Companion stringer
A companion stringer is a repair component fastened alongside a damaged stringer to restore its strength, instead of replacing the stringer outright. The Uniform Standard lists companion stringers with plugs, C-blocks and metal connector plates as recognized pallet repair methods.
Also called sister stringer, stringer repair, sistered stringer
Reviewed
How it is used
A cracked or broken stringer is reinforced by fastening a second stringer-sized piece alongside it, spanning the damaged section. The deckboards are then renailed as needed. Other repair components in the Uniform Standard include:
- Plugs
- C-blocks
- Metal connector plates
Repair rules to know
- The Uniform Standard defines repair classes and recommends a repair mark on the pallet showing class of repair, repairer ID, date and owner
- In the PDS service-life simulation, stringers can be repaired twice and replaced once
- Repaired pallets used for export must be re-treated and re-marked to ISPM 15
Why it matters
Companion stringers let recyclers return a pallet to service quickly and cheaply, which is central to the remanufactured pallet market. Buyers who do not want repaired stringers should say so in the spec, for example by specifying new manufacture or a recycled grade that excludes them. See recycled pallet.
Questions
- Are pallets with companion stringers acceptable?
- They are a recognized repair under the Uniform Standard. Whether they are acceptable depends on the buyer's grade and repair requirements.
Related
- Remanufactured palletA remanufactured pallet is rebuilt from recycled components, often resized. For export it must be re-treated and re-marked to ISPM 15.
- StringerA stringer is the continuous beam that runs the length of a stringer pallet under the deckboards. A GMA 48x40 uses three 1-3/8 x 3-1/2 x 48 in stringers.
- Recycled pallet: grades, repairs and remanufacturingRecycled pallets are used wood pallets that are sorted, repaired or rebuilt. Grades A and B, repaired vs remanufactured vs combo, and ISPM 15 re-treatment.
- Recycled pallet lumber and remanufactured palletsRecycled pallet lumber comes from dismantled pallets and goes into repairs and remanufactured or combo pallets. Repaired pallets need ISPM 15 re-treatment.
- CP palletCP pallets (CP1 to CP9) are nine standard block pallet designs for the chemical and plastics industry, from CP1 at 1000 x 1200 mm to CP9 at 1140 x 1140 mm.
- CreepCreep is the slow increase in pallet deflection under a sustained load. PDS reports deflection after 30 days; plastic pallets are especially creep-sensitive.
Sources
- Uniform Standard for Wood Pallets (NWPCA, now Woodpack Global), 2012 edition
- Guide to Understanding the PDS Specification and Analysis (stringer, inches)