Functional Safety Certification for Collaborative Robots (Cobots): ISO 13855 Explained

Date: 2027-05-31
Location: Online
Host: Zach L

About this event

A Lunch-and-Learn for Risk Assessors pursuing functional safety certification. A live 30-minute lunch-and-learn on ISO 13855 (Positioning of Safeguards) for collaborative robots (cobots), built for risk assessors pursuing functional safety certification. What We'll Cover: What ISO 13855 (Positioning of Safeguards) requires and how its scope applies to collaborative robots (cobots) Mapping ISO 13855 clauses to the certification evidence assessors expect System-specific hazards and safety functions typical of collaborative robots (cobots) Common findings that delay certification, and how to avoid them A practical readiness roadmap for risk assessors preparing for assessment Related topics: ISO 13855 · Collaborative Robots (Cobots) · functional safety certification · functional safety assessm

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About ISO 13855 (Positioning of Safeguards)

This event covers the compliance, engineering, and verification requirements defined by ISO 13855.

EN ISO 13855 provides the methodology for positioning protective equipment with respect to human approach speeds: computing the minimum distance so a hazard is neutralized before a person can reach it after detection or opening.

What it regulates

Minimum distance formulas S = K·T + C for light curtains, scanners, pressure mats, two-hand controls and interlocked guards, with approach speeds, intrusion allowances, and reach-over/reach-through additions from ISO 13857.

Who must comply

Integrators positioning ESPE and guards on every safeguarded machine; validation engineers measuring stopping performance to confirm calculated distances.

Key requirements of ISO 13855

K values: 1600 mm/s walking, 2000 mm/s hand movement for close approach

T: total stopping performance (detection response + machine stopping time)

C additions for detection capability (finger/hand/body) and reach-over via table lookups

Specific procedures for vertical, horizontal and angled detection fields

Key concepts: ISO 13855

Detection capability C-addition

Penalty distance growing with coarser resolution (14 mm finger detection adds little; body detection adds much more).

Reach-over height matrix

ISO 13857-derived tables adding distance when the protective field's top edge can be reached over.

Stop-time measurement

Periodic verification (drift of brakes/valves) that installed distances remain valid.

Stopping performance T

Measured worst-case time from initiating detection to hazard cessation, including control and actuator lag.

Frequently asked questions: ISO 13855

Does ISO 13855 apply to interlocked guards too?

Yes — for guards without guard locking, the same time-based approach ensures the hazard ends before a person can open the guard and reach it; otherwise guard locking per ISO 14119 is required.

Why did my light curtain end up so far from the hazard?

Distance is K·T + C: long machine stopping time or coarse resolution inflate it quickly. Reducing stopping time (better braking, SS1) or finer resolution moves the curtain closer; sometimes a different safeguard concept wins.