EN ISO 13851:2019 PDF

Overview

EN ISO 13851:2019 - Safety of machinery - Two-hand control devices (THCD) - Principles for design and selection - specifies safety requirements and selection guidance for two‑hand control devices used to protect operators during hazardous machine operations. It defines the relationship between hand actuation and output signals, describes main characteristics and combinations of functional features for three THCD types, and sets out requirements to prevent defeat, avoid faults and verify compliance. The document applies to all THCDs (pre‑assembled or assembled by integrators), irrespective of the energy source, and supersedes EN 574:1996+A1:2008.

Key Topics and Requirements

• Two‑hand operation: Requirements for simultaneous use of both hands and for synchronous actuation to ensure operator hands are kept away from danger zones.
• Actuation–output relationship: Rules governing how hand actuation controls output signals and how output cessation and re‑initiation must behave.
• Prevention of defeat and accidental operation: Design and selection requirements to prevent bypassing (defeat) using a single hand, forearm, elbow, other body parts, or external objects.
• Safety functions: Functional requirements including prevention of unexpected start‑up and safe releasing of actuators.
• Verification and validation: Procedures for visual inspection, performance testing, measurements, and tests for defeat prevention to confirm compliance.
• General design requirements: Ergonomics, operating conditions, enclosures, mounting/installation guidance, environmental influences, and measures against unintended outputs (e.g., acceleration forces).
• Marking and documentation: Requirements for product marking and comprehensive information for installation, operation and maintenance.
• Scope limits: Not applicable to enabling devices, hold‑to‑run devices, special control devices, or THCDs manufactured before publication. The standard does not mandate which THCD type to use for a particular machine nor prescribe exact safety distances (guidance provided only).

Applications and Who Uses It

• Machine manufacturers and integrators selecting or integrating two‑hand control devices into presses, cutting machines, forming equipment and similar hazardous machinery.
• Safety engineers and risk assessors performing risk assessments to determine whether a THCD is suitable and which functional characteristics are required.
• Product designers and control system engineers designing THCD hardware and safety logic to meet prevention of defeat and verification requirements.
• Compliance officers and notified bodies using EN ISO 13851:2019 as a harmonized means to demonstrate conformity with safety directives (see Annex ZA for relation to Directive 2006/42/EC).

Related Standards

• Supersedes: EN 574:1996+A1:2008.
• Developed by ISO/TC 199 and CEN/TC 114; for machine‑specific suitability, refer to relevant type‑C standards.

Keywords: EN ISO 13851:2019, two‑hand control devices, THCD, safety of machinery, design and selection, prevention of defeat, risk assessment, verification and validation, safety distance.