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New Regulations

On 1 January 2018 Ionising Radiation Regulations 2017 (IRR17) replaced Regulations (IRR99).

For more information go to the draft Approved Code of Practice and guidance.

We are in the process of updating the guidance below to reflect this change.

Appropriate designation of classified persons

Supplementary information to the guidance in paragraphs 367 to 380 of ‘Work with ionising radiation’ (L121), designed to assist the employer in the appropriate designation of classified persons under regulation 20 of the Ionising Radiations Regulations 1999 (IRR99).

This information will be of interest not only to those employers who routinely work with ionising radiation, but also to those employers (including the self-employed) whose employees occasionally work where sources of ionising radiation are present e.g. contractors working temporarily on licensed nuclear sites.

When is classification appropriate?

Radiation employers (i.e. employers who in the course of a trade, business or other undertaking carry out work with ionising radiation) are required, under IRR99, to designate as classified persons those employees who are likely to receive an effective dose in excess of 6mSv per year or an equivalent dose in excess of 3/10ths of any relevant dose limit (regulation 20). Where this is the case, relevant employees will be made subject to medical surveillance and have their doses appropriately assessed and recorded.

The employee's own employer is responsible for determining whether classification is appropriate, however it should be noted that duties imposed on the employer are also imposed on the holder of a nuclear site licence in so far as those duties relate to the licensed site and in such cases it is important that there is co-operation between employers as required by IRR99 Regulation 15. In determining the need for classification the employer is likely to need to consider a number of factors and may also consult other parties, including a radiation protection adviser (RPA), to obtain sufficient information to decide whether classification is necessary.

The overarching duty in IRR99 is to restrict exposure so far as is reasonably practicable (IRR99 regulation 8(1) and L121 paragraphs 59-118). Designation of individuals as classified persons should be considered when, despite all reasonable steps having been taken, there remains a likelihood that the dose criteria specified in Regulation 20 will be reached. The flow chart may help in deciding whether classification is appropriate.

Employees may be required to enter controlled areas as part of their work. Where this is the case, such entry is only permitted to those designated as classified persons or those working in accordance with suitable written arrangements. Written arrangements must ensure that working practices are planned to ensure that radiation doses to individuals are below those levels that would require them to be designated as classified persons. In accordance with Regulation 18(3) personal dose monitoring or monitoring by other suitable means is required to demonstrate appropriate restriction of exposure.

Classification should not be used to avoid the work involved in preparing suitable written arrangements.


The decision as to who needs to be designated as a classified person should be relatively straightforward where work with ionising radiation is undertaken by employees with a single employer and where exposure of any other employer's employees is unlikely.

The radiation employer should, in consultation with their RPA, carry out an assessment of the risk associated with the proposed work in accordance with regulation 7 of IRR99 or regulation 3 of the Management of Health and Safety at Work Regulations 1999 (MHSWR) (The Approved Code of Practice & Guidance supporting the Regulations ‘Management of Health and Safety at Work’ L21 ISBN 0 7176 2488 9 may be obtained from HSE Books) . The output of the risk assessment should be the key to the decision-making process and the need to designate certain employees as classified persons is likely to be one outcome (L121 paragraphs 36 to 58 cover prior risk assessment).

If an assessment of the potential exposure shows that the work could be done by employees who are not classified persons, HSE would normally expect entry into controlled areas to be allowed under suitable written arrangements.

However, if the assessment of potential exposure shows that restriction of their doses below the levels specified in regulation 18(2) IRR99 could not reasonably be ensured even with written arrangements, people working in the area should be classified. Entry under suitable written arrangements should not involve a system of work sharing simply to avoid classifying the people working in the controlled area.

Cooperation between employers

The cooperation needed when employers share the same workplace is discussed in paragraphs 241 to 242 of L121. Paragraph 243 of L121 discusses the cooperation needed if an employee has more than one employer. See ‘Examples’ for further guidance on these situations.

Exposure caused by other employers’ work

If it is likely that an employee will be exposed to ionising radiation in another employer’s work area, or as a consequence of another employer's work, then the two employers must exchange enough information to allow each to comply with their statutory duties (Regulation 15 of IRR99 refers, as does regulation 12 of MHSWR). Information regarding both potential and likely exposure to ionising radiation should be shared, along with details of any controlled areas that have been designated on sites to which access is required. This helps employers to judge whether they should classify their workers.


Employees having multiple employers

Where an employee has several employers, cooperation will be necessary to ensure that relevant information, typically relating to exposure, is shared. For example, where an interventional radiologist works for both an NHS Trust and a private hospital, both employers have a duty to share information in relation to the total dose the employee is likely to receive, to determine whether classification is appropriate. This cooperation should begin in advance of work, because classification relates to projected doses before exposure is incurred.

Checklist for classification

Should the employer decide that designation as a classified person is appropriate, the actions outlined in the checklist should be taken. A periodic review of the continuing need for classification should be undertaken.

Classification flow chart

Classification flow chart

Updated 2018-01-03