Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Safety standards

ISO 13855

Also known as: EN ISO 13855

ISO 13855 is the international standard addressing the positioning of safeguards with respect to the approach speed of parts of the human body. It gives the method and parameters for calculating the minimum distance between a protective device and the hazard zone, so that the hazard is stopped before a person can reach it.

  • Standards
  • Technical documentation

In one sentence

ISO 13855 gives the method for calculating the minimum distance between a protective device and a hazard, based on human approach speed.

Example

For a light curtain in front of a press brake, the engineer multiplies the approach speed by the overall stopping time of the machine and adds an intrusion allowance based on the curtain’s resolution to find the mounting distance.

How it applies

  • Machine safety: The general formula is S = (K × T) + C: approach speed K, overall system stopping performance T, and an additional distance C depending on the device, for example its detection capability. It applies to electro-sensitive protective equipment, pressure-sensitive devices, two-hand controls and certain interlocking guards.
  • Inputs: T includes the response time of the protective device, the control system and the machine's stopping time. Use measured or guaranteed values for the worst case, not typical values.
  • Technical documentation: Record the calculation, the values used and their sources. The manual should state the required stopping performance and require re-measurement after changes that can affect it, such as brake wear or new drives.
  • Evidence: A changed stopping time invalidates the minimum distance calculation.

ISO 13855 vs. ISO 13857

ISO 13855 deals with timing: where to place a device that triggers a stop so the hazard ends before it is reached. ISO 13857 deals with geometry: distances that prevent reaching a hazard over, around or through a guard at all.

By knowledge.aitechdoc.world · Published September 25, 2026 · Last reviewed

Source: ISO 13855, Safety of machinery — Positioning of safeguards with respect to the approach of the human body

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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