From Shifting to Stable: Mastering Load Securing with Dunnage Bags (Inflatable)

What inflatable dunnage bags are and why they matter

Dunnage bags (inflatable) are air-filled cushions positioned between cargo items, between cargo and walls, or between palletized units to eliminate voids, absorb shock, and stop lateral and longitudinal movement during transit. For beginners, think of them as temporary airbags that stabilize loads so goods arrive intact, drivers remain safe, and carriers avoid costly claims and delays.

Common types and materials

There are two main construction styles: single-use paper-based bags and reusable woven-polypropylene (PP) or laminated fabric bags.

• Kraft paper bags: Often multi-layered and used for single or limited reuse. They are lightweight, cost-effective, recyclable, and common in truck and container shipments of palletized goods.
• Woven/laminated fabric bags: Made from polypropylene, polyester, or reinforced laminates for higher strength and multiple reuses. These are preferred where puncture resistance and repeated operations are required.

Bags also vary by valve type (simple check-valve, screw valve, or specialist low-pressure valves) and shape (flat, gusseted, or round) to suit different void geometries.

Where they are used

Dunnage bags are versatile and used across modes: road trailers to prevent trailer-shift of pallet stacks; intermodal containers to secure mixed pallet and piece-loads; railcars to prevent lateral movement during cornering; and ocean containers to limit shifting during heavy seas. They serve freight forwarders, shippers, warehouses, and carriers alike.

How to choose the right dunnage bag

Begin with the size of the void and the weight and fragility of the cargo. Matching bag size to gap thickness is critical: small gaps need thinner or gusseted bags; large voids require larger or multiple bags. Choose material based on reusability needs and exposure risks (e.g., sharp edges, moisture). Always follow manufacturer guidance on maximum recommended bag size and intended application.

Step-by-step basic use

1. Inspect cargo and measure gaps: Walk the load to identify where cargo might move and measure voids. Check for sharp corners and address them with edge protection.
2. Select bag type/size: Pick a bag that fits the void with some compression allowance; too large a bag may not inflate correctly, too small will over-compress.
3. Place protective materials: Use cardboard, plywood, or edge protectors between the bag and fragile or sharp surfaces to prevent punctures and distribute pressure.
4. Position the bag: Lay the bag flat in the void with the valve accessible. For long gaps, use multiple bags spaced evenly.
5. Inflate carefully: Use a blower or pump recommended by the bag manufacturer. Inflate slowly and stop when the bag is firm but not over-pressurized. Most bags are designed for low-pressure inflation; follow the manufacturer’s guidance rather than guessing.
6. Secure and check: Ensure the bag fills the void and the cargo is immobilized. Re-check after short road movement if possible.

Best practices

• Always protect edges: Use edge protectors or sheet material where the bag contacts straps, metal, or pallet corners.
• Use the right number of bags: One large bag may not be as effective as several appropriately sized bags spread across the void.
• Follow manufacturer instructions: Each bag has recommended uses, maximum pressures, and inflation methods. Follow them to avoid failures.
• Train staff: Proper placement and inflation technique significantly reduce damage claims and improve safety.
• Combine with other methods when needed: For extremely heavy or valuable loads, pair dunnage bags with strapping, blocking, or lashing.

Advantages compared with alternatives

Dunnage bags are faster to deploy than building custom timber bracing and typically cost less in labor. They’re flexible for mixed loads—where fixed bracing would be difficult to install—and can reduce transit damage, improve loading efficiency, and lower claims. Reusable fabric bags can also be more sustainable over multiple trips than one-time-use bracing materials.

Limitations and when not to use them

Dunnage bags are not a universal solution. They don’t perform well when voids are extremely large or irregularly shaped, on loads with many sharp protrusions unless adequately protected, or when the cargo must resist very high forces (for example, heavy machinery subject to dynamic loads without additional lashing). In such cases, mechanical blocking/bracing, chain lashings, or engineered cradles may be necessary.

Safety and inspection

Key safety rules for beginners: do not overinflate, protect the bag from sharp edges, always use a proper inflation tool, and keep a visual inspection routine. Inspect bags before each use for abrasions, cuts, or seam failures. If a bag shows signs of damage, discard or return it to the supplier as per manufacturer guidance. Never use improvised inflation methods that can over-pressurize the bag.

Sustainability and disposal

Kraft paper bags are often recyclable after use where facilities exist. Woven or laminated bags can be reused many times; when they reach end-of-life, check local recycling for polypropylene materials or consult suppliers about take-back programs. Using reusable bags and reducing wood blocking can lower overall environmental impacts for frequent shippers.

Common mistakes to avoid

• Wrong size selection: Using a bag too large or small for the gap leads to poor stabilization or bag failure.
• Skipping edge protection: Direct contact with sharp edges is a leading cause of punctures and failures.
• Overinflation or guessing pressure: Inflating beyond manufacturer recommendations risks bag rupture and sudden load movement.
• Assuming they replace all other methods: Relying solely on dunnage bags in heavy or high-risk shipments rather than using complementary securing methods.
• Reusing single-use bags: Reusing kraft paper bags beyond intended use increases failure risk.

Real-world example

A regional food distributor loading mixed pallets into an articulated trailer used a combination of kraft dunnage bags and cardboard edge protectors. The bags filled gaps between pallet stacks, preventing lateral movement during cornering. Damage claims dropped substantially, loading time reduced versus building timber braces, and drivers reported a more stable ride.

Final advice

Start by practicing on non-critical loads and follow the bag manufacturer’s guidance. Train your loading team to measure voids, protect edges, use the correct inflation equipment, and treat dunnage bags as one part of a layered load-securing strategy. When used correctly, inflatable dunnage bags are a simple, effective tool to move cargo from shifting to stable.