Along with its recent revision of ANSI MH16.3-2025: Design, Testing, and Utilization of Industrial Steel Cantilever Storage Racks, the Rack Manufacturers Institute (RMI) has also updated its R-Mark® Certification program for cantilever storage rack systems. These racks hold long, bulky, or irregular loads on arms extending from upright columns. The updated R-Mark Certification gives buyers a new level of assurance that a cantilever rack has been engineered, reviewed, and manufactured in accordance with RMI’s ANSI MH16.3 requirements.
Andrew Bishop, Principal Engineer at RMI member UNARCO Material Handling, is Chair of RMI’s Standards Advisory Committee. He worked extensively on the revisions to both MH16.3 and the R-Mark Certification program for cantilever rack.
“R-Mark helps confirm proper design of a rack system, whether that’s selective or cantilever,” Bishop said. “The updates to the cantilever R-Mark certification program bring it in alignment with the latest ANSI standard.”
R-Mark Certification Covers a Complete System
As with selective rack, R-Mark for cantilever rack is not a certification of an individual upright, arm, or base. Instead, it confirms that a cantilever rack system—its geometry, components, material specifications, seismic considerations, and installation—has been engineered for a specific project site.
“R-Mark isn’t a blanket stamp. Companies can’t say every cantilever rack they make is R-Mark certified,” emphasized Bishop. “It applies only to a system that’s been reviewed and designed for a specific project.”
That project-specific focus ensures the cantilever system meets:
- The applicable RMI standard, ANSI MH16.3.
- Seismic and environmental conditions at the site.
- The actual load patterns and arm configurations.
- Manufacturing and material requirements.
- Installation verification by a qualified inspector.
This structure keeps the R-Mark accurate, enforceable, and tied to real-world performance conditions.
How Buyers Verify a Cantilever Rack Is R-Mark Certified
As with selective rack, the only way to confirm that a cantilever rack system is R-Mark certified is to review the system’s load application and rack configuration (LARC) drawings or the load capacity plaques provided by the manufacturer. Both will display the R-Mark logo and certification number.
Because system configuration drives capacity, distributors or resellers cannot apply the R-Mark independently.
“If someone wants a certified cantilever rack, the drawings must come from the manufacturer,” Bishop explained. “Only the manufacturer can issue an R-Mark design package. For safety-critical structures like cantilever systems—which handle long, heavy, or irregular loads—this verification step matters.”
What Manufacturers Must Demonstrate to Earn the R-Mark
Earning the R-Mark is a rigorous process. Manufacturers must submit documentation demonstrating compliance with RMI standards. They also must attest that their engineering, manufacturing, and quality processes are consistent and reliable. An independent professional engineer with deep experience in storage rack design reviews the application.
“It’s the same idea as selective rack,” noted Bishop. “Manufacturers must show they follow good engineering practices, use proper steel, comply with welding standards, and that their designs are reviewed correctly. They also need to test the components they intend to sell.”
The application requires evidence of:
- Engineering calculation packages.
- Component testing data.
- Material specifications and steel verification.
- Compliance with American Welding Society (AWS) welding standards.
- Manufacturing process controls.
- Quality assurance and quality control documentation.
- Facility certifications, where applicable.
If a manufacturer produces multiple rack types—such as structural cantilever, roll-formed cantilever, or mixed-material systems—it must submit testing and calculation packages for each. Further, manufacturers must reaffirm compliance every year, keeping accountability high.
Why R-Mark Certification Matters for Cantilever Rack Buyers
Cantilever systems support long and heavy loads, including steel bar, lumber, pipe, coils, furniture, or sheet goods. Further, they are often installed in high-hazard environments. Variations in arm spacing, base design, column strength, or load positioning can dramatically change structural behavior. That makes independent engineering review even more valuable.
“The biggest advantage of R-Mark Certification is it confirms for end users that their cantilever rack design is safe,” Bishop said. “R-Mark helps ensure the system was engineered correctly and that the manufacturer’s processes meet the safety requirements.”
How to Find an R-Mark Certified Cantilever Rack Manufacturer
RMI maintains an updated list of R-Mark licensed manufacturers on its website. Buyers can confirm a company’s status, review certification details, and request information about certified systems. For more details, visit mhi.org/rmi.
