Fog nozzles can be used with foam solution to produce:

• A. High-expansion foam
• B. Low-expansion, long-lasting foam
• C. Medium-expansion foam
• D. No expansion foam

Answer: (B)

Fog patterns create a fine, lightweight spray, and when foam concentrate is added into that stream, the mixture forms a dense, adherent foam blanket rather than a highly foamy, airy mass. This yields low-expansion foam that clings to surfaces and lasts longer, providing sustained cooling and burn suppression. High-expansion foam requires devices designed to introduce a lot of air and generate huge volumes of bubbles, which a fog nozzle does not provide. So the combination of a fog pattern with foam solution best produces low-expansion, long-lasting foam.