ISTA Issues Thermal Packaging Guideline

Document outlines test for insulated transport packages.

In April, the International Safe Transit Association (ISTA; East Lansing, MI) unveiled a guideline for a focused simulation test of temperature-controlled packaging. Project 5-14 shows how to evaluate the performance of insulated transport packages, which are often used to ship drugs and medical devices, in the most extreme temperature conditions possible.

The guideline was explained in full for the first time at the ISTA Con 99 conference, held April 6 in Orlando, FL. Presenting the guideline were three of its designers: Tom Pringle, president of ISC Inc. (Phoenix); Jeff Seeley, a senior packaging engineer at Merck & Company, Inc. (West Point, PA); and Brian Hickey, manager–packaging laboratory at Abbott Laboratories Diagnostics Div. (Abbott Park, IL).

Project 5-14 will be a trial procedure for one year, and during that period it can serve as the basis of tests. After one year, ISTA will review it and decide whether to upgrade it from a trial to a formal procedure.

Product shippers need to determine the acceptance criteria of the tests, such as exact product temperature requirements and acceptable time limits for exposure to higher or lower temperatures than those desired.

The guide recommends that the actual package be tested whenever possible. If a packaging system must be tested using samples or prototypes, equivalency testing for the real package should be conducted later. The product inside the package must resemble the actual product as closely as possible in terms of content, composition, and consistency as well as in temperature, so that changes in temperature occur at the same rate. The exact refrigerant, dry ice, or temperature stabilizer to be used in shipping should be used in the test. Each packaging configuration for the product must be tested.

Each packaging system should be tested with its minimum and maximum product load and with each type of insulation or refrigerant. Each variation in transport system, shipment method (such as overnight or two day), and season should generate a sample size of at least 25.

Acceptable recording equipment includes battery-operated thermistor data recorders or thermocouple wire–based multiple-channel data loggers with a readable resolution of 0.1°C and an accuracy of ±1.0°C.

Battery-operated recorders must be precalibrated by the manufacturer and not calibrated during testing. Hard-wired thermocouples should be calibrated according to the manufacturer's instructions before and after testing.

Testing should be performed in a draft-free environmental room or specifically designed test chamber. The area must be big enough to accommodate the package and must be programmed to follow specified temperature profiles with an accuracy of ±3°C.

Possible extreme temperatures that the packaged product may face should be based on actual measurements of the distribution and handling environment. These figures should then be used to form an ambient profile, which is used during testing. The ambient profile should reflect the high and low limits of temperature exposure at each interval of handling and transport. If temperature is expected to be constant throughout the whole process, continuous exposure to one temperature is also acceptable during testing.

If the package is expected to encounter a series of differing constant temperatures, then a cyclic profile should be used. The testing environment should be programmed at specific intervals for specific lengths of time. For example, the room could be set at 22°C for four hours, then 35°C for two hours, then 30°C for 12 hours, and then 35°C for six hours.

If the package is expected to encounter incremental increases or decreases from a constant temperature, the changes can be reflected in a ramp profile. For example, the room could go from 22° to 45°C in four hours and then back again in another four hours.

The thermal test procedure should be conducted with at least two people present. The product should be loaded into the package as soon as the temperature recording process begins. Thermocouple probe wires should not create air leaks or gaps upon closing the lid of the package. Each package should be weighed and the probes or monitors affixed to its exterior. Then the package must be put in the testing room on a pallet or open platform, at least six inches away from any floor, wall, or other object. After the test, the probes or monitors used should be verified for accuracy. Then the test data can be collected and a graphic profile of the package's performance created. Retesting is required when the package or transport method changes.

Final test reports should be sent for certification to ISTA, 1400 Abbott Rd., Ste. 310, East Lansing, MI 48823-1900. For more information, call 517/333-3437.

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