Laser Safety Practical Application Seminar

Transcription

1 Laser Safety Practical Application Seminar Designing Your Enclosure to Meet Class 1 Requirements Thomas Lieb Course Instructor March 24, :00pm Room: Pavilion C

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3 Practical Applications Seminar 6: Designing Your Enclosure to Meet Class 1 Requirements Tuesday, March 24 2:00pm, Room: Pavilion C Session Chair: Thomas Lieb, L*A*I International, Elk Grove, CA, USA Session Overview: In today s laser community, especially in high powered laser processing, there is a growing trend for users and third party machine integrators to provide safety enclosures. This is even more prevalent with the rise in popularity of fiber lasers, which are sold almost exclusively as components, thereby necessitating further system assembly by the purchaser. While laser standards exist, they are not always known or applied correctly. There are few resources available to guide the integrator on materials or design criteria to meet the performance requirements detailed in the standards. The purpose of this session is to give a practical outline for creating a Class I product protective housing (enclosure or safety containment system) for lasers in various powers and applications. Discussion includes robots and 5-axis concerns, material selection, and design parameters, with information for designers and source documents world-wide. The session is lecture and interactive workshop discussion. Session Chair Biography: Thomas Lieb holds B.S./B.A. from the University of Redlands, with graduate studies in optical physics and mathematics. While at major laser companies, he held several executive positions including; General Manager of a Business Unit; Manager - International Marketing; Manager of Quality and Reliability; and Regulatory Affairs Officer (at a medical-surgical laser company). Mr. Lieb is a BLS Certified Laser Safety Officer and provides both U.S. and EC laser safety guidance worldwide. Mr. Lieb is a senior member of SME, a member of LIA, Chairman of ASC Z136 standards subcommittee 9; delegate to AWS C7C; ANSI ASC Z136; ANSI B11.21; ISO TC 172/SC 9; and IEC TC 76. He is currently Convener of IEC/TC 76 WG 10, Convener ISO/TC 172/SC 9 WG 3; Secretary IEC/TC 76 WG 7, Secretary to ISO/TC 172/SC 9 WG 5; U.S. Delegation Leader (Select) to ISO/TC 172/SC 9 and the Technical Committee Liaison for IEC/TC 76. Mr. Lieb has authored a variety of articles on industrial lasers, and lasers for use in the EC, including trade publications Photonics Spectra and The Fabricator, as well as publication in the proceedings of the International Congress on Applications of Lasers & Electro-Optics (ICALEO ) and the International Laser Safety Conferences (ILSC ). He has contributed to the text book Laser Materials Processing, Migliore, et al, Mr. Lieb is a 2008 recipient of the International Electrotechnical Commission s 1906 Award for significant contribution to furthering the interest of electrotechnology and the work of the IEC.

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5 Reno, Nevada March 23-26, 2009 Practical Applications Seminar 6: Designing Your Enclosure to Meet Class 1 Requirements Tuesday, March 24 2:00pm, Room: Pavilion C

6 International Laser Safety Conference Laws & Standards Special Types Automation & Walk-in Shields & Seals Fiber laser concerns Interlocks & Sensors Issues, Discussion, Q&A

7 International Laser Safety Conference Laws & Standards Manufacturers FAA FDA 21 CFR ACGIH ANSI B11.21 Z136.7 Eyewear Draft ANSI RIA/R15.06 IEC/EN IEC/EN TR SAE-G10 Laser Z136.1 Main NFPA Z136.2 Fiber ANSI Z136.6 Outdoors Z136.5 Schools OSHA Pub Ch. 17 National Electric Code 115 Fire Z136.8 Lab Z136.3 Medical Z136.4 Measure Draft USERS Z136.9 Mfg. Z Demo STATES CRCPD Model State

8 Laws & Standards 21 CFR CDRH / FDA FDA Laser Policy Notices 54 since 1976 are incorporated as interpretations of the FLPPS. They have the de facto force of law, in this context IEC (EN) International

9 Laws & Standards Are You a Laser Product Manufacturer? Any electronic product that incorporates or is intended to incorporate a laser is a laser product Some exemptions can be claimed for truly own use

10 Laws & Standards Basic cornerstone of all standards, for both user and laser products,, is the concept of classification of hazards. Classifying hazards is a convenience adopted for universal understanding of degree of harmful potential of a given transmitted laser energy Class IV (4) is most hazardous; Class I no hazard

11 Laws & Standards Protective Housing Each laser product shall have a protective housing. Protective Housing must be Class I except where access to radiation is necessary for the function of the product

12 Laws & Standards Considering Class I Protective housings. For Class IIIb and IV "Human Access", Is two Part No part of Human body (in IEC 12 X 80 mm probe) No reflection from (hypothetical mirror) thru any hole

13 Laws & Standards....in the protective housing of the product. Class 3B or 4 Protective Housing Single Surface Reflector Laser Source Gaps in....in the protective housing of the product. housing must be closed Radiation needed for Product Function, here.

14 Special Types Automation 1) In automation applications (material processing), the RIC (Remote Interlock Connector) may not be feasible for housing interlock. 2) Non-moving parts most desireable for entrance exit strategies.

15 International Laser Safety Conference Special Types Walk-in Workstations (Laser Policy Notice #37) IEC Requirement (and the ANSI, therefore OSHA Requirement): a) enclosure is safety interlocked and labeled as required by the FLPPS. b) a means provided as part of the overall safety interlock scheme to detect the presence of persons within the enclosure, And c) means to prevent operation of the laser when a person is inside the enclosure, AND The user information clearly instructs operators to avoid procedures that could give access to hazardous levels of laser radiation.

16 Shields & Seals Guarding material can be selected from a wide variety Criteria is prevention of transmission of hazardous radiation (above Class I) Select by performing hazard analysis of expected radiation.

17 Shields & Seals

18 Shields & Seals Hermetic Seals are often not preferable Exhaust systems require intake air Labyrinth seals can be constructed, since light does not bend

19 Shields & Seals Use IEC Guards FEL vs. PEL

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22 Fiber Laser Concerns component, not a fully certified laser or system product. Component products are not required to have all the features of certified laser products many fiber lasers do not have a safety beam attenuator built in, for instance. Hence, a physical safety shutter must be added by the system integrator, or end-user, before the final system

23 Fiber Laser Concerns High beam quality, long focal length Fiber Breakage interlock

24 Interlocks and Sensors Each laser product, regardless of its class, shall be provided with at least one safety interlock for each portion of the protective housing which is designed to be removed or displaced during operation or maintenance, if removal or displacement of the protective housing could permit, in the absence of such interlock(s), human access to laser or collateral radiation in excess of the accessible emission limit

25 Interlocks and Sensors Each required safety interlock, unless defeated, shall prevent such human access to laser and collateral radiation upon removal or displacement of such portion of the protective housing

26 Interlocks and Sensors Either multiple safety interlocks or a means to preclude removal or displacement of the interlocked portion of the protective housing shall be provided, if failure of a single interlock would allow;(a) Human access to a level of laser radiation in excess of the accessible emission limits of Class IIIa; or(b) Laser radiation in excess of the accessible emission limits of Class II to be emitted directly through the opening created by removal or displacement of the interlocked portion of the protective housing

27 Interlocks and Sensors Laser products that incorporate safety interlocks designed to allow safety interlock defeat shall incorporate a means of visual or aural indication of interlock defeat. During interlock defeat, such indication shall be visible or audible whenever the laser product is energized, with and without the associated portion of the protective housing removed or displaced.(v) Replacement of a removed or displaced portion of the protective housing shall not be possible while required safety interlocks are defeated

28 Interlocks and Sensors Interlocks shall either: a. Prevent human access upon removal or displacement of the protective housing, or b. Prevent removal or displacement of the protective housing if exposure should occur.

29 Operation Protective Housing Open During Maintenance Always Access Required? (To Internal Laser Radiation Never Sometimes Service No SI NIPHL Req. Always Access Required? (To Internal Laser Radiation Never Sometimes No SI Product Class NIPHL Req. No SI SI w/ defeat Product Class DIPHL Req. No SI NIPHL Req. No SI SI w/ defeat Product Class DIPHL Req.

30 Interlocks and Sensors Walk in workstations Laser scanners are sweeping transceivers that can detect presence and provide a signal to shut down the laser. Their primary assets are high zone coverage and accuracy. Drawbacks include the fact that they are easily confused by motion systems (robots) that are part of the process, and they can be very expensive to implement especially where internal structures form blind spots requiring multiple scan units to accomplish full coverage.

31 Interlocks and Sensors Walk in workstations Light-curtain configurations are widely used in industrial applications as non-contact barriers for motion systems or other hazards. These electric eye or beam-interruption devices have been configured to trigger when someone breaks through the light within walk-in workstations. The technology is well known in industry, and the cost is moderate. However, because they work only in one plane and the beam is static, careful design effort is required to plan an effective control function sometimes requiring many devices and raising the cost.

32 Interlocks and Sensors Walk in workstations Safety mats are widely used to protect people inside hazard zones. Their prevalence makes them easy to implement, and they can be inexpensive. However, many fiber-laser workstations have multiple planes upon which humans stand, or sit, when performing work inside the workstation. This means mats would have to be applied to nearly every horizontal surface, again increasing the cost and complexity

33 Interlocks and Sensors Walk in workstations People counters devices that count the number of persons entering or leaving a structure were previously limited to highsecurity applications. The detector systems and software are highly sophisticated, customized to location, and expensive. Recently a concept was developed using relatively inexpensive detectors (sold for commercial applications) coupled to standard safety-rated PLCs that determines the number of people entering and compares that against the exiting number to establish that nobody remains inside. Part of the development was to define configurations of the detectors and software to resolve tail-gating or multiple-abreast entry. This method may offer a broadly adaptive and comparatively inexpensive alternative or augmentation to mats, light curtains, and scanners.

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37 Discussion Q & A

38 Discussion Q & A

39 Discussion Q & A

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41 ILSC 2009 Laser Safety Practical Applications Seminar Evaluation Session #6: Designing Your Enclosure to Meet Class 1 Requirements Course Instructor: Thomas Lieb Please rate the following: (circle) Very Course Excellent Good Good Fair Poor Overall Course Course Instructor Presentation of material Organization of material Course well paced Would you recommend this course to others in your profession? yes no What was the strongest feature of the course? What was not covered that you felt should have been covered (if anything)? What would you like to hear more about next time? What was covered that left an impression/impact on you? Suggestions & Comments (for this course or courses you would like in the future): Name: (optional) Please Use Reverse Side for Additional Comments. Please return evaluation form to the Registration Desk by Wednesday afternoon or fax to LIA upon your return home. THANK YOU!