How to Choose the Right Dunnage Bag for a Container Load

Start with the void and the load

Choose a dunnage bag by measuring the actual gap between stable cargo faces, the height and width of those faces, the weight the bag must restrain, and every transport mode on the route. Then confirm the specific bag's permitted gap, working pressure and force capacity with its manufacturer. A printed bag size alone cannot establish that it will secure a container load.

For warehouse and shipping managers deciding a container loading spec, the key distinction is between the empty space a bag expands into and the surface that supports it. The same nominal bag can make less contact with cargo as the gap grows, so a larger void is not automatically solved by choosing a taller bag. Record the layout before selecting a size or writing a purchase specification.

Sources: Cordstrap, D-Connect Dunnage Bag Hand Book

Measure three dimensions before selecting a bag

The measured void is the clear horizontal distance between the two surfaces the inflated bag will touch. Measure it at several heights and along the planned placement area, especially when cartons bulge, pallets are uneven, or the load is staggered. Use the largest relevant gap and note any narrow points or protrusions that would pinch the bag.

The bearing width is the usable face of the cargo on each side of that void, and the bearing height is the supported vertical area above the pallet. Measure the smaller face when the two sides differ, because a bag cannot gain useful contact from air extending beyond one side's cargo. Cordstrap's sizing handbook instructs users to measure the goods' width and height, excluding the pallet, and the space between pallets.

Sketch the container from above and mark each bag position, the direction of possible movement, and whether the opposite face is another stable cargo unit or a container wall. Include pallet height, cargo height, cargo width, gap, and any door-end space in the measurement sheet. A photograph of the loaded arrangement can help the supplier understand irregular faces, but dimensions still need to be written down.

• Gap: clear space at the planned bag position, measured in inches.
• Faces: usable width and height of the cargo on both sides, measured above the pallet.
• Load: weight and packaging of the cargo that could press on the bag.
• Route: road, rail, ocean, or a combination; identify the most demanding leg for the securement design.

Sources: Cordstrap, D-Connect Dunnage Bag Hand Book

Which One Pack size should you consider?

One Pack lists six Tuffy poly woven dunnage bag sizes in its catalog. Their stated dimensions give a starting set of candidates once the cargo faces have been measured; they do not state a permitted void, working pressure, force capacity, or rail performance level. Ask for the current product instructions and performance sheet before approving any of these sizes for a load.

The table shows the catalog's bag dimensions and skid quantities, so procurement can compare a trial specification with a recurring purchase quantity. The bags are sold by each according to the catalog; the skid quantity is a pack reference, not a minimum order stated here. The 36 in wide option is useful to consider when the supported face is shorter, while the 48 in wide options offer different listed lengths for different cargo heights.

For example, a measured 8 in gap beside a 48 in wide, 72 in high cargo face might put the listed 48 x 72 in bag on a short list. That observation is only a dimension screen, not a selection or a performance claim: the supported face may be smaller, and the allowable gap and restraint force still need product-specific verification. An unsupported 96 in long bag does not become suitable merely because it fills more vertical space.

Sources: Cordstrap, D-Connect Dunnage Bag Hand Book

Confirm restraint capacity for the whole route

Dunnage bag performance depends on more than the flat dimensions printed on a product listing. The contact area changes as a bag expands into a wider gap; the supported load, friction, and direction of possible movement also affect the force it must resist. A manufacturer's force table or engineering guidance should be checked for the actual void and the specific bag, rather than borrowing a value from a different brand or model.

For a container that will move by truck and then rail or ocean, give the supplier the full route and load layout. A bag suited to one transport leg should not be assumed adequate for every leg, and a rail level or approval should not be inferred from the phrase poly woven. Ask for the applicable performance designation, limits, instructions, and any carrier requirements in writing.

If the load is tall, heavy, or liable to tip, review the broader restraint arrangement with the party responsible for loading and securing it. The manufacturer needs the weight of the cargo that can bear on the bag, the gap, the contact faces, and the intended placement to recommend a product. If those inputs or a product rating are missing, hold the size decision open rather than treating the catalog dimensions as a capacity chart.

Sources: Cordstrap, D-Connect Dunnage Bag Hand Book; FMCSA, Cargo Securement Rules

Placement and inflation affect the result

A correctly sized bag still needs a sound bearing surface and the right installed pressure. Inspect the cargo faces, bag and valve for damage, sharp points, and gaps in support before inflation. For the trucking leg, 49 CFR 393.104(d) says dunnage bags and other blocking materials must not have damage or defects that compromise the securement system.

Cordstrap's handbook advises placing a bag above the pallet rather than on the container floor, keeping it within the goods' width and height, and using barrier material against a container's exterior wall. Those instructions describe a useful placement check, but the Tuffy bag's own directions must govern its installation. If a void exceeds the chosen product's limit, change the loading layout or use an approved combination of restraint methods rather than forcing a bag into that gap.

Inflate only to the pressure specified for the exact bag and application, using an inflator compatible with its valve. One Pack lists a Trigger Style Dunnage Airbag Inflator, SKU PA-1M, but the catalog does not establish its valve compatibility or pressure control for each Tuffy bag. Include the bag and inflator details together in the quote request so that compatibility and operating instructions can be confirmed.

• Inspect the bag, valve, cargo faces, and any barrier before use.
• Position the bag against supported cargo faces and keep it clear of pallet edges and the floor as directed.
• Use the product's specified inflation pressure; document who checks it and when.
• Check that the loaded door area and final arrangement do not leave another unrestrained gap.

Sources: 49 CFR 393.104(d), standards for securement materials; Cordstrap, D-Connect Dunnage Bag Hand Book

When should you use another restraint method?

A dunnage bag is suited to a bounded void with stable faces on which it can bear. If a load has no opposing face, an irregular edge that can puncture a bag, or a gap outside the manufacturer's range, redesign the layout or evaluate blocking, a shoring bar, or another rated restraint. Do not assume that a bag can replace a tiedown required for a particular cargo arrangement.

FMCSA's general rule for covered commercial motor vehicle transport allows cargo to be immobilized or secured with adequate structures, dunnage bags, shoring bars, tiedowns, or a combination. It also says commodity-specific rules can add requirements, so the correct choice depends on the vehicle and cargo. A load bar bears against the vehicle structure, while a dunnage bag expands between faces; either still needs a suitable installation and verified capacity.

For alternatives, review One Pack's cargo control supplies and the ratchet strap guide when tiedowns are part of the design. The latter is most relevant to loads with usable anchor points and a need for a rated tiedown system. This post gives general information for purchasing and load planning, not legal or compliance advice; the responsible carrier and loader must confirm the applicable rules and the final securement plan.

Sources: 49 CFR 393.106, general cargo securement requirements; FMCSA, Cargo Securement Rules

Turn the measurements into a quote specification

A useful quote request identifies a repeatable loading pattern rather than naming a bag dimension alone. Send the measured void range, each adjacent cargo face, pallet and cargo dimensions, weight bearing on the bag, container or trailer type, route, and expected number of bags per load. Add photographs or a simple sketch if the faces are irregular, and state whether the load is a trial or a standard operating pattern.

Separate the purchase quantity from the loading quantity. Estimate bags per load from the actual bag positions, multiply by the planned number of loads, and then compare that result with the catalog's per-skid figures only if skid purchasing is relevant. For instance, three positions across 40 planned loads implies 120 bag uses; that is arithmetic for planning, not a recommendation that three bags will secure a particular load.

Ask the supplier to confirm the exact bag's void range, performance rating, pressure instructions, valve and inflator match, and any required barrier or other restraint. Browse the dunnage bag category to identify catalog sizes, then request a quote with the measurement sheet and the quantity you expect to use. A clear request lets sales identify the correct item and obtain the missing technical documentation before a loading spec is finalized.

Frequently asked questions

These dunnage bag questions come up after a candidate size has been identified. Each answer depends on the actual loaded gap and the specific bag's instructions.

Sources: 49 CFR 393.106(b), general cargo securement requirements