. It must be monitored
          on a regular basis to demonstrate dose rates are satisfactory. Equipment
          for such monitoring (contamination monitors or dose-rate meters) must be
          provided and maintained by user departments but they will be annually
          tested and examined under the direction (and the budget) of the URPO.

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        University of Bath. Guidance for work with ionising radiation. March 2009

              Monitors used for monitoring in Controlled Areas must be calibrated
              annually. Test results will be maintained by the URPO for at least 2 years.
              Instrument test failures will be reported to the user department and they may
              be disabled before being returned to them.
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         Designation of IR workers.
         All members of the University working with ionising radiations - except
          undergraduate students participating in supervised class work only - must
          be registered as radiation workers. The register is compiled and
          maintained by the URPO, but each RPS provides prospective departmental
          users with a registration form and must ensure that the URPO is informed
          immediately of all changes to the register.
         Following completion of their registration, radiation workers will be informed
          by the URPO of their status and any requirement for dosimetry.
         The URPO must be consulted when:
              any person who is an employee of another establishment intends to
                work with ionising radiation on the University premises. They must
                register with the URPO before beginning such work and must provide
                evidence of previous training; or
              when a Classified worker from another establishment requires access
                to a Controlled Area.
         There are currently no classified workers in the University of Bath.
         Employees who, as a result of their work activities, may receive a dose of
          ionising radiation exceeding one-tenth of any relevant dose limit but are not
          likely to receive a dose which exceeds three-tenths of any such limit, will be
          registered by the University as Non-Classified radiation workers. Currently,
          all radiation workers registered in the University are in this category and, as
          such, require no routine medical examination or blood test.
         All radiation workers are required to be familiar with the requirements of the
          University policy and guidance document10, this Guidance Document, any
          relevant Local Rules (available from your RPS), and, if working with RAMs,
          the Guidance for users of radioactive materials 11.
         Undergraduate project students are not prohibited from handling
          radioactive materials but specific guidance is available12 on recommended
          limits of activity they may work with.
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         Female radiation workers.
         Dose limits for the abdomen of women of reproductive capacity are more
          restrictive than those for other radiation workers, and are intended to protect
          the foetus which, at some stages of development, is particularly sensitive to
          ionising radiation.
         Radiation workers who become pregnant or who are breast-feeding an infant
          must inform their line manager, supervisor or the SH&E Unit as soon as
          possible so that advice may be given and, where necessary, steps taken to
          ensure that it is possible to comply with the special dose limits
          recommended for the duration of the pregnancy or breast-feeding. In most


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        University of Bath. Guidance for work with ionising radiation. March 2009

          cases there should be no need to restrict work with radioactive materials as
          the doses received are unlikely to approach the permitted limit, but
          occasionally it may be considered prudent for a pregnant worker to curtail a
          particular aspect of her work e.g. radioiodinations.
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         Restriction and limiting of radiation doses.
         The University is committed to take all necessary steps to restrict, so far as is
          reasonably practicable, the extent to which anyone is exposed to ionising
          radiation (IRR99 Reg 8). Dose limits are set for exposures to the whole
          body, extremities and individual organs (IRR99 Reg 11 and Schedule 4, part
          1). As examples, the effective (whole body) dose limit for adults is 20 mSv
          per year, and effective dose for fingers, 500 mSv.
         A ‘dose constraint’ for a foetus during the term of pregnancy is set as 1 mSv.
         Dose constraint is not strictly a limit, but a reasonably achievable target to
          keep below, indicating best practice. There is no reason why, in a University
          context with no Classified Workers, all radiation workers should not keep to
          within a dose constraint of 1 mSv. This target is reasonably achievable and
          means that men and women can then be treated the same with no undue
          concern should a woman become pregnant. (This should be compared to
          the average annual UK background radiation level of about 2.5 mSv we are
          all exposed to.)
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         Minimising external radiation exposures.
         The fundamental ways of reducing external radiation exposure are:
            (i) Limit the activity of the source (or energy of the X-rays) used.
            (ii) Shielding placed around the source.
            (iii) Distance. Operate the inverse square law concept in which the
                  intensity of the dose is inversely proportional to the square of the
            (iv) Time of exposure minimised should (i) to (iii) not be feasible.
          This latter option, in particular, necessitates the use of a dose-rate meter
          and an understanding of the units of dose and dose limitation.
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         Assessments of radiation exposure.
         The policy of this University, irrespective of the dose limits imposed by
           IRR99, is to operate the ALARP concept.
         IRR99 Reg 7 requires prior risk assessment of all work involving the use of
           ionising radiation.
         Specific Risk Assessments for the use of radioactive materials must be
           undertaken (as part of a scheme of work) by the radiation worker before any
           can be ordered. This is accomplished as part of our on-line management
           system which computes a realistic assessment of dose rate. Such risk
           assessments need initial approval by the URPO, as well as annual approval
           following review by the radiation workers.
         Local Rules for machine sources of IR will provide an assessment of
           possible doses and ways to minimise exposure as well as levels of exposure
           or leakage which would initiate an investigation.
         Any employee, whether Classified or not, who receives a dose of ionising
           radiation in excess of twice the annual dose limit should notify the RPA

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        University of Bath. Guidance for work with ionising radiation. March 2009

          without delay, and may be required to undergo a special medical
         The University is required to retain the health record of each Classified
          radiation worker for fifty years from the date of the last entry.
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         The University operates a personal monitoring service administered through
          the Safety, Health & Environment Unit.
         From the information given in the prior risk assessment, in general, all
          workers using sources emitting penetrating ionising radiation (those aligning
          X-rays, or using gamma-ray, or high energy (Emax>300keV) beta-emitting
          radioisotopes) will be required to wear body dosemeters, conventionally
          clipped to the lapel or breast pocket of a laboratory coat. For short-range
          radiation such as that from 1-125, the badge may be attached to the cuff of
          the arm of the coat. All workers using P-32 will be issued with a finger
          dosimeter (to be worn on their dominant index finger under a disposable
          glove) as an indicator of the maximum dose that the individual will receive
          from his/her activities.
         Dosimeters may also be issued to persons who have not previously worked
          with ionising radiation regardless of the result of the risk assessment. Such
          monitoring will not necessarily be continued once an adequate measure of
          the doses has been obtained.
         Workers issued with a dosimeter must wear it when working with IR. The
          purpose, for non-classified radiation workers, is
             to reassure them and their supervisors that they are exposed to doses
                as low as reasonably practicable (ALARP),
             to demonstrate that designation as a classified worker is not required,
             to monitor both their technique and the working environment. (There
                have been occasions when recorded doses have indicated poor
                practice and this can be investigated and corrected.)
         Personal dosimeters will be issued for such periods of time as the URPO
          considers appropriate, taking into consideration both the type of dosimeter
          and the nature of the work. All dosimeters must be returned promptly at
          the end of the wear period (usually 2 months, or less if a short project).
          Failure to do this will result in the worker’s Department being asked to pay
          the cost of a non-returned dosimeter.
         External dose levels to individuals will be reported to those individuals if they
          consistently (over 2 successive 2 month monitoring periods) receive a dose
          however low. Levels in excess of 0.1 mSv per 2 months for film badges
          (whole body dose) and 0.3 mSv per 2 months for finger dosimeters will be
          reported to the individuals concerned. Under the ALARP concept efforts will
          be made to effect a dose reduction. Individuals may request from the SH&E
          Unit at any time the reports of their exposure doses.
         Site monitoring around Controlled Radiation Areas is also to demonstrate
          that doses (from primary sources and scattering) are ALARP.
         Emergency dose assessments will be required when an accident or any
          other incident occurs which is likely to result in a person being exposed to
          ionising radiation in excess of three-tenths of any relevant dose limit. This
          will be achieved, where applicable, by examination of the personal

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        University of Bath. Guidance for work with ionising radiation. March 2009

           dosimeter, or by other means such as examination of biological specimens
           or computation of dose received from measurements of dose rates,
           contamination levels, exposure time and distance etc. The circumstances
           leading to the accident will be fully investigated by the URPO so that
           appropriate action may be taken both to deal with the current situation and
           to prevent future occurrences. Such incidents may be reported to the
           relevant Trades Union Safety Representatives in accordance with University
           Safety Office procedures.
         Biological Monitoring involves measuring radioactivity in samples such as
           urine, to calculate the activity in the body. It is normally required only if very
           large activities of open sources are being handled and there is a significant
           risk of intake of radioactivity or excessive skin contamination, or following an
           accident, but users of radioiodine should regularly monitor their thyroid to
           check for possible intake.
         In cases of accidental intake and/or contamination the RPS must be notified
           immediately as it may be necessary to request biological samples to
           calculate the intake. The RPS must notify the URPO or the RPA
           immediately for the correct actions to be taken.
         Doses received by Classified workers have to be assessed by an approved
           dosimetry service, and records kept for 50 years from the last entry.
           Records of dose assessments made following an accident or other incident
           must also be kept for 50 years.
         Classified workers will be sent a copy of their termination dose record on
           ceasing employment with the University. This can only be done when the
           classified worker has notified the URPO that they are leaving the University.
         Formal Investigation Levels (IRR99 Reg 8(7)) are identified in individual
           Local Rules. In addition, should any worker receive an effective dose of
           ionising radiation >1mSv in any calendar year, a formal investigation will be
           undertaken by the URPO in order to ensure that exposure to ionising
           radiation is being restricted as far as is reasonably practicable.
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         End of document.

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