SC39 - Static magnetic fields

Static Magnetic Fields

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Contents

• 1. Purpose
• 2. Scope
• 3. Responsibilities
  
  • 3.1 Managers responsible for sources of static magnetic fields >0.5mT that extend into the working environment.
  • 3.2 Managers responsible for sources of strong static magnetic fields, >0.2T, that extend into the working environment.
  • 3.3 STFC Staff, visitors, facility users, tenants and contractors.
• 4. Appendices
  
  • Appendix 1 - Summary of hazards associated with static magnetic fields
  • Appendix 2 - Training
  • Appendic 3 - Audit checklist

Revisions

• 1. Initial Launch - March 2011

1. Purpose

Static magnetic fields are used in a range of applications across the STFC sites, for example superconducting magnets in NMR machines or permanent magnets in particle accelerator wigglers or undulators. The code aims to minimise so far as is reasonably practicable, the health and safety risks to staff and other persons who may be affected by static magnetic fields.

While the biological affects of strong static magnetic fields are subject to current debate and investigation there are clear hazards associated with such fields arising from their impact on implanted medical devices, specifically magnetic or electronic devices for example pace makers, and their ability to attract magnetisable objects at distance and speed (projectile and crush incidents), see appendix 1.

This code has been written to comply with The European Physical Agents (Electromagnetic Fields) Directive (2004/40/EC amended 2008/46/EC), although the Directive has not yet been incorporated in UK law. The Directive is currently being reviewed, a process which may last until at least April 2012. This code will be reviewed following incorporation of the directive in UK Law.

2. Scope

This code applies to all static magnetic fields which extend into areas readily accessible to people, and applies to all such fields on all STFC sites irrespective of ownership of the apparatus generating the fields.

This code is not intended to cover every piece of equipment in which magnetic fields are present. For example, the code is not intended to apply to electric motors, loudspeakers and magnetrons in normal use. However, if magnets from such pieces of equipment were removed and made into an assembly for some new purpose generating a magnetic field extending into areas readily accessible to people then this code would apply.

This code does not address the hazards associated time varying electro magnetic fields, see STFC SHE Code 23 - Managing risks from strong time-varying EMFs.

3. Responsibilities

3.1 Managers responsible for sources of static magnetic fields >0.5mT that extend into the working environment shall:

• 3.1.1 Locate warning signs at all entrances to areas containing such magnetic fields

3.2 Managers responsible for sources of strong static magnetic fields, >0.2T, that extend into the working environment shall:

• 3.2.1 Ensure that documented Risk Assessments address the hazards from strong static magnetic fields, see SHE code 6 - Risk Management: Appendix 1 (PDF - 195kB - link opens in a new window). Such risk assessments must be undertaken by individuals with sufficient expertise in such hazards (see appendix 1), and based upon an assessment of the magnetic field based as appropriate on: field calculations; manufacturer’s guidance; or a site survey using a calibrated gauss meter of the magnetic field strength to determine the field contour for the strong static magnetic field.
  
  
• 3.2.2 Develop and implement local procedures for the safe operation of equipment generating the static magnetic fields, see Appendix 1.
  
  
• 3.2.3 Ensure that only sufficiently competent people are authorised to operate equipment and work in the areas where strong static magnetic fields are present, and that they are aware of the hazards, risk assessments and local procedures for the safe operation of equipment generating static magnetic fields.
  
  
• 3.2.4 Ensure that warning signs and other measures, e.g. barriers or floor marks, are set up around areas where hazards arising from static magnetic fields >0.2 T may be present.

3.3 STFC Staff, visitors, facility users, tenants and contractors shall:

• 3.3.1 Comply with the local procedures for the safe operation of equipment which is capable of generating strong static magnetic fields.
  
  
• 3.3.2 Ensure, if any one of them has an implanted medical device such as a heart pacemaker, that he or she informs his or her manager or other person responsible for his or her safety before entering an area where static magnetic fields greater than 0.5 mT (5 gauss) are present in the working environment. Anyone with an implanted medical device may wish to contact Occupational Health or the SHE Group for advice on the likely sensitivity of the implanted medical device to magnetic fields.
  
  
• 3.3.3 Report all incidents relating to strong static magnetic fields through SHE enterprise following SHE Code 5 - Incident Reporting and Investigation.

4. References

• 4.1 European Physical Agents (Electromagnetic Fields [EMF]) Directive (2004/40/EC amended 2008/46/EC).
  
  
• 4.2 International Commission for Non-Ionising Radiation Protection (link opens in a new window) (ICNIRP) Guidelines on Limits of Exposure to Static Magnetic Fields (PDF - link opens in a new window). Health Physics 96(4):504-514; 2009 and associated Fact Sheet (PDF - link opens in a new window), 2009.
  
  
• 4.3 Amendment to the ICNIRP “Statement of medical magnetic resonance (MR) procedures: protection of patients (PDF - link opens in a new window)”.
  
  
• 4.4 NRPB Publication ‘Review of the scientific evidence for limiting the exposure to electromagnetic fields (0-300GHz)’: Documents of the NRPB Volume 15 Number 3: 2004.
  
  
• 4.5 World Health Organization (WHO), Static Fields Environmental Health Criteria Monograph No.232.