Regulations 2, 14(1), (4) and (5), 15(4), 16(1), (2) and (3), 18 and 49(1)
Dose Limits For Radiation Workers
| (a) | Except as provided in paragraph (d) of this Part, the dose limits for radiation workers shall be those given in the following table. The dose from any medical or dental exposure as a patient, from the exposure to natural background radiation or from other exposures received by the radiation worker as a member of the public shall not be taken into account.
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| (b) | Where only a part or parts of the body are irradiated by external radiation, the effective dose received from external radiation shall be determined by calculating the sum of wTHT over all the organs and tissues irradiated, where —
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The values of the tissue weighting factors to be used for determining the weighted equivalent dose wTHT, shall be those given in the following table:
Tissue weighting factor WT | |
3 The equivalent dose in the remainder is the estimated mean equivalent dose over the whole body excluding the specified tissues and organs. |
| (c) | The occupational dose limit for women who are not pregnant shall be the same as that of men. |
| (d) | Once pregnancy has been declared, the equivalent dose limit to the surface of the woman’s abdomen (lower trunk) shall be 2 mSv for the remainder of the pregnancy and the intake of radionuclides shall be limited to one-twentieth of the ALI specified in the Third Schedule. |
Dose Limits For Individual Members Of The Public
The annual dose limits for individual members of the public shall be those listed in the following table. The dose from any medical or dental exposure as a patient or from the exposure to natural background radiation shall not be taken into account.
Dose limit per year | |
Effective dose (whole body) | 4 In special circumstances, a higher value of effective dose for the whole body could be allowed in a single year, provided that the average over 5 years does not exceed 1 mSv per year. The limit shall apply to the sum of the relevant doses from external exposure in the specified period and the committed effective dose. |
5 The limit of 50 mSv for skin is averaged over areas of no more than 1 cm2 regardless of the area exposed. |
Values Of Radiation Weighting Factor For Different Types Of Ionising Radiation
The values of radiation weighting factor to be used in determining the equivalent dose in a tissue or organ shall be those given in the following table. All values relate to the radiation incident on the body or, for internal sources, emitted from the source.
Type of ionising radiation and energy range | Radiation weighting factor |
Electrons and muons, all energies | |
Neutrons, energy < 10 keV | |
Protons, other than recoil protons, energy >2 MeV | |
Alpha particles, fission fragments, heavy nuclei |