Regulatory Framework
Understanding which standards apply to your installation before designing safeguards saves significant rework. The relevant standards depend on robot type and use case:
- ISO 10218-1:2011 — Safety requirements for industrial robots (the robot itself). Applies to the robot manufacturer. As an integrator, you must ensure the robot you purchase is certified to this standard.
- ISO 10218-2:2011 — Safety requirements for industrial robot systems and integration. This is the integrator's standard — it covers your installation, guarding, and programming. Non-compliance is the most common gap in lab deployments.
- ISO/TS 15066:2016 — Collaborative robots. Specifies the requirements for robots operating in close proximity to humans without fixed guarding. Defines the Power and Force Limiting (PFL) contact force thresholds by body region: hand dorsum 280N limit, upper arm 110N limit. Critical for any installation where operators work within the robot's reach.
- OSHA 1910.212 — General machine guarding requirements in the United States. OSHA inspectors will cite this standard for inadequately guarded robots even if ISO standards are met. Ensure your guarding meets both.
Risk Assessment Steps
A risk assessment is a structured documentation process, not just a mental checklist. The output must be a written document that can be reviewed by a safety auditor.
- Step 1 — Identify all tasks: List every task the robot will perform: normal operation, programming, maintenance, cleaning, recovery from fault. Each task creates different hazards.
- Step 2 — Identify hazards per task: For each task, identify all hazards: collision, entrapment, sharp edges, electrical, noise, heat.
- Step 3 — Estimate risk: For each hazard, estimate risk using a 3-factor matrix: Severity (minor injury / serious injury / fatality) × Frequency of exposure × Probability of avoiding the hazard. Most organizations use a 1–5 scale per factor, computing a risk priority number (RPN = S × F × P).
- Step 4 — Apply risk reduction measures: Reduce risk for any hazard with RPN >12 (on a 1–5 scale) or any hazard with Severity = 3 (fatality risk) regardless of RPN.
- Step 5 — Evaluate residual risk: Re-evaluate risk after controls are applied. Document the residual risk and confirm it is "acceptable" per your organization's criteria. Risk is never zero — the goal is acceptable residual risk.
Hazard Types and Limits
- Collision hazard (cobot near humans): For collaborative operations under ISO/TS 15066, limit robot TCP speed to ≤0.25 m/s when the human-robot separation distance is <0.5 m. Above 0.5 m, speed can increase per the speed-separation monitoring calculation in ISO/TS 15066 Annex A.
- Clamp/crush hazard (gripper): Pneumatic and electric grippers can exert forces far exceeding ISO/TS 15066 thresholds. Limit gripper closing force to ≤140 N for contact with human hands (ISO/TS 15066 Table A.2, hand dorsum). Implement this via a force/current limit in the gripper controller.
- Sharp edge hazard: Any robot tooling with edges sharper than R2.5 mm requires guarding or must be restricted from the collaborative workspace.
- Electrical hazard: Follow IEC 60204-1 for machine electrical safety. Verify that the robot's safety-rated I/O (for emergency stop and enabling device) uses a Category 3 or PLd safety function per ISO 13849-1.
Control Measures Hierarchy
Always apply risk reduction in hierarchy order. Higher-order measures are more reliable because they do not depend on human compliance:
- 1. Eliminate: Remove the hazard entirely. Example: redesign the gripper tip to be blunt — no sharp edge hazard remains. This is always preferred.
- 2. Guard (engineering control): Physical barriers, light curtains, safety laser scanners. These protect humans passively without relying on their behavior.
- 3. Warn (administrative control): Safety signage, floor markings, written procedures, training. Effective only when combined with higher-order controls — cannot substitute for guarding.
- 4. PPE (Personal Protective Equipment): Safety glasses, gloves, steel-toed shoes. Last resort — PPE fails when people forget or remove it.
Safeguarding Options
| Device | Example Product | Detection Range | Response Time | Approx. Cost |
|---|---|---|---|---|
| Safety laser scanner | Sick S300 Mini | Up to 4m radius, 270° field | <80ms | $2,000–$4,000 |
| Light curtain | Keyence GL-R series | 0.1–9m height, 0.5–6m width | <10ms | $800–$3,000/pair |
| Pressure-sensitive mat | Tapeswitch Corp. Series 300 | 0.5–10 m² coverage | <10ms | $400–$1,500 |
| Safety camera (vision-based) | Pilz SafetyEYE | 3D zone monitoring up to 8m | <40ms | $5,000–$12,000 |
For most manipulation labs, a Sick S300 safety laser scanner combined with floor zone markings provides the best balance of coverage, flexibility, and cost. The S300 can define multiple protective fields and warning fields simultaneously, allowing the robot to slow down (speed warning field) before stopping (protective field).
Cobot-Specific Requirements
Robots marketed as "collaborative" (Universal Robots UR-series, Fanuc CR-series, ABB YuMi) still require a risk assessment — "collaborative" is a capability, not a safety certification. Three collaborative operating modes are defined in ISO/TS 15066:
- Power and Force Limiting (PFL): The robot continuously monitors motor currents and stops if contact force exceeds the ISO/TS 15066 thresholds. Requires force/torque monitoring in every joint. Most cobots support this mode natively.
- Speed and Separation Monitoring (SSM): Uses a safety-rated sensor (laser scanner or camera) to track human position. Robot speed is reduced as the human approaches. Full stop if the human enters the minimum separation distance.
- Hand-Guiding: Operator physically guides the robot with a hand-guiding device (force sensor in the tool). Must have a safety-rated enabling device (3-position switch) to prevent unintended motion.
Documentation Requirements
For any commercial deployment, you must maintain:
- Risk assessment report: The complete written risk assessment per the five steps above. Must be signed by a qualified person and kept current with any system changes.
- CE Declaration of Conformity: Required for sales in the EU. Certifies compliance with the Machinery Directive 2006/42/EC. Requires a Notified Body review for robots in specific high-risk categories.
- OSHA compliance checklist: For US installations, document compliance with OSHA 1910.212 guarding requirements and any ANSI/RIA R15.06 robot safety standard requirements. Keep on-site for OSHA inspector access.
- Operator training records: Document that all operators have received safety training, with dates and signatures. Required by both OSHA and ISO 10218-2.
Practical Lab Implementation
- Emergency stop placement: Install a physical e-stop button at every workstation within reach of the robot, and one at the room entrance. The rule of thumb: an e-stop must be reachable within 3 seconds from any location a person might stand in the workspace.
- Clear zone markings: Use high-visibility tape (yellow/black pattern) to mark the robot's maximum reach radius on the floor. A secondary marking at the collaborative speed boundary (0.5 m from TCP at maximum reach) helps operators understand safe approach zones.
- Operator training: All operators must complete safety training before their first session. Training must cover: emergency stop location and use, prohibition on reaching into the operational zone during motion, what to do if the robot behaves unexpectedly.