Guidance on the Safe Use of Lasers
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GUIDANCE ON THE SAFE USE OF LASERS 0 CHRISTOPHER SMITH Disclaimer To the best of our knowledge the information in this publication is accurate; however the author does not assume any responsibility or liability for the accuracy or completeness of, or consequences arising from, such information. This guide is intended for informational purposes only. Mention of trade names or commercial products does not constitute endorsement or recommendation for their use by the author. Final determination of the suitability of any information or product for any use, and the manner of that use, is the sole responsibility of the user. Anyone intending to carry out actions based upon any recommendation of materials or procedures mentioned in this manual should be carried out in direct consultation with the College Laser Safety Officer. This cover image or file is in the public domain. This version of the manual was completed in March 2015. For any Laser accident that involves the eyes seek immediate medical attention EMERGENCY INFORMATION College emergency number 1999 You may well be in shock seek help from a colleague then go together to the Hospital Immediately. Accident & Emergency Royal Victoria Eye and Ear Hospital Adelaide Road Dublin 2 Telephone 01 6644600 Do not use the laboratory or disturb the equipment until after the accident has been investigated Report all accidents to the: Laser Safety Officer and School/Department General Safety Officer More details on emergency procedure are given in ANNEX 10 on page 92 at the end of this guide. 1 Preface Conducting research using lasers can be a very exciting and rewarding endeavour but it can also be the cause of a life changing accident if not conducted correctly and safely. This guide is part of the Laser Safety program in Trinity College and is intended to provide a framework for good practice regarding Laser systems and users. It should aid in the identification of the hazards associated with lasers and assist in the assessment of risk and in the implementing of control measures in both teaching and research laboratories. Many of the technical aspects in this guide are explained at a level to accommodate people without a background in lasers or optical physics. Much of the content of this manual is based on publications which will be referenced where necessary. If you wish to access these documents active hyperlinks will take you to them where possible. This document is for preliminary guidance only and does not imply that the laser system or the laser user is fully compliant with the registration process within Trinity College. Only through full consultation with the College Laser Safety Officer can the registration process be completed. Intending laser users must attend the Laser Safety Workshop to become fully registered to carry out work with or within the vicinity of laser systems. Important changes to regulations in Ireland will be detailed and discussed, especially those changes controlling Laser classification and safety eyewear. Laser users and their supervisors should be aware of the following changes [1]. Important Changes New laser classes ‐ 1M, 1C, 2M and 3R Table 1-1 Changes to the testing of safety eyewear and labelling system Table 1-2 New measurement conditions for classification, which are of particular benefit to high divergence laser sources Overhaul of MPE levels especially values for ultra‐short pulses and shorter‐wavelength visible radiation under long exposure conditions (retinal photochemical damage) Improved treatment of extended source viewing New wording of laser warning signs The European Union decision to severely restrict or ban European consumer access to Class 3R, 3B and 4 lasers. CLASS Meaning Old New Reason for Change 1M ‐ diverging / low power density devices that could be hazardous if beam 1 is focussed. 1C used with a specific target Class 1 Normally Safe 1 1M only with no leakage, these laser products 1C would include medical and cosmetic laser systems. Eye protected by 2 2M ‐ diverging/low power density devices Class 2 aversion response 2 2M that could be hazardous if beam focussed (visible only) Low eye hazard, power density restriction 3A & 3B* 3R Class 3 Eye hazard removed 3B** 3B No significant change Class 4 Eye and skin hazard 4 4 No significant change Table 1-1 Laser Class changes [1] 2 EN207 Beam Diameter D63* Exposure time Labelling 1998 2mm 10s or 100 pulses L 2010 1mm 5s or 50 pulses LB Table 1-2 Changes to Laser safety eyewear testing and labelling. *D63 diameter is when 63.2% of the total power is contained in a variable aperture. Regulations have been introduced by the government under the Safety, Health and Welfare at Work act of 2007, amended in 2010 to include the Control of Artificial Optical Radiation at Work Regulations 2010 (S.I. No. 176 of 2010) . The Regulations set out requirements relating to the control of the exposure of employees to artificial optical radiation at work, including exposure limit values, determination of exposure and assessment of risks, provisions aimed at avoiding or reducing exposure, employee information and training and health surveillance. It is my intention to review and update this document on a regular basis and to publish it on the Trinity College Laser Safety website This guide is for Trinity College personnel only and is not to be reproduced or used outside of the college. Finally I would like to acknowledge Ken Barat who kindly granted permission to use images from his book Laser Safety Management [2] . Also I would like to extend my gratitude to Dr Vincent Weldon for his continuing help. Contact Information Christopher Smith Patrick Flanagan College Laser Safety Officer Interlock specialist School of Physics School of Physics Trinity College Dublin Trinity College Dublin Telephone: ++ 353 1 896 3649 Telephone: ++ 353 1 896 2714 Email: [email protected] Email: [email protected] 3 TABLE OF CONTENTS Disclaimer ............................................................................................................................... 1 Preface .................................................................................................................................... 2 Important Changes ................................................................................................................. 2 Contact Information ............................................................................................................... 3 List of Tables ........................................................................................................................... 7 List of Figures.......................................................................................................................... 8 1 Introduction .................................................................................................................... 9 1.1 Directives and Regulations .......................................................................................... 9 1.2 How to use this guide ................................................................................................ 10 2 Laser Safety Policy & Administrative Arrangement ...................................................... 10 2.1 College Laser Safety Officer ...................................................................................... 10 2.2 Departmental / School Laser Safety Officers ............................................................ 11 2.3 Responsibilities of the Laboratory supervisor........................................................... 11 2.4 Responsibilities of the Laser Users ............................................................................ 11 2.5 College Policy on Lone Working ................................................................................ 12 3 Properties of Laser Radiation ........................................................................................ 12 3.1 Collimation ................................................................................................................ 12 3.2 Coherent .................................................................................................................... 13 3.3 Monochromatic ......................................................................................................... 13 3.4 High Power and Energy density ................................................................................ 13 3.5 Emission Type ............................................................................................................ 13 3.6 Irradiance Comparison .............................................................................................. 14 4 Laser Radiation Hazards ................................................................................................ 15 4.1 Beam Hazards ............................................................................................................ 15 4.1.1 Thermal Effects ...................................................................................................... 15 4.1.2 Acoustical Effects ................................................................................................... 15 4.1.3 Photochemical Effects ........................................................................................... 16 4.2 Non-Beam Hazards .................................................................................................... 16 4.2.1 Electrical ...............................................................................................................