As explained in the previous post, rack stability is among the most important—yet frequently unrecognized—aspects of warehouse safety. The reason is because engineers design industrial steel storage racks for maximum capacity with minimal material use.
According to Ronald D. Ziemian, Ph.D., P.E., Professor in the Department of Civil and Environmental Engineering at Bucknell University and a technical consultant to the Rack Manufacturers Institute (RMI), that combination means a sustained concern for rack stability should be an essential part of an operation’s safety practices. iemian is a specialist on stability who serves as the editor of the Guide to Stability Design Criteria for Metal Structures.
Why Small Damage Can Compromise Rack
Because rack systems operate so close to their design limits, even minor damage can have a disproportionate impact on stability. Small dents, bends, down-aisle leaning, or misalignments—particularly in critical components like uprights or bracing—can reduce the system’s ability to resist buckling under load.
Ziemian illustrated this concept with a simple analogy: an empty soda can that appears strong under a vertical load can collapse instantly if it is slightly dented. The same principle applies to rack systems, where minor imperfections can significantly weaken structural performance.
“Seemingly small issues can significantly increase the risk of a rack collapse,” he emphasized. “This sensitivity makes it critical to promptly identify and address damage, rather than assuming that minor issues are inconsequential.”
How Configuration Changes Affect Rack Stability
A rack’s physical condition is not the only factor influencing its stability. Configuration and use are also key. That means adjustments—such as changing beam elevations, altering load distributions, or modifying rack connections—can all impact how forces move through the structure.
Here, Ziemian uses an analogy: when a hiker puts on a heavy backpack, their balance is reduced, making them more susceptible to falling because of a slip or unintentional lean.
“The same holds for racks, where placing heavier loads higher in the rack increases instability, while removing loads from certain sections can affect adjacent bays. This is particularly true in interconnected systems. Even temporary changes made during maintenance or reconfiguration of the systems that are being leaned on can introduce unintended risks if not properly evaluated,” cautioned Ziemian.
On the subject of loading, Ziemian also notes that the structural efficiency of racks is increased still further when the future owner provides the rack designer with both the average and maximum load per storage level, a practice more characteristic of racks than of buildings. Although using average loads in stability design is a sound practice, the owner should take care not to understate the average load at the outset, since it cannot be less than two-thirds of the maximum load. Once the rack is in service, the owner should also monitor loading on an ongoing basis to ensure compliance with the specified average loads.
Enhancing Stability Through Design Standards
Given the complexity and sensitivity of rack systems, proper design is essential to ensuring long-term stability. Ziemian emphasized the importance of specifying rack systems engineered in accordance with established standards, such as those published by RMI.
“These are highly engineered systems,” he explained. “You need engineers who understand the standards and know how to interpret and apply them properly based on real-world conditions.”
Working with qualified rack engineers helps to ensure that a system’s design prioritizes rack stability. Doing so reduces the risk of future issues and helps protect both personnel and inventory.
How Inspections and Incident Reporting Support Rack Stability
Routine inspection and maintenance are critical to preserving rack stability over time. Because damage and wear are inevitable in active warehouse environments, facilities must have structured processes in place to identify and respond to issues before they escalate.
“With something as stability sensitive as a rack structure, maintenance and inspection are incredibly important,” Ziemian emphasized.
This includes regular inspections, clear criteria for evaluating damage, and defined procedures for repair or replacement. A proactive approach not only helps maintain rack stability, but also supports safer and more reliable warehouse operations.
Additionally, Ziemian noted that unreported damage is one of the most common and preventable risks to rack stability. In certain facilities, employees may hesitate to report impacts or issues out of concern for repercussions.
“In some operations, there can be a reluctance to report issues,” he said. “Someone might think a small dent is inconsequential, but it may be much more significant than it appears. Therefore, it’s essential to create a culture where employees feel comfortable reporting damage.”
He advised establishing clear processes for reporting, evaluating, and addressing issues, as well as reinforcing the importance of proactive safety practices.
Looking for Additional Details About Rack Design?
Connect with RMI members for insights into rack design and use. As the industry’s leading suppliers of industrial steel storage racks and related structural systems, they provide industrial rack solutions worldwide and in virtually every major manufacturing and distribution sector.
Additionally, RMI offers a variety of rack safety resources and publications. Among them are videos, technical guidance, and educational materials designed to help end users better understand safe rack design, installation, inspection, and operation. Find more online at mhi.org/rmi.
