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Air Dunnage Bags: A Comprehensive Guide (2017 Update)

Posted by Packaging Group on

Air Bag Definition & Functions

Introduction

A Dunnage air bag is a poly bladder surrounded by numerous plys of paper, equipped with an inflation valve, and is used to minimize front-to-back load shifting in tractor sales, railcars, and overseas containers.

Before we dive in, here are some terms and abbreviations that are commonly used for Dunnage Airbags:

  • AR: Abrasion Resistant
  • SE: Sewn End
  • DEF: Double End Fold
  • MTO: Made To Order. Bags with 15 business day lead time and 500 piece minimum.
  • Stock or “A” Bag: Less than truck load order: 3 day Truck Load: 10 business days
  • LTL: Less Than Truck Load
  • TL: Truck Load / 20+ skids
  • OTR: Over The Road
  • TOFC / Piggyback: Trailer On Flat Car
  • OSC: Overseas Container
  • Pin Wheeling: Action to rotate a pallet in order to reduce the void

Frequently Asked Questions:

What are Dunnage Air Bags?

Dunnage Air Bags are paper bags made up of 2, 4, 6, or 8 plys (layers) of paper. They come with an internal inflatable Polyethylene Bladder. They are an innovative and efficient blocking and bracing tool.

What are they used for?

Dunnage Air Bags are best used to control movement of cargo loads in railcars, trucks, or overseas containers. They manage the movement of cargo by bracing loads, filling voids, protecting cargo from in-transit damage, and absorbing vibrations. Dunnage Air Bags protect cargo better than any other form of bracing ("dunnaging").

How has cargo been braced in the past?

Loads have long been braced by using a combination of empty cardboard cartons, 2 x 4's, and pallets. Shipments which included fragile goods as part of the overall load required stair-stepping standard freight back-to or away-from the fragile freight.

What are some of the benefits of using Dunnage Air Bags?

Dunnage Air Bags are a more economical alternative for bracing and blocking cargo than using other more costly methods such as rubber air bags or lumber and nails.

What benefits does the shipper reap from using Air Bags?

With ever-changing and constantly rising operating costs, the trucking industry is an ongoing fight for survival. With insurance premiums continuously on the rise, taxes and fuel costs souring, and wage increases and discounts continuing to consume the bottom line, operating improvements must be made to sustain profit margins. Air Bags will have the largest impact on the load factor (a carrier's single greatest expense). One of the main goals of the shipping quality process is to advance organizational productivity. Time lost installing Air Bags will be saved at the destination terminals because the carrier can do away with the "Re's"(Re-working Restacking, Re-shrink-wrappping, Recouping, and Re-banding the load). Consequently, more efficient use of container space can be made at the same time.

How is this accomplished?

Air Bags allow double and triple-decking of skids, and stair-stepping can be done away with. Air Bags allow for fragile freight to be loaded anywhere in the trailer. To achieve maximum cube utilization skids can be double or triple-decked and air-bagged either in front of or behind (or both) the fragile freight. Since using Air Bags will allow normal loading behind the fragile freight, doing away with the need for stair-stepping improves the load factor and lowers the transportation or line-haul.

What are the effects of shifting loads and damaged freight?

Customer satisfaction is the primary and greatest effect. Undoubtedly when a customer receives damaged freight they are going to be unhappy. Valuable time is wasted at destination terminals putting the damaged freight back together. The need for "Re's" hinder customer relations and negatively affect dock production.

What are the most common causes of freight damage?

The most frequent causes of freight damage are associated with double and triple decked skids bouncing and freight falling forward to backward during transit.

Can Dunnage Bags be damaged during filling?

Dunnage Bags can burst due to over-inflation and can also be cold burned. Each bag contains a label located near the valve indicating suggested pressure. However, correctly following simple inflation check points with eliminate these issues.

Do Dunnage Bags require any type of protection?

To ensure product integrity, it is crucial for a corrugated or some other type of smooth surface be placed on either side of the Dunnage Bag to protect it from anything sharp such as pallets, wooden crates, or other rough edges.

What can be done to utilize Dunnage Bags if void exceeds maximum recommended void?

Should this condition arise, reduce unusually large voids with some type of void filler such as old pallets or corrugated.

Is a re-usable bag available?

Yes, however, our concerns with selling re-usable bags are:

  1. We have no control over how a bag is used. Therefore, we cannot guarantee how many times it can be used.
  2. The re-usable air bags are a more costly option.
  3. Most customers do not have enough control to get the bags returned. Therefore, they pay for a bag with the intentions of re-using it but do not actually get to.
  4. To release the air, many times a bag will be punctured. This renders the bag unusable. We offer labels for the air bags which read "Re-usable Bag DO NOT Puncture."

How many pounds can a Dunnage Air Bag restrain?

  • 2 ply - 40,000 pounds
  • 4 ply - 60,000 pounds
  • 6 ply - 100,000 pounds
  • 8 ply - 120,000 pounds

What size and ply bags are available?

(See "Available Sizes")

How do I determine what size Dunnage Air Bag I need?

  1. Measure the length of the pallets or whatever you are trying to restrain.
  2. Measure distance from floor to top of load
  3. Measure void between cargo

What type of Dunnage Air Bag is recommended for truck shipment?

2 ply bags.

What type of Dunnage Air Bag is most commonly used for rail shipments?

4 ply, 6 ply, or 8 ply

What type of bag is most commonly used for overseas shipments?

4 ply

What is the maximum void recommended for Dunnage Bags?

  • 8" void - 24" wide Air Bag is recommended
  • 10" void - 30" wide Air Bag is recommended
  • 12" void - 36" wide Air Bag is recommended
  • 15" void - 48" wide Air Bag is recommended
  • 20" void - 60" wide Air Bag is recommended

What equipment is needed to inflate Dunnage Bags?

  1. Air gauge
  2. Inflator tool
  3. Compressed air from an air compressor

What kind of Inflator Equipment is available?

  1. Air compressor
  2. Rapid fill inflator tool
  3. Hose and reel
  4. Quick fill snap on inflator
  5. Quick fill combination inflator tool

Why use our Dunnage Air Bags instead of our competitors products? 

  1. Only the highest quality materials are used and every 12th bag off the assembly line or 8% of our bags is physically tested to ensure top quality.
  2. Our paper dunnage bags are the oldest on the market today and years have been spent adjusting and making improvements on it.
  3. The manufacturing process is integrated to ensure our competitiveness in the market place.

What is the cost of Dunnage Air Bags?

Contact one of our expert sales representatives today to discuss pricing, as well as any other questions or concerns you may have regarding any of our Dunnage Air Bags.

Practical, easy to install, and versatile. Dunnage Air Bags lower cargo damage and reduce labor costs. They improve load factor, reduce transportation costs, compliment quality process, and increase the company's bottom line.

Characteristics of an Air Bag:

Compacting or positioning the lading

Compacting and positioning takes place during air bag inflation. The air bag surface pushes uniformly out against the load. As the air pressure increases, it overcomes frictional forces, eliminating small voids remaining in the load. No matter how tightly a load is positioned, either by fork truck or by hand, a build-up of small voids will remain. These voids are eliminated by air bag compacting/positioning.

Cushioning the lading

The second characteristic of air bag bracing is the cushioning that occurs during impact. For example, when a railcar is humped, the compacted lading in the front half acts as one unit rather than individual units which can slam into one another. The rear half of the load is cushioned by squeezing the air bag, increasing its internal air pressure, until equalization of forces occurs. The cushioning effect diminishes the shock of impact.

Repositioning the lading

When the forward motion of the lading ceases, repositioning of the lading begins. After the lading moves forward, squeezing the air bag, the internal pressure is greatest. The increased air pressure is reduced by pushing the lading back to its original position when the forces stop. Both the cushioning and repositioning of the load will take place in a fraction of a second.

Enlarging the void size after inflation

The fourth characteristic of air bag bracing is its ability to fill an increased void as the lading settles. Even with rigid products, which have been tightly loaded, settling takes place. In-transit vibration causes the lading to loosen. With other types of bracing, constant pressure cannot be exerted on the load. Air bags have the ability to expand, thus maintaining somewhat reduced but continuous pressure.


Air Width vs Void Size

3:1 Safety Factor

At maximum void size, the air bag still has a 50% or better contact area. Exceeding the maximum void may result in premature air bag failure. When voids are greater that 24”, use drop filter, honeycomb panels, etc. to reduce the void. You can also simply turn the pallets where you use an air bag ¼ turn. ZEBRA STRIPES will show the proper air bag width: void width ratio.

Recommended Air Bag Width vs. Void Size

Air Bag Width Maximum Void
24" 8"
30" 10"
36" 12"
48" 16"
60" 20"


Applications Mode of Transportation

Mode of Transportation Paper Air Bags Level

OTR / TL / LTL

1 Ply AR
2 Ply SE&DEF

Level 1
Level 1

Piggy Back / Intermodal

2 Ply / SE & DEF
4 Ply

Level 1
Level 2

Sea Container

2 Ply / SE & DEF
4 Ply

Level 1
Level 2

Rail

6 Ply paper
8 Ply paper
Medium Polywoven
Heavy Polywoven

Level 3
Level 4
Level 3
Level 4 & 5

Vessel

8 Ply paper
Heavy Polywoven

Level 4
Level 4



Mode of Transportation - Truck Dunnage Air Bags for Intermodal Transportation AAR Approved Freight Dunnage Air Bags Dunnage Air Bags for Sea Freight Large Freight Air Bags
Truck Intermodal Railcar Sea Container Vessels

 


 

Example of optimizing a dunnage load profile

 

Dunnage Operating Pressure

Introduction

A Dunnage air bag is a poly bladder surrounded by numerous plys of paper, equipped with an inflation valve, and is used to minimize front-to-back load shifting in tractor sales, railcars, and overseas containers.

It is important to make sure that you properly inflate dunnage air bags according to the specified guidelines.

Recommended Operating PSI And Burst

Current Bags

Max PSI Rating

Burst Test avg.

Group

1 ply AR

2-3 psi

8 psi

Lightweight

2 ply SE

2-3 psi

7 psi

Lightweight

2 ply DEF

2-3 psi

9 psi

Lightweight

4 ply Kraft

5 psi

17.75 psi

Heavyweight

6 ply Kraft

8 psi

29.4 psi

Heavyweight

8 ply Kraft

10 psi

31.9 psi

Heavyweight

Poly Woven Medium

8 psi

25 psi

Heavyweight

Poly Woven Heavy

10 psi

30 psi

Heavyweight

Product Performance Profile for Pneumatic Dunnage (PPPPD)

Product Performance Profile for Pneumatic Dunnage

  • General Information Bulletin No. 9
  • Effective July 1, 2005
  • Replace K,AAR Pamphlet #14

Product Performance Profile for Pneumatic Dunnage

  • Level 1: Pneumatic dunnage used as lateral (crosswire) void filler (Intermodal)
  • Levels 2-4: Pneumatic dunnage used as lengthwise void fillers in flat platen type applications (Boxcar)
  • Level 5: Pneumatic dunnage used as lengthwise void fillers in horizontal application between concave surfaces (Boxcar)

Product Performance Profile for Pneumatic Dunnage

 

Dunnage Air Bag Type

Maximum useable inflation pressure

Maximum load in pounds

Maximum testing pressure & void size

Level 1

2 Ply

2.5 PSI

40,000 lbs max per load

8 PSI

Level 2

4 Ply

5PSI

Less than 75,000 lbs in a railcar

17 PSI

Level 3

6 Ply Medium Polywoven         (5.2 oz sq/ft)

8 PSI

Between 75,000 and 160,000 lbs in a railcar

25 PSI

Level 4

8 Ply Heavy Polywoven (6.8 oz sq/ft)

10 PSI

Between 160,000 and 205,000 lbs in a railcar

30 PSI

Level 5

Heavy Polywoven (8.5 oz sq/ft)

10 PSI

Between 160,000 and 205,000 lbs in a railcar

21 PSI (18" Void Horizontal)

How to properly inflate your dunnage air bag


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