Laser Safety and Classification
The CrossCheck laser profile sensor uses a CDRH Class 3A or (IEC 3R) semiconductor laser emitting diode with 685nm visible light. The maximum emitting power is less than 5mW when a 7mm diameter aperture is positioned 100mm from the point the laser radiation exits the sensor.
3R sensors are compliant with standards relating to laser products specified in IEC 60825-1 and U.S. FDA CFR Title 21 Part 1040 except for deviations pursuant to Laser Notice No. 50.
The following table lists some key precautions and requirements for CDRH Class 3A (IEC 3R) according to the IEC 60825-1 Summary of User.
| CDRH Class 3A (IEC 3R) | |
|---|---|
| Laser Safety Officer | Not required for visible emission |
| Remote Interlock | Not required |
| Key Control | Not required |
| Beam Attenuator | Not required |
| Emission Indicator Device | Not required for visible emission |
| Warning Signs | Not required |
| Beam Path | Terminate at end of useful length |
| Specular Reflection | Prevent unintentional reflections |
| Eye Protection | No requirements |
| Training | Required for Operators/Maintenance |
The following information is taken from the ANSI Z136.1 standard
Beam Path: Class 3R laser devices shall terminate or block the axis of the unobstructed laser radiation beam at the end of its useful length. A metal plate, roller, ground or riser on the machine frame can be used to block the beam.
Specular Reflection: a mirror like reflection. Reflection is the deviation of radiation following incidence on a surface. Diffusely reflected beams are generally safe, but should not be viewed longer than 10 seconds.
Training: if a certified LSO is not available, 3R training Videos & CDs are available for operators and maintenance personnel at the Laser Institute of America.
Example of Laser Class 3R Warning Labels
Warning! Regardless of laser class, “DO NOT stare into laser beam”.
Use caution, any modification or adjustment without manufacturer permission may result in hazardous radiation exposure.
Laser Safety Resources
- International Standard IEC 60825-1 Ed. 2.0, Safety of laser products – Part 1: Equipment classification, requirements and user’s guide. Available from the International Electrotechnical Commission or the Laser Institute of America.
Other related IEC documents:
• IEC 60825-14 Ed. 1.0; General safety of laser products.
• IEC 60825-4 Ed. 2.0; laser guarding for equipment.
• IEC 60825-5 Ed. 2.0 Safety of laser products – Part 5; Mfr's checklist for IEC 60825-1.
• IEC 60825-13 Ed. 1.0; Measurements for classification of laser products.
• IEC 60825.10 Ed. 1.0; Application guidelines and explanatory notes to IEC 60825-1. - Laser Notice No. 50: describes harmonization of CDRH to IEC 60825-1 regulations. Laser Products – Conformance with IEC 60825-1, Am. 2 and IEC 60601-2-22; Final Guidance for Industry and FDA (Laser Notice No.50). View PDF document here.
- OSHA laser safety topics, Click to view list of topics on the OSHA website.
- FDA CFR (Code of Federal Regulations Title 21 Part 1040. View regulations here.
- ANSI Z136.1-2000, establishes guide-lines for users of the devices based on laser class. As secretariat to ASC Z136, the Laser Institute of America (LIA) administers the process and provides financial and clerical support to the committee.
- Laser Institute of America, has many resources, sells all documentation, labels, signs, eye protection and conduct laser safety training seminars. Learn more at their website.
Laser Class Definition
Note: Use the graph above and safety resources to determine user and OEM responsibilities.
CDRH Class 3A (IEC 3R)
The 3R laser classification directly relates to the Class 2 specification as stated for reference. The only difference is you must terminate the beam path at the end of its useful length, block any secondary reflections from shiny mirror surfaces (not diffuse) and provide training for operators and maintenance personnel.
CHRH Class 2 laser diodes must emit visible radiation in the wavelength from 400nm to 700nm, and have a laser power less than 1mW. If the eye is subjected to direct intrabeam exposure, under normal circumstances, damage to the eye is deemed not possible due to the natural aversion response (blink or move head) within 0.25 seconds. The emission duration of 0.25 seconds is the calculated Maximum Permissible Exposure (MPE) for visible radiation of a 1mW laser power entering an aperture of 7 mm diameter (assumed size of a pupil) which is equal to 25 W per square meter. MPE is the level of laser radiation a person may be exposed to without hazardous effect.
3R lasers can emit in the wavelength range from 400 nm to 1400 nm (1.4mm) where direct intrabeam viewing is potentially hazardous but the risk is lower than for 3B lasers. Fewer manufacturing requirements and control measures for users apply, than for 3B lasers. Laser power cannot exceed 5mW which is 5 times the calculated accessible emission limit (AEL) of a Class 2 device. Nominal Ocular Hazard Zone (NOHD) calculates the safe eye distance along the axis of the unobstructed beam, from the laser device to the human eye, where radiant exposure does not exceed the appropriate MPE.
The information contained in this document should be used as a reference only. Bytewise takes no responsibility for turn key installations that have inadequate administrative control measures. Updated May 2009.
