The Robots are Here. How Do We Work Safely with Them?

• Nov 19, 2019

The idea of robots in the workplace is no longer a sci-fi plot. The future is here – and so are those robots.

Rapid advancements in technology have introduced many types of physical robotic systems in the workplace. Industrial robots now paint, weld, push, pull, lift and assemble products. Collaborative robots, which have one or more mechanical arms, provide workers with a (literal) extra set of hands.

We have overcome the initial skepticism that robots can do what humans can, and in many cases, we put considerable trust in this technology: Physicians, for instance, trust robots to perform delicate surgical tasks, relying on them to save lives.

But while robots are proving their utility across industries, there are real hazards to consider. As robots become integrated into our daily work life, the safety of people working with or around them is a growing concern.

What are the types of hazards associated with industrial robots, and what are possible solutions to mitigate risks?

OSHA’s technical manual identifies four categories of accidents that can occur when working with industrial robots:

1. Impact or collision accidents resulting from unpredicted movements, component malfunctions, or unpredicted program changes related to the robot’s arm or peripheral equipment can occur.

2. Crushing and trapping accidents of workers’ limbs or other body parts caught between a robot’s arm and other peripheral equipment can happen, or the individual may be physically driven into and crushed by other peripheral equipment.

3. Mechanical part accidents resulting from the breakdown of the robot’s drive components, tooling or end-effector, peripheral equipment, or its power source constitute mechanical accidents. These include the release of parts, failure of a gripper mechanism, or the failure of end-effector power tools (e.g., grinding wheels, buffing wheels, deburring tools, power screwdrivers, and nut runners).

4. Accidents from leaking high-pressure lines, arc flash, metal spatter, dust, electromagnetic, or radio-frequency interference can also occur.

Why do accidents occur?

Given the significant potential for accidents, it is essential to understand why these incidents happen. According to OSHA’s technical manual, typically these problems arise from human error, control errors, unauthorized access, mechanical failures, environmental sources, power systems, or improper installation.

By far, the most common cause is human error. Workers get comfortable with the equipment and sometimes complacent about the dangers. They may place themselves in unsafe areas when programming or performing maintenance on a robot, for instance.

Robots require complex programming to operate, and accidents can also result from a human-introduced programming error. Other hazards may result from improper installation, failure to properly maintain equipment, and malfunctions in the hydraulic and electrical systems.

Industrial robots are capable of powerful movements across a large area, even beyond the base of their unit. Changes to the materials or the environment may affect the preprogrammed movements of the robot. The use of physical barriers typically protects workers from industrial robot hazards – but accidents do happen.

In 2017, an employee working for an automobile parts manufacturer leaned through a light curtain to change a welding tip on a robot. Another robot unexpectedly energized. The robotic arm struck the employee who sustained a fracture and dislocation of his left hip, requiring hospitalization.

A risk assessment is the first critical step to protect employees

Employers should ensure that workers understand and recognize these hazards. Even before the business uses any robots, it’s essential to conduct a risk assessment during the design phase. At this point, employers must identify the robot’s physical and operational limitations, purpose, and use (or misuse). Next, they should pinpoint any reasonably foreseeable hazards and relevant hazardous conditions that may arise. One consideration is any human interaction during the lifecycle of the machine and possible states of the machine. The goal is to eliminate as many identified hazards as possible. Then, through the risk assessment process, employers should determine the appropriate type of functional safety controls to reduce risk to an acceptable level.

How to leverage the risk assessment to minimize dangers

The information collected during the risk assessment determines the type of hardware and controls used for the safety control system. Engineering controls, for instance, can restrict access to a hazard zone. They may include reliable electromechanical door interlocks, fixed barriers, two-hand actuation control systems, and presence-sensing devices such as light curtains, area laser scanners, or pressure mats. These devices cut the probability of exposure to the hazard (i.e., harm) but don’t reduce the potential severity of the injury.

Administrative controls are generally the least favored preventative measures, because they still rely on human actions and may only marginally reduce the probability of harm. These controls include awareness devices like signs, audible alarms, and visual warning lights to alert workers to danger. They also include procedures (operating and maintenance) and training.

OSHA recommends that workers who program, operate, maintain, or repair robots or robot systems should receive adequate safety training, and they should be able to demonstrate their competence to perform their jobs safely. When engineering, work practice, and administrative controls do not provide enough protection, employers must provide personal protective equipment (PPE): respirators, gloves, face shields, hearing protection, hard hats, and safety glasses that workers wear as a final layer of defense against injury.

The capabilities of robots are astounding, and they stand to deliver even greater efficiencies in the near future. However, the complexities of robotics introduce serious workplace hazards: collisions, crushing, unexpected restarts, and electrical shocks, to name a few. By conducting assessments and implementing the proper balance of controls, we can ensure industrial robots operate safely – both on their own and alongside their human colleagues.

About the Author
Donna McEntee is the Workplace Safety and Health Solution Manager at Skillsoft Compliance Solutions. Managing Skillsoft's global library of more than 800 Workplace Safety and Health courses, she helps customers design effective compliance training programs. Donna holds a master’s degree in Safety, Security, and Emergency Management from Eastern Kentucky University.