Working with lasers: controlled equipment (Classes 3B/4)

Laser products that fall into Class 3B and Class 4 present significant risks and are therefore subject to the provisions of a mandatory University Standard (formal health and safety rules). In addition to this, you should follow the guidance below:

Key risks

Different lasers classes pose different risks and will therefore require different controls. The key risks for each class can be found below.

Please note: Class 4 lasers are more likely to cause harm than Class 3B lasers in the ways listed below.

  • Looking directly into any laser beam is always hazardous.

  • Specular reflections from Class 3B and Class 4 laser equipment can harm the eyes.

  • Specular reflections from high-powered lasers (i.e. 0.5W and above) can also harm the skin.

  • Diffuse reflections from Class 4 laser equipment is also harmful to they eyes.

  • Class 4 lasers can also ignite or damage material, and may emit dangerous fumes when in contact with certain materials or during ablation or drilling.

What you need to do

  • Register on the VIRGIL system before working with any controlled laser equipment.

  • Complete the relevant training, workshops and inductions before using any controlled laser equipment. See the New Laser Users page.

  • Do not allow any controlled laser beam and its reflections to come into contact with people (particularly their eyes). This means ensuring that laser beams and their reflections do not leave the optical bench (e.g. using a beam stop and guarding) and that no one stares into them.
    Note: laser goggles should only be used as a last resort: you should rely on good experimental design rather than a pair of safety goggles.

  • Design experiments involving any controlled laser equipment safely, following Safe Operating Procedures.

  • Follow the beam alignment flow chart when aligning any controlled laser beam.

  • Ensure that Class 4 laser beams cannot be directed towards people or any materials not being used for the experiment. This can also be done using a beam stop and heat sink.

  • Consider ventilation and fire precautions when working with Class 4 laser equipment.

Risk assessments

Before you begin work with controlled lasers, you will need to complete a relevant risk assessment on VIRGIL. These must be completed following the methodology of the VIRGIL database.

Contact the Radiation Protection Manager if you need more guidance or advice.

Related downloads

Lasers

Laser Standard (PDF)

Laser Guidance (PDF)

Standard Operating Procedures (PDF)

Alignment Flowchart (JPG)