Collaborative Robot Safety Standards: ISO 10218, ISO/TS 15066, and ANSI/RIA R15.06

Three standards govern collaborative robot safety. ISO 10218 covers robot design and system integration. ISO/TS 15066 defined human-robot contact force and pressure limits. ANSI/RIA R15.06 is the US adoption of ISO 10218-2. As of 2025, ISO/TS 15066 has been integrated into ISO 10218-2, making the contact limits part of the core standard rather than a separate technical specification.

This is a reference guide. It covers what each standard requires, who it applies to, how the four collaborative operation modes work, and what changed in the 2025 revision. For the force and pressure measurement process, see the cobot safety testing guide. For the full body region limits table, see the ISO/TS 15066 body region force limits reference.

The Standards Framework

Six documents define the compliance landscape for collaborative robots. They’re not independent: they form a hierarchy, with general risk methodology at the base and robot-specific requirements building on top.

The hierarchy works like this: ISO 12100 establishes the general risk assessment methodology that all machinery standards reference. ISO 10218 applies that methodology to industrial robots, with Part 1 addressing what robot manufacturers must build into the product and Part 2 addressing what system integrators must verify during installation. ISO/TS 15066 (now absorbed into Part 2) specified the force and pressure limits for power and force limiting mode. ANSI/RIA R15.06 is the path US facilities typically follow, adopting the ISO 10218-2 framework with some additions for OSHA compliance.

A point that trips up many integrators: ISO 10218 covers all industrial robots, not only cobots. The collaborative operation requirements are a subset within the larger standard. A traditional robot with full physical guarding still falls under ISO 10218.

ISO 10218-1: Requirements for Robot Manufacturers

Part 1 of ISO 10218 tells robot OEMs what they must build into the robot before it leaves the factory. System integrators don’t certify to Part 1 directly, but they depend on the robot meeting it.

Key requirements Part 1 places on manufacturers:

Safety-rated control functions. The robot must provide safety-rated monitored stop, safety-rated speed monitoring, and safety-rated axis and space limiting. These are not software features that can fail silently. They require dedicated safety-rated circuits with defined performance levels (typically PLd or PLe per ISO 13849-1).

Emergency stop. The robot must implement emergency stop per IEC 60204-1, with defined stop categories (typically Category 0 or 1). Stop performance must be documented by the manufacturer.

Collaborative operation capability. If the robot is marketed as collaborative, Part 1 requires the manufacturer to document which collaborative modes the robot supports and under what conditions. A robot without manufacturer documentation for a specific mode can’t be deployed in that mode and still claim ISO 10218 compliance.

Documentation for integrators. Part 1 requires manufacturers to provide all information the integrator needs to perform the Part 2 risk assessment. This includes payload envelopes, stopping distances, force characteristics under different loads, and safety function performance levels.

Type examination. Robots sold in the EU under the Machinery Directive require type examination by a notified body. The CE mark on a collaborative robot indicates this examination has been completed and Part 1 requirements are satisfied.

ISO 10218-2: Requirements for System Integrators

Part 2 is where integration work actually begins. It defines what the system integrator must verify, document, and validate before a cobot installation goes into production. This is the standard most safety engineers work against day to day.

Risk assessment. Part 2 requires a formal risk assessment per ISO 12100 before any other design decisions are made. The risk assessment identifies hazards, estimates risk level, and determines what safeguarding measures are required. For collaborative installations, it must also identify the collaborative operation modes appropriate for each hazard scenario.

Safeguarding selection. Based on the risk assessment, the integrator selects safeguarding: physical guards, safety devices (light curtains, scanners, mats), collaborative operation, or some combination. The standard doesn’t prescribe which approach to use. It requires that whatever approach is selected brings risk to an acceptable level.

Safety function verification. Every safety function implemented in the cell must be verified. Stopping distances, safety device response times, performance levels. Verification is documented and must be repeatable.

Validation. Validation confirms that the complete installation as built matches the design intent. This is distinct from verification. Verification checks that each component works. Validation checks that the system as a whole behaves as intended under the conditions defined in the risk assessment.

Documentation package. Part 2 specifies what documents must accompany the completed installation: the risk assessment, safeguarding design rationale, verification records, validation records, and operator/maintenance instructions. This package must be handed to the end user.

The 2025 addition. The 2025 revision absorbed ISO/TS 15066. Compliance testing for power and force limiting mode is now mandatory within Part 2 rather than guidance from a separate technical specification. The force and pressure limits themselves haven’t changed, but the compliance framework around them is now binding rather than advisory for integrators claiming PFL mode.

Periodic re-assessment. Part 2 requires establishing a schedule for periodic re-assessment and specifying what changes trigger immediate re-assessment. Program changes, tool changes, payload changes, and cell layout modifications are the typical triggers. This schedule must be documented.

The Four Collaborative Operation Modes

ISO/TS 15066 defined four collaborative operation modes. These are now part of ISO 10218-2:2025. The modes aren’t mutually exclusive: a cell can combine them. A robot might operate in power and force limiting mode during normal production and switch to safety-rated monitored stop during a maintenance procedure.

Safety-rated monitored stop is the simplest to implement and the most restrictive. The robot pauses when a human enters the defined workspace and resumes when they leave. No robot motion occurs while a person is present. This mode works well for infrequent operator access (occasional part loading) but isn’t productive when operators need to work adjacent to the robot during its cycle.

Hand guiding lets an operator physically move the robot. The robot’s joints are back-driven, with safety-rated speed limiting active to prevent dangerous velocities. The main application is programming and teaching, though some assembly processes use hand guiding for operator-guided path correction. Hand guiding requires a dedicated hand-guided device with a safety-rated enable switch.

Speed and separation monitoring is the most demanding to implement correctly. A safety-rated sensor (laser scanner, camera, radar) continuously measures the distance between the robot and any person. When a person is within the protective field, the robot slows or stops. The minimum distance threshold must account for the robot’s stopping time at the current speed. Implementing this correctly requires careful calculation of minimum distances and safety-rated sensing with documented response times.

Power and force limiting is the mode most people mean when they say “collaborative robot.” The robot detects contact with the human body (through torque sensing, current monitoring, or dedicated force sensors) and limits the contact force and pressure below the thresholds defined for each body region. ISO/TS 15066 Table A.2 defines 29 body regions with different limits. The robot can continue moving while in contact with a person, within those force limits. This mode requires validation testing: the actual forces and pressures must be measured, not assumed. See the cobot safety testing guide for the measurement process.

Force and Pressure Limits

Power and force limiting mode depends on body region-specific limits derived from biomechanical research on pain onset thresholds. The research established how much force and pressure different body regions can tolerate before pain begins. The standard uses pain onset rather than injury as the threshold because pain functions as a warning that allows the person to react and withdraw.

The standard defines limits for two contact scenarios:

Transient contact (impact): The robot strikes a body part and the person can recoil. Limits are higher because the contact is brief and the body can move away.

Quasi-static contact (clamping): The robot traps a body part against a fixed surface. The person can’t escape. Limits are significantly lower because force is sustained.

Each of the 29 body regions has a spring constant (in N/mm) that defines how stiff that tissue is. A measurement system must match the spring constant of the body region being tested. A standard load cell doesn’t simulate body tissue response and won’t give valid results for compliance purposes.

For the complete table with spring constants, transient force limits, and quasi-static force limits for all 29 body regions, see the body region force limits reference.

ANSI/RIA R15.06 and the US Pathway

ANSI/RIA R15.06-2012 is the primary robot safety standard referenced in the United States. It’s a US adoption of ISO 10218-2:2011, with some US-specific requirements added during the adoption process. OSHA references R15.06 in its guidance on industrial robot safety, and most US manufacturers and insurers expect compliance with it.

Because R15.06 is based on ISO 10218-2:2011, it predates the 2025 update and the formal integration of ISO/TS 15066. For collaborative robot installations in the US, the standard practice is to comply with R15.06 and supplement it with ISO/TS 15066 for collaborative-specific requirements. This combination gives OSHA-aligned compliance while covering the collaborative operation modes and force limits that R15.06’s 2012 vintage doesn’t address.

RIA TR R15.806-2018 is a separate US technical report specifically covering human-robot collaboration testing methodology. It’s not a mandatory standard but provides the most detailed US guidance on how to perform PFL mode validation testing.

The update path: RIA typically adopts revised ISO standards with a delay of one to three years. An update to ANSI/RIA R15.06 based on ISO 10218-2:2025 is expected but not yet published as of 2026. For new US installations, the safest approach is compliance with the current R15.06, ISO 10218-2:2025 where it adds requirements, and ISO/TS 15066 for the force limit tables.

The 2025 Standards Update

The 2025 revision of ISO 10218-2 is the most significant update to collaborative robot safety standards since ISO/TS 15066 was published. The key change: the force and pressure limits from ISO/TS 15066 are no longer in a separate technical specification. They’re in the core integration standard.

Practically, this means two things. First, compliance testing for power and force limiting mode is now unambiguously mandatory for any integrator claiming Part 2 compliance with PFL-mode robots. Before 2025, an integrator could argue that ISO/TS 15066 was a technical specification (guidance) rather than a normative requirement. That argument doesn’t hold with the 2025 revision. Second, the documentation package for a PFL-mode installation must include force and pressure measurement records as a Part 2 compliance deliverable.

The force and pressure limits themselves haven’t changed. The 29 body regions, spring constants, transient limits, and quasi-static limits are the same values published in ISO/TS 15066:2016. What changed is where they live and whether testing against them is required.

Existing installations certified under ISO 10218-2:2011 don’t automatically require re-certification for the 2025 version. New installations and significant modifications to existing ones should reference the 2025 version. Transition timelines vary by jurisdiction and certification body. Check with your notified body for the specific requirements in your market.

Practical Compliance Checklist

The three gate items determine whether the installation is fundamentally compliant. Everything else can be iterated. An installation with an incomplete risk assessment, an undocumented mode selection, or missing PFL force measurements isn’t compliant regardless of how thorough the verification records are.

A common sequence error: integrators begin cell design before completing the risk assessment, then retrofit the risk assessment to match what’s already built. Part 2 requires the risk assessment to drive design decisions, not document them after the fact. An auditor reviewing the risk assessment dates against the cell build dates will flag this.

Frequently Asked Questions

For the measurement process, see the cobot safety testing guide. For the complete body region table with force and pressure limits, see the ISO/TS 15066 body region force limits reference.