Local Rules for the Use of Lasers

NOVEMBER 1997 (Updated October 2011)

Status and Responsibilities:

These Local Rules form part of the University's  Health, Safety and Wellbeing (HSW) Policy, being the arrangements for controlling health and safety risks arising from the use of lasers and compliance with the Control of Artificial Optical Radiation at Work Regulations 2010. IN accordance with the health, Safety and Wellbeing Policy, all employees are therefore required to comply with the these Local Rules.

The general responsibilities given in the HSW Policy apply to the management of health and safety risks  to staff, students and the public arising from the use of lasers.  The HSW Policy should be consulted for full responsibilities. A brief summery is given below:

Heads of Department have overall responsibility for ensuring their Department complies with the University’s requirements relating to the control of health and safety risks arising from work with lasers. 

Academic supervisors are responsible for the safety of staff and students whilst they are under their supervision, which includes ensuring that they understand the health and safety risks associated with academic activities and follow health and safety instructions.

 In relation to work with lasers, Academic Supervisors are responsible for ensuring that the University’s Local rules for use of lasers and departmental rules are implemented in their area of responsibility.

Principal Investigators: are responsible for the health and safety management of their research projects and must ensure laser risks are assessed during the planning of the project and kept under review throughout.

Departmental Non-Ionising Radiation Protection Advisers (DNIRPAs): provide advice on the purchase and safe management of lasers and monitor compliance with the local rules in their Department.

Contents

Emergency Procedure
Contact Names and Telephones Numbers
Preface
Introduction
Classification of Lasers
Registration of Lasers
Use of Class 2 and Class 3A Lasers
Use of Class 3B and Class 4 Lasers
Lasers Out of Doors
Use of Lasers Off University Premises
Laser Displays
Electrical Hazards
Chemical Hazards of Lasers
Radiation Hazards of Lasers
Training
Summary
Addendum to Local rules, Optical fibre comms. Systems
Addendum to Local rules, Laser Pointers (Revised Feb 02)

Emergency Procedure

Accidents involving lasers and/or laser operators should be reported as soon as possible to the Departmental Non-Ionising Radiation Protection Adviser (DNIRPA) and the University Non-Ionising Radiation Protection Adviser (UNIRPA). Equipment should be made safe - but otherwise nothing should be moved until the University Non-Ionising Radiation Protection Adviser (UNIRPA) or in her absence, the Head of Health and Safety has inspected the scene of the accident.

Injured persons whose eyes may have been exposed to a laser beam should be taken to the General Hospital Casualty Department. The Casualty Officer should be informed that the casualty may have been exposed to a laser beam

Contact Names and Telephone Numbers:

Names and contact telephone numbers of the Departmental Non-Ionising Radiation Protection Advisors and the University Non-Ionising Radiation Protection Advisor and the Head of Health and Safety are available by following the contact us link at www.essex.ac.uk/OHSAS . Emergency contact numbers are held by the Patrol Officers who are authorised to contact them in an emergency outside normal hours.

Preface

The use of lasers for teaching and research purposes is subject to controls imposed by the UNIRPA acting on behalf of the Council of the University.

Every laser and every potential laser user must be registered with the Departmental Non-Ionising Radiation Protection Adviser (DNIRPA).

Lasers used in undergraduate teaching and in lecture demonstrations should be restricted to CLASSES 1, 1M, 2, 2M and visible CLASS 3R or preferably totally enclosed systems where practicable. Undergraduates should be allowed to use CLASS 3B and 4 lasers only with the approval of the UNIRPA and the DNIRPA.

The following Local Rules are intended to be an introduction to Laser Safety. All users and those who supervise the use of lasers must be familiar with the Association of University Radiation Protection Officers Guidance Note No. 7: GUIDANCE ON THE SAFE USE OF LASERS IN EDUCATION AND RESEARCH (2006 Edition).

Academic Supervisors must be familiar with BS EN 60825-1 2007

Lasers should not be used before they are registered.

Lasers should not be used out of doors without prior permission from the University Non-Ionising Radiation Protection Adviser.

Laser displays for entertainment purposes must be approved by the UNIRPA and the University's Fire Safety Officer.

Introduction

Lasers present two specific hazards.

Firstly they are sources of intense light/heat radiation which can be focused to a small spot which has the potential to damage eyes, skin, etc. and to be a possible fire hazard.

Secondly, many lasers require power supplies which generate very high voltages (5-100KV). Such power supplies are potentially lethal.

Other hazards which may be presented by laser systems include:

(a) X-rays, particularly from high voltage thyratrons used with pulse lasers;

(b) toxic chemicals used in lasers or produced in lasers by chemical reaction;

(c) explosion of capacitors etc. or of the gases used to fill some lasers;

(d) ultra-violet radiation from flash lamps used with some lasers

Classification of Lasers

Lasers are classified into the four classes as shown below. However, any laser used in a Totally Enclosed System is considered to be completely safe. It is unusual for lasers in the University environment to satisfy the requirements of total enclosure.

Every laser must be labelled according to BS EN 60825-1 (Amendment 1 and 2 June 1997) Section 5 Labelling. If you re unsure about labelling requirements please, refer to the AURPO Guidance on the Safe Use of Lasers in Education and Research or seek advice from the UNIRPA.

Class 1: Considered safe

Lasers which are safe under reasonably foreseeable conditions of operation. Class 1 products may contain a higher class of laser  system but access to the beam is controlled by engineering means. Example:  Compact disc player.

Class 2: Low power

These are low power devices emitting VISIBLE radiation (400nm-700nm). Protection of the eyes is afforded by natural aversion response of the eye (blink reflex). Hazards can be controlled by relatively simple procedures. Example: Laser pointers.

Classes 1M and 2M : Safe without viewing aids

The lasers may have a higher powered beam, but is it widely divergent (spreads out quickly with distance) or of a large diameter. The beams are not safe if viewed with magnifying optics such as lenses. Example: LED torch

Class 3R: Low/medium power

Risk of injury is greater than for lower classes but not as high as for class 3B. Example: Laser surveying equipment

Class 3B: Medium/high power

Maximum 5mW power. Hazards arise from direct beam viewing. 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. Safe to the skin. 

Class 4: High power

Require extreme caution. Direct beam or reflected beam viewing is always hazardous, an likely to result in injury. Capable of producing hazardous diffuse reflections. Eye, skin and fire hazard.

It must be stressed that the Class 4 category covers a very wide power and energy range. For example, Class 4 CO2 lasers have a minimum power of 0.5W C.W. but devices which emit more than 100KW C.W. exist. Clearly the latter require more precautions than the former although both are in the same classification.

The classification of pulsed lasers may require quite complex calculations to be undertaken (see BS EN 60825-12) and users must consult their Departmental Non-Ionising Radiation Protection Adviser if there is any doubt about their classification.

Registration of Lasers and Laser Users

Each DNIRPA should maintain a register of lasers and laser users in the Department. Members of staff must inform the DNIRPA of all lasers in their possession and advise when new lasers are ordered or designed. NB: It is not necessary to record inherently safe Class 1 or Class 2 devices or embedded laser products such as those in laser printers or CD players. It is also not necessary to record users of such products unless they could or are going to modify Class 1M or 2M devices.

The DNIRPA will arrange for the department records to be made available to the UNIRPA who will maintain a central record.

Use of Class 2 and Class 3A Lasers

These lasers may be used in research and graduate student areas provided that precautions are taken to ensure that the laser beam cannot be viewed directly. These precautions include the use of beam stops and the mounting of lasers such that the beam is NOT at eye level. Lasers should always be switched off before they are moved or rotated. Even Class 2 lasers can cause eye damage if they are misused.

In undergraduate areas, lasers should be locked away or rendered inoperative by a key switch when they are not in use. The use of any laser by undergraduates must be sanctioned by the DNIRPA and a written Approved Scheme of Work must be drawn up and approved by the UNIRPA. This scheme must be displayed so that it can be clearly seen by persons carrying out the experiment. (See CVCP Booklet page 27).

Use of Class 3B and Class 4 Lasers

These lasers must only be used in Laser Controlled Areas where access is limited to authorised personnel. Staff responsible for Class 3B and 4 lasers must discuss the use of these lasers with the DNIRPA and ensure that the systems comply with such safety requirements as are specified before the equipment is used. Such systems are preferably totally enclosed: otherwise warning lights, door switches, safety screens and eye protection to conform with the requirements of BS EN 60825-1:2007.  Protective eyewear should conform to 207:2009 (general use) or BS EN 208:2009 (for use when aligning visible laser beams) and be of the appropriate scale number to provide adequate protection.

Any undergraduate who is to work in a Laser Controlled Area must have the specific authorisation of the UNIRPA. The DNIRPA and the member of staff responsible must together produce an Approved Scheme of Work which must be submitted to the UNIRPA for approval. A copy of the Scheme of Work must be displayed in the Laser Controlled Area.

Lasers Out of Doors

The use of open laser beams outdoors can present significant risks as:

• Members of the public can be harmed by laser beams that may travel long distances or be reflected off of surfaces

• Those exposed to the beam may have impaired blink reflexes (e.g. though the effect of alcohol or medication) or may deliberately stare at the beam

• The intense beam of light created by lasers can dazzle. If they affect pilots, drivers or others undertaking hazardous activities this can result in a serious accident.

Laser surveying equipment can be used outdoors provided it has been purchased from an reputable UK supplier and is used in accordance with suppliers instructions.

The use of any other open beam lasers outdoors will need to be subject to a thorough safety assessment, Care will need to be taken to avoid reflection hazards from objects such as lamp posts, scaffolding, glazed areas, stretches of water, wet surfaces.

Details of any proposed outdoor experiments  involving open beams or  displays must be given to the DNIRPA. The HSE Guidance: The Radiation Safety of Lasers for Display Purposes must be followed.

If the beam intrudes into "air space", the Civil Aviation Authority will also need to be consulted. For details see:

Operation of Directed Light, Fireworks, Toy Balloons and Sky Lanterns within UK Airspace

Use of Lasers off University Premises

Lasers (other than Class 1 and 2 devices) must not be used away from the University without the formal permission of the Head of Department. Users must also inform the Departmental Non-Ionising Radiation Protection Adviser and University Non-Ionising Radiation Protection Adviser and act on any advice that they might give.

Laser Displays

Laser displays for entertainment purposes must be approved by the UNIRPA and Fire Safety Officer. Approval will only be given if the display conforms with the Health and Safety Executives Guidance "Radiation Safety of Lasers used for Display Purposes" HS(G)95.

If the laser display is to be presented to members of the public permission may also be required from Colchester Borough Councils Public Entertainment Licensing Officer. The UNIRPA must be consulted before any such booking is made.

Electrical Hazards

It cannot be emphasised too strongly that in many lasers the electrical hazard is much greater than that from laser radiation.

A Class 2 He/Ne laser typically has a power supply capable of delivering 5mA at 2.5kV. It is most important that laser power supplies have safety features which render them inoperative and safe when covers are removed. Capacitors which operate at high voltage must be protected with automatic discharge circuits.

All high voltage terminals and leads must be adequately insulated or enclosed to prevent accidental contact. Properly designed transparent covers give good protection and good visibility. Polycarbonate is recommended.

The provisions of the Electricity at Work Regulations 1989 must be observed.

Chemical Hazards of Lasers

Some laser fuels are toxic chemicals (e.g. cadmium). Others present explosion hazard (e.g. methane). Others are corrosive (e.g. hydrogen bromide). Some fuels undergo chemical reaction to produce toxic compounds such as hydrogen cyanide. Carbon monoxide is produced in carbon dioxide lasers.

High voltage capacitors can explode causing damage and possible chemicals hazard.

Users of the more exotic types of lasers especially, must consider the inherent chemical hazard of the laser they are using and take appropriate precautions. It there is any doubt consult the DNIRPA.

The provisions of the Control of Substances Hazardous to Health (COSHH) must be observed.

Radiation Hazards

Lasers operating at high voltage are potential sources of X-rays. High voltage thyratrons are a specific hazard and the DNIRPA will maintain a register of all such devices and consult with the University Ionising Radiation Protection Officer (UIRPO) to ensure that they are operating safely.

Flash tubes are very likely to be sources of ultra-violet radiation and users should protect these lamps with suitable shielding.

Training

DNIRPAs should ensure that all new laser users are given sufficient training and instruction so as to ensure they understand all aspects of safety associated with the use of lasers.

All training should be recorded.

Summary

Lasers can be very hazardous instruments, but will be low risk provided that sensible precautions are taken such as:-

(a) enclosure

(b) shielding

(c) use of beam stops

(d) measures to determine and control reflections

(e) keeping the beam path free of reflective materials

(f) keeping the whole work area tidy.

It is much easier and nearly always cheaper, to include these precautions at the design stage of the laser installation and its associated working environment.

Expert advice is available - please take it and act on it.

Addendum to Local Rules:

Safety of Optical Fibre Communication Systems

Where an optical fibre communications system is being installed as part of the University’s infra structure the system it should be installed to BS EN 60825-2 Safety of laser products, Part 2 Safety of Optical Fibre Communication Systems.

Where such a system is used for research the system should comply with the above. If this is not practicable the system should conform to the Local Rules.

Laser Pointers (Revised 21/02/2001)

Laser pointers used by members of staff and post graduates will no longer be required to be registered with the UNIRPA provided the following conditions apply;

 The laser pointers are purchased from a reputable manufacturer or supplier, i.e. they are not home built,

 The laser pointers have not been modified in any way,

The laser pointers are only used for presentation purposes,

The laser classification does not exceed Class 2.

You should note that if laser pointers are used with malicious intent or in such a way as to potentially cause harm, action will be taken by the University.

Use of Laser pointers

Laser pointers purchased from reputable UK suppliers will normally be classified as CLASS 2 will not normally have the potential to cause harm.  However  the rules below are “Good Practice” and should be applied irrespective of the laser pointer’s Class.

Under no circumstances should the pointer be directed towards the audience.

Unless dictated by the nature of the presentation the room should not be entirely blacked out.

A visual check of the room must be carried out before the presentation to ensure there are no reflective surfaces which might divert the beam back into the audience or towards the presenter.

Always switch the pointer off and put it down when you are not using it.

In the event that the presenter or a member of the audience suffers an exposure to the eye from the laser beam they must be taken to the Accident and Emergency Unit at Colchester General Hospital and the Casualty Officer informed that exposure to a laser beam has occurred. The HSAS should be notified and a Health and Safety Incident Form completed.

 

This page was last updated Monday September 17, 2012