Warehouse Rack FAQ

There is no "official" limitation, but factors that will affect the height include your building's height, the reach of your equipment, your local building codes, the type of material you are storing, and similar.

We generally advise against this. The reason is the forces that affect each become tied to each other, which is never desirable. That said, in lower seismic areas, wall ties are sometimes used. If that is the case, everyone should be on board (e.g., the building and rack engineers, local building inspector, etc.), and anticipate / design for the transfer of forces. But really, it's best to avoid doing this, and instead solve any stability issue with heavy-duty anchors / larger base plates, cross aisle tie, or similar.

Yes there is. In 2016, the Rack Manufacturers Institute (RMI) of MHI (Material Handling Institute) released "ANSI MH16.3-2016, Specification for the Design, Testing and Utilization of Industrial Steel Cantilevered Storage Racks". This is a standard for both free-standing and top-tied cantilever storage racks (both cold-formed or hot-rolled), and includes both the cantilever racks themselves and add-ons, such as decking, shed roofs, and canopies. You can find the specifics at the MHI website at https://www.mhi.org/rmi.

Typically yes. The definitive answer will reside in your local building codes, but we find that almost all municipalities' codes will include language regarding storage racks, pallet racks, mezzanines, and similar. If there are no specific local codes, the locality may still follow the International Building Code, and/or the NFPA code. It is ultimately up to the end-user to be certain of these codes. Next Level storage is happy to help our customers with this - see our permitting page for more details.

Yes and no (sorry - we'll explain). Average load is only used for determination of seismic down-aisle horizontal force, and is not used in static design (this prevents the down aisle seismic analysis from becoming overly conservative). The RMI Specification allows the average load to be used for seismic down-aisle horizontal force simply because only the load that's in the rack at the time of a seismic event will be affected. But RMI spec does not permit average load to be used for cross-aisle seismic forces because there could be heavier loads in individual bays.
The user and designer are reminded that for the rack design, once the horizontal seismic forces are determined, the RMI Specification requires the racks to be designed for these forces in combination with the maximum gravity loads. The loads are to be combined using the appropriate load combinations.

Absolutely. The frame braces are vital in stabilizing the rack frame in the cross-aisle direction and support the individual columns. Any damage compromises their ability to perform this important function. If you have a damaged frame brace, immediately (and carefully) unload the entire area (including side bays), and contact the manufacturer. If that manufacturer is not us, but you'd like help, we can offer it. See our Rack Repair page for more details.

For normal applications and workloads, vertical deflections that do not exceed 1/180 (or 0.55 percent) of the horizontal beam length (as measured from the ends of the beams) is acceptable. Lesser deflection requirements are sometimes called for visual appearance and/or the use of more precise retrieval equipment. More information is available at https://www.mhi.org/rmi.

There is no official time period, but we recommend an annual inspection by a qualified professional. If your racks have not been inspected in a while, you may want to think about a professional audit.

Generally, a pick module is a warehouse-only structure built for efficient picking. There are usually several platform levels, with case flow / pallet flow bays feeding to a central aisle. We say "warehouse-only" because they are designed to be used by trained employees in a commercial setting, and not retail consumers.

Yes it is important. Ultimately, when it comes to liability, it is the building owner's responsibility to ensure the floor slab (either new or existing), and the soil underneath are capable of supporting the racks, the loads, the equipment, etc. This requires a qualified engineer to inspect the area and give the A-OK. While not a complete list, aspects checked will include the strength of the concrete (compressive yield ppsi) slab thickness, how level it is, joint strength, and subgrade composition.

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We generally think column protectors are a good idea, especially if any type of moving vehicle / forklift / pallet jack are utilized. In short, column protectors protect rack columns from collision damage. There are many types of column protectors, such as fenders, bumpers, deflectors, aisle guides, and more. Ask your warehouse rack professional (that's us!) what's best for your operation.

It depends on 1) your seismic area, and 2) if you've had a seismic survey. Areas in Seismic Design Category A are generally safe from seismic forces, and do not need to be checked. However, Seismic Design Category B and above do. This is why seismic engineering is a large part of any racking system (for more information, see the ANSI/RMI Specification section 2.7).

We don't think it's a good idea, especially since the only real reason to buy used and/or refurbished racks is to save money. In reality, working with a manufacturer-direct rack manufacturer like Next Level comes out to about the same price for new racks custom designed and fabricated for your operation. We have an extensive blog post on this exact topic here.

Get them checked. All parts of any storage rack are designed to work together, transferring weight and forces for support. Like a chain, if any link is weakened, the overall strength and stability is compromised. However, if your racks are indeed damaged, rack repair can be a viable option.