laser inventory - Manchester Metropolitan University

Guidance Notes Concerning THE USE OF LASERS

HEALTH AND SAFETY UNIT

AUTUMN TERM 2007

CONTENTS INTRODUCTION ................................................................................. 4 ADMINISTRATIVE ARRANGEMENTS ............................................................ 5 Laser Users/Operators ...................................................................... 5 Supervisor/principal investigator ......................................................... 5 Departmental Laser Safety Officer ....................................................... 6 University Laser Safety Adviser ........................................................... 7 HAZARD CLASSIFICATION FOR LASERS ....................................................... 7 Example AELs ................................................................................ 9 Maximum Permissible Exposure (MPE) ................................................... 9 GENERAL SAFETY PROCEDURES .............................................................. 9 Laser Inventory .............................................................................. 9 Registration of Laser Users................................................................. 9 Training ....................................................................................... 9 Undergraduate work ....................................................................... 10 Designation of Laser Areas ................................................................ 10 Labelling of Lasers ......................................................................... 10 Experimental design ....................................................................... 10 Laboratory design .......................................................................... 11 BIOLOGICAL EFFECTS OF LASER RADIATION ............................................... 12 Laser damage to the eye .................................................................. 12 Ultraviolet wavelengths ................................................................ 12 Visible and near Infra-red wavelengths .............................................. 12 Infra-red wavelengths ................................................................... 12 Penetration of laser radiation into the eye .......................................... 13 Laser damage to the skin ................................................................. 13 Penetration of radiation into the skin ................................................ 14 Summary of laser radiation hazards .................................................. 15 SAFETY PROCEDURES FOR SPECIFIC CLASSES OF LASER ................................. 15 RISK ASSESSMENT AND SYSTEM OF WORK .................................................. 18 Optical hazards ............................................................................. 18 Non-optical hazards ........................................................................ 18 Assessing Risk ............................................................................... 19 Risk control measures ..................................................................... 19 Record of Assessment ...................................................................... 20 Review ....................................................................................... 20 PERSONAL PROTECTIVE EQUIPMENT ........................................................ 20 Protective eyewear ........................................................................ 20 Other protective equipment .............................................................. 21 ACCIDENTAL EXPOSURES AND EMERGENCY EYE EXAMINATIONS ........................ 21 LASER POINTERS ............................................................................... 22 CONCLUSIONS .................................................................................. 23 LASERS FOR DISPLAY PURPOSES ............................................................. 24 LASER SIGNS AND LABELS .................................................................... 25 Designated Laser Areas .................................................................... 25 Laser Labels ................................................................................. 25 Aperture Labels for Class 3R, Class 3B & Class 4 lasers ............................... 28 Radiation Output and Standards Information .......................................... 29

FORMS........................................................................................... 30 SUMMARY OF WARNINGS & PROTECTIVE CONTROL MEASURES ....................... 30 LASER SURVEY FORM ....................................................................... 31 LASER INVENTORY .......................................................................... 33 REGISTRATION FORM FOR LASER USERS ................................................. 34 USE OF CLASS 1M, 2M,2 AND 3R LASERS – HAZARD & RISK ASSESSMENT ............ 35 USE OF CLASS 3B & 4 LASERS – HAZARD & RISK SSESSMENT .......................... 37 SYSTEM OF WORK FOR LASERS ............................................................ 41 EMERGENCY PROCEDURE FOR EXPOSURE TO CLASS 3B OR 4 LASER ................. 47 TRAINING RECORD FORM .................................................................. 48

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INTRODUCTION This Guidance is intended to be used as a reference document for all users of lasers within Manchester Metropolitan University and applies to both employees and students. The guidance draws from a number of reference documents including the relevant British Standard series of documents BS EN 60825 and associated amendments, and the AURPO Guidance on the safe use of lasers in education and research. This document forms the basis of Laser Safety Management in the University and is a general guidance to good practice and assistance in the identification of hazards, risk assessment and appropriate control measures associated with the use of lasers as required by the Health and Safety at Work Act. The current classification for lasers (implemented in 2001) is used which is based on seven classes of laser (1, 1M, 2, 2M, 3R, 3B and 4). The Safety of laser products is covered by British Standards BS EN 60825 which is based upon the corresponding International Electrotechnical Commission’s 60825 document. Of particular importance to laser users is the Technical Report PD IEC TR 60825-14 a detailed user’s guide.

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ADMINISTRATIVE ARRANGEMENTS The responsibilities of those working with or involved with laser activities in the University are as follows:

Laser Users/Operators Laser Users/Operators have the following responsibilities:     

to observe Local Rules and Systems of Work applicable to the lasers that will be used and follow the guidance of supervisors and the Departmental Laser Safety Officer. to keep the supervisor fully informed of any proposal to depart from established safety procedure. not to leave a laser experiment running unattended unless a risk assessment has established that it is safe to do so. for their own safety and that of others who may be affected by their acts or omissions. When working with Class 3B and Class 4 lasers where there is a possibility of stray laser beams that could damage eyesight, the appropriate laser eyewear must be worn.

Supervisor/principal investigator Research Supervisors have duty delegated to them from the Head of Department, to provide “such supervision as is necessary” to ensure the safety of all the students for whom they responsible. This includes all postgraduate and undergraduate students working with lasers. Supervisors also have responsibility for the following:      

All work involving hazardous lasers must be covered by risk assessments and where appropriate written Systems of Work and protocols. There should be procedures in place to ensure lasers and any associated hazardous materials are disposed of properly. The Supervisor should ensure that their laser users/operators are adequately trained and supervised. New lasers must be registered with the University Laser Safety Adviser (using the Laser Inventory form) with the exception of laser pointers and embedded lasers e.g. CD/DVD players and laser printers. Users of Class 3R, 3B, 4 and modified 1M and 2M lasers must be registered with the University Laser Safety Adviser (using the Registration Form For Laser Users). Notifying the University Laser Safety Adviser of any accident involving lasers.

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Departmental Laser Safety Officer The Departmental Laser Safety Officer plays a fundamental role in supporting that the University complies with the requirements of the Health and Safety at Work Act and the Management of Health and Safety at Work Regulations. He or she should be directly involved with the Department’s work with lasers in order to allow them to exercise sufficient supervisory authority. It is recognised that in some departments the DLSA may not be the immediate supervisor overseeing the work with lasers. In these cases the Supervisor/principal investigator takes on these duties. The functions of the DLSO will include: 

The promotion of awareness by all persons who use Lasers within the Department to which the DLSO is assigned of any potential hazards.



Drafting and reviewing of Local Rules/Systems of work and observing that they are applied in the appropriate areas.



Drafting and reviewing Risk Assessments for work being carried out with lasers.



To monitor that all users have attended or are booked to attend an appropriate Laser Safety training course.



To restrict or stop any laser activity that does not comply with the local rules/System of Work.

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To keep a record of all users working with lasers. Users of Class 3R, 3B, 4 and modified 1M and 2M lasers must be registered with the University Laser Safety Adviser (using the Registration Form For Laser Users).



To inform the University Laser Safety Adviser (ULSA) of details of any new lasers. New lasers must be registered with the University Laser Safety Adviser (using the Laser Inventory form) with the exception of laser pointers and embedded lasers e.g. CD/DVD players and laser printers.



To inform the Laser Safety Adviser of any new or significantly different activities involving lasers.



The bringing to the immediate attention of the Health and Safety Unit of any ‘incident’ involving lasers

In addition to the above the DLSO will undertake to attend appropriate training in order to carry the above duties effectively.

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University Laser Safety Adviser The University Laser Safety Adviser has responsibility for the administration and auditing of systems of control relating to Laser Safety in order to ensure compliance with the Health and Safety at W ork Act and provide advice and assistance in order to implement the requirements of BS EN 60825. The University Laser Safety Adviser will conduct routine inspections of laboratories in which laser work is undertaken and provide information and advice. In addition the ULSA has the following responsibilities:       

To provide assistance in evaluating and controlling hazards To maintain a register of lasers and users To co-ordinate laser safety training of laser users, supervisors/principal investigators and Departmental Laser Safety Officers. To participate in any accident investigations involving lasers. To restrict or stop any laser activity that does not comply with the Health and Safety at Work Act and BS EN 60825 To inform all Departmental Laser Safety Officers of any change in existing or new legislation applicable to the use of lasers. To provide guidance on the safe use of lasers.

HAZARD CLASSIFICATION FOR LASERS

Lasers produce electromagnetic radiation in the wavelength range 100nm (ultraviolet) to 1mm (infrared) which includes the visible range 400nm-700nm. The output from a laser may be continuous (CW) or pulsed which produce short bursts of radiation. Because of the wide ranges of wavelength, energy and pulse characteristics of laser beams, the hazards arising from their use varies widely. Lasers are grouped into seven categories depending on the potential to cause harm. Accessible Emission Levels (AELs) have been determined for each class of laser. The AEL depends on the wavelength, exposure duration and the viewing conditions and specifies the maximum output within each laser class. Laser classes are as follows: Class 1: Lasers that are safe under reasonably foreseeable conditions either because of the laser’s low emission or because of engineering design such that it is totally enclosed and access to higher levels is not possible during normal operation e.g. CD/DVD player or a laser printer. NB If access panels on a totally enclosed system are removed then the laser product is no longer a Class 1 laser product and the precautions applicable to the embedded laser must be applied.

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Class 1M: Laser products emitting in the wavelength range between 302.5nm and 4000nm whose total output is in excess of a Class 1 laser but, because of their diverging beams or low power density, do not pose a hazard under reasonably foreseeable conditions. However, they may be hazardous to the eyes under the following conditions: a) With a diverging beam if optics are placed within 100mm of the source to collimate/concentrate the beam. b) With a large diameter collimated beam where optics are used to increase the proportion of the beam entering the eye e.g. binoculars or telescope. Class 2: Lasers emitting in the visible wavelength region between 400nm and 700nm and whose output is less than the appropriate AEL. Safe for accidental viewing as protection of the eyes is provided by the aversion response (blinking and/or moving the head). Class 2M: Laser products emitting in the visible wavelength region between 400nm and 700nm whose total output is in excess of a Class 2 laser but, because of their diverging beams or low power density, are safe for accidental viewing under reasonably foreseeable conditions. However, they may be hazardous to the eyes under the following conditions: a) With a diverging beam if optics are placed within 100mm of the source to collimate/concentrate the beam. b) With a large diameter collimated beam where optics are used to increase the proportion of the beam entering the eye e.g. binoculars or telescope. Class 3R: Lasers emitting in the wavelength range 302.5nm to 1mm where direct intrabeam viewing is potentially hazardous but the risk is lower than for Class 3B lasers. The AEL is below five times the Class 2 AEL in the visible region (400nm-700nm) and below five times the Class 1 AEL for all other wavelengths. Class 3B: Lasers in both the visible and invisible range of wavelengths. Direct intrabeam viewing near (i.e. within the Nominal Ocular Hazard Distance where the radiant exposure will exceed the Maximum Permitted Exposure limit) is always hazardous. Viewing diffuse reflections is normally safe provided the eye is no closer than 13cm from the diffusing surface and the exposure duration is less than 10 seconds. Output levels must be less than the appropriate AEL for Class 3B devices. Class 4: High power lasers from which direct beam or reflected beam viewing is always hazardous. Likely to cause both eye and skin injury. Environmental damage (fire and hazardous fumes) is also a serious possibility. Class 4 laser use requires extreme caution.

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Example AELs The AELs for Helium-Neon lasers emitting a continuous narrow beam at 633nm are as follows: Class 1 and 1M 0.39 mW Class 2 and 2M 1.00 mW Class 3R 5.00 mW Class 4 500.00 mW The above limits will also apply to other narrow beam visible CW lasers except for Class 1 and 1M devices where there further restrictions apply to wavelengths below 500nm. For full details of restrictions see BS EN 60825-1. Maximum Permissible Exposure (MPE) The Maximum Permissible Exposure (MPE) is the level of radiation below which no adverse effects to the eye and skin should occur. There is a safety factor incorporated into the MPEs to take account of individual variations in sensitivity to laser radiation. MPE levels are specified in BS EN 60825-1 and in particular in – Safety of Laser Products – Part 14: A user’s guide, PD IEC TR 60825-14:2004. Planned ocular exposure to lasers should not exceed the MPE.

GENERAL SAFETY PROCEDURES Laser Inventory All Class 3R, 3B and Class 4 lasers should be identified and recorded on the Laser Inventory Form, a copy of which should be sent to the University Laser Safety Adviser. In addition Class 1M, 2M and Class 2 lasers should also be recorded except for laser pointers and embedded lasers in products such as laser printers and CD/DVD players. It is not necessary to register low powered Class 1 devices. Registration of Laser Users All persons intending to work with lasers except for inherently safe Class 1 and Class 2 devices or embedded lasers in products such as laser printers and CD/DVD players, should register with the University Laser Safety Adviser using the Registration form for Laser Users. Training Persons intending to use Class 3R, 3B and Class 4 lasers should attend training before commencing any laser work and should also be familiar with System of Work for the lasers they intend to use. Training in the use of individual lasers is the responsibility of the Student/Research Supervisor and a record of this training should be made. The Training Record for Authorised

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Laser Users must be filled in and a copy sent to the University Laser Safety Adviser. Laser Safety Training Sessions can be arranged by contacting the University Laser Safety Adviser. Undergraduate work Wherever possible undergraduate work should be restricted to Class 1, 1M, 2, 2M or visible 3R lasers. For class experiments it is important to introduce students to good safety practice and a written system of work/local rules should be drawn up and posted in the laboratory. In addition, clear written instructions should be provided for each student experiment. Students involved in project work with Class 3B and Class 4 lasers will be treated as laser workers and must register with the University Laser Safety Adviser using the Registration for Laser Users. In addition they must receive appropriate Laser Safety Training. Laser Safety Training Sessions can be arranged by contacting the University Laser Safety Adviser. These students must work under close supervision if working with high-powered lasers. Designation of Laser Areas Points of access to areas in which Class 3B and Class 4 lasers are used must have appropriate warning signs (see section on Laser signs and labels). Areas in which open beam work with modified Class 1M,2M or 3R lasers are used will also require appropriate warning signs. Labelling of Lasers All lasers must be labelled correctly in accordance with BS EN 60825-1 (see section on Laser Signs and Labels). Where lasers and laser systems are not adequately labelled e.g. imported lasers, they must be relabelled. NB For mains powered equipment the labelling of lasers must comply with European Standards and any institution obtaining a laser directly from the US will assume the responsibilities of the importer and supplier. Experimental design Before using a laser the following points should be considered:        

Is it possible to use a lower powered laser? Can the laser output power be restricted? Can the laser be used in a screened off area? Can work be carried in a total enclosure? Can intrabeam viewing be avoided by engineering design? Are beam paths as short as possible? Have optical reflections been minimized? Use of anti-reflective coated components or shrouds. The beam should be terminated with an energy absorbing, nonreflective beam stop 10

     

Lasers should be securely fixed. Keep beam paths above or below eye level Make sure laser is facing away from laboratory entrance Keep optical benches free from clutter Remove jewellery, wristwatches etc. Alignment of lasers should be at lowest possible power, if practicable use low-power lasers for alignment or introduce neutral density filters. Alternatively remote viewing techniques can be considered.

Laboratory design The following relates to Class 3B and Class 4 lasers: 



If practicable the laboratory should have a high level of illumination that will minimize pupil size and reduce the risk of stray laser light reaching the retina. Windows may need to be covered or protected with blinds. These should be non-reflective and may need to be fireproof if high powered lasers are used. Walls, ceilings, and fittings should be painted with a light coloured matt paint to enhance illumination and minimize specular reflections. Reflecting surfaces should be avoided. Ventilation is an important factor particularly if cryogens are used or toxic fumes produced. Extraction of toxic fumes will need to be close to the source. Some dye lasers are associated with toxic chemicals which will require appropriate facilities for handling and storage. Appropriate fire fighting equipment should be available

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Electrical supplies, switch and control gear should be sited to:

   

o Allow shut down by a person standing next to the laser o Prevent accidental firing of the laser o Provide an indication of the state of readiness of the laser o Enable persons to stand in a safe place o Enable the laser to be made safe in an emergency from outside the laser area if reasonably practicable o Provide sufficient and adequate power supplies so that the use of trailing cables is kept to a minimum

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BIOLOGICAL EFFECTS OF LASER RADIATION When the body is exposed to laser radiation some of the radiation is absorbed by the body tissues. The parts of the body most susceptible to injury are the eyes and skin. The amount of radiation absorbed by the eyes and skin will vary with wavelength, type of tissue, energy or power of the incident beam, size of the irradiated area and duration of exposure.

Laser damage to the eye Tissue damage will only occur when energy is absorbed by it. Different wavelengths affect different parts of the eye because of the specific characteristics of the particular tissues involved: Ultraviolet wavelengths UVC and UVB (180nm-315nm) are primarily absorbed in the cornea resulting in keratitis. This is a painful condition feeling like grit in the eye accompanied by excessive tear flow and an aversion to bright light. The eye usually recovers from this within 48 hours. When UVC and UVB wavelengths are absorbed by deeper layers of the cornea a photochemical reaction may cause the cornea to turn milky usually between 6 and 12 hours after exposure. UVA (315nm-400nm) is primarily absorbed by the lens of they eye and can result in yellowing of the lens and cataract formation. Visible and near Infra-red wavelengths Visible and IR-A (400-1400nm) wavelengths are transmitted by the eye and focussed on the retina. Short pulsed high peak power lasers are particularly hazardous as they deliver a lot of energy in a short period of time. IR-A beams are also particularly hazardous as they are invisible and will be focussed on the retina without the person being aware of it until damage has been caused. Infra-red wavelengths IR-B (1400nm-3000nm) and IR-C (3000nm-1mm) wavelengths are absorbed by the cornea which can cause infrared cataracts and above 2000nm flash burns. If the IR radiation is great enough to damage the cornea, the pain associated with it will be enough to trigger the aversion response which could help to minimize the tissue damage.

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Penetration of laser radiation into the eye

Laser damage to the skin Damage to the skin by laser radiation is usually considered less significant than damage to the eye since skin injuries will usually heal even following penetrating damage leading to infection. Skin damage may lead to scarring. All laser wavelengths with sufficient power density can cause surface burns and particularly with high powered Class 4 laser where there may be no warning of this occurring. Near infrared lasers are also of particular concern as they can penetrate the subcutaneous layers of the skin. Chronic exposure to lasers in the Ultraviolet region can increase the long term risk of skin cancer.

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Penetration of radiation into the skin

UV

Visible

IR-A

IR-B/C

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Summary of laser radiation hazards

More information on biological hazards can be found in Annex B to BS-EN 60825-1:1994 or Annex C to PD IEC TR 60825-14:2004.

SAFETY PROCEDURES FOR SPECIFIC CLASSES OF LASER

The following gives the minimum safety requirements for using lasers of different classes within the University: Class 1 1)

The laser must be labelled correctly (see section on laser signs and labels).

2)

Class 1 lasers, laser products and systems do not require any special safety controls.

NB

If the laser system is class 1 due to engineering controls and contains a laser of a higher class than 2M then significant hazards may occur during servicing, alignment etc. In this case, it should be included in the laser inventory and there should be a system of work for that activity. This does not apply to laser printers, CD/DVD players or other devices not serviced by the user. If in doubt contact the University Laser Safety Adviser for advice. 15

Class 1M 1)

The laser must be labelled correctly (see section on laser signs and labels).

2)

Avoid intrabeam viewing with condensing optics such as telescopes, binoculars, microscopes or other lens based systems. Modifications need to be carefully assessed and reclassified if necessary.

Class 2 1)

The laser must be labelled correctly (see section on laser signs and labels).

2)

Beam should be terminated at the end of its useful path.

3)

Keep beam paths above or below eye level.

Class 2M 1)

The laser must be labelled correctly (see section on laser signs and labels).

2)

Avoid intrabeam viewing with condensing optics such as telescopes, binoculars, microscopes or other lens based systems. Modifications need to be carefully assessed and reclassified if necessary

3)

Beam should be terminated at the end of its useful path.

4)

Keep beam paths above or below eye level.

Class 3R 1)

The laser must be labelled correctly (see section on laser signs and labels).

2)

Beam should be terminated at the end of its useful path.

3)

Keep beam paths above or below eye level.

4)

Avoid open beam paths and where practicable enclose the beam.

5)

Safety interlocks required on access panels.

6)

Where non-visible wavelengths are used an emission indicator is required to indicate the laser is energised.

7)

Training to an appropriate level. (If required Laser Safety Training Session can be arranged by University Laser Safety Adviser).

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8)

Provide appropriate PPE if necessary. See section on Personal Protection)

9)

Register laser using with University Laser Safety Adviser using Laser Inventory form.

10)

Register users with University Laser Safety Adviser using Registration form for Laser Users.

Class 3B and 4 1)

The laser must be labelled correctly (see section on laser signs and labels).

2)

Beam should be terminated at the end of its useful path.

3)

Keep beam paths above or below eye level.

4)

Prepare risk assessment (see Use of 3B & 4 Lasers – Hazard & Risk Assessment form)

5)

Prepare scheme of work following risk assessment (see System of Work for Lasers form. In grey text on this form are the considerations which should be taken into account, exact detail will vary between different laser systems). The scheme of work should be displayed in a prominent position or readily available within a laboratory folder) along with an Emergency Procedure for Exposure to Class 3B or 4 Lasers form, an example of which is in these Guidance Notes for the All Saints site.

6)

Avoid open beam paths and where practicable enclose the beam.

7)

Provide appropriate PPE if necessary. (See section on Personal Protection).

8)

Safety interlocks required on access panels.

9)

Remote interlock for door or enclosure.

10)

Emission indicator is required to indicate the laser is energised.

11)

Beam stop or attenuator/shutter

12)

Users must attend Laser Safety Training Session (Laser Safety Training Session can be arranged by University Laser Safety Adviser).

13)

Areas need to be defined and warning signs used.

14)

Register laser with University Laser Safety Adviser using Laser Inventory form.

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15)

Register users with University Laser Safety Adviser using Registration form for Laser Users.

16)

Local Laser Safety Officer to be appointed.

RISK ASSESSMENT AND SYSTEM OF WORK The main areas at risk from laser radiation are the eye and the skin. When carrying out a risk assessment it is important to know the effects of laser radiation on biological tissue (See section Biological Effects of Laser Radiation). Before the appropriate controls can be selected and applied, laser hazards must be identified and evaluated along with any other hazards associated with the laser system. Special considerations apply to the use of lasers for medical and dental purposes as well as lasers used for display purposes (see section on The use of Lasers for Display Purposes). To assist in assessing hazards and risk control methods see the following forms: 

Use of Class 1M,2M,2 and 3R lasers – Hazard and Risk Assessment

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Use of Class 3B and 4 Lasers – Hazard and Risk Assessment

Optical hazards Class 3B and Class 4 lasers can cause significant eye injury to anyone looking directly into the beam or its specular reflections. Diffuse reflections from a high powered laser can also cause permanent eye damage. High powered laser beams can also cause skin burns, ignite flammable materials and heat materials causing hazardous fumes.

Non-optical hazards Electrical Hazards (Most lasers contain high voltage power supplies and often large capacitors that store lethal amounts of electrical energy) Laser Dyes (Laser dyes are often hazardous dissolved in flammable solvents) Compressed and Toxic Gases (Hazardous gases may be used in laser applications (e.g. excimer lasers (fluorine, hydrogen chloride) Cryogenic liquids (Cryogenic liquids may create a hazard. Adequate ventilation must be provided)

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Laser generated fumes, vapours and air contaminants (High energy laser beams may vapourise a target creating hazardous fumes or vapours that may need to be captured or exhausted) UV and visible Radiation/plasma emissions (UV and visible radiation may be generated by laser discharge tubes , pump lamps or plasmas which may create an eye and skin hazard) Explosion hazards (High pressure arc lamps, filament lamps, and capacitors may explode if they fail during operation. Laser targets and some optical components may shatter if heat is not dissipated quickly enough) Ionising Radiation (X-rays can be produced from high voltage vacuum tubes of laser power supplies such as rectifiers, thyratrons and electric discharge lasers. Any power supply that requires more than 15kV may produce x-rays) Additional hazards may also a arise from the environment in which the laser is used – temperature and humidity, low level lighting, mechanical shock or vibration, interruptions to power supply, computer software problems, ergonomic problems created by design and laboratory layout. Issues such as cleaners and maintenance staff inadvertently disturbing equipment and unsupervised access must also be taken into account.

Assessing Risk Identify people at risk in addition to the laser user/s. Consider other people such as cleaning, maintenance personnel, contractors, visitors and the public. Risk from the laser can be assessed by using quantitative measures that combine the likelihood of occurrence with the severity of the injury, however, in laser safety it is usually more important to eliminate the risk of injury by adopting appropriate control measures in all situations where the Maximum Permissible Exposures (MPEs) are likely to be exceeded (MPE levels are specified in BS EN 60825 in particular in Safety of Laser Products – Part 14: A user’s guide, PD IEC TR 60825-14:2004. Risk from non-optical hazards need to be evaluated for each hazard taking into account existing controls.

Risk control measures The simplest rule to follow to avoid eye injury is not to look directly into a laser beam or any specular reflections from it, regardless of the Laser’s power, classification or eyewear being worn. Maximum Permissible Exposure, MPE calculations are based on the radiated wavelength(s), output power(s) or energy(ies) and if appropriate, the pulse duration and repetition rate. MPE’s will apply to a specific combination of these parameters and will usually change if any of the parameters changes.

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Engineering and administrative controls should be used to keep exposures below the MPE whenever practicable. Skin and eyewear should be used where engineering and administrative controls are not practical. All open beam work must have an appropriate protocol/operating procedure/system of work. To assist in drawing up a system of work see the System of Work for Lasers form. The grey text on the form is an indication of the points that should be considered and will vary between different laser systems. All users must read and sign the system of work.

Record of Assessment The following forms should be used to record your assessment and a copy sent to the University Laser Safety Adviser along with a copy of the System of Work for each laser system. Use of Class 1M,2M,2 and 3R lasers – Hazard and Risk Assessment Use of Class 3B and 4 Lasers – Hazard and Risk Assessment

Review Risk assessments and systems of work should be routinely reviewed and particularly whenever there is a significant change in the activity.

PERSONAL PROTECTIVE EQUIPMENT Personal Protective Equipment is an important element of personal laser protection, however, reliance upon PPE should be avoided through engineering and administrative controls and should not be regarded as a convenient alternative to a thorough safety evaluation. Situations in which protective goggles or gloves are necessary do arise and selecting the correct PPE is crucial to ensuring safety. Protective eyewear Safety eyewear should 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. Information on specifying eye protection is given in PD IEC TR 60825-14: A user’s guide. Protection by safety eyewear is afforded by incorporating optical filters to reduce the level of transmitted laser radiation such that the eye is not exposed to laser radiation above the Maximum permissible exposure. As maximum permissible exposures are wavelength dependent the eye protection supplied must provide adequate attenuation at the appropriate wavelength and comply

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with the requirements of BS EN 207 – Filters and equipment used for personal eye protection against laser radiation and BS EN 208 – Personal eye-protection used for adjustment work on lasers and laser systems. BS EN 207 applies to filters and equipment designed to provide protection against laser radiation in the wavelength range 180nm to 1mm. BS EN 208 applies to eye protectors for use in adjustment work on laser or laser systems in the wavelength range 400nm to 700nm i.e. visible. The protective eyewear which meets the requirements of the standard reduces the level of incident radiation upon the eye to the MPE level for a Class 2 laser and is therefore still reliant upon the aversion response (blink reflex). The required optical filter must have a sufficient optical density (OD) at the laser wavelength(s) to reduce the incident radiation to a level below the MPE. The optical density is a numerical quantity which indicates how much of the laser radiation will be transmitted through the filter. As the transmission properties of materials vary with wavelength, the optical density should be quoted for the given wavelength(s). In addition the protective filter must also withstand the intensity of radiation for a sufficient time to allow the user to respond and take appropriate avoiding action. Whilst the filter should have a low transmittance at the laser wavelength the percentage of the visible spectrum that is not filtered by the eyewear should be as high as possible in order to minimise vision impairment.

Other protective equipment Class 4 lasers present a fire hazard and protective clothing made from suitable flame retardant and heat resistant material may be required. When working with Class 4 and some Class 3B devices emitting in the ultraviolet region skin protection may be required. Gloves should be worn when preparing chemicals for dye lasers, optics cleaning chemicals, handling cryogenic materials and filters fromextraction systems used for materials processing. Face masks/respirators may be needed where fume and dusts are a hazard. Personal protective equipment should be personal, i.e. it should be appropriately cleaned between users, or each user has their own.

ACCIDENTAL EXPOSURES AND EMERGENCY EYE EXAMINATIONS Eye examinations for laser users are not recommended as part of a safety programme. The value of routine examinations for laser users has been reviewed and it is generally accepted that routine examinations are of little value.

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It is important, however, to have procedures in place in the event of suspected ocular exposure. In the event of an accident or incident involving suspected injury to the eye, and emergency examination by a qualified specialist should be carried out as soon as possible and within 24 hours. All persons working with Class 3B and Class 4 lasers need to be aware of the action to take in the event of an accident/incident. The form Emergency Procedure for Exposure to Class 3B or Class 4 Laser should be available for each laser to take with the casualty to the Hospital. (Please note the form is designed for use on the All Saints Campus, for other areas the form should be modified appropriately to include the nearest Accident and Emergency Department). Where an emergency eye examination is required, the University Laser Safety Adviser and School/Departmental Laser Safety Officer will carry out a detailed investigation of the accident/incident. All accidents and incidents, whether involving emergency examination or not, must be reported to the Health and Safety Unit using the appropriate Accident Report Form.

LASER POINTERS Laser pointers are small battery operated devices which emit a thin powerful beam of light for distances of about 100 meters or more, and are intended for use by teachers and lecturers as hand held pointers. The beams themselves are invisible but appear as brilliant spots when they hit a screen or other surface. When considering the safety implications of the laser beam an important parameter is the amount of power in the beam divided by the crosssectional area of the beam. This is called the irradiance and is usually quoted in watts per square metre or W/m2. The pointers are cheap and readily available from certain shops and market stalls. Although there have been no reported incidents of permanent injury in the UK, there have been reports of incidents concerning the misuse of pointers by persons deliberately targeting people such as footballers, bus, taxi drivers and fire fighters. There have also been reports of people using the pointers in discos and night-clubs. The laser beams have caused temporary eye irritation or blurring of sight. In addition, there have been several instances of MMU Security staff being targeted whilst on patrol and in one case from a car on Oxford Road. Misuse of laser pointers can lead to prosecution for common assault and more serious charges if this leads to serious injury to eyesight or a motoring accident. The degree of adverse effect on the eyes depends on the power of the beam and the duration of exposure. By law all laser devices have to carry a label with a warning symbol and power classification. This can range from the weakest class 1 such as those used as bar code readers at supermarket

22

checkouts to class 4 which can cut through metal and require very stringent regulation. Laser pointers sold in the UK should be classified in accordance with the current British Standard (BS EN 60825) on laser safety. This document specifies requirements for the manufacturers of laser products to ensure that the risk of accidental exposure is minimised through the use of engineering control features and product labelling, and by specifying minimum requirements for the supply of product information to allow for its safe use. The British Standard also provides advice on the use of lasers for demonstrations, displays and exhibition and states that only Class 1 or Class 2 devices should be used in unsupervised areas unless under the control of experienced well-trained operators. The Health Protection Agency has examined several laser pointers currently available to the general public in order to assess their laser class and many laser pointers which are either unlabelled or labelled as class 2 lasers have been found to be Class 3R or class 3B devices when measured. Green laser pointers have given a particular cause for concern and many of these cause afterimages in people viewing the beam on a projection screen. Because of the way the green beam is generated, there may also be additional invisible laser beams emitted.

Direct ocular exposure close to a class 3b lasers is always hazardous and will cause damage to the eye. The risk of a permanent eye injury from a laser pointer is small; however, a transient eye exposure from a laser will cause a bright flash, a dazzling effect, which is likely to cause distraction and temporary loss of vision in the affected eye and possible after-images. Recovery from these effects will vary for different individuals. Medical attention should only be sought if after-images persist for hours, or if a disturbance in reading vision is suddenly apparent.

CONCLUSIONS 1. The Health Protection Agency considers the professional use of a Class 1 or Class 2 laser pointer as a training aid in the workplace to be justified and regards these Classes of laser product as being generally adequate for such use. 2. Only members of staff and postgraduate students undertaking teaching or presentations should be permitted to use laser pointers. They should be aware of the hazards and exercise caution insuring that they do not direct pointers towards any person within the range of the beam. 3. Staff and students who do not meet the above criteria must not be permitted to use laser pointers on University premises.

23

4. It is not possible to recommend particular laser pointers since even pointers from reputable sources may be incorrectly labelled according to European standards. When purchasing a laser pointer, however, the following points should be considered: a) The pointer should be classified either Class 1 or Class 2 in accordance With the requirements of the current British Standard (BS EN 60825). b) It should carry with it sufficient accompanying information to enable the user to operate the product in a safe manner. c) The pointer should be labelled as either a Class 1 Laser Product or a Class 2 Laser Product and in the latter case should also state “Do not stare into beam”. 5. Anyone who suspects that he/she has been assaulted by a laser pointer should report it and arrange to seek prompt medical attention if it is suspected that the eyes have been affected. If possible the device involved should be confiscated, both to prevent further misuse, and to find the label to ascertain its classification. This information may assist medical staff. An incident report form should be completed and forwarded to the Health and Safety Unit in Minshull.

LASERS FOR DISPLAY PURPOSES Guidance on laser displays and shows can be found in IEC 60825 Part 3 and the Health and Safety Executive Guidance Note HS(G)95 The Radiation Safety of Lasers used for Display Purposes. Organisers of events at which lasers are used for display should: 1) Carry out a general risk assessment to identify relevant hazards and appropriate control measures are in place, in advance of any display. 2) Contact the University Laser Safety Adviser with details of the intended display 3) Comply with the requirements of HS(G)95 and ensure that any statutory notifications are made. Where the relevant precautions above are not implemented for a particular class of laser, a justification needs to made in the appropriate documentation/protocol for the display. Deliberate scanning of an audience with laser beams will not be permitted unless a rigorous assessment of the likely exposure, and any foreseeable fault conditions show that the applicable Maximum Permitted Exposure limit will not be exceeded.

24

LASER SIGNS AND LABELS Designated Laser Areas

The points of access to areas in which Class 3B or Class 4 laser products are used must be marked with warning signs complying with BS 5378 and the Health & Safety (Safety Signs and Signals) Regulations 1996. The signs shall incorporate the following information: 1) hazard warning symbol

2) highest class of laser in the area 3) responsible person with contact details For the area signs the specifications are quite simple -50% of the area should be yellow and the width of the black border is 0.06 x the length of the side. A more detailed specification is given for the symbol used in labels, see spec on p65 of BS EN 60825-1

Laser Labels Laser labels are required for all laser products except for low power Class 1 devices. They are designed to give a warning of laser radiation, the class of laser, basic precautions and the laser's characteristics. The laser warning uses the same symbol as for the door sign in an appropriate size for the laser to be labelled and should be clearly visible. Supplementary information should be black text on a yellow background in accordance with BS EN 60825-1. Where the size of the laser product does not permit the affixing of a reasonably sized label, a sign should be displayed in close proximity to the laser with all appropriate information on. Information over and above that specified by BS EN 60825-1 is required for

25

Class 1 products that are Class 1 by engineering design. For these types of laser product we specify that they are totally enclosed systems and give details of the laser enclosed. The BS requirement is just to describe them on the outside as a Class 1 laser product. Details of wording required on explanatory labels are given below: Class 1 (by engineering design) No hazard warning label. Explanatory label bearing the words:

CLASS 1 LASER PRODUCT A TOTALLY ENCLOSED LASER SYSTEM CONTAINING A CLASS ..... LASER In addition each access panel or protective housing shall bear the words: CAUTION - CLASS ....... LASER RADIATION WHEN OPEN with the appropriate class inserted and then followed by the hazard warning associated with that class of laser (see warning statements in following labels). Class 1M No hazard warning label. Explanatory label bearing the words:

LASER RADIATION DO NOT VIEW DIRECTLY WITH OPTICAL INSTRUMENTS CLASS 1M LASER PRODUCT

NB-'Optical Instruments' can be supplemented with either 'Binoculars or Telescopes' (for a large diameter collimated beam) or 'Magnifiers' (for a highly diverging beam).

Class 2 Label with hazard warning symbol.

26

Explanatory label bearing the words:

LASER RADIATION DO NOT STARE INTO BEAM CLASS 2 LASER PRODUCT

Class 2M Label with hazard warning symbol. Explanatory label bearing the words:

LASER RADIATION DO NOT STARE INTO BEAM OR VIEW DIRECTLY WITH OPTICAL INSTRUMENTS CLASS 2M LASER PRODUCT

NB-'Optical Instruments' can be supplemented with either 'Binoculars or Telescopes' (for a large diameter collimated beam) or 'Magnifiers' (for a highly diverging beam). Class 3R Label with hazard warning symbol. Explanatory label bearing the words: For wavelengths 400nm-1400nm ONLY. LASER RADIATION AVOID DIRECT EYE EXPOSURE CLASS 3R LASER PRODUCT

NB - For other wavelengths replace 'AVOID DIRECT EYE EXPOSURE' with 'AVOID EXPOSURE TO BEAM'

27

Class 3B Label with hazard warning symbol. Explanatory label bearing the words: LASER RADIATION AVOID EXPOSURE TO BEAM CLASS 3B LASER PRODUCT

Class 4 Label with hazard warning symbol. Explanatory label bearing the words:

LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT

Aperture Labels for Class 3R, Class 3B & Class 4 lasers Each Class 3R, Class 3B and Class 4 laser product shall display a label close to where the beam is emitted bearing the words 'LASER APERTURE' or 'AVOID EXPOSURE - LASER RADIATION IS EMITTED FROM THIS APERTURE'. This label can take the form of an arrow if this displays more meaning:

LASER APERTURE

28

Radiation Output and Standards Information All laser products, except for low power Class 1 devices, shall be described on an explanatory label with details of :• maximum output • emitted wavelength • whether laser beam is visible, invisible or both • pulse duration (if appropriate) • name and publication date of classification standard It may be found useful to also put on the labels details of the type of laser and the lasing medium, although this is not a BS requirement. Information put on explanatory labels may be combined and LED shall be used to replace the word 'laser' when appropriate. A selection of labels is available from the Laser Safety Adviser in the Health and Safety Unit.

29

FORMS SUMMARY OF WARNINGS & PROTECTIVE CONTROL MEASURES CLASS

PROTECTIVE CONTROL MEASURES

1

No protective control measures for normal use (NB special precautions may be needed for service work on embedded laser products.)

1M

Prevent direct viewing with magnifying optics. (NB fitting external optics that decrease beam divergence may affect classification) + see footnote

2

Do not stare into beam. Do not direct the beam at other people or into public areas.

2M

Do not stare into beam Do not direct the beam at other people or into public areas. Terminate beam at end of useful path with a non-specular beam stop. Prevent direct viewing with magnifying optics. (NB fitting external optics that decrease beam divergence may affect classification) + see footnote

3R

Prevent direct eye exposure to the beam. Do not direct the beam at other people or into public areas. + see footnote

3B and 4

Class 3B and Class 4 laser products should not be used without first carrying out a risk assessment to determine the protective control measures necessary to ensure safe operation. Where reasonably practicable engineering means should be used reduce the laser class to a totally enclosed Class 1 laser product. The use of any Class 3B or Class 4 laser without an interlocked enclosure will require a written scheme of work. Even with an enclosure written procedures will be necessary if the user is involved in any alignment procedures that require over-riding of interlocks. Class 3B and Class 4 laser products require the control of access to the area where the laser is operated by the use of a remote interlock, the use of key control, emission indicators, beam shutters, removal of reflecting surfaces that could be struck by an errant beam, beam enclosures wherever practical, the use of eye protection and protective clothing as appropriate, training of staff and the appointment of a Laser Safety Officer.

+ Classes 1M, 2M and 3R may also require training of staff, care with beam paths and specular reflections - see BS EN 60825 -1 and PD IEC TR 60825-14:2004 for more details. Special attention should also be given to other non-optical hazards such as risk of electric shock, hazardous chemicals, cryogenic liquids and flying debris from targets to name but a few. It is often the non-optical hazards that pose the greatest risk - one could be blinded in one eye from a powerful laser but electrocution could be fatal. Some non-optical hazards may be present with even Class 1 laser products. 30

LASER SURVEY FORM Date: Dept: Lab: Make:

Type:

Model:

Continuous/Pulsed

Serial No.

Wavelength

Max. Power: Precautions Remote Interlock Key Control

Class Class Class Class Class Class 1 (E) 1 1M 2 2M 3R N/A N/A N/A N/A N/A N/A N/A

N/A

N/A

N/A

Safety Interlocks

N/A

N/A

N/A

N/A

Emission Indicator Beam Stop/Shutter Beam terminator

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

Beam level

N/A

N/A N/A

N/A

N/A

N/A

Beam enclosure

Class 4

N/A

N/A

Eye protection

N/A

N/A

N/A

N/A

N/A

Protective clothing Training

N/A

N/A

N/A

N/A

N/A

N/A

N/A

Class 3B

N/A

Laser labels Door signs/Area signs

N/A

N/A

N/A

N/A

N/A

N/A

Eye Examinations

N/A

N/A

N/A

N/A

N/A

N/A

Class 1(E) refers to a Class 1 totally enclosed system 31

Administrative controls

Recommendations

1

Remote interlock -

connection provided by the manufacturer for door or enclosure interlock for Class 3B and Class 4 lasers

2

Safety interlocks -

required for access panels on Class3R, 3B and 4 laser systems

3

Key control

a key or similar device is required to control unauthorised operation of Class 3B and Class 4 lasers

4

Emission indicator -

an audible or visible indicator should be provided by the manufacturer for each Class 3R laser ( except wavelengths 400700nm) and each Class 3B and Class 4 laser system

5

Beam stop or attenuator/shutter -

should be provided by the manufacturer for each Class 3B or Class 4 laser system

6

Beam termination -

the user should ensure that all beam paths are terminated at the end of their useful path. (Does not apply to Class 1 devices)

7

Beam level -

avoid eye level

8

Beam enclosure -

to guard against specular reflections from Class 3R, Class 3B and Class 4 lasers - can mean anything from screening the experimental area or piping the beam up to a total enclosure.

9

Eye protection -

required for open beam work with invisible beam Class 3R and all Class 3B and Class 4 devices.

10 Protective clothing

mainly required for Class 4 lasers but be careful with Class 3B UV lasers as well, may need fire resistant material for some lasers

11 Eye examinations -

only required after an accident but may be important to people with poor eyesight working with Class 3B or Class 4 lasers

12 Training -

required for people working with any Class 3 or Class 4 laser and any modified Class 1M or Class 2M devices.

13 Laser labels -

required for all lasers except low power Class 1 ( though need not be directly affixed if the size of the laser product does not permit this)

14 Door/Area signs -

required for Class 3B and Class 4 lasers indoors and also for Class 1M, 2M and 3R if used outdoors

32

LASER INVENTORY

Manufacturer and Model

Type

Location Wavelength Power Output (for CW) or Pulse Power, duration and repetition rate

Laser Class

Note: Do not include office based Class 1 laser products or equipment containing them i.e. Compact Disc/DVD players, laser printers etc. School/Department:

Laser Supervisor/Officer:

Date: 33

REGISTRATION FORM FOR LASER USERS

Surname: Forename(s): Title (Mr, Ms, Dr etc)

Status (Lecturer, Student, Technician, Research student etc)

email:

Supervisor:

Department: Lasers to be used:

Laboratory to be used:

34

USE OF CLASS 1M, 2M,2 AND 3R LASERS – HAZARD & RISK ASSESSMENT Class 1M, 2M and class 2 devices do not create an eye hazard as long as a person does not stare into the beam as eye protection is normally afforded by the aversion response. Exposure hazard to the eye is possible if: a) Exposure is in excess of 0.25 seconds from class 2/2M lasers b) Class 1M/2M lasers are modified. Modified devices may need to be reassessed to a higher classification c) A Class 3R laser is viewed directly There is no skin or fire hazard. FACULTY

SCHOOL/DEPARTMENT

LOCATION OF ACTIVITY

DESCRIPTION OF ACTIVITY

Brief description of Laser set up and purpose LASER SPECIFICATION

Complete the following table Type (e.g. He-Ne, NdYAG) Model Max Power Wavelength LASER CLASS

35

1) HAZARDS Non-optical and Optical (1M/2M) Hazard

Control measure

Detail the significant risks and control measures necessary for any nonoptical hazard identified and any optical hazard from 1M/2M devices

2) PERSONS AT RISK

Staff, students, visitors 3) RISK CONTROL METHODS

1. Avoid eye level and do not point beam at other persons 2. Follow the manufacturers safety instructions 3. Keep the laser on only when necessary 4. Terminate the beam at the end of its useful path 5. Do not point at highly reflective surfaces 6. Do not look directly into the laser aperture or stare into the beam 7. Do not use direct optical viewing aids 8. Restrict unauthorized use 4) CONTACT Report Accident/Incident to Health and Safety Office ext 3317 NAME AND TITLE OF ASSESSOR

SIGNATURE

DATE

REVIEW DATE

36

USE OF CLASS 3B & 4 LASERS – HAZARD & RISK SSESSMENT FACULTY

SCHOOL/DEPARTMENT

LOCATION OF ACTIVITY

DESCRIPTION OF ACTIVITY Brief description of laser set up and purpose

LASER SPECIFICATION Complete the following table including all lasers such as low power alignment lasers Laser 1

Laser 2

Laser 3

Laser 4

Type (e.g. He-Ne, NdYAG) Manufacturer Model Serial Number Maximum Power Maximum pulse energy Wavelength range Wavelength used Power used Pulse energy used Pulse length Pulse repetition rate Beam diameters (x,y) Beam shape (e.g. ellipse, circular) Beam divergence (x,y) LASER CLASS

37

1) HAZARDS Identification of non-beam hazards

Electrical hazards (Most lasers contain high voltage power supplies and often large capacitors that store lethal amounts of electrical energy) Are any special precautions/procedures required?

Yes

No

Laser Dyes (Laser dyes are often hazardous dissolved in flammable solvents) Are laser dyes used?

Yes

No

If yes, give details

Compressed and Toxic Gases (Hazardous gases may be used in laser applications (e.g. excimer lasers (fluorine, hydrogen chloride) Are compressed and/or toxic gases used?

Yes

No

If yes, give details

Cryogenic liquids (Cryogenic liquids may create a hazard. Adequate ventilation must be provided) Are cryogenic liquids used?

Yes

No

If yes, give details

Laser generated fumes, vapours and air contaminants (High energy laser beams may vapourise a target creating hazardous fumes or vapours that may need to be captured or exhausted) Are there likely to be laser generated fumes, vapours or air contaminants?

Yes

No

If yes, give details

UV and visible Radiation/plasma emissions (UV and visible radiation may be generated by laser discharge tubes , pump lamps or plasmas which may create an eye and skin hazard) Is there likely to be significant UV/visible radiation produced

Yes

No

If yes, give details

38

Explosion hazards (High pressure arc lamps, filament lamps, and capacitors may explode if they fail during operation. Laser targets and some optical components may shatter if heat is not dissipated quickly enough) Is there an explosion hazard?

Yes

No

If yes give details

Ionising Radiation (X-rays can be produced from high voltage vacuum tubes of laser power supplies such as rectifiers, thyratrons and electric discharge lasers. Any power supply that requires more than 15kV may produce x-rays) Is there an ionizing radiation hazard?

Yes

No

If yes give details

Other hazards not specified above (Please give details)

2) PERSONS AT RISK Authorized laser users Project supervisors Staff and students in the immediate vicinity

3) RISK CONTROL METHODS Reduction of Laser beam risk Are open or partially enclosed beams used

During initial setting up and beam alignment During the addition of new optical elements/lasers During maintenance

Yes

No

Are there protocols, procedures or systems of work to control risks from eye and skin hazards Yes No

Yes

No

Yes

No

Yes

No

Yes

No

List operating protocols/procedures/systems of work ALL OPEN BEAM WORK MUST HAVE AN APPROPRIATE PROTOCOL/OPERATINGPROCEDURE/SYSTEM OF WORK

39

Protective Eyewear Please give details of optical eyewear: Location

Optical Density

Wavelength

Number available

Reduction of risk of associated hazards (as identified in Secion 1) Detail the significant risks and the control measures necessary (i.e. by reference to protocols/procedures/systems of work) For hazardous substances specify the location of the appropriate COSHH assessments Training Authorised laser users must receive appropriate training and instruction. Specify the instruction and training arrangements. Instructions All users must read and sign System of Work. Audit Methods It is the responsibility of the individual laser operator to follow the guidelines on laser safety. Where control measures have failed or have been suspect then laser users should report these. Supervisors should monitor that users are complying with procedures. Departmental Laser Safety Officers and the University Laser Safety Officer will carry out periodic checks. Review arrangements If the laser system or work deviates from standard procedures described in the system of work. During University Laser Safety Officer visit.

4) CONTINGENCY ARRANGEMENTS Suspected Malfunction – See System of work Suspected Overexposure – See System of work Faculty fire evacuation procedures will apply and the EM Plan for the Faculty. NAME AND TITLE OF ASSESSOR

SIGNATURE

DATE

REVIEW DATE

40

SYSTEM OF WORK FOR LASERS System of work for the safe operation of Please enter type of a laser located in Dept:

, Room

, and building

Departmental Laser Safety Officer: University Laser Safety Officer: Date:

Description of Activity Description of activity/expermient and its purpose

Description of Laser Class:

Please enter class of laser

Model Serial Number Name and type of laser (e.g. Nd;YAG, He/Ne, etc. ) Wavelength Pulsed or continuous Length and energy of pulse Maximum power Beam delivery system Open or enclosed beam, Mirrors?, How is output terminated? e.g. photo-multiplier tube, beam dump, beam stop. Laser process High voltages, chemicals, gases involved 41

Calculations Maximum Permissible Exposure (MPE) and Nominal Ocular Hazard Distance calculations. Description of safety eyewear i.e. Optical density at appropriate wavelength. Authorised users Only persons who are adequately trained state howand authorised may work with the laser/carry out user maintenance Authorised users of the above laser(s) are: Student Other, please specify: Laser controlled area Describe extent of laser controlled area and conditions under which one exists. Access, interlocks, illuminated signs and how they operate.

Protection measures A Risk Assessment must be completed prior to carrying out the laser activity. Identify safety critical operations e.g. Setting up and alignment of the beam

Describe control measures which need to be carried out for each operation (for guidance and examples please refer to Appendix 1 of the this form) Maintenance Maintenance applies to adjustments and procedures specified in the information supplied by the manufacturer of the laser product which are carried out by the user to order to assure the intended performance of the product. This may require access within the laser enclosure which may lead to an increased risk to the laser worker to higher energy laser beams, high voltages and toxic chemicals. These 42

activities will vary depending on the laser product and specific protocols will need to be prepared for each laser. Servicing carried out by the manufacturer is outside the scope of this document.  Before commencing maintenance procedures the manual for the laser system should be consulted for recommended methods.  If the laser manual does not give a method or in the case of nonroutine maintenance, the advice of an experienced laser technician should be sought. Some procedures should only be carried out by an experienced laser technician.  A written risk assessment of the procedure should be carried out. In the case some routine procedure e.g. changing the dye in a dye laser reference to an existing protocol may be sufficient.  Maintenance procedures involving beam alignment inside an enclosure can lead to an increased risk of exposure to high power laser beams which are normally enclosed. The protocol in the previous section for setting up and alignment should be consulted. Contingency plan In the event of an accident Report accident to Health and Safety Ext 3317 office during normal office hours. All accidents and incidents must be reported to the Health & Safety office using the current Accident Report Form In the case of accidents involving exposure to Class 3B and Class 4 lasers the casualty should be taken to: Accident & Emergency Royal Eye Hospital Nelson Street, M13. Tel: 0161-276 1234 (NB the above applies to the All Saints site. In the case of other sites please fill in appropriate information)

The form ‘The Emergency Procedure for Exposure to Class 3B or 4’ Laser should be filled in and taken with the casualty. In the case of serious injury dial 999 for an ambulance. Laser Safety Officer Date 43

Declaration Declaration that authorised users sign to say that they have understood and agree to work to the local rules.

Name (in block capitals)

Signature

Date

44

Appendix 1 Setting up and alignment of the beam In grey text are the principal risk control measures which should be taken into account, exact detail will vary between different laser systems.

 Discuss installation/changes with a supervisor prior to operation of Class 3B/4 laser systems  When new work is being carried out the Departmental Laser Safety Officer and/or University Laser Safety Adviser must be consulted and invited to visit the lab.  Laser beam paths and optics should be arranged so as to minimise stray reflections  Laser beam paths should be arranged so that the eyes are well above the level of laser beams  Termination of the beam should be planned e.g. using beam stops or beam dumps where necessary.  Suitable laser safety eyewear should be provided.  Keys and key switches – where and how to get them  Before starting work beam paths should be inspected for items that should not be there.  Laser warning signs should be on, barriers and beam covers in place, unauthorised persons excluded and doors closed.  Class 3B and Class 4 lasers require the control of access to the area where the laser is operated by the use of remote interlock.  Reflective jewellery and wristwatches should be removed.  Turning water on/off  High voltages on/off  Appropriate safety eyewear should be worn if practicable. If this is not possible e.g. when the beam cannot be seen on a card when eyewear is worn, then extra caution needs to be taken.  Initial laser beam alignment should be carried out with a Class 2 or Class 1 laser e.g. He-Ne or small CW diode laser.  Flight tubes should be used to enclose long runs of laser beam; these should be designed to allow limited access to the beam for alignment checking without having to remove them.  Secondary alignment may be carried out using a Class 3B/4 laser beam at low power. This should be done using the lowest possible laser energy. Visualisation is dependent on the wavelength e.g. UV or visible beams can be viewed on fluorescent card infrared beams may be viewed on LCD heat sensitive paper or possibly burn paper or a laser power meter. 45

 In the case of UV or IR beams appropriate eyewear should be worn during alignment at all times when the laser energy exceeds the MPE.  In the case of visible or multi-wavelength beams, alignment may have to be carried out without laser safety eyewear in order to visualize the beam on a card. If possible the laser should be operated below the MPE and in any case at the lowest practicable pulse energy. The blocking of stray reflections should be double checked before alignment. Alignment of each laser beam to variable diameter apertures (iris diaphragms) should be employed where possible to minimise the necessity for multi-wavelength alignment.  Under no circumstances must direct viewing of the laser beam be attempted even if the beam has been attenuated.  Remote viewing using a video camera should be considered.  All optics should be checked for damage, and the stability of the optical mounts checked prior to operating the laser.  Minor re-alignment may sometimes be necessary during the experimental activity when the beam is at full power. In this event extra caution should be exercised. If possible minor alignment should be carried out using the experimental signal as a guide so that visualizing the beam is not necessary.  Attention should also be given to any other hazards such as chemicals, gases, hot surfaces, electricity, cryogenic liquids and flying debris from targets. Adding new elements  Initial laser beam alignment should be carried out with a Class 2 or Class 1 laser e.g. He-Ne or small CW diode laser.  All optical elements in the beam path must be analysed for stray reflections. This can be done by predicting the likely path of specular (non-diffuse) reflections and from the actual reflections from the Class 1/2 alignment laser. Suitable beam blocks which are opaque to the appropriate wavelengths should then be installed where necessary to block stray reflections.  All optics should be checked for damage, and the stability of the optical mounts checked prior to operating the laser.

46

EMERGENCY PROCEDURE FOR EXPOSURE TO CLASS 3B OR 4 LASER REPORT TO: Accident & Emergency, Royal Eye Hospital, Nelson Street, M13

Tel: 0161-276 1234 IF OTHER A&E please specify: Enter address details As soon as possible and within 24 hours of the incident. Do not drive yourself, get a friend or colleague to take you. Out of hours: Contact local Security or Emergency Services i. State Building and Department ii. Location and nature of incident/accident iii. Request ambulance to take the casualty to the Royal Eye Hospital (as above) iv. Take the information below to the Hospital EMERGENCY OPHTHALMIC EXAMINATION LASER EXPOSURE LASER DETAILS: Type: e.g. NdYAG, He-Ne Continuous Wave / Pulsed Wavelength (nm): Power Output (CW): or Pulse Energy, Duration, and Rate (pulsed): Laser Classification: EXPOSURE DETAILS: Circumstances of accident/injury:

Time of Injury Eye affected: Was protective eyewear being worn?

Date of injury Left/Right/Both Yes No

REPORT ACCIDENT/INCIDENT TO: Health and Safety Office Ext 3317 during normal hours. Fill in Accident Report Form. All accidents and incidents, whether involving an emergency examination or not, must be reported promptly to the Health and Safety Office using the current Accident/Incident Report Form. The Laser Safety Adviser and School/Departmental Laser Supervisor/Officer must also carry out a detailed investigation of the accident/incident. Any serious injury or 3 days absence from work has to be reported to the Health and Safety Executive under 'The Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995’

47

TRAINING RECORD FORM

Researcher Room number Lasers used

Registered as University laser user Familiar with hazards and risk assessments within the laboratory Familiar with laser System of Work Trained in use of lasers named above Attended Laser Safety Training Session Read University Laser Safety Guidance Notes

Signed …………………………………………………………….

Researcher

Date

Supervisor

Date

48