Flameless ration heater

In 1980, Natick learned that the U.S. Navy had developed a magnesium-iron alloy powder for buoyancy devices and heated diving vests.

This was more cost efficient, so the University of Cincinnati was contracted to develop it into a prototype MRE heater, which was called the Dismounted Ration Heating Device (DRHD).

The inventors later incorporated under the name Zesto-Therm Inc. and patented the meal heating product (now called the ZT Energy Pad), and began selling it for civilian use.

Although, it was discovered that in cold climates, two or even three trioxane bars would be needed to adequately heat the meal, making the FRH cheaper overall.

It is recommended to place the bag within the cardboard carton the MRE is issued with to prevent injury, and to prop it upright so the water does not leak out and prematurely stop the reaction.

When water is added to a ration heater, it dissolves the salt to form a salt-water electrolyte, thereby turning each particle of magnesium and iron into a tiny battery.

Because the magnesium and iron particles are in contact, they essentially become thousands of tiny short-circuited batteries which quickly burn out, producing heat in a process the patent holders call "supercorroding galvanic cells".

Upon adding one US fluid ounce (30 ml) of water, this mixture can raise the temperature of a 8-ounce (230 g) meal packet by 100 °F (38 °C) in about 10 minutes, releasing approximately 50 kilojoules (47 BTU) of heat energy at about 80 watts.

[7] The United States Department of Transportation (DOT) Federal Aviation Administration (FAA) conducted testing and released a report which in summary states "... the release of hydrogen gas from these flameless ration heaters is of a sufficient quantity to pose a potential hazard on board a passenger aircraft.

Un-activated MRE heaters pose a potential fire hazard if they become wet when turned in at a landfill site.

MRE heaters must be disposed of in approved solid waste containers aboard the installation after they have been properly activated.