Exposure limits ionising radiation

The main aim of the Regulations and the supporting ACoP is to establish a framework for ensuring that exposure to ionising radiation arising from work activities, whether from man-made or natural radiation and from external radiation (e.g. X-ray set) or Internal radiation (e.g. inhalation of a radioactive substance), is kept as low as reasonably practicable and does not exceed dose limits specified for Individuals. IRR99 also ... 

L7 Ionising radiations (part 4) Dose limitation — restriction of exposure. 

All three principles apply to the protection of workers and the public. However, to protect patients during the medical use of ionising radiation only justification and optimisation apply. Dose limits are not applicable to medical exposure, but guidance levels which show what is achievable by good practice may be established for use by medical practitioners. Dose limits are also inapplicable to interventions, which are concerned with reducing exposure. 

Directive 96/29/EURATOM (Basic safety standards) provides safety standards for the protection of health workers and the general public against the dangers of ionising radiation [18]. Directive 97/43/EURATOM (Medical exposure directive) gives rules concerning radiation in relation to medical exposure and provides dose limits [19]. 

The dose limits for employees over the age of 18 years are those recommended by ICRP. Lower limits apply to trainees under the age of 18 years. Special restrictions apply to the rate at which women of reproductive capacity can be exposed and to the exposure of pregnant women during the declared term of pregnancy. The limits for any other person are 5 mSv in a year for the effective dose and SOmSv in a year for the dose to individual organs or tissues other than the lens of the eye for which the value is 15 mSv in a year. The main requirement however is for employers to take all necessary steps to restrict so far as reasonably practicable the extent to which his employees and other persons are exposed to ionising radiation. ... 

Ionising radiation occurs naturally as well as from man-made processes and about 87% of all radiation exposure is from natural sources. The Ionising Radiations Regulations 1999 specify a range of dose limits, some of which are given in Table 17.8. 

Matthes, R., Bernhardt, J.H. and McKinlay, A.F., International Commission on Non-Ionising Radiation Protection publication ICNIRP 7/99, Guidelines for Limiting Exposure to Non-ionising Radiation. Markl-Druck, Munchen (1999)... 

The objective of this study is to determine the electric field and magnetic level radiated by the 275kV transmission line as well as to assess the potential EMF exposure received by the residence living at the selected study sites. The electric and magnetic fields level were evaluated and compared to the exposure limit recommended by International Commission of Non-Ionising Radiation Protection (ICNIRP). 

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