Valves are a key component of heating, air-conditioning and refrigeration equipment. For example, in systems that use water as a medium for heating and cooling, balancing valves regulate the flow of hot or cold water to the various terminals in the system. In air-conditioning and refrigeration systems, expansion valves control the flow of refrigerant between the compressor, condenser and evaporator.

In 1951, at the height of the Cold War, the U.S. Army Chemical Corps and Ordnance Corps initiated a program to develop a new rocket that could deliver chemical weapons over a large area. The result was the M55 rocket, which was equipped with a unitary warhead filled with sarin or VX—highly toxic nerve agents. The rocket was rushed into production, and tens of thousands were produced from 1959 to 1965.