What is the expansion ratio of AFFF concentrate when mixed with seawater in an in-line eductor?

The correct choice reflects the commonly accepted mixing ratio for Aqueous Film Forming Foam (AFFF) concentrate when used in conjunction with seawater in an in-line eductor system. Specifically, AFFF is typically mixed at a concentration of about 6%, which means that for every 100 parts of the combined mixture, 6 parts would be AFFF concentrate and 94 parts would be seawater. This ratio is effective for generating a stable foam that can suppress and control flammable liquid fires, particularly in marine environments where seawater is readily available.

Using a 6% ratio ensures that there is enough foam agent present to provide effective coverage and create a film that helps extinguish the fire while also preventing re-ignition. The characteristics of AFFF enhance its performance when mixed at this concentration, allowing it to work effectively against various types of fuels.

An understanding of the correct expansion ratio is crucial for damage control personnel, as improper mixes can lead to decreased effectiveness in fire suppression efforts.