Eilon Engineering, KDH Precision Team Up for Enhanced Production Safety on Metallica M72 World Tour

	"I have complete confidence in the calibration, up-to-date status, and reliability of the equipment I have," Koehler affirms. "The load cells not only allow us to perform our job safely, but it's a win-win for everyone involved.

Columbus, Ohio-based KDH Precision has, since 2017, provided rigging services for Metallica. Founded by Chad Koehler, the company has also worked with Rihanna, Beyonce, The Rolling Stones, Shania Twain, Carrie Underwood, Kid Rock, and, most recently, Chris Stapleton and Zach Bryan. He has relied on Eilon Engineering load cells to monitor loads for the past 15 years.

When working with a show design, KDH collaborates with staging and production companies to determine the most effective monitoring system required for safe load handling. Koehler says the number of load cells necessary varies depending on the design. "For the current Metallica tour, we worked with StageCo and Tait to determine the number of pick-up points and load dispersal," he says. "Once we knew how many screens we had, we then put the load cell system together." To cover the Metallica M72 World Tour, KDH Precision acquired 130 units, including 120 active load cells and ten spares.

KDH Precision has played a key role in many Metallica events, including the band's 2017 WorldWired Tour -- a massive 100-plus-ton production featuring kinetic LED cubes, with safety ensured by 40 load cells. KDH also contributed to performances of the S&M2 live album and the band's 40th anniversary shows.

KDH initially employed Eilon load cells in 2008 to monitor a large locomotive train set piece that became an iconic visual during AC/DC's two-year Black Ice World Tour and has used Eilon load cells on a previous Metallica tour. Impressed by their performance, the decision was made to use the Eilon system again for Metallica's M72 Tour.

Given that M72 is an extensive outdoor production, it presents several challenges. The setup involves eight towers comprised of 30'-tall circular LED screens, which are essential components of the design. To monitor the screen loads from setup to tear down, KDH relies on Eilon Engineering's Ron StageMaster four-ton G4 wireless load cells.

Each tower features three screens, and each screen has five motor points, resulting in a total of 120 points that can be monitored. Koehler explains, "When you have a significant number of hoists positioned closely together, maintaining perfect levelness to the ground becomes challenging. Even a slight deviation of half an inch can affect the applied load on the structure above. When we have five hoists supporting one-third of a screen, and a total of 15 hoists collectively, a difference of half an inch to an inch can lead to significant swings in weight distribution. You can't tell by just looking at it. We need to precisely know the load, and the only way to achieve that is through our Eilon system."

While the different forces on a load must be managed in any setting, the importance of monitoring is particularly magnified in outdoor shows, where adverse weather conditions, especially wind, can destabilize the rig. "In a controlled arena setting," Koehler says, "my focus is more about adapting the show so it looks exactly like it did in the previous city. It involves dealing with scoreboards and staying within the structural tolerances. However, in an outdoor show, where all the gear is exposed, the working environment becomes more challenging. The wind can be the real enemy when we're trying to get all the elements in place and then down again."

While raising and lowering the screens on the M72 Tour, precautions are taken to ensure stability, but the wind remains a formidable challenge. "The wind exerts additional force and load on the structure, and the screens can act like sails," Koehler says. "Every element has tolerances, and load cells allow us to stay within those limits when dealing with such big moving objects. Particularly in high winds, load monitoring becomes absolutely crucial. When hit by strong winds, the weight of the screens can escalate from 5,500lb to as much as 7,200lb. Consequently, adjusting the weight during the lifting process becomes extremely critical, and monitoring that wouldn't be possible without load cells." He says they were fortunate on the European leg of the tour with little wind and rain, but mentions encountering rain and exceptionally high winds in Belgium at the StageCo grounds, just before the tour commenced.

Koehler adds that he has found that a curved screen acts differently than a straight screen, providing another reason for weight monitoring. "The screens used on Metallica are curved, and a curved screen tends to roll until you get them fully built. So, having the load cells, making sure the load is equal and where it's supposed to be, is essential."

To monitor the 120 load cells, KDH Precision employs a portable Ron StageMaster PRR receiver in conjunction with an iPad. The wireless system allows him to view load maps while moving around the stadium. The load cells transmit data via radio frequency to the PRR (portable radio receiver), which serves as a handheld, Bluetooth-compatible load monitoring system. Riggers can conveniently download the app to a tablet or smartphone. The plug-and-play system is quick to install, easy to operate, eliminates the need for cumbersome cables, and boasts a remarkably short response time. Koehler commends its convenience, reliability, and durability, stating, "The ability to move around freely is priceless, and I don't have to worry about any cables or other complications. The system is not only highly convenient but has also proven to be extremely reliable and robust."

If the load approaches the overload or underload limit, the system triggers an alert, prompting immediate adjustments to ensure safety. Additionally, a close eye is kept on weather forecasts and wind conditions using anemometers installed atop the structure.

"I have complete confidence in the calibration, up-to-date status, and reliability of the equipment I have," Koehler affirms. "The load cells not only allow us to perform our job safely, but it's a win-win for everyone involved. Among the various systems we have used, I find Eilon's load cells the most user-friendly in terms of maneuverability, installation, and dismantling. The battery life is exceptionally long, and the load cells are remarkably energy-efficient. They also provide excellent support, assisting with technical aspects and updates whenever needed, and they have been instrumental in helping set up systems for each tour."

The consequences of unpredictable load distribution can be severe, and Koehler emphasizes that any show involving suspended loads above people should be executed with comprehensive knowledge of the forces involved. Despite this, load cells have not been universally adopted, even in large-scale productions. It's a tool he hopes will be a requirement in the future.

"The technology is there but it's often not being utilized, leading to incidents where people are unaware of the loads they are applying. As shows continue to grow in size and weight, and as people become increasingly concerned about liability and safety, I believe load cells will see more widespread use. We need to embrace the tools available to us. It's a matter of responsibility," he concludes.