Robot Safety: It’s Not Science Fiction, It’s the Law
Some journalists and commentators can’t seem to write about industrial robots without making the inevitable references to science fiction writer Isaac Asimov and the “Terminator” movies. The truth is that robots have been around for many decades—and so have the laws and regulations addressing their safety issues.
It was 1987 when the Occupational Safety and Health Administration (OSHA) issued its Guidelines for Robotics Safety. The agency said at that time, “With the burgeoning use of robots in industry, it is feared that without adequate guarding and personnel training, injury rates for employees working with robots may increase.”
Robots have long been deployed to perform unsafe, hazardous, highly repetitive and unpleasant tasks, with the express intent of reducing potential hazards associated with those functions while increasing productivity. Perhaps the only labor leader to fully embrace automation was John L. Lewis, president of the United Mine Workers Union, precisely because it made underground mining safer for his members.
Attorneys for the law firm of Seyfarth Shaw LLP point out that early robots, which mainly conducted pre-programmed tasks and did not have the advanced computer intelligence that many now possess, created potential hazards not only under normal operating conditions, but also during programming, adjustment, testing, cleaning, inspection and repair periods.
From the robots’ introduction, it was quite common for employees—such as operators, programmers and maintenance workers—to walk within the robot’s work envelope while power remained available to the device’s moveable elements.
“Now, some 30 years after their widespread appearance in the workplace, robotics and computer automation have permeated nearly every industry, including manufacturing, warehousing and even retail, potentially exposing additional workers to hazards. In Japan, some coffee shops now serve coffee utilizing robotic baristas,” the lawyers observe.
Some safety experts believe OSHA’s current regulations are inadequate and need extensive updating. Last year the National Institute for Occupational Safety and Health (NIOSH) created a Center for Occupational Robotics Research to assess potential benefits and risks of robot workers and develop guidance for safe interactions between humans and robots.
The center is the result of an alliance agreement that OSHA, NIOSH and the Robotic Industries Association signed in October 2017. The pact calls for them to work together to enhance OSHA’s and NIOSH’s technical expertise, improve awareness of workplace hazards associated with robots and identify areas of needed research to reduce workplace hazards.
“Robots working collaboratively with humans present a new workplace risk profile that is not yet well understood,” said John Howard, NIOSH’s director at the time. "Not only is this a new field for safety and health professionals; little government guidance or policy exists regarding the safe integration of robots into the workplace.”
When the new center was announced, NIOSH researchers had already been able to identify at least 61 robot-related workplace deaths that took place between 1992 and 2015.
“We suspect fatalities will increase over time because of the growing number of industrial robots being used by companies in the U.S., and from the introduction of collaborative and co-existing robots (cobots), powered exoskeletons and autonomous vehicles into the work environment,” says Dawn Castillo, director of NIOSH’s Division of Safety Research and the center’s program manager.
OSHA Is Watching
While there are no OSHA regulations that specifically address robot safety at present, that doesn’t mean the agency won’t come after an employer when an accident involving a robot occurs. Just ask automaker Nissan North America Inc., which in August was forced to pay a $12,675 OSHA penalty after it was upheld by an administrative law judge.
In July 2016, a Nissan contract employee was in the process of replacing a motor on a robot on the first floor of a company facility at the same time that three company maintenance technicians conducted a preventive maintenance inspection on a conveyor on a floor above. When the contract employee was done with his work, he started the conveyor back up. At that moment, a technician placed his hand on the conveyor belt and was pulled into it, amputating three of his fingers.
The judge upheld Nissan’s citation for violating the OSHA standard covering training requirements. “The standard requires initial training be sufficient for employees to acquire the skills necessary to perform safe lockout,” the judge said. “For the technicians working on [the overhead conveyor], Nissan’s training did not meet this standard.”
OSHA’s Lockout/Tagout (LOTO) and other regulations require employers to protect employees from unexpected energization of machinery by, among other things, making sure all sources of energy are dissipated when the machines are not in use and installing a lock to prevent accidental startup.
When it comes to robots, the primary source of protection from unexpected movement is a programmable logic controller (PLC). Under OSHA’s rules, PLCs are expected to limit robots from moving when not performing their pre-programmed tasks and functions, or if a certain condition is met—such as when an interlocked door is open.
While these PLC devices typically “fail to safe,” OSHA has been reluctant to accept them as equally effective means of employee protection along the lines of machine guarding or LOTO, the Seyfarth Shaw attorneys note.
Intrinsic faults within the PLC control system of the robot include errors in software, electromagnetic interference, as well as radio frequency interference, OSHA believes. In addition, the agency holds that these errors can occur due to faults in the hydraulic, pneumatic, or electrical sub-controls associated with the robot or robot system.
OSHA’s Tech Manual
To help employers, OSHA has created an online technical manual for employers to learn about the hazards associated with robotics and automated machinery, including those that stem from malfunctions or errors in programming or interfacing with peripheral equipment.
In addition, the Robotics Industries Association offers an extensive safety program for employers on its website that covers everything from ANSI standards and RIA technical reports (which OSHA relies on) to public and in-house safety training opportunities that are available from the association.
The OSHA technical manual groups robotic incidents into four categories: impact or collision accidents, unexpected movements, component malfunctions, and unpredicted program changes related to the robot’s arm or peripheral equipment that result in contact accidents.
Here are some specific dangers OSHA says you should look out for:
Crushing and trapping accidents. Situations where worker’s limbs or other body parts can be trapped between a robot and other peripheral equipment, or the individual may be physically driven into and crushed by other peripheral equipment.
Mechanical part accidents. OSHA defines a mechanical accident as one that involves breakdown of the robot’s drive components, tooling or end-effector, peripheral equipment, or its power source. Examples of mechanical failures include the release of parts, failure of gripper mechanism, or the failure of end-effector power tools, including grinding wheels, buffing wheels, deburring tools, power screwdrivers and nut runners.
Other accidents resulting from working with robots. This category includes equipment that supplies robot power and control and represents potential electrical and pressurized fluid hazards. For example, ruptured hydraulic lines could create dangerous high-pressure cutting streams or whipping hose hazards. OSHA also lumps into this category environmental accidents from arc flash, metal spatter, dust, electromagnetic, or radio-frequency interference that also can occur, and equipment and power cables on the floor that can present tripping hazards.
OSHA adds that other expected sources of potential robotics hazards include human errors in programming, interfacing peripheral equipment, or connecting live input-output sensors to the robot or a peripheral device which can cause dangerous, unpredicted movement or action by the robot.
The incorrect activation of the “teach pendant” or control panel is a frequently-found human error, the agency observes. “The greatest problem, however, is operators’ familiarity and complacency with the robot’s redundant motions so that an individual places himself in a hazardous position within the robot’s ‘work envelope’ while programming the robot or performing maintenance on it.”
Another problem is unauthorized access by employees who may not be familiar with safeguards in place or their activation status. Pneumatic, hydraulic, or electrical power sources with malfunctioning control or transmission elements in the robot power system can disrupt electrical signals to the control or power-supply lines. Other hazards include electromagnetic or radio-frequency interference (transient signals) that can affect robotic operation, OSHA warns.
“While OSHA does not have regulations specific to robots in the workplace, employers would be wise to conduct job hazard analyses and evaluate any existing or potential robotic equipment installation, to abate any hazards posed by these machines,” the Seyfarth Shaw attorneys stress.
David Sparkman is founding editor of ACWI Advance, and a contributing editor to EHS Today.
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