Radiation safety

Ionising radiation

The University has a clear policy and extensive guidance for working with ionising radiation. All radioactive sources, waste and workers are monitored, recorded and managed by Safety and Health Services.

This is a legal obligation for the University and it demands compliance from all staff and students working with ionising radiation.

Notify your local Radiation Protection Supervisor (RPS) well in advance if you:

  • anticipate working with ionising radiation, including any sealed radiation source
  • plan to visit a laboratory or facility where ionising radiation is to be used

Contact your supervisor for further information.

Your local RPS and supervisor will:

  • help you register with Safety and Health Services through the Radioactive Source Database
  • arrange for you to attend all relevant University training courses and refreshers
  • record your training and log these with Safety and Health Services

All aspects of working with radioactive materials are strictly controlled:

  • Using radioactive material: All projects must be covered by a risk assessment. Contact your supervisor for further information.
  • Purchasing radioactive material: Only University of Bristol members of staff may purchase radioactive material.
  • Transporting radioactive material: No radioactive material may be transported without approval form the local RPS.
  • Disposing of radioactive material: Never dispose of radioactive material before checking with your supervisor and local RPS. 

Any work that involves additional hazards, such as biological or chemical, may require a separate risk assessment to be completed in advance.

Exposure to ionising radiation is primarily limited by means of lead shielding and safety interlocks on equipment. Only authorised users may operate any additionally x-ray generating equipment.

To be an authorised user you must have:

  • received full operator training
  • completed x-ray safety training from the local RPS
  • read and understood the risk assessment for using the equipment and any local rules

Once all of that is achieved, you must be signed off as an authorised user by both your supervisor and the local RPS.

Non-ionising radiation

The University has a clear policy and extensive guidance for working with non-ionising radiation. For instance, laser users must follow the University's laser safety guidance. 

Laser safety

When identifying the hazards associated with laser systems, consider:

  1. Is it mounted in a commercial system? Mounting and encasing lasers within a piece of equipment, such as a laser welder or cutter, encloses the beam path of the laser and usually introduces control measures that reduce the level of risk.
  2. What is the classification of the laser?

These lasers cause no damage to either the eyes or skin under reasonably foreseeable circumstances and therefore can be treated as safe. 

Class 1 lasers are often used in CD players and printers. 

These are considered to be low hazard lasers as they only emit radiation in the visible region.

These lasers are safe to the skin and cause no damage to the eye as long as the exposure time is less than 0.25 seconds (the time it takes to look away). 

Class 2 lasers are often used in supermarket scanners.

Both laser types are considered low hazard, but contain magnifying optics and therefore the class takes into account amount of beam that can enter the eye. 

These are considered to be low-medium hazard lasers. Direct exposure to the beam of a Class 3R laser is potentially hazardous so must be treated with respect, however the risk is lower than that for the Class 3B products. 

Class 3R lasers are often used in surveying equipment. 

These lasers are considered to be medium-high hazard as these have sufficient intensities to cause eye damage through the direct beam.

Open beam exposure should be minimized as much as possible and the relevant eye protection must be worn. Always check that the wavelength range of the eye protection is correct for that laser.

These are considered to be high hazard because these lasers have sufficient intensities to cause eye damage both through the direct beam and specular reflections. These lasers also have an associated fire hazard.

Extreme caution must be used when using these lasers. The amount of open beam exposure should be minimized (as described for Class 3B).

Magnetic fields

High magnetic fields can pose health risks, particularly to people with wearable or implanted medical devices, such as pacemakers or insulin pumps.

Some buildings have equipment that produces strong magnetic fields. Hazard signage is clearly displayed in the areas where equipment is located to warn those at risk.

Electromagnetic fields (EMF)

EMF is produced by all electrical and electronic equipment when in use. Fields may be static or time-varying, electric, magnetic or electromagnetic (radio wave) and have frequencies up to 300 GHz.

The University takes reasonable steps to prevent harm from EMFs. Hazards associated with EMF include:

Uncontrolled attraction of ferromagnetic items, interference with medical devices (worn or implanted), sparks and shocks causing fires or explosions in flammable or explosive materials.

Nausea, vertigo, metallic taste in the mouth, flickering sensations in peripheral vision, auditory effects such as perception of clicks or buzzing caused by pulsed radar systems.

Microshocks, nerve stimulation, tingling, muscle contraction, heart arrhythmia, contact currents resulting in shocks or burns, thermal stress, heating effects, RF shock or deep tissue burns.