Lasers have the potential to deliver large ‘packets’ of energy in a very controlled and focused way, in fact most laser applications take advantage of this. But those same properties if not controlled effectively, can present significant hazards to staff working with them and to adjacent materials and activities, for example risks of eye damage and burns, risk of fire from ignition of materials hit by a laser beam and risk of damage to material surfaces.
Lasers are grouped into seven classes depending on the potential for the beam to cause harm. The hazard and hence the classification depends on the wavelength, power, energy and pulse characteristics. The class of laser can be used to help decide what safety control measures are required when using the laser.
Class 3B and 4 lasers have the potential to blind or to cause burns depending on the way in which people are exposed. Expert users of Class 3B or 4 lasers are required to understand the health hazards and risks to health and safety and the necessary control measures that they must implement to prevent exposure of people to the laser beam and the associated risks to health.
The following activities must be carried out prior to laser work. Responsibility for ensuring that this takes place rests with the Principle Investigator or a competent person designated by the PI. It applies to all lasers with the exception of inherently safe Class 1 lasers or Class 2 devices including embedded laser products such as those in laser printers or CD players. No modification of Class 1 or 2 devices is permitted without consulting and approval from the Universitys Radiation Protection Officer.
1. Laser Registration.
All lasers must be registered before they can be used.
2. Get registered as a laser user.
All users of laser equipment must register prior to them starting work.
3. Complete a laser risk assessment
A laser safety risk assessment must be completed by staff trained specifically in laser risk assessment before a laser is powered up. This assessment must be done in conjunction with a full risk assessment of the experiment or laser application and recorded in writing using this form. Further guidance is provided on hazards and laser risk assessments, control measures and ocular hazards and controls.
Anyone carrying out work involving lasers must be provided with, and understand, the risk assessment for the work and be clear about the control measures which have been identified.
4. Complete a safe system of work (SSoW)
A safe system of work (also known as local rules) must be written. This accompanies the risk assessment and must describe how work procedures will be carried out, what and how controls identified in the risk assessment will be used, and what actions must be taken in the event of accidents (contingency measures). The safe system of work must be written before work starts and everyone involved with the work must be made familiar with it and understand the content. The safe system of work is of particular importance where an experiment contains open access to laser radiation without enclosure. Any system using un-enclosed laser beams must detail the reasoning behind this in the risk assessment and describe the safe operating procedure for the experimental process within the safe system of work. A pro-forma and guidance are provided for producing your safe system of work.
5. Get trained in laser safety.
All users of laser equipment must know and understand the risks associated with laser work and be competent to work safely.
Anyone working with Class 3B and Class 4 lasers must attend laser safety training. There are two levels of training, basic laser safety awareness and more in-depth training about hazards associated with laser applications and methods of controlling hazards. Details of the training courses can be found on the H&S training website
Untrained or unauthorised staff must not be left to use lasers without supervision.
A description of local training procedures must be included as part of the safe system of work. Local training must be completed before starting work with a laser / laser application. The training must be given by a competent supervisor and include instruction based on information specified in the safe system of work e.g. a supervised session with the laser or laser application, following safe working procedures described in the safe system of work.
6. Use Personal Protective Equipment (PPE) where identified as a control measure by risk assessment
Personal Protective Equipment e.g. laser protective eyewear (goggles) must only be used if a beam path cannot be enclosed or there is a risk of a laser user being exposed to the beam (Class 3B and 4 lasers). Protective eyewear must be appropriate for the power and wavelength of the laser used and the wavelength and scale number (L rating) must be clearly marked. For work with visible lasers, alignment goggles are recommended that permit the safe accidental viewing of the laser light. High L rated goggles must always be used when working with invisible laser beams. Visible light transmission and the ability to see warning lights are important considerations when choosing safety eyewear.
Safety eyewear must never be relied on to provide protection against deliberate exposure to a laser beam but should be regarded as a means of providing some protection against accidental exposure.
Fireproof protective clothing must be used if it is identified as a control measure.
7. Display correct Lasers warning signs and labels
Laser areas and instruments must be labelled correctly - The correct type and style of labelling and warning signs is described in the Laser Classification guide.
8. Accidental exposure to class 3B or Class 4 laser beam
All persons working with Class 3 / 4 lasers must be aware of the following requirements:
i) In the event of an accident involving known or suspected eye injury an emergency medical examination must be carried out as soon as possible and within 24 hours.
ii) Principle Investigators must ensure that each Class 3 / 4 laser has a completed Emergency Procedure Card, for use following eye exposure to Class 3 or 4 Laser beside it which can be taken with the casualty to hospital.
iii) All accidents / incidents involving lasers must be reported promptly using the University Accident / Incident reporting process.
Please contact the j dot brannon at warwick dot ac dot uk with any queries.