A pallet rack is the warehouse structure for storing pallets at multiple vertical levels.
Detailed Definition
Pallet rack is a steel storage structure built from upright frames and horizontal load beams that hold unit loads at several levels. Common types are selective rack (single-deep, every pallet directly accessible), double-deep, drive-in and drive-thru (high-density lanes on rails), push-back (pallets on nested carts on inclined rails, last in first out) and pallet flow (pallets roll forward on inclined rollers with speed controllers, first in first out). In the US, rack design, testing and use are covered by ANSI MH16.1, developed by the Rack Manufacturers Institute.
Reading rack capacity and load plaques
Rack capacity is stated in two parts: the capacity of each beam pair at a level and the capacity of the upright frame, which depends on how far apart the beam levels are. Industry guidance calls for posted load plaques showing these limits. Moving beam levels, adding levels or changing the type of load can change frame capacity, so check with the rack manufacturer or an engineer before reconfiguring. Published capacities generally assume loads are evenly distributed across the beams.
Matching pallets to the rack
A pallet that is fine on the floor can fail on a rack, because in a rack it is supported only at the beams. Check which way the stringers or deck boards run relative to the beams, how much the pallet overhangs the beam faces, and whether the pallet's racked capacity covers the load. Pallets that cannot span the beams safely need pallet supports or wire decking. See pallet load capacity.
Inspection and damage
- Bent or creased uprights and damaged bracing.
- Missing or loose anchor bolts and beam locks.
- Beams showing permanent sag.
- Loads overhanging the aisle or sitting crooked.
Unload damaged sections and repair them using the manufacturer's guidance.
Authoritative Sources
- Rack Manufacturers Institute (RMI): an independent trade association affiliated with MHI that develops ANSI MH16.1, the US specification for the design, testing and utilization of industrial steel storage racks.
- Material Handling Institute (MHI): the largest US trade association for material handling, logistics, and supply chain technologies.
- ASTM International (ASTM): the global standards body that publishes ASTM D1185 (Standard Test Methods for Pallets and Related Structures Employed in Materials Handling and Shipping).
Related Glossary Terms
Frequently Asked Questions
Does OSHA have a pallet rack standard?
OSHA has no standard written specifically for pallet rack. Its general industry rule on materials storage, 29 CFR 1910.176, requires stored materials to be stable and secure, and the general duty clause covers recognized hazards. In practice ANSI MH16.1 is the recognized design and use specification in the US. Local building codes, seismic requirements and fire codes may also apply, especially to tall rack, so check with the local building and fire authorities.
Can any pallet be stored in any rack?
No. The pallet must be strong enough when supported only at the beams, sized to bear properly on them, and oriented as the rack design assumes. Weak, broken or undersized pallets can drop loads through the rack. Damaged pallets should be kept out of rack positions. When pallet types vary, for example mixed vendor pallets at receiving, pallet supports or wire decking can provide a safer bearing surface.