Explosion protection for optical radiation in hazardous
locations Three protection schemes are under consideration.
Industry uses optical equipment for surveying, communications,
sensing, and measurement. Often the installation is inside or
close to potentially explosive atmospheres, and radiation from
this equipment may pass through these atmospheres, exposing them
to a potential ignition source. The explosive mixture may absorb
the radiation, leading to a local temperature increase or
photochemical process, and ignition or focused laser radiation
may cause formation of plasma capable of causing ignition. In
practice, the greatest danger is absorption of the radiation by
a solid target (surfaces or particles), causing the heated
surface to become an ignition source. The International
Electrotechnical Commission (IEC) has set up Working Group 8 to
develop requirements for optical equipment used in hazardous
atmospheres. Continuous wave radiation Several publications,
including a European standard, deal with i