When looking to retrofit a robot or install a new one, the term “risk assessment” may surface. And for good reason. With any industrial or collaborative robot integration, adhering to the necessary safety standards is paramount to ensure the robot usage does not compromise worker safety or application integrity. Therefore, a detailed look by a qualified professional into how the entire robot system will operate on the shop floor and interact with human workers is a must.
However, in preparation for this step, and to meet all expectations required for successful robotic implementation, manufacturers should do their due diligence to guarantee compliance for inspection purposes. For this reason, OSHA distributes a free reference manual clarifying to OEMs, integrators and end users alike the steps that should be taken to implement a robot application with the utmost safety.
In the newly revised OSHA Technical Manual (OTM) Section IV: Chapter 4, the topic of industrial robot systems and industrial robot system safety is discussed. A collaborative effort between OSHA, the National Institute for Occupational Safety and Health (NIOSH) and the Association for Advancing Automation (A3), this document offers specific guidance on the hazards associated with industrial robot applications, risk assessments and risk mitigation measures. Likewise, examples and references to OSHA and other industry-specific standards relating to industrial robot systems are also provided.
More specifically, the OTM walks readers through nine separate sequential sections designed to build the foundational understanding needed to successfully complete a risk assessment and apply the appropriate risk reduction measures. Here are those nine sections explained.
Sections 1 through 4
Extremely helpful to readers, the initial four sections of the manual address how to correctly identify the key components that comprise an industrial robot system, the different types of robots that may be encountered and the type of robot application that needs to be assessed such as collaborative, non-collaborative and mobile robot applications.
Key to creating a task-based risk assessment, Section 5 takes a deep dive into the hazards associated with industrial robot applications. Here, concepts on how to correctly identify risks an operator may encounter over the life cycle of a robot application can be found as well as concepts for any foreseeable misuse that may occur. Keep in mind, according to the ANSI/RIA R15.06-2012 safety standard, the term “operator” refers to all persons performing tasks, including those that may perform maintenance or repair. That said, OSHA characterizes this hazard identification process by breaking it up into four well-defined, manageable sections.
1. Robot application hazards – with respect to the hazards associated with the robot or industrial mobile robot application, particular attention should be given to evaluating the operator’s exposure to any crushing, trapping, impact or collision hazards, including the potential of being struck by a dropped part or part projectile. Similarly, attention should also be paid to the hazards induced from sources such as electrical, hydraulic, pneumatic and stored energy. Along with this, environmental hazards such as noise, fumes, dust, heat, hazardous light, etc., should be considered when evaluating the robot application.
2. Robot application hazards by process – taking the entire robot life cycle into account, this step begins with the manufacturing phase of the robot system and includes assembly, integration, testing and installation processes. Note, these stages can be particularly hazardous because the system may be partially completed and any inherent design, fabrication or installation issues will likely appear during testing and validation before shipment to a customer.
3. Sources of robot application hazards – integration at the final destination presents its own unique challenges that must be taken into account during the hazard assessment. This part of the robot application life cycle encompasses all of the ancillary equipment, parts, safeguarding fixtures, etc., that may not have been present at the time of the initial testing and validation. Further information is accessible in the ANSI/RIA R15.06-2012 safety standard, part 2, which stipulates that a commissioning plan shall be created to ensure that information for protective measures during the commissioning phase has been provided.
This includes the selection of interim safeguards and protective measures such as:
- Installed, but in an interim manner
- Different or additional interim safety devices
- Temporary obstruction or barriers
- Specifically written safe operating procedures
- Any additional or interim awareness means
- Specific training necessary for safe operation
4. Accidents (past studies) – the final step in analyzing the hazards associated with the robot application process is to evaluate how the operators and other workers will interact with the newly installed equipment. For this, the OTM outlines several key areas that should be considered. From concepts like the operator’s unfamiliarity with the robot’s programmed movement due to program complexity or part variation to adjacent robot systems with overlapping restricted spaces, best practices for these situations should be followed. Standards for stored energy and interaction with other peripheral equipment are also important to note.
Other possible sources of robot application hazards may include:
- Human error during programming or maintenance involving direction of movement or application familiarity
- Electrical- or hardware-related failures
- Unauthorized entry into the robots’ restricted space
- Production requirements that may lead to shortcutting safe operating procedures
- Environmental sources such as heat water, electromagnetic or radio-frequency interference
- Power system issues
- Improper assembly and installation
Here, the OTM addresses the methodology of Hierarchy of Controls as a strategy for risk reduction and specifies that OEMs, integrators and employers should be following applicable RIA standards necessary for the safe integration of robot applications. Previously mentioned, ANSI/RIA R15.06-2012, part 2 is integral to this process and specifies, “the integrator shall perform a risk assessment to determine the risk reduction measures required to adequately reduce the risks presented by the integrated application.”
This clearly sets user expectations that the employer is responsible to ensure that the integrator has designed and implemented a safe robot application. This is typically accomplished by following the relevant guidance found in ANSI/RIA R15.06-2012 and RIA TR R15.606-2016 safety standards.
With respect to collaborative robot safety, it must then be verified that compliance with RIA TR R15.606-2016 has been achieved. Additionally, OSHA points out that employers should also be following the guidance provided in RIA TR R15.706 under “User Responsibilities.” This section provides the reader with OSHA’s expectations for:
- Safety considerations for robot system integrators
- Safety considerations for robot system operators and maintenance workers
- Safety considerations during planning of the robot application
- General safety requirements
- Additional safety requirements for collaborative robot applications
With all foundational elements in place, this section addresses OSHA’s expectations for robot system risk assessments and stipulates that the general duty clause directly applies here. It states, “the employer’s responsibility under OSHA is to maintain a safe workplace for their employees.” Similarly, “the employer should require the integrator to provide and train the integrator’s risk assessments to the employees prior to commissioning. If not provided by the integrator, the employer should provide these functions.”
This section also highlights the expectation that the risk assessment should be a collaborative process involving a team of both knowledgeable employees and affected persons. The goal is to identify the task/hazard pairs and corresponding required risk reduction measures. An important aspect of this section is the necessity of verification and validation to ensure that the safety system was designed correctly, that it operates as designed and that all of the risk reduction measures specified in the risk assessment have been implemented such as PPE, signage, training, etc.
Vital knowledge for risk reduction measures, this section begins by pointing out that training of the affected personnel is a critical aspect of the effective risk reduction process. If the affected persons do not understand the process, the hazards associated with the process and the specific risk reduction measures put into place to mitigate those hazards (and their effective use of the risk reduction measures) could be less effective. All “users (employers),” as stated in the OTM, must be able to demonstrate an understanding of the above as well as knowing when the safety reduction measures are required to be validated, ensuring correct functionality.
Another key aspect of this section is the distinction made from a risk reduction standpoint between non-collaborative and collaborative tasks and the considerations that should be taken into account for each. Of particular note are the considerations for collaborative operation – as a collaborative application may involve both non-collaborative and collaborative tasks. With a collaborative task, the entire application must be considered from a risk assessment point of view and involve the part, end effector, fixtures and ancillary equipment as well as other aspects of the robot system that may contact the operator.
The OTM is clear on these terms, and the integrator or user should confirm that contact events do not exceed the force and pressure biomechanical limits specified in RIA TR R15.606-2016. Likewise, proper verification and validation should be performed and documented by a competent worker. RIA TR R15.806-2018, “Testing Methods for Power and Force Limited Collaborative Applications,” gives specific guidance on how to accomplish this testing.
Overall, decision makers need to have a strategic plan for robotic implementation that includes a detailed risk assessment. Along with this, proper employee training must be given. If an employer is the responsible party for educating the internal workforce where robot usage is concerned, key steps should be taken to identify the necessary skills required to safely operate the robot system, so the proper education can take place. Moreso, thorough project communication with employees and maintaining a high level of enthusiasm for robotic implementation will go a long way to garner success.