New Changes with ISO 13855:2021, Position of safeguards

ISO 13855 is one of most commonly used standard in machinery safety applications. Anyone who thinks about position of safeguards (Light curtain, laser scanner etc) definetely have a looked on ISO 13855 in the past.

Now, this harmonized standard’s new version open for vote and it includes a lot changes which will effect stop time measurement service provider’s calculations.


It looks like we will use “Seperation Distance” term instead of “Minimum Distance”

S = (K x T) + C, C is changed with Dds, and Z term appeared which is supplemental distance factor

There is a little surprise change about content of calculation Ddt which is previous Crt ( C reach through) for below than 20mm diameter resolution, equation is same with previous standard

But, for resolution between 20mm < d < 55mm, which most hand protection light curtain resolution 30mm and under this scope,

Normally we get 128mm with 30mm resolution on previous standard while we reach 78.2mm with new one

There are more changes in this draft standard but in my opinion, it s important, people who perform stop time measurement service should follow this standard update when 13855:2010 supersede with new one

Let me know your comments, opinions about this new version and have a nice day!

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