Dunnage Bags: Selection, Sizing, and Installation Best Practices

Dunnage Bags: Selection, Sizing, and Installation Best Practices

Dunnage Bags are an adaptable tool for securing cargo, but their effectiveness depends on selecting the correct type, sizing them to voids, and installing them properly. This comprehensive guide outlines decision steps, sizing principles, inflation techniques, and on-the-job best practices for logistics managers, warehouse supervisors, and transport operators.

Step 1 — Assess cargo and transport conditions:

Begin by cataloguing cargo characteristics (weight, rigidity, surface hardness), transport mode (sea, road, rail), expected accelerations, and container or trailer dimensions. Heavier or more dynamic transport environments (ocean crossing, intermodal transfers) require dunnage with higher burst strength and potentially multiple placement points. Fragile goods may demand additional edge protection and lower contact pressure.

Step 2 — Choose material and construction:

Options include kraft (paper) bags for lightweight, single-use applications; laminated kraft for moisture resistance; woven polypropylene for reusability and higher burst strength; and rubberized or PVC bags for heavy-duty industrial loads. Consider factors such as moisture exposure, rough handling, and the need for multiple reuse cycles when selecting materials.

Step 3 — Determine bag size and pattern:

Dunnage bags are specified by bag width and effective height when inflated. Sizing should match void dimensions while leaving allowance for surface irregularities.

A practical approach:

• Measure the clear void height and width at the planned placement point.

• Select a bag that, when inflated, will fill the void and achieve contact across opposing surfaces without excessive over-expansion.

• Use wider bags for larger voids and to distribute pressure more evenly over fragile surfaces.

Placement patterns depend on load configuration. Common patterns include:

• Edge or border placement: Bags placed around the perimeter to prevent side-to-side movement.

• Intermediate or staggered: Bags placed between pallet rows or columns for distributed restraint.

• Continuous filling: Multiple bags placed end-to-end to create an unbroken bracing wall for very large voids.

Step 4 — Determine inflation pressure: Manufacturers provide recommended working pressures and safe fill procedures for each model.

Key considerations include the restraint requirement (calculated using cargo weight and allowable movement), the bag’s maximum working pressure, and the strength of opposing surfaces. A prudent practice is to use a pump with an accurate pressure gauge and to inflate progressively: partially inflate to seat the bag, then incrementally increase pressure while checking cargo alignment and container stresses. Avoid overinflation that might over-stress cargo or container walls.

Step 5 — Installation sequence and technique: Proper sequence ensures uniform load support:

• Pre-position all bags loosely in the intended voids before inflation.

• Partially inflate each bag to a low holding pressure to provide initial seating.

• Adjust cargo as needed to correct misalignments.

• Progressively inflate bags in a balanced pattern (e.g., diagonally or alternating sides) until all voids are filled uniformly.

• Perform a final check for secure contact points and proper valve closure.

Tools and accessories that improve outcomes include air pumps with pressure gauges, pressure relief fittings for safety, plywood or edge protectors to distribute pressure over fragile packaging, and valve caps to prevent inadvertent deflation. Use of check valves and tamper-proof seals is common when long-duration containment is required.

Common mistakes to avoid:

• Undersizing: Using a bag too small for the void leaves residual movement and undermines load security.

• Overinflation: Inflating beyond recommended pressure risks bag burst, cargo damage, or container deformation.

• Poor placement: Allowing sharp edges to contact the bag, or placing bags against compressible loads without support, can cause punctures or sinkage.

• Ignoring manufacturer guidance: Each bag has a rated working pressure and expected cycle life; disregard invites failure and voided warranties.

Operational examples and workflows:

• A 53-foot truckload moving supermarket pallets uses 30–50 cm wide kraft bags between pallet rows. Workers pre-place bags and sequentially inflate to seat pallets, then top up each bag until pallets are snug with no audible movement when the truck doors are closed.

• An exporter packing mixed furniture loads into a 20-foot container uses reusable woven bags and hardwood plywood panels under the bag contact points for extra protection. Bags are inflated with a regulated pump set to the manufacturer’s working pressure and checked before sealing the container.

Record-keeping and training: Implement a simple checklist for bag selection, placement pattern, inflation pressure, and inspection before dispatch. Train loaders and forklift operators on proper bag handling, valve operation, and the importance of edge protection. For reusable bags, log the number of cycles, inspection dates, and repairs.

When applied with care, proper selection, sizing, and installation of inflatable dunnage deliver a cost-effective load restraint solution that reduces cargo damage, speeds loading operations, and integrates cleanly with modern warehouse workflows. The key is planning—matching bag type and pattern to cargo characteristics and transport mode, and following disciplined inflation and inspection practices.