Storage and surface temperatures in the humid tropics

The United States Army Tropic Test Center conducted a study of the surface skin and inside temperatures of several typical Army storage enclosures in the humid tropics of the Panama Canal Zone. The study was conducted in the 1974 dry season and the 1973 rainy season. Storage enclosures included a large warehouse, an ammunition bunker, Butler building, a two-man general purpose tent and a CONEX container. The purpose of the study was to characterize the immediate thermal environment of the stored items of material and relate that environment to outside weather conditions. Major conclusions were as follows: (1) Maximum surface temperatures in the tropics rose as high as 176 F. This is higher than some other geographic areas, including Yuma, Arizona; (2) Storage enclosures ranged from most thermally severe to least, as follows: General purpose tent, Butler building, CONEX container, concrete warehouse, and concrete ammunition bunker (least); (3) for most enclosures, inside temperatures always exceeded outside temperatures; (4) Outside weather conditions in the humid tropics varied little during the day or the year, but thermal build-ups in and on enclosures were formidable. Attempts to mathematically predict enclosure temperatures from ambient conditions failed; (5) Mean dry season enclosure temperatures were only slightly higher than mean rainy season temperatures. The single highest individual maximum temperatures were found in the rainy season. It was recommended that tropic storage tests of materiel shift emphasis from ambient weather conditions to enclosure temperatures.