Packaging Design Consideration and Testing

Introduction

Distribution testing is an important aspect of ensuring that the product goes safe and undamaged from the manufacturer to the end user. To deliver damage free packaging / product to the consumer at the minimum cost, a packaging engineer must design the correct packaging delivery test for that particular product. There are two ways to go through for considering distribution test methods-ASTM (American Standard for Package Testing) and ISTA (International Safe Transit Association). But the question arrives in deciding which testing method is suitable for your product. In order to make the correct decision between the testing methods, it is important to first understand the product’s distribution environments. Assessment of the distribution environment of the product can determine which hazards the product will likely encounter and the level of intensity of those hazards. The handling, transport and storage of packages can result in a range of hazards within the shipping environment which includes vertical drops, horizontal impacts, transport vibrations extreme temperatures and compression loads. According to the method of package transportation the product may face different hazards, by understanding the major transportation methods and hazards associated with it will provide better understanding about package testing and finding solution to minimize the package damage in the transit. The shipping modes includes Sea Freight, which is used to ship large amount of goods at once. It is the longest mode of transportation and the slowest mode of transportation which means the product may be subjected to environmental hazards and undesirable movements during shipping for a longer period of time. This can lead to product damage if it is not packaged properly. The next is Air Freight, in which package is transport via flight. Companies such as FedEx which require their packages to be delivered in lesser time choose air freight. If you prefer to ship your package through air, you must consider that the package is subjected to some associated with the mode of transport such as atmospheric changes, In-transport movement, shocks, etc. The next shipping mode is Road transport and almost all packages at some point are transported through road transport. When considering road transport for your package, it is important to ensure that is properly protected from hazards such as vibrations from the vehicle. Rail transportation also provides alternative as an intermodal transportation for air and road transport in package distribution as it doesn’t have to face traffic and roadway congestions. For this transportation the package must be prepared to protect against damage due to shunting and vibrations of the rail.

The distribution method greatly influences the presence and magnitude of these hazards; thus it is crucial to understand the shipping environment in order to develop a test plan for the package that will adequately protect its product.

There are several standards used for evaluating packaging products and ASTM and ISTA provides specific tests that can be implemented to a particular design or material being used. These tests include simulation of various real-life hazards that a package might undergo in the actual distribution environment. In distribution testing there are two different procedures that can be used:

ASTM (American Society of Testing Material)

ASTM is an international standards organization that designs and publishes technical standards by mutual agreement for a variety of materials, products, procedures, and services. The ASTM D-10 Standards Committee is responsible for implementing technical understanding and developing packaging standards. The main ASTM D standards used in package testing are ASTM-D3078 (Bubble Emission Leak Test), ASTM-D4169 (Distribution Simulation Testing), ASTM- D4332(Conditioning Package Prior to Testing), ASTM-D4728 (Random Vibration Testing), ASTM-D5276 (Drop Test), ASTM- D642 (Compression Test) and ASTM-D 999 (Vibration Testing). In particular ASTM D4169 Testing, which provides a guide for the evaluation of shipping units in accordance with a uniform system. It uses established test methods which represents the occurrences in the actual distribution environment. According to ASTM, the recommended test levels are based in the available information on shipping and handling environment and current industry practices. As per ASTM D4169, there are 18 different distribution cycles,10 different test schedules and three assurance levels. Following tables represents the distribution cycles and test schedules used in ASTM D4169:

Source:( https://www.tek.com/testing-services/astm-d4169-testing)

Source:( https://www.tek.com/testing-services/astm-d4169-testing)

ASTM D4169-16 has three "Assurance Levels”. Level 1 is the highest intensity, Level II medium intensity and Level III is the lowest intensity of the assurance level. Among the most unique attributes of ASTM D4169-16 is its flexibility in selecting what test intensity is best suited to packaging performance.To better understand the assurance level consider the above tables for distribution cycles and Test Scheduels for this example,To test package that is of high value can be considered for Assurance Level 1(AL 1), variables for AL1 ASTM D4169-16 include the drop height in Schedule A, the specified compression load in Schedule C, and the frequency and duration of random and fixed vibrations in Schedules F and E. Similarly, The variables for ALII ASTM D4169-16 include reduced drop height in Schedule A, lower target compression load in Schedule C, and shorter duration and reduced random and fixed vibration in Schedules F and E.

ISTA (International Safe Transit Association)

The International Safe Transit Association (ISTA) is the organisation that determines how packages should be performed to ensure their product is protected. ISTA test procedures are internationally recognized as they are based on state-of - the-art technologies and the latest data on the global transport environment. The organisation through its packaged-product performance test processes, offers final approval of package revisions. ISTA testing standards are segemented into three types: Non-simulation Integrity performance testing, Partial Simulation performance testing,and General Simulation perfromance Testing. Following are the standards specfic to each type:

ISTA 1A (Non-simulation Integrity performance testing)

For carrying out the non simulation Integrity performance tests ISTA 1A is used. ISTA is used for packaged product that weigh upto 150 lb or less. It is used to test the strength and robustness of the prodcut and package  to withstand transportation hazards. ISTA 1A procedure is utilized to evaluate a shipping setup for drop testing and repetitive shock vibration in a cost effective way. The vibration method  used for ISTA 1A is fixed displacement which is similar to ASTM D999. ISTA 1A fails to take random vibration into consideration. To address that ISTA has a similar testing procedure which is called ISTA 1G. The ISTA 1G takes random viberation into account  whereas The drop test type for ISTA 1A and 1G are free fall tests. 

ISTA 3A (General Simulation Performance Tests)

ISTA 3A is a general simulation study for individual parcel delivery systems which weighs upto 150 lbs or less. It simulates a wide sets of circumstances such as vehichle types and routes or various handling situations. ISTA 3A includes characteristics such as simple shaped random viveration , differnet drop heights for the package sample and different atmospheric conditions which relates to tempertaure variations such as humid, frozen, hot.

ISTA 3A tests are ideal for standard, small, flat, and elongated types of packages which are generally delivered as individual packages, either by air or by ground. ISTA 3A also has a optional test which takes random vibertaion under low Pressure which simulates high altitude. In this test the primary package’s seal retention capacity without leaking the product is tested. However, the test procedure does test the effects of low pressure high altitude for non porous packaging.

ISTA 2A (Partial Simulation Performance Tests)

ISTA 2A test procedure is a combination of basic test elements from ISTA 1A  which are non simulated integrity testings and advanced simuation testings from ISTA 3A. ISTA 2A simulates actual transport hazards like temperature and humidity differences. For example, A packaged product that weighs upto 150 lbs or less which is going to come across a desert like shipping condition where temperature is 65 degree celcius and relative humidity is 10 per cent. The ISTA 2A can provide results about the pacakge whether is going to sustain the harsh environmental condition or not.

ASTM vs ISTA standard test procedure, which is better?  

The major differnece between ASTM and ISTA standards is that ASTM is a public organisation in which the procedures are developed in democratic process and undergoes a subcomittee review and approval followed by main comitte review and approval.whereas, ISTA is a private industry association. ASTM D4169 is recognised by both ISO11607 and FDA. Similarly, ISTA 1 series tests are also allowed for  Medical Device Manufacturing by ISO 11607 but not included in FDA “consensus standards” list. The benefit of using ASTM D4169 standard over ISTA is that ASTM D4169 DC 2 test procedure have almost all the tests which are identical to ISTA tests.

In ISTA 1 Series, the test results may not correlate to actual field results. Also, if we only consider ISTA 1 Series as the only available method then it is important to take into consideration the viberation time as the viberation time is very high in ISTA 1 Series. Moving on to ISTA 2 series, which is often used as a transit test in medical devices. Although, this test offers lower cost and less time and the compression test is much easier as compared to that in ASTM D1469.

In my opinion, if a boxes weighing under 20 lbs dropped ten times from a 38 inch drop height then it can damage the sterile barrier of the package. Instead using using ISTA 2A, ASTM D4169 can be used eventhough it is a bit costier testing method than ISTA. It provides more certinity that the package is subjected under realistic testing also it can be modified to fulfill the specific transport environment based on the assurance level.Also, the in lab damages observed on the package is fairly similar to what the package could undergo in the real world transportation hazards.

Hazards encounter in shipping modes

As disscussed earlier, There are differnet hazards associated with the type of transportation by the package is going to be shipped.The distribution hazards consists of four categories: Shock, Viberation, Compression, and Atmospheric.

For small parcels that weigh less than 60 lbs the the most common hazard associated with it is the improper handling of the package which leads to dropping of the package from an undesirable height and the impact may damge the product. The small packages  when loaded improperly, bumps and bad condition of the roads can cause boxses to shift and rub against each other which cause the small pacakage to undergo loose load viberation. In order to analyse the severity of the of the hazards the the small parcel can undergo shock tests and viberation tests so that it can be packaed properly to sustain the hazard. ASTM D5276 provide drop test that will provide the ability of  the package to withstand sudden shock due to free fall or rough handling. This shock resembles the real events that the package could possibly face in the distribution environment. Similar tests are also available in ISTA 1A. For vibration testing, ASTM D999 will test the ability of the package to protect the contents from transportaion viberation. The package is subjected to vertical motion and rotaional motion to produce vibration motion to the individual packages which are subjected to repettive shocks due to vibertaions.

Now, for the Full truck loads The most common hazard associacted with full truck load is the vibrations that occures due to the movemnet of the vehichle, and improper condition of the roads. Also, in the full truck load the package  experiences compression due to stacking of the pallet loads on top of the other, The full truck loads are meant to cover long distances in the distribution environment which means that they might be subjected to atmospheric changes for example tempreature changes and humidity variations. Some products are sensitive to temperture changes and might get damged in the dirstribution process.

The tests associated to vibration hazards in the full truck load may include testing the fixed displacements, variable displacement and random displacements. ASTM D999 is the standard test method for this.The vertical stack resonance test will determine the presenece and the effect of resonance in the pallete loads and multiple unit stacked loads, this will determine the ability of the conatiners to withstand the dynamic loads when stacked. Further, For compression testing, ASTM D642, will help in determining the compressive ressistance of the unit load in the truck. Also, for, determining the ability ot sustain the atmospheric conditions, ASTM D4332 provides for conditioning atmospheres that are used before transit simulation test.

The most common hazard associated with less-than-truckload  is the intransit stacking which results in vibrtaionsand when the the truck is not fully loaded, this means that the packages inside might get loose stacked due to viberations caused by the vehicle. ASTM D999 is the suitable test method along with switching the package assurance level to 1. This, in my opinion will allow us to determine the impact, that the pacakage will sustain in LTL truck load.

A small package weighing less than 60 lb if shipped through air freight, the hazards than can occur to the package may include damges due to in-transport movement. This can happen due to aceleration, take- off of the flight, and turbulance. Turbulance is nothing but the package experiencing immense compression due to atmospheric pressure change. ASTM  D6653 will determine the effect of high altitude or pressure differnces when the pacakged prodcutis transported thorugh aircrafts or through roads over high mountain passes.

References

• https://www.westpak.com/wp-content/uploads/2019/11/westpak-astm
• https://lso-inc.com/medical-package-testing/astm-d4169.html
• https://www.tek.com/testing-services/astm-d4169-testing
• https://www.nefab.com/en/insights/transport-packaging-solutions/