In today’s episode of the Dust Safety Science podcast, Adam Haroz, Director of Engineering at Conversion Technology, Inc. discusses robotic systems and addresses the question “Can we use robots in hazardous areas?”
In his current role, Adam oversees all the engineering departments and has been working with combustible dust for nearly 12 years. “I’m an associate voting member for NFPA 191, 654, and 664 on the combustible dust side, as well as a voting member for ANSI/RIA R15.06, which is the safety standard for industrial robots, and ANSI/RIA R15. 08, which is a safety standard for mobile robots.
Adam Haroz and Dr. Chris Cloney initially went over this project during a previous discussion on static discharge. At that time, Adam shared details about a unique project that combined robotics and hazardous areas, specifically related to combustible dust. It originated with a company that manufactures components for robotic systems and serves as an integrator responsible for installing and implementing these systems at client facilities.
This company reached out to him with a project that combined both robotics and combustible dust – two areas he frequently addresses. They were working on a robotic system that needed to be installed in a Class II, Division II hazardous location. The system itself consisted of an articulating six-axis arm equipped with a servo motor, sensors, and a vision system that included cameras, all intended for use in sanding operations.
This system presented a unique challenge, as sanding operations, while producing airborne dust, do not typically reach explosive concentrations. Nevertheless, the location had been rated as Class II, Division II, and the company wanted to ensure the robotic system could be safely operated in such an environment. They sought Adam’s expertise to assess and document whether the system could be used in this hazardous area.
What Are the Differences Between Class II, Division I and Class II, Division II Hazardous Locations?
Adam elaborated on the key differences between Class II, Division I, and Class II, Division II hazardous locations. According to NFPA 499, Class II, Division I locations are environments where a combustible dust cloud is present during normal operations. Adam provided the example of a paint booth, where the concentration of combustible particulate in the air is consistently high, similar to what one would find inside a dust collector, especially during filter pulls when dust clouds are thick.
In contrast, Class II, Division II locations only experience hazardous dust concentrations during abnormal conditions or malfunctions. Adam gave an example of a sanding operation, where dust is present but typically below explosive concentrations due to dust collection systems and housekeeping measures. The only time this dust might reach dangerous levels is if something goes wrong, such as a dust collector malfunctioning or a compressed air line bursting. During these abnormal situations, hazardous concentrations of dust could accumulate, posing a risk.
Why Is It Harder to Get a System Certified for Class II, Division II Instead of Class II, Division I?
Adam clarified that while it’s not necessarily more difficult to get a system certified for Class II, Division II, the infrastructure and resources for doing so are not as readily available compared to Class II, Division I. For Class II, Division I, many manufacturers have already invested in explosion-proof systems because they know there’s a market for it. These systems are built to meet very specific and strict requirements, such as electrical connections and spacing between conduits.
However, Class II, Division II systems have less stringent requirements, and manufacturers have not invested as much in developing the infrastructure for certification. As a result, getting a system certified for Class II, Division II often requires additional effort, time, and resources. Adam noted that flexible wiring methods, for example, are less established for Class II, Division II environments, meaning that companies must often develop their own solutions to meet the necessary safety standards.
What Are the Ignition Sources for a Robotic Arm in Hazardous Locations?
In this particular project, Adam identified three main ignition sources for the robotic arm being used in the hazardous location. The first and most significant concern was electrical ignition, particularly due to the flexible wiring required for a robot that moves across six axes or more. Unlike fixed conduits, which are easier to safeguard, flexible wiring poses a higher risk in hazardous environments. Adam explained that the flexible wiring, motors, and electrical components present potential ignition sources.
Another concern was static electricity, which can accumulate in the system, especially when dust or powder is in motion. This static buildup, combined with electrical systems connected to the grid, increases the risk of ignition. Adam pointed out that this type of risk is often present in systems where dust particles can build up and create static electricity.
The third source of ignition was mechanical, particularly related to the robot’s design. Robotic systems often include high-efficiency servo motors, which, while small and highly efficient, still have the potential to create mechanical sparks. Additionally, the robot’s mechanical stops, which are used to physically prevent itfrom moving past certain points, could also generate sparks if improperly designed or maintained. Adam explained that these mechanical components need to be carefully evaluated to prevent ignition risks in hazardous environments.
What Were the Project Findings?
After thoroughly assessing the project, Adam’s team began by exploring existing systems for Class II, Division I environments, which are more readily available and well-established. These systems are specifically built for hazardous locations and have been around for some time, especially as mobile robotics and legged robotics have become more common in dangerous environments like mines and chemical plants.
However, finding a solution for Class II, Division II environments proved to be more challenging. Adam and his team considered the possibility of building a dust-tight enclosure for the robotic arm to protect it from the hazardous environment. However, the client’s timeline for launching the product was short, and creating a custom enclosure would have required extensive testing and certification, which would have delayed the project.
Instead, the team decided to focus on the individual components of the system, reviewing their specifications and determining whether they could be safely used in the hazardous environment. Through communication with manufacturers and careful review of mechanical design calculations, they found that several components, including the servo motors and cameras, had IP66 and IP67 ratings, meaning they were dust-tight and suitable for Class II, Division II environments. This allowed them to recommend the system for use without requiring a full enclosure, though they acknowledged that the client might pursue full certification down the line.
What Is the Process for Certifying Other Systems for Use in Hazardous Locations?
For Class II, Division I environments, certification is a rigorous and time-consuming process. Manufacturers must invest significant resources to ensure that their systems meet the strict requirements for explosion-proof design. These systems must undergo extensive testing to prove that they can operate safely in environments where combustible dust is present during normal operations.
In contrast, the certification process for Class II, Division II environments is less stringent, but still requires careful attention to detail. Adam likened the process to obtaining a driver’s license – you may be able to drive, but without a license, you can’t legally prove your competence. Similarly, while a system may be designed to function safely in a hazardous location, it must go through testing and certification to prove that it meets the necessary standards.
Adam also explained that one of the key differences between certified and non-certified systems is the level of testing involved. Certified systems have undergone extensive testing to prove that they can operate safely in hazardous environments without creating an ignition source. Non-certified systems, while they may be designed with safety in mind, have not gone through the same rigorous testing process.
Conclusion
Adam emphasized the importance of conducting thorough risk assessments for robotic systems, particularly when they are used in hazardous locations. A robot system is required to undergo a risk assessment by both the manufacturer and the integrator, and Adam stressed the need for facilities to conduct their own risk assessments once the system is installed. In many cases, the integrator may not be an expert in combustible dust atmospheres, so it is up to the facility to ensure that all necessary precautions have been taken.
Adam also underscored the value of proactive planning in the design phase of a project. By identifying potential risks early on, manufacturers can address them during the design process, rather than waiting until the system is already operational. This approach not only saves time and resources but also ensures that systems are as safe as possible when they are installed in hazardous environments.
Finally, Adam encouraged companies to continue pushing the boundaries of automation technology, particularly in hazardous environments. As robotics and automation systems become more advanced, they offer new opportunities for improving safety and efficiency in industries that deal with combustible dust and other hazards. By expanding into Class II, Division II environments, companies can create more options for automation while also improving overall safety in the industry.
If you would like to discuss further, leave your thoughts in the comments section below. You can also reach Adam Haroz directly:
Website: https://www.conversiontechnology.com/
LinkedIn: https://www.linkedin.com/in/adam-haroz-eit-lmss%E2%84%A2-1a902727/
Email: [email protected]
If you have questions about the contents of this or any other podcast episode, you can go to our ‘Questions from the Community’ page and submit a text message or video recording. We will then bring someone on to answer these questions in a future episode.
Resources mentioned
The resources mentioned in this episode are listed below.
Dust Safety Science
Combustible Dust Incident Database
Dust Safety Science Podcast
Questions from the Community
Companies
Conversion Technology, Inc
Standards
NFPA 499
ANSI/RIA R15.06
ANSI/RIA R15. 08
IP Ratings
Previous Episodes
DSS237: Robotics Standards for Safety and Compliance with Adam Haroz
Download the episode
DSS282: Robot Systems Update: Can We Use Robots In Hazardous Areas With Adam Haroz
