Industrial standards for robotic machinery
Are any OSHA/ANSI codes applicable to robots and collaborative robots?
Responding is Carrie Halle, vice president of marketing, Rockford Systems LLC, Rockford, IL.
Yes – there are standards for both types of robots. Industrial robots are machines, defined by ISO 8373:2012 as “an actuated mechanism programmable in two or more axes with a degree of autonomy, moving within its environment, to perform intended tasks.”
Industrial robots must be safeguarded in ways similar to those presented for any hazardous remotely controlled machine. Industrial robots are guarded to prevent humans from coming in contact with the robot.
Although OSHA doesn’t have a specific robot requirement, safeguarding industrial robots falls under the General Duty Clause (5)(a)(1), which requires employers to provide a safe and healthful workplace free from recognized hazards likely to cause death or serious physical harm. Also applicable are OSHA 1910.212 General Requirements for All Machines, OSHA 1910.219 Mechanical Power Transmission Apparatus, OSHA 29 CFR 1910.147 Control of Hazardous Energy (Lockout/Tagout), and NFPA 79 2015 Electrical Standard for Industrial Machinery.
Published by the American National Standards Institute and the Robotic Industries Association, ANSI/RIA R15.06 Robot Safety Standard for Industrial Robots and Robot System Requirements is a U.S. consensus standard that provides guidance on the proper use of the safety features embedded into robots, as well as how to safely integrate robots into factories and work areas.
The most comprehensive standard, ANSI/RIA R15.06-1999, provides comprehensive and detailed information on point of operation safeguarding. However, the latest revision of the standard, ANSI/RIA R15.06-2012, references for the first time ISO 10218:2011 to achieve global harmonization with international standards already in place in Europe and other countries that adopted the ISO 10218 standard.
Part 1 of ISO 10218 details safeguarding requirements for the manufacturer of the industrial robot, which includes specifically the robot arm and the robot controller. Part 2 of ISO 10218 addresses the responsibilities of the integrator or installer regarding the entire industrial robot system, which includes the industrial robot plus the end effector plus the workpiece plus any peripheral equipment.
So, today, ANSI/RIA R15.06-2012 equals ISO 10218-1,2:2011. Additionally, four ANSI-registered technical reports support the R15.06 standard: RIA TR R15.306-2016 Task-Based Risk Assessment Methodology (“TR 306”); RIA TR R15.406-2014 Safeguarding (“TR 406”); RIA TR R15.506-2014 Existing Systems (“TR 506”); and RIA TR R15.606-2016 Collaborative Robot Safety (“TR 606”), or ISO/TS 15066:2016. Further, a new standard, ANSI/RIA R15.08, is under development for Industrial Mobile Robot Safety, specifically addressing robots with mobile bases.
Unlike industrial robots, collaborative robots – or “cobots” – are designed to work in collaboration with humans through physical interaction in a shared workspace. As mentioned, ANSI/RIA R15.06-2012 and TR 606, which is globally harmonized with ISO/TS 15066:2016, address collaborative robots. The standard clarifies four types of collaboration: Safety Monitored Stop, Hand Guiding, Speed & Separation Monitoring, and Power & Force Limiting. These categories are not mutually exclusive. For example, a PFL collaborative robot might also have a Safety Monitored Stop. The standard provides key information, including guidance on maximum allowable speeds and minimum protective distances, along with a formula for establishing the protective separation distance and data to verify threshold limit values for power and force limiting to prevent pain or discomfort on the part of the operator.
The requirement for task-based risk assessments is one of the biggest changes in the new ANSI/RIA R15.06-2012 standard. The integrator, or the end user if they’re performing the job of an integrator, now must conduct a task-based risk assessment of each robotic system and summarize ways to mitigate these risks. Risk assessments calculate the potential severity of an injury, the operator’s exposure to the hazard and the difficulty in avoiding the hazard to arrive at a specific risk level ranging from negligible to very high. Task/hazard pairs are identified in a risk-level decision matrix that corresponds with risk levels ranging from very high to negligible.
The appropriate level of risk-reduction measures determined by the task-based risk assessment then should be applied – such as incorporating machine safeguarding or administrative measures, or providing warnings and personal protective equipment – to basic safety management.
Do collaborative robots need to be safeguarded?
There is no one-size-fits-all answer to this question. Per ANSI/RIA R15.06-2012, safeguarding a collaborative robot depends on the type of collaborative robot, the type of application the collaborative robot is performing, the speed at which it is operating, and the results of the task-based risk assessment.