This International Standard specifies the minimum operational requirements for thermal efficiency to ensure that perishable cargoes in insulated standard airborne containers are kept in prime condition during the ground handling and air transportation cycle for a maximum period of 36 h. It is applicable to all insulated air cargo containers irrespective of their size and designation. It does not provide details concerning refrigerated or heated containers and/or the methods and equipment used to obtain the required thermal effect, such as cryogenic, gaseous or liquid fluids, or mechanical compressors/heaters. NOTES 1 The term "perishable cargo" refers, for example, to dairy produce, fruit, vegetables, flowers, frozen foods, meat, fish, etc., requiring maintenance of specific temperature ranges during door-to-door transportation involving air transport. 2 It should be noted that throughout this document environmental (atmospheric) temperatures are expressed in commercial values of degrees Celsius/Fahrenheit (°C/°F) and technical (scientific) temperatures are expressed in the International Standard measure, kelvin (K). A temperature conversion table is given for convenience in annex A.