First Section
Laser Safety Standards for OEMs/System Integrators
The U.S. Federal Government has requirements that impact the manufacture or import of any products containing lasers that are sold in the United States. These mandatory regulations are published and enforced by the FDA’s Center for Devices and Radiological Health (CDRH). They specify product classification procedures, and they require a protective housing as well as engineering features and labels for each product class. The CDRH regulations also require manuals, test procedures, test and distribution records, and a certification report.
The regulations exempt lasers shipped to Original Equipment Manufacturers (OEMs) for resale (requirements described herein for OEMs apply equally to System Integrators). However, to help reduce the effort required by OEMs and system integrators in certifying their end products, the Synrad line includes “keyswitch” versions of CO2 lasers that have been certified to the CDRH regulations. Please note that end-use products sold to users must still be certified, even if they include a certified Synrad laser.
Product Classification - Products are classified in accordance with the laser energy that is accessible during normal operation. Energy that is accessible only during routine maintenance or during service will determine the need for interlocks, labels, shields,
and protective eyewear, but it would not affect the product class.
The CDRH classification categories are Class I, IIa, II, IIIa, IIIb, and IV, in accordance with increasing hazard levels. In general, fully enclosed laser systems are Class I, while systems that allow access to the CO2 laser energy are Class IV (the other classes would not apply for these products since the output of Synrad lasers is Class IV). CO2 laser energy is considered “accessible” by the safety standards if a finger or a very thin, straight probe can contact a beam.
Product Housing - During normal operation, the housing of the end product that contains a Synrad laser must prevent access to laser energy, unless access to that energy is necessary for the product function. That is, systems should be Class I unless it is unreasonable to fully enclose the beams (e.g., due to loading and unloading procedures or the need to process different material configurations). Even if it is not feasible to prevent access to laser energy at the beam focus, the beam paths at other locations usually must be enclosed during operation.
On systems with marking heads, for example, the beam tube supplied must be installed to seal the beam path between the laser head and the marking head. Also, if part handling precludes full enclosure of the marking area, blockage of laser energy beyond the part and other shields should be used to the extent feasible.
In addition to sheet metals, polycarbonate and acrylic (eg., Lexan and Plexiglas) and most other plastic materials are typically acceptable for a product enclosure. The material thickness must be selected to provide mechanical stability as well as the ability to withstand diffuse reflections of the CO2 laser energy. Metals should be used for portions of the enclosure on which a collimated beam is likely to be incident, as well as for exposures of a focused beam within several feet of the beam focus. Reflected beams should be treated the same as the incident beam, since at the CO2 laser wavelength most of the laser energy can be reflected from bare aluminum or other metals even though they do not have polished surfaces. Plastic curtains can be used if the mechanical characteristics are adequate and if a hazard evaluation shows that the incident energy under worst case conditions would not cause the material to degrade.
If a product housing has panels or doors that are openable during operation or routine maintenance by an operator and thus allow access to laser energy, interlocks are normally required. Such interlocks must be redundant or fail-safe, and they may be defeatable if specified requirements are met. If a panel or cover is to be removed only for service (e.g., repair by trained personnel), a warning label may be used for protection in lieu of an interlock - while it is not stated in the CDRH regulations, the need for a tool to remove a non-interlocked cover is recommended. The manual should clearly indicate if a procedure is considered “service” to be performed only by trained personnel.
Product Features - Once a system has been classified as Class I or Class IV by the OEM or system integrator, the required features can be determined. Other than the protective housing, labels, and (possibly) interlocks, no features are needed for Class I systems.
Class IV lasers and systems must include the following accessible features: a keyswitch to prevent unauthorized access (a computer password would be acceptable); an indicator (typically a light) to provide a warning of laser emission in advance of and during the emission time; a beam shutter to block the beam; a connector to facilitate the remote
interlocking of room/cabinet doors by the customer; and the requirement for the operator to manually restart the product after a line voltage interruption. Most Synrad lasers can be ordered with these features (“keyswitch” models); however, the system housing may require additional interlocks and labels.
Viewing windows, microscopes, and protective eyewear must prevent access above Class I. That is not normally a problem for CO2 laser energy since the 10.6 µm energy is absorbed by polycarbonate, acrylic, and most other plastic and glass window materials.
Other CDRH Requirements - A certification report must be filed by the OEM or system integrator with the CDRH before a product is delivered to customers or imported into the U.S. The report must provide a description of the product that discusses how it complies with the regulations. Copies of the test procedure, manuals, labels, and sales literature should be part of that report. A reference to the report that Synrad has provided to the CDRH on a certified laser may reduce the documentation that is needed.
The test procedure must verify operation of each required laser safety feature, verify that there is no unnecessary access to laser energy, and verify the specified labels are affixed at the proper locations. Measurements of output power/energy levels are not normally required. The system manuals must include warnings and precautions for operation, maintenance, and service procedures.
Warning logotypes and aperture labels are required for Class IV systems. All products need warning labels for removable portions of the housings that are not interlocked, and an identification/certification label is specified. Wording for these labels is provided in the regulations. If a warning logotype is required on the product, it must also appear on the sales literature.
