International standards for robot safety (Comprehensive guide)

robot safety

International standards play an important role in setting the baseline for best practices in robotics safety, hazard analysis, project planning, design, system requirements specification, system verification and validation, and quality assurance.

Perhaps, compliance with standards is not mandatory. Yet, standards can capture the international consensus and set general guidelines to certify the “mission-worthiness” of new products and systems and accelerates their commissioning process.

Globally harmonized standards help meet market demands, lower costs by standardizing designs, and allow products to be global. They can also provide risk management assistance by helping to limit liability for products.

International bodies like the International Organization for Standardization (ISO) and the International Electro Technical Commission (IEC) are instrumental in introducing relevant international standards.

There are three kinds of standards when we talk about safety standards:

1. ISO Standards

ISO is a highly structured and organized standardization to minimize overlapping scopes and is supposed to use other standards (and not “reinvent the wheel”). ISO standards are voluntary unless adopted as regulations and are meant to allow globalization of trade by unifying border requirements. They are often adopted by the EU as a harmonized standard. This means that the EN ISO standard provides a presumption of conformity (complies with Directives). They apply to manufacturers, suppliers, integrators of the components or machines. The compliance can be used as a legal presumption of conformity with the machinery directive (if harmonized).

2. ANSI Standards

ANSI standards are based on market demand without oversight as to technical content. They accredit an organization to be an SDO (Standards Development Organization) for a specific market/ scope. They are voluntary – unless adopted as a regulation (law). They apply to manufacturers, integrators, and users of the components or machines. Compliance can be used as a means of complying with OSHA requirements of a safe workplace (since there are many more ANSI standards than regulations) but NOT presumption of compliance.

3. OSHA Standards

OSHA standards are regulatory standards (required by law) and are NOT comprehensive. There are VERY few OSHA machine safety standards (e.g., mechanical power presses, forging machines, cooperage machines). There is NO OSHA robot standard. However, OSHA references R15.06 as being the standard applicable to robot systems. OSHA standards provide requirements only to Users (Employers) for occupational safety but can include employees’ responsibilities (ex. Lock-out).

All ISO/IEC safety standards are organized in a three-level hierarchy from the most general and relatable to generic machinery – type A – to machine-specific – type C.

  • Type A norms establish basic concepts, conception principles, and general requirements by defining the strategy for risk assessment and risk reduction, which involves determining the robotic system limits, identifying risks and hazards, risk estimation, and risk evaluation.
  • Type B norms specify safety aspects or safeguards applicable to machinery. These norms are split into two categories – the B1 norms related to general safety aspects (e.g.,
    safety distances, surface temperature, noise levels, etc.), and B2 norms about safeguard (e.g., bimanual commands, interlock devices, pressure-sensitive devices, protective equipment, etc.).
  • Type C norms identify specific safety requirements applicable to a machine category, and they are used as templates and take precedence over more general standards. Type C norms often refer to standards of types A and B to address, for example, risk assessment and other safety-related details.

The international standards on machine and robot safety are as follows:

ISO 10218-1 and ISO 10218-2 are standards that discuss the robots and robotic devices and safety requirements for industrial robots. Part 1 Robots (ISO 10218-1:2011), dedicated to robot manufacturers, sets the requirements of the robot for the design of manipulators for industrial environments, such as mechanical and electrical design, pendant controls, operational modes, etc.

ISO 10218-2 (Part 2), dedicated to robot system integrators, deals with robot systems and integration, setting the requirements for integrating industrial robots into automation systems, such as collaborative modes like monitored stop, hand guiding, velocity, or force control. It defines guidelines for safeguarding personnel, commissioning, functional testing, programming, operation, and maintenance. ISO 10218-2 also narrows down the scope of the risk assessment process by focusing on topics relatable to robotic systems.

The Annex G of ISO 10218-2 includes a comprehensive table to verify the compliance of the safety requirements and measures for robotic systems. The topic of collaborative robotics is referred to in ISO 10218-2 (section 5.11 and Annex G). Still, given the complexity of the subject, it is supplemented by the technical specification ISO/TS 15066. Annex A compiles a list of the most significant hazards of different sources (mechanical, electrical, thermal, noise, etc.) relatable to robotic applications. The norm proceeds to address the safety requirements and protective measures. It extends and particularizes requirements for SRP/CS in the B norms to address robot applications.

ISO 13482:2014 specifies requirements and guidelines for the inherently safe design, protective measures, and information for the use of personal care robots, in particular the following three types of personal care robots: mobile servant robot, physical assistant robot, and person carrier robot. It describes hazards associated with the use of these robots and provides requirements to eliminate, or reduce, the risks associated with these hazards to an acceptable level. It also covers human-robot physical contact applications.

ISO/TR 20218-2:2017 is a technical report that supplements ISO 10218-2:2011 and provides additional information and guidance on reducing the risk of intrusion into hazardous zones in the design and safeguard of manual load/unload installations. (ISO/TR 20218-2 2017)

ISO/TS 15066 deals with technical specifications for the robots and robotic devices, such as collaborative robots that provide guidance for collaborative robot operation where a robotic system and people share the same workspace. It is not a standard, although it is now accepted as best practice, together with ISO 10218 on human-robot collaboration. The specification supports the industrial robot safety standards ISO 10218-1 and ISO 10218-2 and provides additional guidance on the identified operational functions for collaborative robots. (ISO/TS 15066 2016)

ISO/TR 20218-1:2018 is another technical report that provides guidance on safety measures for the design and integration of end effectors used in robot systems. From the manufacturing, design, and integration of end effectors to the information necessary for their use. (ISO/TR 20218-1 2018). This technical report also mentions shape and surface forms, safety-related control system performance, examples of hazards from end effectors and workpieces, etc.

ISO 11161:2007 specifies the safety requirements for integrated manufacturing systems (IMS) that incorporate two or more interconnected machines for specific applications, such as component manufacturing or assembly. It gives requirements and recommendations for the safe design, safeguarding, and information for the use of such IMS.

ISO 13850:2015 specifies functional requirements and design principles for the emergency stop function on machinery, independent of the type of energy used. This International Standard requirements apply to all machines, except hand-held machines and machines where an emergency stop would not reduce the risk.

ISO 13851:2019 specifies the safety requirements of a two-hand control device (THCD) and the dependency of the output signal from the actuation by the hand of the control actuating devices. It provides requirements for design and guidance on the selection (based on a risk assessment) of THCDs, including the prevention of defeat, the avoidance of faults, and verification of compliance.

ISO 13855:2010 establishes the positioning of safeguards concerning the approach speeds of parts of the human body. It specifies parameters based on values for approach speeds of parts of the human body. It provides a methodology to determine the minimum distances to a hazard zone from the detection zone or from actuating devices of safeguards.

ISO 13849-1:2015 provides safety requirements and guidance on the principles for designing and integrating safety-related parts of control systems (SRP/CS), including the software design. For these parts of SRP/CS, it specifies characteristics that include the performance level required for carrying out safety functions. It applies to SRP/CS for high demand and continuous mode, regardless of the type of technology and energy used (electrical, hydraulic, pneumatic, mechanical, etc.) for all kinds of machinery. Part 1, which deals with general principles for design, introduces required performance levels (PL) for safety-related control systems (e.g., velocity and position control, collision avoidance, stability control, etc.).

ISO 12100:2010 focuses on machinery safety, general principles for design, risk assessment, risk reduction. It specifies general requirements for machines (e.g., emergency stop buttons, start-up) and risk assessment principles and risk reduction to help designers achieve this objective. These principles are based on knowledge and experience of the design, use, incidents, accidents, and risks associated with machinery.

IEC 60204-1:2016 deals with the electrical equipment of machines concerning safety. This international standard defines three categories of stop functions for the electrical equipment of machines: Stop category 0 – Stopping by immediate removal of power to the machine actuators; Stop category 1 – A controlled stop with power available to the machine actuators to achieve the stop and the removal of the power when the stop is achieved; Stop category 2 – A controlled stop with power left available to the machine actuators.

IEC 61508-1:2010 covers the functional safety of electrical/electronic/programmable electronic safety-related systems.

IEC 62061:2005 specifies requirements and makes recommendations for designing, integrating, and validating safety-related electrical, electronic, and programmable electronic control systems (SRECS) for machines. It also defines safety integrity levels (SIL) for safety-related control systems and the conversion between PLs and SILs. It is also applicable to software functions.

Here is a split-up of standards based on various categories:

Personal care robot safety

  • ISO 13482 (Safety for personal care robots)
  • ISO/CD TR 23482-1 (Verification & validation methods for ISO 13482)
  • ISO/CD TR 23482-2 (Application guide for ISO 13482)

Industrial Safety

  • ISO 10218-1/2 (Safety for industrial robots, published)
  • ISO/TS15066 (Safety for collaborative industrial robots)
  • Technical reports on manual load/unload stations, end effectors (new work items)

Service Robots

  • ISO 18646-1 (Locomotion performance)
  • ISO/WD 18646-2 (Navigation performance)
  • Tasks: Contact with liaisons (IEC, OMG); Explore the need for additional standards

Medical robot safety

  • IEC/DTR 60601-4-1 (Report on autonomy)
  • IEC/NP 80601-2-77 (Safety for surgical robots)
  • IEC/NP 80601-2-78 (Safety for rehabilitation robots)
  • Joint working group with IEC/SC 62A and IEC/SC 62 D