Transport Packaging Faces Daunting Task and Hazards
Dennis Young, an expert in transport packaging, describes the hazards of shipping and the keys to design effective transport packaging.
By Dennis Young
Date Posted: 7/1/2003
Hundreds of years ago, products were made by the users or manufactured nearby and distributed within short distances. Many makers of each product type were needed. Over time, manufacturers became more specialized and differentiated. Demand for better products came from longer distances, and distribution started to become a significant factor in meeting that demand.
In today’s global economy, the intercontinental distribution of products has become commonplace and expected. Manufacturers routinely move facilities to seek low-cost or specialized labor markets, resulting in distribution channels that are thousands of miles long.
Distribution systems are not designed to protect products but rather to move them to where the demand is and at low cost. This creates a set of serious hazards for products — physical hazards that can cause products to break, abrade, melt, crack, bend, fatigue and implode. The job of guarding products against these hazards falls to the protective packaging.
Transport packaging is designed to serve as a temporary mediator between a hostile distribution environment and a damage-sensitive product. It includes such important components as inner dunnage, cushioning, corrugated boxes and unit load packaging, such as pallets.
The development of an effective transport package starts with information. Three types of data are required on:
• hazards of distribution
• product characteristics
• packaging materials and forms alternatives
These data are necessary in order to design the package.
Rather than send the new package into the battle untested, the design’s protective performance should be evaluated by testing. The test parameters are set by knowledge of the distribution hazards. Test results provide feedback to the design process to modify the package if the results were unsatisfactory. A successful test leads to implementation of the design.
Logistics is the business activity that uses procurement, transportation, inventory and information to add value to products by placing product in markets. Logistics, or supply chain management, has three elements that interface with transport packaging: transportation, warehousing and handling.
Once a packaging system has been implemented, changes in logistics make the package less effective. In a global business environment, changes that take advantage of competitive opportunities are common — new transport modes, new markets in far-away places, new warehousing strategy. Packaging must be flexible or must change to respond to this dynamic environment.
Transportation is the logistic element of movement. Putting products in touch with markets means moving them from manufacture to the point of demand. Transportation has an interface with either part of the global infrastructure — roads or rails for ground transportation, or with a fluid medium, water and air for those transit modes.
In any of these cases, the transporting vehicle rides on uneven surfaces —es. This is the starting point of the principal hazard of transportation. The disruption — bumps, turbulence, waves — is modified by the characteristics of the vehicle.
A truck’s suspension and tires, for example, are a major contributor. (Truck steel spring suspensions generally have higher overall vibration levels than air-ride suspensions, and smooth roads input lower levels than rough roads if all other variables are equal.) The rest of the vehicle structure also plays a role along with the loading of packages in the vehicle and other factors. The resulting vibration is a serious potential for damage to products and packages.
The characteristics of transportation vibration have been studied and documented. While there is significant variation, some characteristics are constant. Transportation vibration is broad frequency, generally ranging from a low of 1 to 3 Hertz (cycles per second) up to a high of 100 to 300 Hertz (Hz).
Products and packages may easily be affected by this vibration. Products may over-respond to certain frequencies and suffer damage from fatigue or abrasion by repeated movement while in contact with inner packaging or other products.
It has been shown that vibration levels are also quite low in intensity, although some vehicle types are much worse than others. Overall vibration levels range from low, like a good automobile ride, to a ride that is like being in the back of a pick-up truck on a rough road. The principal characteristic of vehicle vibration is that it is random vibration, meaning that the motion that reaches the packages is a mixture of frequencies (vibrations per second) and vibration intensities or strengths. Some frequencies are more active than others, giving the vibration a ‘shape’ when graphed for analysis. Random vibration is complex and similar to hearing an entire orchestra play at the same time — as opposed to simple vibration, which is like hearing a single note from a single instrument.
Warehousing is the element of supply chain management that deals with time. The inventory velocity of products varies widely, and both supply and demand have some uncertainty —sometimes a lot of uncertainty. The seller always wants to minimize the classic ‘stock out’ situation where the buyer is ready to purchase but the product is not available. Minimizing stock out and maximizing customer service levels at least cost — under conditions of uncertainty of both supply/production and demand/purchase — is a key function of logistic management.
Warehousing serves as the buffer for these uncertainties, providing a supply of product while waiting for production to supply the market, or covering the sudden and unexpected peak of demand. However, warehousing and holding inventory costs money, so warehousing costs need to be minimized by efficient operations. This includes using the capital assets of warehousing efficiently. For example, utilize as much of the cubic space in a building by stacking packages or unit loads on top of each other. Minimize operational costs by eliminating or reducing expensive air conditioning and atmospheric controls.
The result is a warehouse that contains hazards for packages and products. Warehouse hazards fall into two categories:
• top load or crushing from stacking
• atmospheric conditions
Individual packages and unit loads are stacked from 40 to 180 inches high in many cases. Of course, some warehouses minimize stacking with racks or other systems, but stacking is still very common. Another element of the load hazard is time, and time in storage can vary literally from minutes to years. The temperature in a warehouse often is bounded by typical human working conditions on the order of 10 to 110 degrees F. Relative humidity can be expected to reach 100% and condensing on occasion.
All these factors — load, time, temperature and humidity — may affect the integrity of packages and the condition of products. For example, a corrugated box at 90% relative humidity retains less than half its stacking strength compared with 50% relative humidity. After 30 days of storage, a corrugated box will retain abut 60% of its strength as compared with no storage time. Even an interlocking pallet pattern, as compared to a column stacked pattern, reduces stackability by about 40%.
These factors are also cumulative, so a unit load stored for 30 days, with 90% relative humidity, in an interlocked pattern, is reduced to about 18% (0.5 x 0.6 x 0.6 = 0.18) of its potential load carrying capacity. Package and product damage — and personal injury — can result from the reduced capacity of packaging in a typical warehousing environment.
Atmospheric conditions contribute to potential product and package damage in other ways, also. Temperature can weaken or crack some synthetic materials. Moisture can contribute to corrosion. Reduced atmospheric pressure can stress or even burst sealed packages and may affect some products. Atmospheric pressure equivalents of 8,000 feet are typical in pressurized aircraft, both passenger and cargo. Ground transportation in some locales can subject packages to somewhat over 11,000 feet altitude. Specialized air transport to a limited number of locations may have exposures to 15,000 to 20,000 feet in altitude, although these un-pressurized cargo aircraft are not common.
If transportation and warehousing are the activities of logistics, then handling is the interface between these activities. When the location of a package or unit load changes, it will be handled. From manufacturing to warehouse, from warehouse to vehicle, from vehicle to distribution center, from distribution center to delivery mode, and so on. Each of these interfaces involves handling — mechanized, mechanically supported or manual.
Each handling is, in turn, an opportunity for package drops, impacts and shocks. Packages in the light, manually handled weight range of up to 40 pounds or so will routinely be dropped several times in their life. Simple distribution, such as load-transport-unload, will have fewer drops than complex, hub-and-spoke, multi-location handling operations. Average drops around 10-15 inches occur with regularity. Higher drops — 2, 3, 4 feet and more — are more rare but hardly unexpected. One study showed that 10 and 35 pound packages receive an average of about six significant drops per trip with about 15% of these drops being over 24 inches in height and some as high as 40-48 inches. The damage potential is clear for severe product breakage and package degradation.
So, it’s a dangerous world out there, especially when the logistic system is changing to meet changing market demands, sources of supply and growing markets.
Technology has provided us with some important tools to use to understand and deal with these challenges. Using small, battery-powered, computer-compatible devices, it is possible to measure the drops, vibration, temperature, humidity, compressive load, altitude and other factors that endanger packages and products. These measurements are done to provide data on specific distribution systems and help solve persistent problems by understanding what happens in channels of distribution. Generalized data is used to develop test protocols so that the developmental package may be evaluated in the laboratory before shipment.
Test Every Package
Every package should be tested. The key questions are: who tests your package, and who gets the information? If a shipper uses their customers to test the new package or the performance of the current package in a changed environment, a negative result is virtually guaranteed to have a bad effect.
It is far better to evaluate package effectiveness in controlled circumstances, where the results can be used to improve that package, whether more protection or less cost. The answer is often a standardized test protocol, such as those developed by the American Society for Testing and Materials (ASTM www.astm.org) or ISTA, The Association for Transport Packaging (www.ista.org). ISTA is the author of ISTA Procedure 1A, the most widely used test procedure, with a 50-plus year history of helping shippers screen out problems before they reach the customers. ISTA has a suite of about 20 test protocols for different package types and distribution systems.
An early step to understand and benefit from packaging and distribution opportunities is to document the distribution system. This observation step helps select a test protocol from among the standards available or may serve as an outline for aggressive hazard definition efforts. Using boxes for handling and warehousing operations and arrows for transportation, document how packaged products move from manufacturing to end-user, adding specific details whenever available. Once identified, the hazards of distribution can be linked to appropriate laboratory test procedures. Handling equates to drop tests, transportation vibration, and so on. Modern test technology offers a wide variety of possibilities, from simple to sophisticated tests, and the user should select the best tool for the objectives at hand. Third-party independent test laboratories are available to help in this process.
The top technology approach to package testing is focused simulation, where hazards measured in the transport environment are used to set up highly representative test sequences in the laboratory. Measuring handling environments, for example, can tell us the number of significant drops per trip, the distribution of these drops across a range of drop heights, and the orientation of these drops — flat, edge or corner impacts. With this information, a test procedure can be specified that links solidly to known hazards of distribution. While the effort to develop focused simulation tests can be significant, the problem-solving ability of this technique is powerful.
Whether a simple standard test or a customized, distribution-specific protocol, testing of packaged products prior to full-scale production shipping can help avoid costly damage problems, reduce packaging costs to the effective minimum, and validate current packaging for new distribution challenges. Understanding and accounting for the hazards of the logistic environment is the key to success in a dynamic global economy.
(Editor’s Note: Dennis Young is a senior consultant for Dennis Young and Associates Inc., Grand Rapids, Mich., a consulting firm specializing in the development, measurement and verification functions of protective distribution packaging. Dennis Young and Associates utilizes personnel and technology resources to achieve client defined goals, including cost reduction, damage reduction, environmental sensitivity and regulatory compliance. Dennis may be contacted at (616) 459-970 or through the company’s Web site at www.dyainc.com or www.packagetest.com.)
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