Protective Equipment
Laser Barriers and Protective Curtains
Area control can be effected in some cases using special barriers which have
been specifically designed to withstand either direct and/or diffusely scattered
beams. In this case, the barrier will exhibit a Barrier Threshold Limit (BTL)
for beam penetration through the barrier during some specified exposure time (typically
60 seconds). The barrier is located at a distance from the laser source so that
the BTL is not exceeded in the "worst case" exposure scenario. Currently available
laser barriers exhibit BTL's ranging from 10 W/cm(2) to 350 W/cm(2) for different
laser wavelengths and power levels. An analysis is usually required (done similarly
to the NHZ evaluations) that establishes there commended barrier type and installation
distances for a given laser. Important in the design is the factor of flammability
of the barrier. It is essential that the barrier not support combustion and be
consumed by flames following an exposure.
