Laser Safety Resources And Considerations

Information For Laser Safety - Using Lasers In The US And Worldwide

Acuity’s laser sensors put out about the same power levels as the laser pointers that have become quite common, but they are still subject to safety regulations. These devices are potentially hazardous only when the beam enters the eye directly or through optics such as mirrors or focusing lenses. Scattered light or light striking the skin is not classified as hazardous.

Laser Classes

U.S. regulations presently divide laser devices into “classes” based on the power of the laser, whether it is a visible or IR laser, and the potential exposure duration. Class I devices are eye-safe under any circumstances. The maximum permissible output varies with the laser light frequency and other factors. Class II devices are visible lasers with output of less than 1 milliwatt. Classifications apply to both pulsed and continuous wave lasers, with various formulae for determining class.

For cw lasers, Class IIIa lasers are visible lasers with output power of more than 1 mW but less than 5 mW, as measured through a 7 millimeter aperture. Class IIIb lasers are those with output above 5 mW, or any laser outside the visible frequency band that is not unconditionally eye safe. Class IIIb extends up to 500 mW output power.

Regulations for light-emitting devices are governed by the U.S. Food and Drug Administration (FDA) under 21 CFR 1040.10, PERFORMANCE STANDARDS FOR LIGHT-EMITTING PRODUCTS.

Classifications of the AR4000 Versions

The AR4000-RET is a Class I device, meaning that it will not cause damage to skin or eyes. If the target can have retroreflective tape applied to it, the 4000-RET is usually the sensor to use.

The AR4000-LV is a Class IIIa laser device, with a maximum power of less than 5 mW. The aperture cover supplied with the 4000 LV is required for end user sales in the U.S. OEMs and developers may integrate a separate aperture cover, so long as it meets Federal requirements.

The AR4000-LIR and high power LIR are a Class IIIb laser devices. The aperture cover supplied with these sensors is required for end user sales in the U.S. In addition, complete systems (with power supply) must also include a keyswitch and power interlock jack. The key must be removable only when the laser is off. The power jack disconnects power to the laser when it is removed. The AR4000-LIR power supply includes the keyswitch and interlock jack. End users providing their own power supplies must include a conforming keyswitch and interlock. A separate keyswitch/interlock box is available for the 4000-LIR.

Laser classification becomes even more complex when considering scanned beams. Depending on the speed of the scan and whether a scan repeats along one line moves in 2 axes, Acuity’s sensors can be made eye safe while scanning. Regulations require end user scanning systems that are classified as eye safe to include interlocks that turn the laser off if the beam scanning speed or pattern changes in any way that could cause exposure to hazardous light levels. Scanning systems may also be classified as Class II, IIIa, or IIIb, but precautions must be taken to assure that they are used in a safe manner.

The ANSI document Z136.1-1993, “American National Standard for Safe Use of Lasers” describes the classifications of lasers and the precautions to be taken for each class. This document may be ordered from ANSI, which has offices in Hackensack, NJ, and New York, NY. (Phone: 212-642-4900)

Helpful Links For Laser Safety

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