ISO 13850:2015

Overview

ISO 13850:2015 - "Safety of machinery - Emergency stop function - Principles for design" sets functional requirements and design principles for the emergency stop (E‑stop) function on machinery, independent of energy type. It defines what an emergency stop must achieve, how it should behave, and how devices should be arranged and identified. The standard excludes hand‑held/hand‑operated machines and machines where an emergency stop would not reduce risk. Electrical/electronic implementation guidance is covered in IEC 60204‑1.

Key topics and technical requirements

• Emergency stop function (E‑stop):
  • Intended to avert or reduce hazards and initiated by a single human action.
  • Must be available and operational at all times and override other functions without impairing other protective measures.
  • Activation must be maintained until a deliberate manual reset; reset must not automatically restart the machine.
• Span of control:
  • Each E‑stop’s span of control should cover the appropriate sections, whole machine, or groups of machines.
  • Spans can overlap but must be clearly defined and identifiable at the actuator location (pictograms or location cues preferred).
• Stop categories:
  • Category 0: Immediate removal of power to machine actuators (e.g., switching off electrical power).
  • Category 1: Controlled deceleration/stop with power available, then removal of power once stopped.
  • Selection of category is determined by risk assessment.
• Disengagement and reset:
  • Disengagement (e.g., unlatching) must be intentional and only allow restarting procedures, not an automatic start.
  • Instructions must include inspection of machine before resetting after actuation.
• Device design and placement:
  • Requirements cover emergency stop devices, prevention of unintended actuation (shrouds, placement), use of wires/ropes as actuators, portable operator control stations, and environmental/operating conditions.
• Safety-related control parts:
  • Defines emergency stop equipment (input, processing, output) and their role in the safety function.

Applications and who uses this standard

ISO 13850:2015 is used by:

• Machine designers and OEMs to implement compliant E‑stop systems
• Safety engineers and risk assessors performing machine safety design and compliance checks
• System integrators and control engineers defining control strategies and layouts
• Plant managers and maintenance teams for safe operation, emergency procedures, and layout planning
• Compliance officers and certification bodies evaluating machine conformity

Typical practical uses: locating E‑stop devices, defining spans of control, choosing appropriate stop category, writing operator instructions, and integrating E‑stop behavior into machine safety concepts.

Related standards

• ISO 12100 - General principles for design, risk assessment
• ISO 13849‑1 - Safety‑related parts of control systems
• IEC 60204‑1 - Electrical equipment of machines (electrical/electronic realization of E‑stop)
• IEC 60947‑5‑5, IEC 62061, ISO 4413, ISO 4414 - referenced for device and subsystem specifics

Keywords: ISO 13850:2015, emergency stop, E‑stop, safety of machinery, emergency stop device, span of control, stop category, machine safety, design principles.