Laser Safety The UNC Asheville laser safety program requires that all lasers and laser systems be operated in accordance with the American National Standards Institute (ANSI) Z136.1 2007, American National Standards for Safe Use of Lasers; and other applicable federal and state regulations. The safe use of laser systems depends upon the basic principles of safety, which are: 1. Recognition of potential hazards. 2. Evaluation of potential hazards. 3. Control of potential hazards. The primary objective of the UNC Asheville Laser Safety Program is to ensure that no laser radiation in excess of the Maximum Permissible Exposure (MPE) limit reaches the human eye or skin. Additionally, the program is designed to ensure that adequate protection against collateral hazards is provided. These collateral hazards include the risk of electrical shock, fire hazard from a beam or from use of dyes and solvents, and chemical exposures from use of chemicals and vaporization of targets. Scope This Laser Safety Program applies to the acquisition, use, transfer, and disposal of all Class 3B and 4 lasers at UNC Asheville. Class 3B Laser: A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as those from paper or other matte surfaces are not harmful. The Accessible Emission Limit (AEL) for continuous lasers in the wavelength range from 315 nm to far infrared is 0.5 W. For pulsed lasers between 400 and 700 nm, the limit is 30 mj. Other limits apply to other wavelengths and to ultra-short pulsed lasers. Class 4 Laser: Class 4 is the highest and most dangerous class of laser, including all lasers that exceed the Class 3B AEL. By definition, a Class 4 laser can burn the skin, or cause devastating and permanent eye damage as a result of direct, diffuse or indirect beam viewing. These lasers may ignite combustible materials, and thus may represent a fire risk. These hazards may also apply to indirect or non-specular reflections of the beam, even from apparently matte surfaces meaning that great care must be taken to control the beam path. Responsibilities It is the responsibility of the Lab Supervisor where Class 3B or 4 lasers are located to comply with the requirements of this plan.
UNC Asheville Laser Safety Program The UNC Asheville Laser Safety Program consists of the elements listed below. Most of these elements are included in ANSI Z136.1-1986, the American National Standard for the Safe Use of Lasers. Other requirements have been included to maintain an effective laser safety program at UNC Asheville. A. Establishment of Laser Safety Officer The UNC Asheville Laser Safety Officer responsibilities reside in the Department of Environmental Health and Safety (safety@unca.edu) in conjunction with Laser Laboratory Supervisors. The UNC Asheville Laser Safety Officer is responsible for overseeing the University Laser Safety Program. The duties of the Laser Safety Officer include: 1. Maintain an inventory of all Class 3B and 4 lasers. 2. Provide assistance in evaluating laser hazards. 3. Participate in Incident investigations involving lasers. 4. Audit departmental Laser Safety Programs. B. Obtaining a Laser The UNC Asheville EH&S Office must be notified of the acquisition of Class 3B and 4 lasers. The EH&S Office is responsible for keeping an inventory of all Class 3B and 4 lasers on campus. C. Laser Safety Training Documented Laser Safety Training is required for all users of Class 3B and 4 lasers to be administered by the Laser Lab Supervisor. It is recommended that this training be refreshed on an annual basis. This training will cover the following topics: General Laser Safety Principles UNC Asheville Laser Safety Requirements D. Hazard Assessment A hazard assessment must be performed on all active Class 3B and 4 lasers. Assessments also must be conducted when preexisting lasers are relocated or whenever a significant change is made to a laser. A hazard assessment will include consideration of the properties of the laser (power, wavelength, etc.), the environment in which it is located, existing emergency controls, work practices and procedures, and the potential for exposure. E. Class 3B and 4 Design Requirements
Design requirements are based on the assumption that the nominal hazard zone includes the lab or area where the laser is located and extends through an open doorway into the adjacent hallway. A. Entry way protection - Entry ways into Class 3B and 4 laser labs must include the following elements: No windows may be present which could allow either direct or reflected beams to leave the work area. Entry to the lab must be controlled while the laser is in operation. Key locks or cipher locks should be present to prevent unauthorized and unprotected personnel from entering the nominal hazard zone. If a key lock is used to protect exterior entry, the laser user must be able to exit the lab through use of the inside door handle which overrides the door lock. All doors must have door closers unless the door is interlocked to the laser with a non-defeatable interlock. For Class 4 lasers - when doors are open, it must not be possible for direct or reflected beams to pass into the hallway. This can be accomplished through the use of a non-defeatable door interlock. Alternatively, procedural or administrative controls such as the use of a curtained area inside the lab may be used if judged appropriate by the lab supervisor and the laser safety officer. Warning signs must be posted at the entrance to the laser area. B. Protection Inside the Laser Area - Measures are necessary to protect the laser user and others inside the work area. Complete beam path enclosure is the primary control measure to be considered. If this is not practical, the following preventative measures must be implemented. Beams must be positively terminated through use of permanently attached beam stops or attenuators. The laser work area should be free of specular surfaces which may cause specular beam reflections and, for Class IV lasers; exposure to hazardous diffuse reflections is prevented. Where Class 4 lasers are in use, curtain materials (and other materials that may contact the beam) must be selected which are fire resistant to direct and prolonged beam contact. Labs with Class IV lasers must contain a clearly labeled "panic button" which kills power to the laser. For Class 4 lasers a warning light must be located outside of the lab door to indicate when the laser is firing. F. Warning Sign and Labels All Class 3B, and 4 laser laboratories must have laser signs posted at the entryway to the lab or work area. Signs will comply with ANSI requirements and will include the following information: "DANGER" For Class 3B - "Laser Radiation - Avoid Direct Exposure to Beam" For Class 4 - "Laser Radiation - Avoid Eye or Skin Exposure to Direct or Scattered Radiation"
For Invisible Beams - substitute words "Invisible Laser Radiation..." Type of radiation or emitted wavelength Pulse duration, if appropriate Maximum output Class of Laser When a lab contains more than one laser, the sign will convey the hazard information for the highest power laser in the lab. G. Standard Operating Procedures Written Standard Operating Procedures (SOPs) are required to be submitted to the Laboratory Safety Committee for use of all Class 3B and 4 lasers. The approved SOP is to be provided by supervisors to all laser users and inserted into their lab safety manuals. H. Protective Equipment Selection of Eyewear - Laser protective eyewear is required whenever persons are within the nominal hazard zone (NHZ). During maintenance and alignment procedures, the nominal hazard zone is considered to be the entire lab area. After a beam path has been clearly defined and contained, the nominal hazard zone may be reduced in size. Remember that class 4 lasers can produce hazardous diffuse reflections, so the nominal hazard zone will need to account for this. Eyewear must be of the correct optical density and protect in the specific wavelength(s) of the laser(s) in use. In some cases, a lower optical density laser goggle may be chosen to permit the laser beam to be seen. Other Protective Equipment - Where Excimer lasers and other UV emitting sources are used, long sleeves and gloves to protect the skin are recommended. Other protective equipment may be identified through the hazard assessment procedure. I. Maintenance Procedures Maintenance procedures need to include the following: Electrical Troubleshooting Gas Cylinder Changes Other maintenance operations where a standard procedure and/or training is needed. J. Laser Accidents and Incidents All injuries and suspected exposures are required to be reported to the Lab Supervisor and the EH&S Office. Report all accidents or other safety related incidents such as near misses to the Lab Supervisor and the EH&S Office for investigation. A near miss is an unanticipated event that did not result in harm or injury but had the potential to do so. Incidents will be reviewed and modifications to SOPs will be completed to prevent the incident from happening again.
K. Transfer of Lasers The EH&S Office should be contacted prior to transferring a laser to another employee or location. This will help assure proper training and design for the new laser user and will keep the site laser inventory accurate. L. Disposal of Lasers The EH&S Office should be contacted prior to disposing of a Class 3b or 4 lasers. Lasers should be rendered "inoperable" prior to disposal. The laser will also be removed from the site inventory.