This page is a library of component-level spec sheets for common unit-load materials. It is written for operational selection and inspection, not for marketing. Where a property is supplier-specific, the spec sheet describes the decision variable (what to ask for and why) rather than a single fixed number. Use this as a reference to standardize conversations between warehouse teams, procurement, and carriers.
Stretch film’s job is to keep layers aligned and reduce carton “walk.” It performs best when the stack is already stable and the film is anchored to the pallet (where safe and permitted). Many wrap failures are not “bad film”; they are contact failures (sharp edges, rough trailer walls) or geometry failures (overhang, protrusions, leaning stacks). When film is expected to act as the only restraint for heavy, tall, or irregular loads, progressive loosening becomes likely.
| Decision variable | Why it matters operationally | Dock verification cue |
|---|---|---|
| Durability / puncture resistance | Reduces tear propagation when the unit load contacts walls, dunnage, or protrusions. Low durability film often looks fine at ship time but fails after repeated vibration. | Check for tears at corners or consistent-height scuffs. If tears appear immediately after loading, identify the contact point rather than adding more wrap. |
| Pre-stretch / application method | Overstretch can reduce film robustness and cause “neckdown” (narrowing) that reduces coverage. Under-tension can lead to loose banding and migration. | Visual cue: overly thin bands, wrinkling, or film that easily peels from itself. Practical cue: push top layer gently—movement should be minimal. |
| Anchoring to pallet | Without anchoring, the load can move on the pallet even if layers are tight. Anchoring couples the unit load to the base and improves handling integrity. | Check for wrap passes that engage the pallet (where allowed). If the wrap only contacts product, the base may slip under braking. |
- Wrap tears at corners or a consistent band height (contact point signature)
- Loose tails, peeling layers, or unraveling at the base
- Visible layer migration under intact wrap (stack stability issue)
Using wrap to compensate for an unstable stack, or wrapping over unprotected sharp edges. These scenarios create predictable progressive failures.
Edge protectors convert concentrated forces (straps, wrap bands, incidental impacts) into distributed load across a larger area. They are essential when strapping cartons and useful whenever corners are sensitive. Fit is operationally critical: protectors that are too short, bowed, or floating above the pallet deck allow straps to cut into lower cartons and create a crush line. The best edge protector is the one that stays seated and maintains the load path.
Strapping cartons, mixed-case pallets, fragile packaging, or whenever restraint pressure would otherwise contact corners directly.
- Protector reaches the strap contact height
- Sits flush (no bowing) against the load
- Does not float above the deck if straps are low
Strap marks on carton edges indicate missing or ineffective edge protection. Treat as a corrective action item before shipment.
Straps provide a predictable restraint path, but only if applied with correct geometry and edge control. Operationally, most strapping failures show up as seal slip, strap migration, or package damage under the strap line. Do not over-tension to “force” stability; tension relaxes under vibration and temperature variation. Build stability into the stack and base first, then use straps to maintain that stability.
| Operational question | What to control | Verification cue |
|---|---|---|
| Will the strap damage packaging? | Use edge protectors and top caps/interlayers. Ensure strap does not contact carton corners directly. | No visible strap imprint on corners; protectors seated and not cracked. |
| Will restraint remain after vibration? | Use consistent tension, correct sealing method, and redundant strap count when required. | Seals do not slip; straps remain seated; no migration toward edges after handling. |
| Is the geometry correct? | Strap placement should align with load stability points (top cap, rigid zones) rather than compressible faces. | Unit load stays square; top surface not dented under strap lines. |
In claims and receiving disputes, strap count and placement are often used as evidence of “reasonable packaging effort.” If you strap, document it with photos. The key is not “more straps”; it is correct straps with edge protection and verified seals.
Interlayers and top caps are “quiet controls”: they rarely get credit, but they prevent a large share of crush and shift events. Their job is to distribute compression and restraint forces across a broader area, reduce void-driven buckling, and improve friction between layers when needed. They are especially valuable in mixed-case pallets where carton sizes create uneven top surfaces.
- Creating a level top surface before strapping or load-bar contact
- Reducing carton face buckling when layers contain voids
- Increasing layer-to-layer friction when cartons are slick
- Distributing point loads from irregular items
If straps create visible dents in the top layer, add a top cap/interlayer. If layers migrate under intact wrap, consider friction enhancement via interlayers.
Dunnage and blocking prevent movement inside the trailer. Even a perfectly built unit load can fail if it slides, tips, or rubs against rough surfaces for hours. The operational objective is controlled spacing and controlled contact: keep units from migrating into each other and keep contact points from becoming abrasion zones. Trailer inspection matters here: rough floors, wall protrusions, or moisture can negate good packaging decisions.
- □ Trailer floor intact; no standing water; no sharp protrusions at contact height
- □ Load plan prevents heavy-on-weak stacking and isolates incompatible freight
- □ Free space is controlled with blocking/spacing; units will not “run” under braking
- □ Abrasion risks addressed at known contact points (walls, bars, adjacent pallets)
Moisture is a compression risk multiplier for carton-based packaging. Damp cartons lose strength and can collapse under normal stacking pressures, often with no dramatic “impact” event. Moisture controls include dry trailer verification, protected staging (avoid exposed docks), and appropriate barriers where required. Operationally, the most important step is documentation: if cartons are damp at handoff, record it as an observable condition and decide whether to rework, delay, or tender with exception.
Wet floors, condensation in trailers, uncovered staging, and moisture exposure during loading/unloading.
Soft carton corners, discoloration, or “wavy” faces. If present, treat compression strength as compromised.
Don’t hide moisture under wrap. Either rework and dry/replace, or document the exception clearly before shipment.
If you want a tailored spec pack (e.g., standard pallet height, strap count, edge protector length, interlayer rules), use the Contact Desk and include commodity type, typical unit weight, pallet footprint, and your most frequent damage signature (shift, crush, corner damage, abrasion, moisture).