Most people will think they have a rough idea of what a laser is, but few will really appreciate how dangerous they can be without appropriate safety measures.
Just to be clear from the outset, not all lasers are designed to blast warrior robots on distant planets or to slice through a rogue alien spacecraft as portrayed in popular sci-fi culture. Having been built and demonstrated in the 1960’s, lasers today are very much part of our daily lives. You will see their use in a multitude of everyday situations, such as at music concerts and live events, in equipment like supermarket barcode scanners, range finders, toys, CD & DVD players and of course laser pointers and laser printers.
So, how does a laser work?
The word LASER is an acronym for Light Amplification by Stimulated Emissions of Radiation. Essentially, a laser is a device that emits light through a process of energising by optical intensification. It differs from other light sources in that it emits light which is coherent, allowing it to be focused into a small spot at a single wavelength compared to a lamp or torch bulb, which radiates a large range of multicolour light expanding outwards in a wide area. A laser generates a single colour beam, which can be a powerful and intense light.
Why is laser safety so important?
We have all seen in the news the various incidents of laser misuse, such as pointing lasers at police helicopters in an attempt to blind the pilot, or even more recently the use of a laser by an English football supporter to distract the Danish goalkeeper during a penalty in the recent Euro 2020 semi-finals.
Incidents such as these are what makes laser safety such a serious and important topic. Any laser can be made safe, therefore there is no such thing as a dangerous laser, only dangerous laser users!
Laser safety should ensure the safe use of a laser device in order to prevent or minimise any hazards. It is well understood that even a small amount of laser exposure can result in injury when laser safety guidelines have not been implemented or not followed correctly.
How are lasers controlled?
The use of Lasers is strictly controlled by international regulations, standards and local guidelines governing and controlling laser safety across the globe. In the UK the topic of laser safety is accessible on UK Government webpages, at:
- Laser radiation: introduction and safety advice – GOV.UK (www.gov.uk)
- Laser radiation: safety advice – GOV.UK (www.gov.uk)
Safety classification of lasers
There are 7 different classes of lasers based on potential damaging effects of their use. These are:
- Class 1: it is safe under all conditions of normal use, the maximum permissible exposure (MPE)* cannot be exceeded.
- Class 1M: it is safe and not capable of producing hazardous exposure conditions during normal operation, except if the beam is viewed with an optical instrument for example, when passed through magnifying optics such as a focusing lens, microscope or telescope.
- Class 2: it is relatively safe, it could only cause injury to the eye if the blink reflex is intentionally suppressed as exposure would normally stimulate the glare aversion response like squinting & closing your eyes or turning your head away to bright lights.
- Class 2M: it is relatively safe, except if the beam is viewed with an optical instrument.
- Class 3R: it is only considered safe when handled carefully, with restricted beam viewing, the MPE can be exceeded, but with a relatively low risk of injury.
- Class 3B: is considered hazardous when viewed directly, but diffuse reflections from surfaces are not harmful, eye protection is typically required.
- Class 4: is considered the highest and most dangerous, the direct beam is hazardous to both the eyes and skin, potentially causing burns and eye damage as a result of direct, diffuse or indirect beam viewing even to reflections of the beam from apparently rough or irregular surfaces. Class 4 lasers must be equipped with a key switch and a safety interlock.
* The maximum permissible exposure (MPE) is the highest power density (in W/cm2) or energy density (in J/cm 2) of a light source that is considered safe, so there is only a negligible probability for causing damage.
NOTE: Usually, class 1, 1M, 2, 2M, and 3R lasers do not require control measures and monitoring due to the relatively low risk level. Class 3B and 4 are considered hazardous to the eyes and skin and require stringent control measures when working with them. Most industrial, scientific, military and medical lasers are Class 4.
Good laser safety
To ensure good laser safety, all of the following control measures should be considered:
- Engineering control: these are the inbuilt safety features of the laser system setup installed by the manufacturer in compliance with local, regional, national and international standards.
- Administrative control: this involves the laser safety program of an organisation, including appointing a laser safety officer as the responsible representative, establishing a laser safety committee, specifying training and periodically scheduling retraining.
- Procedural control: this is the policy, plan and processes agreed by an organisation on the use of lasers, involving specified activities, tools, materials, procedures and events, also controlling access into laser operation areas.
- Emergency procedures: an agreed emergency plan should be in place just in case something unanticipated and unforeseen does go wrong.
A Laser Safety plan should be written, communicated, documented and retained for easy access within the laser operation areas.
Control measures for the use of lasers
Specific control measures for the use of lasers include:
- Ensure safe methods with Risk Assessment, Systems of Work and Standard Operating Procedures.
- Laser hazard signs and posters must be visible in laser controlled areas.
- Ensure new operators are fully trained in laser safety procedures and with any changes in the setup or systems the personnel should be retrained for the recognised hazards.
- Use appropriate eye protection.
- Never look directly into a laser.
- Never direct a laser at another person.
- Control the laser radiation level by using the minimum required for the application.
- Prevent untrained personnel from entering laser areas.
- Maintenance and repair work on laser systems should be performed only by certified service personnel who have documented training for the specific laser system.
Laser safety at DataLase
Here at DataLase, we aim to transform a Class 4 laser (the most dangerous) into a Class 1 (safe under all conditions of normal use) by utilising safety setups based on proper and effective engineering controls. Most industrial laser systems will originate as Class 4, but with laser safety aspects implemented, a Class 1 level can be reached and maintained relatively easily and cost effectively. In additional to this, administrative and procedural controls are also introduced to support the engineering controls. Lastly, emergency procedures are established just in case of unforeseen circumstances, or situations that may lead to occurrences outside of the permitted laser safety limits.
So the next time you are using the barcode scanner at the self-service checkout of your local supermarket or utilising a laser pointer when completing a presentation, just remember that today’s laser devices have been designed to comply with all the laser safety requirements for widespread everyday use, and are far removed from the powerful metal cutting weapons glamourised in films.