A Heat Pack is a single-use air-activated chemical heat pack included with shipments of temperature-sensitive livestock and plants when ambient temperatures along the shipping route would otherwise expose animals to cold stress, temperature shock, or mortality during transit. Shrimp, snails, and aquatic plants all have lower temperature thresholds below which their physiological function is impaired -- and sealed shipping bags inside cardboard boxes can drop to near-ambient temperature within hours of packing when outdoor temperatures are cold. The heat pack generates sustained heat through an exothermic chemical reaction that begins on exposure to air and continues for the expected transit duration, maintaining the interior of the shipping box at a temperature above the cold-stress threshold for the livestock inside. It is selected or omitted at packing based on current and forecast temperatures along the shipping route at the time of dispatch.

Transit Temperature Protection