Seismic Standards Explained: RMI 2024 Updates & Impact
The Rack Manufacturers Institute (RMI) released significant updates to seismic design standards in 2024. Understanding these changes is critical for warehouse operators, engineers, and procurement professionals managing racking installations across seismic zones.
What Changed in RMI 2024
The 2024 RMI ANSI MH16.1 standard introduces more precise seismic design criteria, updated load combination factors, and clarified connection requirements. These changes reflect advances in structural analysis and decades of field performance data from racking systems installed in high-seismic regions.
Key Updates Include
- •Revised response modification factors for different racking configurations
- •Updated design base shear calculations aligned with ASCE 7-22
- •Enhanced connection design requirements for high-seismic zones
- •Clarified acceptance criteria for beam-to-column connections
- •New guidance on pushback and pallet flow system seismic design
Impact on New Installations
Jurisdictions adopting the 2024 standard will require compliance for all new racking installations and major modifications. This affects structural calculations, anchor specifications, and connection detailing. Most installations will see minor changes to upright sections or anchor sizing to meet the updated factors.
Seismic Design Category Matters
Seismic Design Categories (SDC) range from A (minimal seismic risk) to E (highest seismic risk). Higher SDC levels trigger more stringent design requirements. California, the Pacific Northwest, and parts of the Intermountain West typically fall into SDC D or E, requiring enhanced engineering and anchoring.
Geographic Considerations
Warehouses in regions like Southern California or the Seattle area face the most stringent requirements. Facilities in the Central US or East Coast often fall into lower SDC categories with less restrictive criteria. However, local amendments to building codes can add additional requirements regardless of SDC level.
Connection Design Requirements
The 2024 standard places increased emphasis on beam-to-column connection performance. Connections must demonstrate adequate strength and ductility under seismic loading. This affects both the connector design and the upright perforation patterns. Testing data and engineering analysis must confirm performance.
Existing System Compliance
Existing racking systems installed under previous standards are typically grandfathered unless substantial modifications occur. However, warehouse operators should conduct periodic assessments to verify structural integrity, especially after any damage events or major loading changes.
When Upgrades Are Recommended
Consider seismic evaluation or retrofit if:
- •Increasing pallet loads beyond original design
- •Adding beam levels or changing rack configuration
- •Observable damage to uprights or connections
- •Original installation predates modern seismic codes
Practical Implementation
Compliance with the 2024 standard requires coordination between rack manufacturers, structural engineers, and local building officials. Proper documentation including engineered drawings, seismic calculations, and anchor specifications must be submitted for permit approval.
Timeline and Adoption
Jurisdictions adopt updated building codes on varying timelines. Some high-seismic regions may have already incorporated the 2024 standard, while others may phase it in over the next 12 to 24 months. Always confirm local requirements before finalizing designs.
The Bottom Line
The 2024 RMI standard reflects ongoing efforts to improve racking system performance during seismic events. While the updates add complexity to design calculations, they ultimately enhance safety and structural reliability. Working with experienced racking engineers ensures compliance while optimizing system cost and performance.