CHAPTER V- Laser Hazard Control Requirements

5.1 Overview of Hazard Controls

In general, the following control measures are required for Class IIIb and IV lasers:

1. Access restrictions including key master switch, interlocked entry or beam enclosure.
2. Training of operators and personnel working on or near lasers (on site or general).
3. Posting and labeling of rooms and equipment, to include a warning light in the hallway or access entrance.
4. Protective eye wear and clothing.
5. Engineering controls such as beam stops, curtains, and enclosures.

The exact combination of these control measures depends on the power and type of laser, laser environment, and procedures conducted with laser equipment. The LSO approves control measures prior to operation of lasers.

5.2 Access Restrictions
5.2.1 Master Switch

Class IIIb and IV lasers must have a master switch that is controlled by a key or coded access. Access by key or code must only be provided to trained operators and other personnel approved by the LSO. Exceptions to this requirement may be approved by the LSO provided other engineering and administrative controls are used to prevent unauthorized use of laser equipment.

5.2.2 Interlocked Entry

Entry to rooms containing Class IV lasers and laser systems must be interlocked with the laser to prevent unexpected entry of personnel while the laser is in operation. These interlocks must be engineered such that:

1. Rapid egress is allowed at all times and admittance to the laser area is allowed under emergency conditions.
2. For emergency conditions, a control disconnect switch, panic button, or equivalent device must be available for deactivating the laser.
3. During continuous operation of a laser, the individual in charge of the interlocked room may momentarily override the safety interlocks to allow access to other authorized personnel if it is clearly evident that there is no optical radiation hazard at the point of entry and if the necessary protective devices are being worn by the entering personnel.

Exceptions to these requirements may be approved by the Radiation Safety Committee provided alternate engineering and administrative controls are used to prevent unexpected entry of personnel into a hazardous area during laser operations.

5.2.3 Exceptions for Lasers Utilizing Beam Enclosure

In applications of laser or laser systems where the entire beam path is enclosed, certain access restrictions are not needed. See section 5.8 and 5.9.

5.3 Training of Operators and Personnel Working on or near Lasers
5.3.1 Training

Training shall be provided to each employee working with or around lasers of Class IIIb or IV.

Laser training must be provided by the LSO or a designated representative. Training must cover the following topics:
1. Fundamentals of laser operation (physical principles, construction, etc.).
2. Bio effects of laser radiation on the eye and skin.
3. Relations of specular and diffuse reflections.
4. Non radiation hazards of lasers (electrical, chemical, reaction by products, etc.).
5. Laser and laser system classifications.
6. Control measures.
7. Overall management and employee responsibilities.
8. Medical Surveillance.

5.4 Posting and Labeling of Rooms and Equipment

5.4.1 Equipment Labels

All classes of lasers or laser systems (except Class I) are required to contain warning labels by the Federal Laser Product Performance Standard. Manufacturers place these labels on laser equipment. These labels must not be removed. Equipment modified or constructed at ASU shall be provided with labels that are clearly visible during operation and affixed to the laser housing or control panel. Labels must be placed on both laser housing and control panel when these are separated by more than 2 meters. Label design and verbiage are provided by the LSO.

5.4.2 Posting of Rooms

Areas containing Class IIIb or IV lasers must be posted with appropriate signs. The design and verbiage of the sign must be approved by the LSO.

5.5 Protective Eye wear and Clothing
5.5.1 Eye Protection Devices.

Eye protection devices specially designed for protection against radiation from lasers must be used by all personnel working with or near lasers during laser operation unless engineering, procedural, or administrative controls are used to eliminate likely exposure.

All protective eye wear must be clearly labeled with the optical density and wavelength for which protection is afforded.

In addition, eye wear must be marked with a unique identifying label that will assist in maintaining inspection and inventory records required by ARRA regulations.

Eye wear will be inspected by ORS staff during semi annual laser inspections. Protective eye wear will be removed from service if damaged or otherwise unable to provide protection adequate for laser equipment in use. For laser eye wear, the ORS has a list of vendors and registrants inventory.

5.5.2 Protective Clothing

Where personnel may be exposed to levels of radiation that may damage the skin, protective clothing is required. The LSO determines the need for protective clothing and the type of clothing to be used.

5.6 Engineering Controls
5.6.1 Beam Enclosures
Beam enclosures should be used whenever practical. Use of enclosures will significantly reduce the need for other engineering or administrative controls (see Sections 5.8 and 5.9).

5.6.2 Activation Warning Systems

Inside the laser control area, an alarm (for example, an audible sound such as a bell or chime), a warning light (visible through protective eye wear), or a verbal "countdown" command must be used with Class IIIb and Class IV lasers or laser systems during activation or startup.

Distinctive and clearly identifiable sounds which arise from auxiliary equipment (such as a vacuum pump or fan) and which are uniquely associated with the emission of laser radiation are acceptable as an audible warning.

A warning light outside the control area must be used with Class IIIb and IV lasers. (The ORS has a list of suitable light sources.)

5.6.3 Emission Delay

For operation of Class IIIb or IV lasers or laser systems, the warning system must be activated a sufficient time prior to emission of laser radiation to allow appropriate action to be taken to avoid exposure to the laser.

5.6.4 Window and Door Barriers

All windows, doorways, open portals, etc., must be either controlled or restricted in such a manner as to prevent escape of potentially hazardous radiation. Typically curtains at door ways are required for Class IIIb and IV lasers in open beam configurations to prevent escape of potentially hazardous radiation. (The ORS has a list of suitable barrier and curtain sources.)

5.7 Administrative Controls
5.7.1 Standard Operating Procedures

Written procedures should be established for operation, alignment, and maintenance of lasers at ASU. The LSO may require these procedures as part of the approved control measures.

5.7.2 Alignment Procedures

Alignment of laser optical systems (mirrors, lenses, beam deflectors, etc.) must be performed in such a manner that the primary beam, or a specular or diffuse reflection of a beam, does not expose the eye to dangerous levels of radiation.

Written procedures outlining alignment methods may be required. The use of low power (Class I or Class II) visible lasers for path simulation of higher power lasers is recommended for alignment of higher power Class IIIb and Class IV visible or invisible lasers and laser systems.

Experience has shown that a significant ocular hazard may exist during alignment procedures. (The ORS can assist in developing a record of alignment procedures.)

5.7.3 Visitors and Spectators

Spectators shall not be permitted within a laser area during operation of a Class IIIb or Class IV laser or laser system unless:

1. Specific protective measures for visitors and spectators have been approved by the LSO.
2. The degree of hazard and avoidance procedure has been explained to spectators.
3. Appropriate protective measures are taken.
The ORS can help registrants ensure visitors obtain the adequate protection.
5.7.4 Servicing of Lasers

Personnel who require access to Class IIIb or Class IV lasers or laser systems contained within protective housing or protected area enclosure for the purpose of service must comply with the appropriate control measures of the enclosed or embedded laser or laser system. The service personnel shall have the education and training commensurate with the class of the laser or laser system contained within the protective housing.

5.7.5 Modifications of Lasers or Laser Systems

The registrant must notify the LSO of any modifications that could change a laser's class and affects its output power or operator characteristics so as to make it potentially more hazardous. The LSO must review the control measures to determine if additional requirements are needed.

5.8 Exceptions for Lasers with Fully Enclosed and Interlocked Beam Paths
In applications of lasers or laser systems where the entire beam path is enclosed, the requirements for Class I laser systems are met and none of the other control measures of this chapter are required, provided:
1. Interlocks are designed to prevent access to laser radiation. The interlock may be electrically or mechanically interfaced to a shutter, or to power supply in such a way that the beam is interrupted when the protective beam enclosure is opened or removed. These interlocks must be of fail safe design.
2. The protective housing interlocks must not be defeated during operation.
3. Adjustments or procedures during service must not cause the interlocks to be inoperative when equipment is returned to normal operating conditions.
4. When requirements 5.1.1. through 5.1.3. are temporarily relaxed, such as during service, LSO approved control measures must be applied. These may include temporary area control, and administrative and procedural controls.

5.9 Exceptions for Lasers with Fully Enclosed Beam Paths Without Interlocks

In application of lasers or laser systems where the entire beam path is enclosed, but the enclosure does not meet the requirements specified in 5.8., the laser is exempt from controls described in Sections 5.2.2, 5.5.1., 5.5.2., and 5.6.4. provided:
1. Beam enclosures prevent access to laser radiation.
2. Beam enclosures are not removed during normal operation.
3. When conditions of a and b are relaxed such as during service, LSO approved control measures are applied.