Glossary
Perimeter base
Also called: picture frame base, perimeter bottom, frame bottom
Reviewed
A perimeter base is a block-pallet bottom deck made of boards running around all four edges, like a picture frame, leaving the middle of each bay open. It supports the pallet evenly in both directions and allows full four-way entry for forklifts and pallet jacks.
How a perimeter base is built
Bottom boards run along the two long edges and the two short edges under the corner and edge blocks, forming a closed frame. Where boards cross, they are either stacked (bottom stringerboards plus bottom deckboards) or arranged to sit flush. Inner openings let pallet-jack wheels reach the floor from any side, and the board edges that wheels cross are chamfered.
Block bottom styles compared
| Base | Layout | Entry |
|---|---|---|
| Perimeter | frame around all four edges | full four-way |
| Cruciform | perimeter plus center boards forming a cross | full four-way |
| Unidirectional | boards in one direction only | full four-way |
| Overlap | bottom deckboards plus bottom stringerboards | partial four-way |
Where it is used
The UK standard 1200x1000 pallet is a perimeter-base design, and CP6 to CP9 chemical pallets have perimeter or frame bottoms. The frame gives stable support on roller conveyors and in racks in both directions. See perimeter base pallet.
Questions
- Why use a perimeter base pallet?
- It supports the load evenly in both directions, runs well on conveyors, and still lets pallet jacks enter from all four sides.
Sources
- Uniform Standard for Wood Pallets (NWPCA, now Woodpack Global), 2012 edition
- Guide to Understanding the PDS Specification and Analysis (block class, metric)
- CP pallets overview (Directpal)