Laser Safety
Laser Safety in Physics
The safe use and management of lasers by University staff, students and visitors is outlined in the University Arrangements Chapter 27 - Laser Safety, which must be followed.
Your LLSA for Physics is Dr Darren Graham, E-mail: Darren.Graham@manchester.ac.uk
1. Laser Classification
Laser classification is your first indicator of the hazard associated with a laser. The classification standard you should take note of on your laser is the international standard set by the International Electrotechnical Commission (IEC), and known as IEC 60825 (previously IEC 825). Within Europe this standard has been adopted as a European Normative standard known as EN 60825, and the British Standards version known as BS EN 60825. Ignore the CDRH (Center for Devices and Radiological Health) standard, which is solely for the USA as they never adopted the international standard. Lasers labelled Class I, II, IIIa, IIIb, or IV are indicating the CDRH classification and these do not directly translate to the IEC classification which are labelled Class 1, 1C, 1M, 2, 2M, 3R, 3B and 4. Where lasers and laser systems are not adequately labelled or do not comply with IEC (i.e. they are instead labelled Class I, II, IIIa, IIIb, or IV indicating the CDRH classification) they will need to be re-labelled. All laser equipment, whether commercially produced or not, should be classified and labelled appropriately to inform the user of the class assigned. Classification of laser products is normally done by the manufacturer of the laser product, but where this is not the case (e.g., laser components, experimental or prototype systems), then the user should ensure that the effective class of the laser is determined based on the level of its accessible emission in accordance with IEC 60825-1. If you are in any doubt about the class of laser you have contact your School Local Laser Safety Advisor (LLSA).
Overview of the different laser classifications
- Class 1, 1C, 1M lasers are safe to the naked eye. Class 1M is only safe provided it is not viewed with a Magnifier (telescope, microscope, magnifying glass etc.).
- Class 2, 2M lasers require the eye’s blink reflex to limit exposure to a safe level. You must however blink. Be aware that alcohol and certain drugs can hinder the blink reflex. Do not stare into the beam. Class 2M is only safe provided it is not viewed with a Magnifier (telescope, microscope, magnifying glass etc.).
- Class 3R, 3B lasers present a hazard from direct exposure to the beam. You must prevent direct exposure to the beam. Class 3B is very hazardous to the human eye and at the highest powers in this class can be harmful to the skin. Your eye must be protected from a Class 3B laser beam.
- Class 4 lasers are hazardous to the eyes and skin from both direct and scattered radiation. Your eyes and skin must be protected from the light from a Class 4 laser.
The Laser Safety Training course (THS42 or THS42e) can be booked through the training catalogue https://app.manchester.ac.uk/training/. Existing laser users are reminded that they should attend a refresher Laser Safety Training course once every 5 years.
Although systems which fully enclosed or interlock Class 3B and 4 lasers are normally safe (e.g. Raman spectrometers) they should still be registered with the Local Laser Safety Advisor who will advise on whether any additional precautions are necessary.
2. The use of laser pointers
Laser pointers must be labelled according to the IEC standard as Class 2 and carry a CE mark. It is acceptable for the labelling to appear on a datasheet accompanying the laser when the laser is too small for the labels to be directly attached. If your laser pointer does not have this labelling on it or on an accompanying datasheet them it must not be used in lectures or presentations.
The document Guidance on the use of laser pointers provides further information and instructions on the use of pointers within the School.
3. Purchasing lasers or a change in use/location
The Local Laser Safety Advisor (LLSA) must be consulted before the procurement, or change in use/location, of any Class 3B or 4 laser equipment. The written permission of the LLSA must also be obtained prior to any Class 3B or 4 laser being brought into the School. Permission can be by e-mail.
Caution when buying laser diodes - When buying laser diodes from some companies the diodes may be sold to you as a laser ‘component’ and not classified. You are advised not to purchase such laser diodes. If you do then you must speak to your LLSA for advice on assessing the hazard associated with the laser.
4. Laser Installation and Service Visits
If an outside agency (e.g., the laser equipment supplier) is engaged to install or service any laser equipment, then a permit-to-work procedure must be adopted for handing the equipment over to the service engineer and accepting it back fully-restored to normal operation when the work is completed.
The following Laser permit to work form must be completed and signed by the School Safety Advisor or by another member of the School’s Health and Safety Committee before any work is undertaken.
5. Risk assessments
While a risk assessment and a set of local rules should be prepared for all laser activities, people developing activities involving the use of a Class 3B or 4 laser must submit copies of these documents to the SLSA for review. Remember the LLSA is there to assist PIs and users with the preparation of risk assessments. Maximum Permissible Exposure (MPE) and Exposure Limit Value (ELV) calculations for the eyes and skin must be included in risk assessments covering open beam work with Class 3B and 4 lasers in order to demonstate that measures are in place to reduce user exposure below the MPE/ELV limits.
Example RA's
ExampleLaserPhysics_ Laser RA and guidance_Open3Band4
ExampleManufacturing_ Laser RA and guidance_Open3Band4
ExampleMicroscope_ Laser RA and guidance_Open3Band4
ExampleSpectroscopy_ Laser RA and guidance_Open3Band4
Template_ Laser RA and guidance_Open3Band4
Example SOP's
ExampleLaserPhysics_ Laser SoW_Open3Band4
ExampleManufacturing_ Laser SoW_Open3Band4
ExampleMicroscope_ Laser SoW_Open3Band4
ExampleSpectroscopy_ Laser SoW_Open3Band4
Template_ Laser SoW_Open3Band4
6. Personal Protective Equipment (PPE) – Laser safety eyewear
Laser safety eyewear should only be considered when it is not reasonably practicable to provide protection by other means (i.e. you cannot fully enclose the laser system). Where PPE is required then the laser risk assessment must include the calculations performed to determine the required eyewear and your and your LLSA must review the choice of eyewear. When PPE is required then it must be worn. Protective eyewear is designed to protect against accidental exposure to laser radiation. It should not be used to protect against deliberate exposure or the intentional viewing of a laser beam.
Eyewear must:
- cover the wavelength range of the laser;
- be labelled for the laser type
‘D’=continuous wave, ‘I’= long pulse (1 ms to 250 ms), ‘R’=Q-switched, short pulse (1 ns to 1 ms), ‘M’=pico- and femto-second lasers (<1 ns); - have a sufficient ‘LB’ rating (a scale number indicating the ability to reduce eye exposure and resistance to laser damage);
- be CE marked;
- be in good condition (i.e. no scratches or cracks).
Eyewear ‘only’ displaying the optical density (OD) numbers should not be used. OD is not enough to specify safe eyewear as it does not account for resistance to laser damage.
7. Useful videos
Laser Safety - Controlled Areas
Laser Safety - Alignment
Laser Safety - Eyewear and Filters
Laser Safety - Classification
8. Accidents and Near-miss events
Laser users must understand that if they suspect they have been struck in the eye by a laser beam or have any immediate concerns over their eyesight they should go to A&E as a matter of urgency. In emergencies the LLSA or a member of staff should assist and ensure a copy of the risk assessment is taken. The assessment will contain information that can help in diagnosis and treatment.
All laser incidents and near-miss events must be reported following the procedures given on the front page of StaffNet (www.staffnet.manchester.ac.uk/ see ‘Top Forms’) and also at www.healthandsafety.manchester.ac.uk/
Further guidance on the University’s policies on laser use can be found here: