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Information on doses

The Ionising Radiations Regulations 1999 (IRR99) establish a good regulatory framework for reducing employees' exposure to ionising radiations and have generally been successful in helping to ensure the continuing reduction in doses to workers since the making of the previous Regulations in 1985 (IRR85). This is confirmed by analyses of data held on HSE's Central Index of Dose Information (CIDI). Over the period 1986-1998 there was more than a 10-fold reduction in the numbers of classified persons with recorded doses above the statutory investigation level prescribed by IRR85.

The limits on effective dose (dose to the whole body) introduced by the IRR99 to replace the limits set previously by the IRR85 are:

  1. for employees aged 18 years or over, 20 millisieverts in a calendar year (except that in special cases employers may apply a dose limit of 100 millisieverts in 5 years with no more than 50 millisieverts in a single year, subject to strict conditions);
  2. for trainees, 6 millisieverts in a calendar year; and
  3. for any other person, including members of the public and employees under 18 who cannot be classed as trainees, 1 millisievert in a calendar year.

The dose limit for the skin now applies to doses averaged over an area of skin not exceeding 1 cm2.

Updated 2012-10-16