visibly clean


absence of surface contamination when examined with a specific light source, angle of incidence and viewing distance using normal or magnified vision


  • NOTE 1 Different inspection methods are available, depending on: a. hardware to be inspected, in term of size and accessibility and sensitivity to contamination b. inspection distance c. light spectra (including UV), intensities and angles
  • NOTE 2 The 'visibly clean' level roughly corresponds to an obscuration factor smaller than 300 mm2/m2 when inspected from a distance of 30 cm to 60 cm with an oblique white light of 540 lx to 1620 lx.
  • NOTE 3 Typical magnification levels range from 2x to 8x.
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