A flameless ration heater (FRH), colloquially an MRE heater, is a form of self-heating meals packaging included in U.S. The heater is a plastic bag crammed with magnesium and iron powders and table salt. When a meal pouch is positioned in the bag and water is added, an exothermic reaction happens which quickly boils the water to heat the meals. Before the development of the FRH, service members heated their meals by boiling the food pouches in a canteen cup heated over a lit Sterno gel or portable stove. 5 This was slow, especially in chilly weather, and was made more difficult in windy or wet circumstances. It additionally produced a visible flame that was undesirable at night time. 2 Sometimes they heated the pouches by placing them on a hot vehicle's engine block or exhaust manifold. Because of these problems, service members continuously ate their meals cold both as a result of a lack of a heating supply, a scarcity of time, or both.

The analysis and growth into a flameless ration heater began in 1973 by the U.S. Army Natick Research, Development, and Engineering Center in Natick, Massachusetts. A patented water-activated magnesium-carbon chemical heating product was investigated. In 1980, efficient room warmer Natick realized that the U.S. Navy had developed a magnesium-iron alloy powder for buoyancy gadgets and efficient room warmer heated diving vests. This was extra value efficient room warmer, so the University of Cincinnati was contracted to develop it right into a prototype MRE heater, which was known as the Dismounted Ration Heating Device (DRHD). The inventors later integrated under the identify Zesto-Therm Inc. and patented the meal heating product (now called the ZT Energy Pad), and started promoting it for civilian use. In 1986 the U.S. Army evaluated the ZT Energy Pad and found that it didn't always heat the food adequately and left a messy residue on the outside of the meals pouches. A focus group of 26 troopers was surveyed to check heating an MRE with a Zesto-Therm pad compared to the canteen cup technique heated with a trioxane fuel bar.

100% preferred the flameless ration heater: efficient room warmer it was compact, disposable, and did not require tools to hold and clean. 4 However, it was about twice as costly as a trioxane fuel bar. Although, it was discovered that in chilly climates, two or even three trioxane bars could be needed to adequately heat the meal, making the FRH cheaper general. Other prototypes had been developed, such as the Mounted Ration Heating Device (MRHD), an electrical gadget that may very well be powered from a car's energy supply and efficient room warmer used to heat up to four rations directly. The MRHD was typically most popular over the Zesto-Therm pads, but not all autos had the correct connections to power the system, and having a single device meant service members needed to take turns utilizing it. A package deal wanted to be developed to safely cook the food in while the chemical reaction was activated. Zesto-Therm already had a line of insulated cooking pouches on the market, but they had been found to be too costly and alpha heater portable heater price impractical to be issued with each MRE.

A high-density polyethylene bag was developed that was food safe, would protect the chemical from unintended activation when saved, may withstand the temperatures required throughout cooking, and was transparent so the service member could easily measure a quantity of water by filling it to a line printed on the bag. Once the design was finalized, the acquisition course of was rapidly accomplished. In May 1990, the FRH was accredited for bulk concern. 34 A process that normally takes 4 to six years to award contracts was as an alternative accomplished in a single yr so the FRH could possibly be used in Operation Desert Storm. 38 fifty one million FRHs were bought for $25 million, and approximately 4.5 million FRHs have been shipped to Southwest Asia for the Gulf War. 35 Beginning in 1993, efficient room warmer one FRH was packaged with every MRE. The flameless ration heater is issued in a plastic bag with directions printed on it. Inside the bag is a small amount of metallic powders, which does the actual heating.

To heat a meal, the bag is first torn open, and a sealed food pouch is placed inside. About 1 US fluid ounce (30 mL) of water is then added to the bag, utilizing the road printed on the bag as a marker. The chemical response begins instantly, and takes about 12 to 15 minutes to heat a food pouch to about 60 °C (140 °F). It's endorsed to position the bag throughout the cardboard carton the MRE is issued with to forestall injury, and to prop it upright so the water does not leak out and prematurely stop the response. Ration heaters generate heat in an electron-switch process called an oxidation-discount reaction. This reaction is analogous to iron being rusted by oxygen, and proceeds at about the same slow rate, which is just too slow to generate usable heat. To accelerate the reaction, metallic iron particles and table salt (NaCl) are mixed with the magnesium particles. Iron and magnesium metals, when suspended in an electrolyte, type a galvanic cell that may generate electricity.