4.1 This test method is intended for use for evaluating the performance of thermal insulated packaging used for high-value, high-risk materials. This test method may also be used for any product that requires accurate internal package temperature readings while being exposed to a range of external air temperatures.

4.2 Certain items, such as biological materials, pharmaceuticals, diagnostics, and blood products, must be shipped inside temperature-controlled packages. Factors affecting the rate of heat transfer of the package include the insulation of the exterior package, the energy source, and the product payload.

4.3 Because of the variety of factors affecting the performance of a thermally insulated package, testing should be conducted with the actual package whenever possible. When simulated packages are used, special care must be exercised so that the simulated payload and coolant will be as close as possible to the actual packages in temperature and other relevant physical properties.