- Class 1, Class 2, lasers may be used for the intended purposes of their manufacturer without restrictions. Any direct eye exposure to these types of lasers should be avoided.
- Class 3a, Class 3B, and Class 4 shall carry a warning label containing the laser classification, type, and other warnings required by ANSI Z136.1 or assigned an equivalent level by the builder. These requirements also apply to non-commercially built lasers that are used on the University of Iowa campus.
- Class 3B and Class 4 lasers must be registered with the Environmental Health & Safety.
- Each Class 3B and Class 4 laser must be assigned to a Principal Investigator who is responsible for safe storage and use of that laser. EHS must be consulted whenever a laser is acquired, reassigned to a new Principal Investigator, transferred off-campus, or disposed. Please contact the University’s Laser Safety Officer at 335-8501 prior to initiating any of these activities.
- All laser operators must complete training specific to the type of laser they operate. See Laser Safety Training. This requirement will be reviewed during EHS audits.
- All lasers must be operated according to the applicable ANSI Z136.1 safety standards and in a manner consistent with safe laser practices. Laser Safety Standard Operating Procedures (SOPs) are required for certain Class 3B lasers and for all Class 4 lasers. (see Laser Safety Standard Operating Procedures for details).
- Each Class 3B and Class 4 laser shall be used in a controlled area that restricts access to unauthorized personnel. The controlled laser areas must be posted with appropriate warning signs.
- Each operator of a Class 3B or Class 4 laser must wear protective equipment (e.g., eye wear and clothing) as appropriate. (see Personal Protective Equipment).
- The EHS will perform periodic audits in order to assess the efficacy of the laser safety program. Any required corrective action resulting from the audit will be communicated to the Principal Investigator in a timely manner.
- All lasers require a protective housing.
- All Class 3B and Class 4 lasers must be equipped with the Center for Devices and Radiological Health (CDRH) mandated engineered safety features that follow:
- Protective housing interlock system that prevent emission of laser radiation when the housing is open.
- Viewing portals in the protective housing must be equipped with filters and attenuators that keep escaping light below the Maximum Permissible Exposure (MPE) limit.
- Optical instruments for viewing the laser system must be equipped with filters and attenuators and interlocks to keep exposures below the MPE limit for all conditions of operation and maintenance.
These features are standard for purchased lasers and should be designed and incorporated in custom built lasers.
- Class 4 lasers shall also be equipped with a removable master key switch if provided by the manufacturer. The laser shall not be operable when the key is removed.
- The lasers should be equipped with electrical connections that allow for an access control system and remote shut-off devices. When the terminals are open-circuited, the laser must not emit any radiation in excess of the MPE. Class 4 laser systems must be equipped with an integral and permanently attached beam stop or attenuator capable of preventing the emission of laser light in excess of the MPE limit when the beam is not required.
Laser Control Areas
Class 3B Laser Controlled Area
The following items are required for Class 3B laser controlled areas:
- Posted with the appropriate warning sign(s).
- Operated by qualified and authorized personnel.
- Under the direct supervision of an individual knowledgeable in laser safety.
- Have any potentially hazardous beam terminated in a beam stop of an appropriate material.
- Have only diffuse reflective materials in or near the beam path, where feasible.
- Have personnel within the controlled area provided with the appropriate eye protection if there is any possibility of viewing the direct or reflected beams.
- Have the laser secured such that the beam path is above or below eye level of a person in any standing or seated position, except as required for medical use.
- Have all windows, doorways, open portals, etc. from an indoor facility be either covered or restricted in such a manner as to reduce the transmitted laser radiation to levels at or below the appropriate ocular MPE.
- Require storage or disabling (for example, removal of the key) of the laser or laser system when not in use to prevent unauthorized use.
Class 4 laser control area
requires, in addition to the items listed for Class 3B areas, the following additional measures:
- Personnel who enter a Class 4 controlled area during laser operation shall be adequately trained, provided with appropriate protective equipment, and follow all applicable administrative and procedural controls.
- Class 4 area/entryway safety controls shall be designed to allow both rapid egress by laser personnel at all times and admittance to the laser controlled area under emergency conditions.
- For emergency conditions there shall be a clearly marked "Panic Button" (remote controlled connector or equivalent device) available for deactivating the laser or reducing the output to the appropriate MPE levels.
- Area or entryway safety controls to deactivate the laser or reduce the output to the appropriate MPE levels in the event of unexpected entry into the laser controlled area.
- These controls may be non-defeatable, defeatable or procedural as determined by the LSO.
Temporary Laser Controlled Area
Where removal of panels or protective housings, over-riding of protective housing interlocks, or entry into the NHZ becomes necessary (such as for service), and the accessible laser radiation exceeds the applicable MPE, a temporary laser controlled area shall be set up. The temporary laser controlled area shall be posted on the outside with a Notice sign and with the appropriate warning sign (Class 3B or Class 4) inside the controlled area to warn of the potential hazard.