Freight doesn’t shift because your driver hit a pothole. It shifts because there was empty space in the load and nothing was there to fill it. That gap, however small, is where product gets crushed, pallets tip, and claims get filed. Dunnage air bags exist to close that gap before it becomes a problem.
If you manage freight, you’ve probably already got a favorite void fill method. Maybe it’s kraft paper, maybe it’s foam, maybe it’s whatever the crew grabbed off the shelf that morning. Dunnage air bags do a specific job that those materials can’t always match: they inflate to fill the exact void between your product and the container wall, then hold that pressure for the length of the haul. When they’re sized and placed right, they turn a loose, shifting load into one that arrives the way it left.
This guide covers everything to know about dunnage air bags:
- Where they fit into your broader load securement solutions
- How paper and polywoven bags differ
- The mistakes that cause bags to fail mid-transit
By the end, you’ll know exactly what to ask for the next time you’re specifying a load plan.
What Dunnage Air Bags Are and How They Stop Load Shift
A dunnage air bag is an inflatable cushion, usually made of paper or woven polypropylene, placed in the gaps between cartons, pallets, or unitized loads to keep everything securely in place during transport. Once positioned, the bag gets inflated with compressed air until it fills the void completely.
A properly inflated bag pushes back against the load on both sides, creating enough friction and resistance to keep pallets from sliding, tipping, or telescoping into each other when the trailer brakes hard, takes a curve, or hits a rough surface. Without something in that space, even a tightly packed load has room to move, and once one pallet shifts, it tends to take its neighbors with it.
Dunnage bags aren’t a substitute for good stacking or proper blocking and bracing. They’re the piece that handles the space you can’t eliminate any other way.
Where Dunnage Bags Fit Into a Load Securement Plan
Research out of Virginia Tech’s Unit Load Stability program backs up what most of us in the industry already know from experience: unit load stability isn’t one variable, it’s a complex system composed of many moving parts.
Dunnage air bags sit in the “gap management” layer of the load securement system. They come into play after you’ve decided how the load is unitized. In a full plan, you’ll typically see bags used alongside corner boards, strapping, and void fill materials, each one addressing a different failure point.
The FMCSA’s cargo securement rules don’t specify dunnage air bags by name, but they do require that cargo be secured to prevent shifting or falling during transport, which is exactly the failure mode dunnage air bags are built to prevent. If your load plan gets audited or your freight gets flagged at a weigh station, having a documented, engineered approach to void fill matters.
Paper vs. Polywoven Dunnage Air Bags: What’s the Difference?
This is usually the first fork in the road once a team decides to add dunnage bags to their process, and the right answer depends on what you’re shipping and how rough the ride will be.
Paper dunnage bags are built from multiple layers of kraft paper with a polyethylene liner inside to hold air. They work well for lighter loads and shorter hauls. Paper bags are biodegradable and easier to dispose of, which matters for shippers trying to cut down on plastic waste in their packaging stream. The tradeoff is durability. Paper bags can puncture more easily and are more likely to burst if not properly inflated.
Polywoven dunnage bags use a woven polypropylene fabric, similar to what you’d find in a heavy-duty tarp or feed bag. The superior material gives them more resistance to punctures, abrasion, and moisture. They hold up better in intermodal shipping, where freight gets transferred between trucks, rail cars, ships, and where the bag might sit compressed for longer periods. If you’re securing heavier loads or shipping through multiple handling points, they are the superior choice.
A rough rule of thumb: if the load is heavy, the trip involves multiple transfers, or the freight has any sharp corners or edges, go polywoven. If it’s a lighter, single-leg haul with a controlled environment, paper will usually do the job.
Sizing, Placement, and PSI: Getting the Fit Right
Getting the right fit and installation is where we see the most common mishaps and failures.
Sizing starts with measuring the actual void, not estimating it. A bag that’s too small won’t make contact with both surfaces once inflated, which defeats the purpose entirely. A bag that’s too large for the space will be under-inflated to fit, which means it won’t hold the pressure needed to resist load movement. Manufacturers publish size charts based on void width, and it’s worth measuring twice before ordering in bulk.
Placement matters as much as size. Bags should go in voids between rows of pallets or cartons, generally at the top third to top half of the load height, since that’s where shifting force has the most leverage. Bags placed too low or too high relative to the load’s center of gravity won’t do much to stop tipping.
PSI, or how much pressure the bag is inflated to, depends on the bag’s rated capacity and the size of the void. Most paper bags run in a lower PSI range, while polywoven bags can generally handle higher pressure. Overinflating a bag beyond its rated PSI risks bursting it mid-transit, which is worse than having no bag at all, since a burst bag leaves the void empty again with no warning. Underinflating leaves slack in the void, which brings back the exact shifting problem you were trying to solve. The bag’s spec sheet will list a recommended PSI range. That range exists for a reason, don’t ignore it.
Common Mistakes That Cause Dunnage Air Bags to Fail
A few patterns show up again and again when we get called in after a claim.
- Using the wrong bag type for the load weight. Paper bags that are expected to do a polywoven bag’s job tend to puncture or lose pressure before the freight even reaches its destination.
- Skipping the void measurement. Grabbing whatever size is on hand instead of matching the bag to the actual gap leads to bags that either can’t fill the space or malfunction.
- Overinflating in the name of “extra security.” More pressure isn’t always better. Past the rated PSI, you’re just increasing the odds of a blowout.
- Placing bags against sharp pallet edges or exposed strapping without corner protection, which is one of the fastest ways to puncture a bag regardless of material.
- Reusing bags. You cannot guarantee the integrity of the bag’s condition, which may cause a load shift or future claim.
Most of these come down to treating dunnage air bags as an afterthought rather than a specified component of the load plan. They work when they’re mindfully and intentionally placed, not just tossed in at the end.
When Shippers Should Ask for Help With a Custom Load Plan
The cost of poorly planned loads is much higher (especially when failures stack up over time) than the cost of a proper securement plan. It’s time to stop guessing and get a professional load plan if you find that your freight is often…
- Irregular in shape
- Unusually heavy
- Moving through multiple transportation modes
- Has a history of arriving damaged
Sunrise Manufacturing works with shipping, warehouse, and procurement teams to map out exactly where and how dunnage should be placed. We match bags to your specific product, container type, and shipping modality, whether that’s truckload, rail, or intermodal.
Research out of Virginia Tech’s Unit Load Stability program backs up what most of us in the industry already know from experience: unit load stability isn’t one variable, it’s the interaction of packaging, restraint, and handling all at once. A custom plan accounts for all three instead of leaving void fill to guesswork on the dock.
Ready to swap the guesswork for a plan built around your actual freight? Talk to our packaging team and we’ll map out the right dunnage setup for your next load.
FAQs About Dunnage Air Bags
What are dunnage air bags used for? They fill empty space between pallets, cartons, or unitized loads inside a trailer, container, or railcar to prevent shifting, tipping, and impact damage during transit.
Are dunnage air bags the same as pneumatic airbags? Yes, “dunnage air bags” and “pneumatic airbags” refer to the same product. Both describe inflatable void fill used for load securement, and you’ll see the terms used interchangeably across the industry.
What PSI should dunnage air bags be inflated to? It depends on the bag’s material and rated capacity. Paper bags typically run at a lower PSI than polywoven bags. Always check the manufacturer’s spec sheet for the recommended range rather than inflating by feel.
How do I choose the right dunnage bag size? Measure the actual void width you’re filling, not an estimate, and match it against the manufacturer’s size chart. A bag that’s undersized won’t make full contact with both surfaces, and an oversized bag won’t hold pressure properly once compressed to fit.
Can dunnage air bags be reused? Polywoven bags can sometimes handle a second use if they’re inspected and show no punctures or pressure loss. Paper bags are generally built for single use and shouldn’t be relied on for a second trip.
What causes dunnage air bags to fail? The most common causes are using the wrong bag type for the load weight, skipping proper void measurement, overinflating past the rated PSI, and placing bags against sharp edges without corner protection.
Are dunnage air bags good for rail shipping? Yes, and in a lot of cases they’re essential. Rail shipments experience higher impact forces than standard over-the-road freight, particularly during switching and coupling, which makes properly rated dunnage bags, usually polywoven, a key part of rail load plans.
Can dunnage air bags be used with void fill? Dunnage air bags are a type of void fill themselves, and they’re often used alongside other methods like corner boards or blocking material to build a complete securement system rather than relying on any single product alone.
