Type V mechanical foam liquid was a solution foaming agent. Foam was prepared by mixing the foam forming liquid with a water stream passing through a hose or pipe, forming a 6% solution. The foam production occurred at the terminal nozzle, which was designed so that air was introduced, causing the foam-water mixture to expand by forming large quantities of foam.

The quantity of mechanical foam liquid provided was determined in the design phase of the ship. At this time, BU-Ships conducted fire load studies. The results, in addition to the appropriate proportioner operating capacity requirements of the unit or system, were considered in determining the quantity provided.

Portable, 5-gallon cans of foam were stored where class “B” fires could potentially develop; these were stowed on racks, two to ten cans per rack. Installed equipment/system tanks could hold 10, 50, 500 or 1,000 gallons of mechanical foam. Ships were loaded out with 120 to 600 spare cans of mechanical foam; larger ships had twenty or more additional 55-gallon drums. The spares were used to refill the high-capacity system tanks after emergencies or after extensive system testing.