Which foam technique should not be used on Class A fires?

The Sweep or Roll-on method is not typically recommended for use on Class A fires. This technique involves applying foam in a sweeping motion, which is more suitable for Class B fires involving flammable liquids. In the case of Class A fires, which usually involve ordinary combustibles like wood, paper, and textiles, the preferred methods focus on creating a blanket of foam over the surface to effectively smother the fire and prevent re-ignition.

Class A fires benefit more from methods that ensure thorough saturation of the burning material, such as the Bank-down, Rain-down, or Direct application methods. These techniques allow for foam to cover the material, interrupting the combustion process by effectively cooling and suffocating the fire. Each of these methods has its own advantages for handling Class A materials, thus ensuring better firefighting efficacy compared to the Sweep or Roll-on method.