Types of Chemical Hot Packs

When you need a quick source of heat for an injury, comfort or keeping supplies, a chemical hot pack provides that needed warmth. Three types of hot packs use different chemical solutions to provide you with a portable source of heat. Some of these packs use chemicals plus water for a heat source, while others use a chemical gel solution or a mixture of chemicals that react to air.

  1. Exothermic Hot Packs

    • Hot packs that use a mixture of water and chemicals are exothermic, or heat-releasing, packs. These packs usually contain calcium chloride or magnesium sulfate in one side of the pouch and water in the other side. Once someone breaks the seal between the two sides, the chemicals mix with the water. The chemicals give off heat as they dissolve in the water.

    Gel Packs

    • Gels packs can be used for heat or cold purposes. To use as a heat source, warm gel packs in a microwave for 20 to 40 seconds. The gel used in these packs is similar to the gel in baby diapers. It is not toxic. The gel is a chemical composition usually consisting of polymer, coated silica or hydroxyethyl cellulose.

    Air-Activated Hot Packs

    • Air-activated heat packs use a chemical mixture of iron powder, vermiculite, cellulose, activated carbon (charcoal), water and salt. As the chemical compounds in these packs mix and make contact with oxygen, they produce a slow chemical burn that releases heat. These packs last anywhere from 5 to 20 hours and you can be use them to keep supplies and food warm in home and commercial applications.