ISO 13851-2019 PDF

Full title and description

Safety of machinery — Two-hand control devices — Principles for design and selection. This International Standard specifies safety requirements and guidance for the design and selection of two‑hand control devices (THCDs), describes main functional characteristics and combinations for three device types, and addresses prevention of defeat, avoidance of faults and verification of compliance. It does not apply to devices intended as enabling devices, hold‑to‑run devices or special control devices, nor does it prescribe which machines must use THCDs.

Abstract

ISO 13851:2019 defines the relationship between manual actuation of the two control parts and the resulting output signal, sets out functional characteristics required to achieve safe operation, and provides guidance on selection based on risk assessment. The document applies to THCDs irrespective of energy type and covers devices supplied as complete units or assembled by machine manufacturers; it is not applicable to THCDs manufactured before its publication date.

General information

• Status: Published (International Standard, confirmed stage).
• Publication date: March 19, 2019.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 13.110 (Safety of machinery).
• Edition / version: Edition 2 (ISO 13851:2019).
• Number of pages: 21 (ISO edition).

Scope

ISO 13851:2019 applies to two‑hand control devices used to protect operators by requiring coordinated bimanual actuation. The standard specifies functional safety requirements and design principles for THCDs, addresses combinations of functional characteristics for three device types, and offers selection guidance based on a risk assessment. It does not mandate the use of THCDs for particular machines, nor provide fixed separation distances to the hazard (although guidance is given). The standard excludes enabling, hold‑to‑run and special control devices.

Key topics and requirements

• Definition of two‑hand control device (THCD) functional behaviour and the dependence of output on manual actuation.
• Classification and combinations of functional characteristics for three types of THCD.
• Design requirements to prevent defeat or circumvention of the device and to avoid faults that could lead to unexpected actuation.
• Guidance on selection of THCDs based on a documented risk assessment (linkage to ISO 12100 and ISO 13849 principles).
• Requirements and guidance for THCDs containing programmable electronic systems.

Typical use and users

Typical users are machine designers, integrators, safety engineers, manufacturers of control devices and conformity assessors. THCDs are used on machines where bimanual operation is an accepted protective measure to keep the operator’s hands away from a hazard during hazardous machine cycles (for example certain presses, shears and forming equipment). Selection and implementation should be carried out as part of the machine risk assessment and in conjunction with other relevant safety standards.

Related standards

Commonly referenced standards and technical reports include ISO 12100 (general principles for design and risk assessment), ISO 13849 (safety‑related parts of control systems) and ISO 14118 (prevention of unexpected start‑up). ISO 13851 replaces the earlier ISO 13851:2002 edition; in many regions it is published or adopted as EN ISO / national variants (for example DIN EN ISO 13851:2019).

Keywords

two‑hand control, two‑hand control device (THCD), bimanual control, machine safety, safeguarding, defeat prevention, risk assessment, ISO 13851, ISO 13849, ISO 12100.

FAQ

Q: What is this standard?

A: ISO 13851:2019 is an International Standard that sets out principles for the design and selection of two‑hand control devices used as a protective measure on machinery.

Q: What does it cover?

A: It covers functional requirements, device characteristics and guidance for preventing defeat and avoiding faults in THCDs, including guidance for devices containing programmable electronics. It defines combinations of functional characteristics for three types of THCD and provides selection guidance based on risk assessment, but does not prescribe which machines must use THCDs.

Q: Who typically uses it?

A: Machine designers, safety engineers, device manufacturers, integrators and conformity assessors use this standard when specifying, designing or verifying two‑hand control solutions for hazardous machine operations.

Q: Is it current or superseded?

A: ISO 13851:2019 is the current (second) edition, published on 19 March 2019; it supersedes ISO 13851:2002. The ISO record shows the 2019 edition as the active confirmed International Standard.

Q: Is it part of a series?

A: It is part of the broader suite of machine‑safety standards and is commonly used alongside ISO 12100 (risk assessment) and ISO 13849 (safety‑related parts of control systems); those standards together support the design and validation of safety functions.

Q: What are the key keywords?

A: Two‑hand control, THCD, bimanual operation, machine safeguarding, defeat prevention, functional characteristics, risk assessment.