RMI / ANSI MH16.3 and Cantilever Rack: What Buyers Should Know
November 7, 2026
ANSI MH16.3 is the standard for the design, testing and use of industrial steel cantilevered storage racks, published through the Rack Manufacturers Institute (RMI). NAWL states its cantilever rack is designed and tested to RMI / ANSI MH16.3. The standard covers the rack's engineering. It does not replace site engineering, local code, or your own safe-use program.
If a supplier says a rack "meets the standard," it helps to know what that claim does and does not tell you.
What is the standard for?
MH16.3 sets out how cantilever racks are designed, how capacities are established and tested, and how users should use them. It exists so a rated capacity means the same kind of thing from one manufacturer to the next: a number backed by calculation and testing, with stated assumptions.
What does it tell you in practice?
| Topic | What to take from it |
|---|---|
| Rated capacity | Backed by engineering and test, under stated conditions |
| Components | Arms, columns and bases are rated, and the ratings apply to the right combination |
| Use | Loads must stay within rating, placed as the rating assumes |
| Records | Capacities should be posted and kept |
Rated capacity
- What to take from it
- Backed by engineering and test, under stated conditions
Components
- What to take from it
- Arms, columns and bases are rated, and the ratings apply to the right combination
Use
- What to take from it
- Loads must stay within rating, placed as the rating assumes
Records
- What to take from it
- Capacities should be posted and kept
What does it not do?
- It does not guarantee your slab or footing can carry the loads
- It does not set your local permit or fire code requirements
- It does not make a mixed set of parts from different suppliers a rated system
- It does not cover damage that happens after installation
- It does not replace training and inspection
What should you still check?
- Site conditions. Slab thickness, soil, frost and drainage. See outdoor cantilever concrete pads and frost depth and anchoring cantilever bases to an indoor slab.
- Load assumptions. Ratings assume loads placed in a particular way. See load placement on cantilever rack.
- Outdoor loads. Snow, ice and wind add to what you store. See the snow load and bracing requirements guide.
- Local rules. Ask your building official whether a permit or engineering review applies. See do you need a permit for cantilever rack in Minnesota.
- Component matching. Keep to matched arms, columns and bases.
What should you ask your supplier?
- Which standard was the rack designed and tested to?
- Which exact components does the rating apply to?
- How is capacity shown, per arm and per column side?
- Can you provide the capacity data for my configuration?
- What do you need from me, like site details, for an accurate quote?
NAWL lists stock ratings of 12,980 lbs per side for the 12-foot column, 11,660 lbs per side for the 16-foot column, and 2,640 and 3,260 lbs each for 48-inch and 60-inch arms. See reading cantilever capacity per side.
What are the user's responsibilities?
Once rack is in service, the owner carries a lot of the safety load:
- Post capacity signs. See cantilever capacity signs: what to post
- Train operators
- Inspect on a schedule and after any strike
- Replace damaged parts. See replacing a bent cantilever arm from stock
- Keep records for insurers. See what insurers ask about cantilever rack
How does this help when comparing suppliers?
A supplier who can tell you what standard applies, show capacity data tied to specific parts, and explain the assumptions is giving you a rating you can rely on. A supplier who can only say "heavy duty" is not. Compare on documentation as well as price. See welded DIY racks vs. engineered cantilever.
Frequently asked questions
Does the standard guarantee my rack is safe? No. It supports a reliable rating. Safe use depends on site conditions, loading and inspection.
Is a stamped drawing the same thing? No. A stamped drawing is site-specific engineering. Ask whether your project needs one.
Does NAWL install? No. NAWL supplies cantilever rack and components. Your crew or an installer handles assembly.
Want capacity data for your configuration?
Send your column height, arm lengths and bundle weights, and we will return the stock ratings that apply.