46 CFR §108.473

1. (a)Each foam agent, each tank for a foam agent, each discharge outlet, each control, and each valve for the operation of a foam extinguishing system must be approved by the Commandant.
2. (b)Each foam agent tank and each control and valve for the operation of a foam extinguishing system with outlets in a space must be outside the space and must not be in a space that may become inaccessible if a fire occurs in the space.
3. (c)Each control for a foam extinguishing system with outlets in a space must be near a main escape from the space.