Laser Safety Guide

Safety Procedures

Laser Controlled Areas

The following control measures apply to Laser Controlled Areas containing Class IIIB and Class IV lasers and laser systems (Laser laboratories containing Class IIIB and Class IV lasers or laser systems are considered laser controlled areas.):

• Laser devices shall be isolated in an area designed solely for laser operations. Access to such an area shall require appropriate authorization.
  
  
• Special emphasis shall be placed on control of the path of the laser beam.
  
  
• All persons using such lasers or laser systems shall be duly informed about the potential hazards of laser operations.
  
  
• Only authorized personnel shall operate laser systems.
  
  
• Visitors shall not be permitted into the laser-controlled area unless appropriate supervisory approval has been obtained and protective measures taken.
  
  
• Alignment of laser optical systems (mirrors, lenses, beam deflectors, etc.) shall be performed in such a manner that the primary beam or specular reflections cannot expose the eye to a level above the appropriate intrabeam MPE.
  
  
• Whenever possible, the entire beam path, including the interaction area, that is, the area in which irradiation of materials by the primary or secondary beam occurs, should be enclosed. Enclosures should be equipped with interlocks so that the laser system will not operate unless such enclosures are properly installed.
  
  
• For pulsed systems, interlocks shall be designed so as to prevent firing of the laser by dumping the stored energy into a dummy load. For cw lasers, the interlocks shall turn off the power supply or interrupt the beam by means of shutters. Interlocks shall not allow automatic reenergizing of the power supply but shall be designed so that after tripping the interlock, the power supply or shutter must be reset manually.
  
  
• Eye protection devices which are designed for protection against radiation from a specific laser system shall be used when engineering and procedural controls are inadequate to eliminate potentially hazardous exposures.
  
  
• Whenever possible, the laser system should be fired and monitored only from remote positions.
  
  
• An alarm system (e.g., an audible sound or a warning light which is visible through protective eyewear) or a verbal "countdown" command should be used prior to activation.
  
  
• The audible system may consist of a bell or chime which commences when a pulsed laser power supply is charged for operation, for example, during the charging of capacitor banks. Systems should be used in which a warning will sound intermittently during the charging procedure (pulsed systems) and continuously when fully charged.
  
  
• In order to safely operate a Class IV laser or laser system, a laser warning system shall be installed.
  
  
  • A laser activation warning light assembly shall be installed outside the entrance to each laser room facility containing a Class IV laser or laser system.
    
    
  • In lieu of a blinking entryway warning, the entryway light assembly may alternatively be interfaced to the laser in such a manner that a light will indicate when the laser is not operational (high voltage off) and by an additional light when the laser is powered up (high voltage applied) but not operating and by an additional (flashing) light when the laser is operating.
    
    
  • A laser warning sign shall be posted both inside and outside the laser controlled area.
    
    
• Under conditions where the entire beam path is not enclosed, safety latches or interlocks shall be used to prevent unexpected entry into laser controlled areas. Such measures shall be designed to allow both rapid egress by the laser personnel at all times, and admittance to the laser controlled area in an emergency condition. For such emergency conditions, a "panic button" (control-disconnect switch or equivalent device) shall be available for deactivating the laser.
  
  
• Under conditions where the entire beam path is not completely enclosed, access to the laser controlled area shall be limited only to persons wearing proper laser protective eyewear when the laser is capable of emission. In this case all other optical paths (for example, windows) from the facility shall be covered or restricted in such a way as to reduce the transmitted intensity of the laser radiation to levels at or below the MPE for direct irradiation of the eye. Specularly reflecting surfaces which are not required when using the laser shall be removed from the beam path.