Use of Fiber Optic Systems in Class I Hazardous (Classified) Locations
|Publication Date:||15 August 2004|
This technical report provides guidance on the safe use of fiber
optic systems and their constituent parts producing or guiding
visible, near infrared, or mid infrared (maximum wavelength of 10
μm) radiation in Class I hazardous (classified) locations.
Hazardous (classified) locations are described in the National
Electrical Code (NEC). Limiting levels prescribed in this
document apply only to the minimum levels of optical power, optical
power density, and optical energy needed to ignite explosive gas
atmospheres. In apparatus where optical energy is transduced to
electrical energy, the limiting values for the electrical energy
must be determined from relevant standards for electrical apparatus
At this time there is minimal awareness of the potential risk associated with optical ignitions even though fiber optics have been used for at least 20 years in hazardous (classified) locations. One purpose of this technical report is to inform industry of potential ignition hazards associated with the use of fiber optic systems in explosive gas atmospheres. The technical report is also intended to suggest engineering and installation practices to reduce the ignition hazard from fiber optic systems in Class I locations.