Optical techniques in industrial measurement : Safety in hazardous environmentsFunded under: FP3-MAT
This synthesis report describes the results of an investigation into the safety of optical measurement techniques in hazardous industrial environments. The mechanism investigated was thermal ignition through radiation heating of an absorber. During the work, the number of individual measurements approached one million, and of those a significant fraction gave rise to ignition events. Five different light sources including lasers and optical fibre delivery, ten different atmospheres (each at many different concentrations) and fifteen different absorbers, both inert and chemically active in the form of both dust layers and clouds, were investigated. A limiting safety criterion has been proposed which shows a satisfactory comparison with the body of experimental results generated within this project and elsewhere. It is concluded that continuous wave devices radiating in the visible and the near visible are not hazardous provided either the radiated power is less than 35 mW, or the peak radiation flux is less than 5 mW/mm2. For pulsed or intermittent light sources, specific atmospheres, sources of area smaller than 0.001 mm2 and where sensitive materials are present, different values of power and flux may be appropriate.
Bibliographic Reference: EUR 16011 EN (1994) 98 pp., FS, ECU 16.50
Record Number: 199411661 / Last updated on: 1995-01-25
Original language: en
Available languages: en