BY STANLEY KAUFMAN AND HONG CHEN
While it is well known that Underwriters Laboratories considers fire hazards in its listing requirements for optical-fiber cables used in buildings, it is not widely known that ocular hazard is also considered in the listing process.
From the first optical-fiber cables listed 20 or so years ago, until recently, UL has had a limit on the optical power permitted in a listed fiber-optic cable. UL required that the tag on a cable reel indicate that the optical power be restricted to "levels of energy transmitted not exceeding those of Class I laser radiation (21 CFR Part 1040)."
Effective Jan. 13, UL/ANSI Standard 1651 requires that the tag on a cable reel state the following: "Where optical-fiber cables are installed in systems that use lasers, the system shall comply with the ANSI Z136 laser safety standards." The ANSI standards, Z136.1, "American National Standard for the Safe Use of Lasers," and Z136.2, "American National Standard for Safe Use of Optical Fiber Communication Systems Utilizing Laser Diode and LED Sources," are in the process of being revised to have the same requirements as the International Electrotechnical Commission (IEC) standards.
Amendment 2 of IEC 60825-1, "Safety of laser products-Part 1: Equipment classification, requirements, and user's guide," redefines the classification of laser radiation. IEC 60825-2, "Safety of laser products-Part 2: Safety of optical fibre communication systems," is being revised to permit the use of higher levels of optical power when the optical communications system automatically reduces the power to a safe level in the event the fiber path is opened. Two obvious scenarios for the fiber pathway to be opened are an accidental cable break or the system being opened for maintenance or reconfiguration.
Stanley Kaufman was the environmental and safety officer at OFS Fitel in Norcross, GA, until his recent retirement. He represented AT&T/Bell Labs/Lucent on Panel 16 of the National Electrical Code (NEC) Committee. He now consults on NEC and cable fire safety issues. He can be reached at tel: 770-394-4152 or e-mail: [email protected]. Hong Chen is a member of technical staff at OFS Fitel, responsible for standards issues and testing and listing of cables. She recently became a member of UL's STP 13, representing OFS. She can be contacted at tel: 770-798-2239; fax: 770-798-4655.
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