Final answer:
Water-based extinguishers are intended for small Class A fires, which involve combustible materials like wood. Dry-cleaning solvents are no longer recommended, while fluorinated solutions in foaming plastics are used for larger fires of organic liquids.
Step-by-step explanation:
The type of portable extinguishers intended for use on small Class A fires only are water-based extinguishers. These extinguishers use water to cool the burning material, effectively extinguishing the fire. It is important to note that these extinguishers are suitable for fires involving combustible materials like wood, paper, and textiles, but they are not suitable for grease fires, electrical fires, or fires involving flammable liquids. Previously, fire extinguisher systems might have used substances like dry-cleaning solvents, but such chemicals are no longer recommended for use.
Today, a fluorinated solution, which can spread across the burning surface, is frequently used in foams to fight large-scale fires of organic liquids. These foaming products are known as foaming plastics and are effective for more complex fire scenarios.