The pattern of pallet loading on a rack, distinguishing point loads, distributed loads, and asymmetric loading.
Detailed Definition
Rack load application describes how a pallet's weight is actually delivered to the beams and decking of a pallet rack. The same weight can act very differently depending on whether it is spread evenly across both beams, concentrated at a few points, or placed off center. Rack capacities are based on assumed load application, so a beam rated for a uniformly distributed load may not carry the same weight as a concentrated one. The rack designer documents these assumptions under ANSI MH16.1.
Common load application types
- Uniformly distributed: the pallet spreads its weight evenly across the front and rear beams. Most beam ratings assume this.
- Point or concentrated load: weight bears on a few spots, such as a machine base, a drum, or a pallet with its stringers running across the beams.
- Asymmetric or off-center: the pallet sits closer to one beam or one upright, or the load is lopsided on the pallet.
- Line loads: long items or pallets whose bottom boards bear along narrow strips.
Why load application changes capacity
A beam carries a concentrated load at midspan with more bending than the same weight spread along its length, so it deflects more and reaches its limit sooner. Off-center loads put more weight on one beam and one column than the design assumed. Pallet orientation matters too: a stringer pallet placed with stringers spanning front to rear behaves differently from one with stringers parallel to the beams. Beam deflection that looks unusual is often the first sign of a load application problem.
What warehouse managers should do
Give the rack supplier real pallet sizes, weights and orientations when the rack is designed, and keep the load plaques current. When a new product or pallet type arrives, check it against the design assumptions before storing it. Pallet capacity in racked use is a separate question, covered by the racking test.
Related Glossary Terms
Frequently Asked Questions
What is a LARC drawing?
LARC stands for load application and rack configuration. It is a drawing or document that records how a rack installation was designed: the bay layout, beam levels, unit load sizes and weights, and how loads are applied. The RMI specification refers to this kind of documentation. Keep it with your rack records so that any change to loads or beam levels can be checked against the original design.
Does pallet orientation on the beams matter?
Yes. A pallet's weight reaches the beams through its bottom boards, stringers or blocks, and turning the pallet changes where that weight lands. A stringer pallet with its stringers running front to back across both beams spreads load differently from one turned the other way, and some orientations need pallet supports or decking. Store pallets the way the rack design assumed, and ask the rack supplier before changing it.