SC23 - Electro-magnetic fields (EMFs)
06 Dec 2010
Yes
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Working with time-varying EMFs

No

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 ​​Summary of STFC EMF monitoring equipment

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Contents​

Revisions

​1
Initial rele​aseFebruary 2009
1.1Update to action valuesMay 2011
1.2Amendments to audit checklistMay 2013
1.3
Add Document retention policy
December 2014
2.0
Update following EMP code audit and EU Physical Agents Directive
November 2016
​2.1
​Minor update to reflect the launch of SHE Assure
​October 2018​
​3.0
Update following code audit and Control of Electromagnetic Fields Regulations 2016​
February 2019​

NB - The changes to version 3.0 were considerable and readers should assume that significant portions of the body and Appendices have changed.

1. Purpose​

The purpose of this code is to ensure that hazards associated with strong and time-varying electromagnetic fields (EMFs) up to a frequency of 300 GHz are managed so as to minimise so far as is reasonably practicable the health and safety risks to staff and others. The code covers work with equipment operating at frequencies from 1 Hz to 300 GHz, which encompasses both power frequencies (and harmonics) and radiofrequencies (RF) (including microwaves).

Devices generating EMFs are widely used at the STFC laboratories. Typical applications can be found in the radio frequency systems of particle accelerators, radars, imaging systems and radio transmission systems. More general applications are found in high current power distribution systems, high output power supplies (particularly switched mode power supplies), uninterruptable power supplies (UPS), motors, microwave ovens and communication devices. It has been recognised that electromagnetic fields and radiations from these devices may, under certain conditions, give rise to health hazards. Since there are no established long-term risks, medical examination is unlikely to identify clinical findings from exposure and there is no benefit to routine health surveillance. The known adverse effects of exposure are briefly summarised in Appendix 1.

This document is an interpretation of relevant laws and standards and cannot cover all conceivable situations.

2. Scope

​.This code establishes requirements for controlling the exposure of STFC staff, visitors, facility users, tenants, contractors and the public to strong EMFs at all STFC sites.

This code is intended to cover operation of equipment capable of generating strong EMFs for example, high output switched mode power supplies or high-power RF systems driving particle accelerators and radar sets.

Any electrically-powered equipment will generate EMFs, but in most cases the fields will be very weak and will not give risk to significant risks. Hence this code does not require action to be taken in respect of equipment that is only capable of generating weak fields.

Examples include:

  • communications equipment and networks, wired;
  • Computer and IT equipment;
  • Office equipment (e.g. photocopiers, paper shredders, electrically-operated staplers;
  • Lighting equipment (e.g. area lighting and desk lamps);
  • Domestic microwave ovens used for heating food;

Some common equipment can theoretically interfere with the function of active medical devices (e.g. cardiac pacemakers and defibrillators), but if used sensibly will not present an unacceptable risk to those reliant on these devices.

Examples include:

  • Mobile phones
  • Cordless phones
  • Standard WiFi/wireless internet systems

Although EMF generated by electrical supply/distribution networks fall within scope of relevant legislation, there is no need to implement additional access restrictions in respect of EMF if access is already adequately restricted due to high voltage.

The hazards associated with strong static magnetic fields are addressed by SHE code 39: ‘Working with static magnetic fields’.

3. Legislation

The STFC is required to comply with the Control of Electromagnetic Fields at Work Regulations 2016.

3.1 Exposure assessment

Like all employers, STFC has a duty under the regulations to carry out exposure assessments and record the results. It may not be necessary to measure or calculate exposure and the first approach should always be to consult the table in Appendix 3. It may be assumed that any equipment, workplace or activity with a ‘no’ in all three columns of the table in Appendix 3 requires no further assessment.

In contrast, any equipment with a ‘yes’ in the first column should be subject to a specific assessment to determine if exposures comply with the exposure limit values specified in the regulations (see below).

An action plan is required if the exposure assessment does not demonstrate that exposures are below the exposure limit values. This must include some or all of the items in the first part of Appendix 5.

3.2 Exposure limits

Exposure limit values are specified for frequencies from 1 Hz to 300 GHz and are intended to protect employees from the adverse effects of exposure. It is a legal requirement to comply with the exposure limit values, subject to certain specific exceptions. Further details of exposure limit values are given in Appendix 2.

As exposure limit values are generally set in terms of internal body quantities that cannot be easily measured, the regulations also provide action levels set in terms of external field quantities. These are not limits, but may be used as a guide to compliance with limits. In addition, there are action levels that are intended to prevent or limit the consequences of specified indirect adverse effects. See Appendix 2 for further details of action levels.

3.3 Risk assessment

There is a legal requirement to carry out an EMF-specific risk assessment if any of the following apply:

  • it cannot be demonstrated that the exposure limit values will not be exceeded
  • it cannot be demonstrated that the indirect effects action levels are not exceeded
  • there are ‘employees at particular risk’ in the workplace

An EMF-specific risk assessment must address the matters listed in Ap​pendix 4.

Any risks identified in the EMF-specific risk assessment must be either completely eliminated or reduced to a minimum.

Anyone who may be exposed to risks identified in the EMF-specific risk assessment must be provided with information and training (see second part of Appendix 6).​​

3.4 Employees at particular risk

Some people are at increased risk from exposure to electromagnetic fields and may not be adequately protected by the exposure limit values and action levels. In the regulations, these people are called ‘employees at particular risk’ (see Section 4) and there is a specific requirement to consider them in the EMF-specific risk assessment. In general, it may be assumed that if exposures do not exceed the reference levels specified in Council Recommendation 1999/519/EC, then there will be no increased risk and no further action is necessary.

As a guide, the second and third columns in Appendix 3 indicate for some common equipment and activities whether further specific assessment is required.

3.5 Medical examination

If a member of staff is exposed above any health effects exposure limit value and reports experiencing a health effect as a result of the exposure, then they must be provided with a medical examination. A record of the examination must be retained.

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4. Definitions

4.1 Exposure limit Value

These are legal limits on exposure to electric, magnetic and electromagnetic fields and radiations. There are two types of exposure limit values:

  • health effects exposure limit values are intended to prevent direct adverse health effects of exposure
  • sensory effects exposure limit values are intended to prevent perception of the field

Further details are given in Appendix 2.

Exposure limit values are generally set in terms of internal body quantities and cannot be easily assessed.

4.2 Action Value

As compliance with exposure limit values cannot be easily assessed by direct measurement, the regulations provide action levels as a guide to compliance. These are specified in terms of external field quantities that can be directly assessed by measurement or calculation. Provided the action levels are not exceeded it can be assumed that exposures are compliant with the exposure limit values.

Further details are given in Appendix 2.​

4.3 Reference levels

Reference levels are similar in principle to action levels, but are defined in Council Recommendation 1999/519/EC and are used as a framework to limit public exposures. Although similar to action levels they are generally simpler to apply.

In addition to being useful for limiting public exposures, reference levels are also helpful for assessing exposures of ‘employees at particular risk’, who may not be adequately protected by the action levels.

Further details are given in Appendix 2​.

4.4 Employees at particular risk

Legally an employee at particular risk is anyone who declares to their employer a condition that may lead to a higher susceptibility to the potential effects of exposure, or any employee who works in close proximity to electro-explosive devices, explosive materials, or flammable atmospheres.

In practice, four groups are recognised as having a higher susceptibility to the potential effects of exposure:

  • those reliant on active implanted medical devices
  • those reliant on body-worn medical devices
  • those with passive implanted medical devices
  • pregnant women

5. Responsibilities

5.1 Directors responsible for activities employing strong EMF sources shall:
  • 5.1.1 Appoint in writing one or more suitably qualified and experienced EMF Protection Advisers (EPAs) for those areas employing EMF generating equipment or devices (see Appendix 6 for EPA training requirements). The letter of appointment should define the geographic/equipment scope of their responsibility and should be recorded in SHE Directory. It would be normal for the technical manager responsible for the day-to-day operation of the equipment to be appointed the EPA.
    5.1.1 Appoint in writing one or more suitably qualified and experienced EMF Protection Advisers (EPAs) for those areas employing EMF generating equipment or devices (see Appendix 6 for EPA training requirements). The letter of appointment should define the geographic/equipment scope of their responsibility and should be recorded in SHE Directory. It would be normal for the technical manager responsible for the day-to-day operation of the equipment to be appointed the EPA.
5.2 EMF Protection Advisers (EPAs) shall:
  • 5.2.1 Provide advice to management on the need to undertake specific exposure assessments on equipment or activities within their areas of responsibility.
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  • 5.2.2 Provide advice to management responsible for strong EMF sources on technical modifications, changes to work practices or engineering controls that could eliminate EMF hazards or minimise their impact so far as reasonably practicable, including the use of appropriate signage for all areas where field strengths are above reference or action levels.​
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  • 5.2.3 Where exposure or risk assessments identify potential for hazardous exposures, regularly survey the electric and/or magnetic field strength of equipment generating strong EMFs that could affect staff and others within their scope of responsibility and ensure that risk controls are appropriate and effective. Specific consideration should be given to undertaking EMF measurements following any changes that could reasonably be expected to affect the emission characteristics of equipment, for example following maintenance/servicing or after modification. Surveys should be documented and identify all areas above the reference and action levels. It is recognised that monitoring equipment capable of magnetic field strength measurements at frequencies >1 GHz are not available. However, at higher frequencies it is normally possible to infer the magnetic field strength from the electric field strength.
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  • 5.2.4 Ensure that only monitoring equipment calibrated to recognised standards is used to measure strong EMFs and to determine compliance with the reference and action levels reproduced in Appendix 2.
5.3 Managers responsible for strong EMF radiation sources shall:
  • 5.3.1 Ensure that exposure assessments are carried out for equipment and activities under their control.
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  • 5.3.2 Ensure that no equipment capable of generating strong EMF fields and radiation is brought on to STFC sites without the approval of the relevant EPA, including equipment borrowed or provided by others, so that managers can ensure that suitable precautions are taken before the equipment is used.
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  • 5.3.3 Where equipment generating strong EMF radiation is designed and manufactured in house, ensure that the reference and action levels are considered and that the appropriate EPA is consulted before the equipment is brought into use.
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  • 5.3.4 Ensure that the advice of an EPA is sought and that documented EMF-specific risk assessments (see Appendix 4) are conducted for all work through which persons may be exposed to EMFs above ‘Action Levels’ (see SHE Code 6: Risk Management) and that suitable controls are established to minimise exposure. These controls should include undertaking a suitable and documented EMF survey.
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  • 5.3.5 Where equipment generates EMFs above the Action levels (see Appendix 2) in places to which personnel have access, ensure that exposure is minimised through suitable engineering controls, work practices and local operating instructions, and that suitable warning signage is in place.
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  • 5.3.6 Ensure that all persons working in areas or with equipment where strong EMF radiation can be generated, in particular EMFs above Action levels, are aware of the hazards and of the need to follow the advice of the local EPA and local control measures.
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  • 5.3.7 Where equipment generates EMFs above the reference levels (see Appendix 2) in places to which personnel have access, ensure that appropriate measures are in place to restrict access and provide warning to groups of employees considered to be at particular risk.
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  • 5.3.8 Ensure suitable warning signs are posted at entrances to areas or on equipment where fields in excess of the reference levels have been identified.
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  • 5.3.9 Where employees at particular risk have been identified in the workplace, ensure EMF-specific risk assessments are undertaken for all equipment and activities with potential for exposure in excess of the reference levels (see Appendix 2).
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  • 5.3.10 Advise any staff identified as being at particular risk to seek a consultation with STFC Occupational Health Teams.
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  • 5.3.11 Establish control measures to ensure that all staff, visitors, facility users, and contractors are adequately protected from risks to safety through indirect effects of strong EMFs (see Appendix 5).
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  • 5.3.12 Ensure that all staff who may be exposed to risks identified in an EMF-specific risk assessment are provided with suitable information or training that includes the matters detailed in the second part of Appendix 6. This will include any staff working areas where field strengths may exceed any action level and any employees at particular risk working in areas where field strengths may exceed any reference level.
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  • 5.3.13 Ensure that all instances where staff or others are exposed to EMFs greater than the relevant action levels (see Appendix 2) are reported according to SHE Group (SHE Code 5: Incident reporting and investigation), and that any staff or others exposed to EMFs above the action levels and experiencing symptoms as a result are referred for professional medical assessment, for example the STFC Occupational Health teams
5.4 STFC staff and tenants shall:
  • 5.4.1 Comply with any local operating instructions relating to equipment which is capable of exposing staff and others to strong electromagnetic fields.

  • 5.4.2 When responsible for visitors, facility users or contractors, ensure that the visitors/users/contractors comply with relevant local operating instructions and that the visitors/users/contractors make STFC staff aware of any devices/equipment they bring on to STFC sites capable of exposing personnel to strong electromagnetic fields.

  • 5.4.3 When responsible for visitors, contractors or facility users in an area where strong EMFs are present, ensure that their attention is drawn to notices warning of access restrictions for those considered to be at particular risk.​
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  • 5.4.4 Report all incidents relating to strong EMFs to SHE Group (see STFC SHE Code 5, Incident Reporting and Investigation).
5.5 SHE Group shall:
  • 5.5.1 Maintain an STFC register of EPAs and their areas of responsibility.
5.6 Occupational Health advisers shall:
  • 5.6.1 Undertake medical assessments of those who have been exposed to EMFs above the action levels and who have experienced symptoms as a result​.
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  • 5.6.2 Provide advice for persons considered to be at particular risk, especially those reliant on active medical devices.

6. References

  • 6.1 This document should be read in conjunction with the following documents:
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  • Control of Electromagnetic Fields at Work Regulations 2016. Statutory Instrument 2016 No. 588 (available to download free from www.legislation.gov.uk).
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  • Non-binding guide to good practice for implementing Directive 2013/35/EU Electromagnetic Fields (available to download free from https://publications.europa.eu).
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  • Council Recommendation of 12 July 1999 on the limitation of exposure of the general public to electromagnetic fields (0 Hz to 300 GHz) 1999/519/EC. Official Journal of the European Communities L199/59 (available to download free from publications.europa.eu).
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  • 6.2 The following publications provide useful background information:
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  • Review of the scientific evidence for limiting the exposure to electromagnetic fields (0-300GHz)’: Documents of the NRPB Volume 15 Number 3: 2004 (available from SHE Group).
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  • ICNIRP Guidelines for limiting exposure to time-varying electric and magnetic fields (1 Hz – 100 kHz). Health Phys., 99(6), 818-836 (2010) (Available to download free from www.icnirp.org).
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  • ICNIRP Guidelines for limiting exposure to time-varying electric, magnetic and electromagnetic fields (up to 300 GHz). Health Phys., 74(4), 494-522 (1998) (Available to download free from www.icnirp.org​). Note that the low frequency section of this document was superseded by the 2010 guidelines and that the high frequency section will shortly be superseded by new radiofrequency guidelines.
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  • Procedure for the assessment of the exposure to electromagnetic fields of workers bearing active implantable medical devices. Part 1: General. BS EN 50527-1:2016.
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  • Procedure for the assessment of the exposure to electromagnetic fields of workers bearing active implantable medical devices – Part 2-1: Specific assessment for workers with cardiac pacemakers. BS EN 50527-2-1:2016.
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  • Procedure for the assessment of the exposure to electromagnetic fields of workers bearing active implantable medical devices – Part 2-2: Specific assessment for workers with cardioverter defibrillators (ICDs). BS EN 50527-2-2: 2018.​


Contact: Baker, Gareth (STFC,DL,CSD)