Which system is NOT a way to proportion foam?

The system that is not a way to proportion foam is a foam container. Foam containers are primarily used to hold foam concentrate; they do not actively participate in the process of mixing foam with water to create a foam solution. Proportioning foam refers to the methods used to mix foam concentrate with water in the appropriate ratios to produce a foam suitable for extinguishing fires.

On the other hand, a self-inducting nozzle, pressure systems, and bypass eductors are all specific devices or systems designed to effectively mix foam concentrate with water.

• A self-inducting nozzle works by drawing foam concentrate from a container when water flows through it, using the Venturi effect to mix the concentrate with water and create foam.

• Pressure systems utilize pressure energy to force foam concentrate into the water stream, ensuring a consistent and effective mix.

• Bypass eductors allow water to flow through while maintaining a specific proportion of foam concentrate by creating a suction effect, blending the two to form a useable foam.

Thus, among the listed options, the foam container does not perform any proportional function, which makes it the correct choice for identifying a system that is not a method for proportioning foam.