What tests are used to rate Class A extinguishers?

Class A extinguishers are specifically designed to combat fires fueled by ordinary combustible materials like wood, paper, and cloth. The rating tests for these extinguishers are standardized to assess their effectiveness against such fires, and they typically involve materials that closely replicate these ordinary combustibles.

The correct testing methods for Class A extinguishers include the Wood Crib, Wood Panel, and Excelsior tests. The Wood Crib test uses a specific arrangement of wood blocks to create a defined fire scenario that simulates a typical Class A fire. The Wood Panel test involves igniting a wood panel to determine the extinguisher's capacity to extinguish a fire of that kind. Additionally, the Excelsior test employs shredded wood to evaluate how well the extinguisher can handle this type of combustible.

These methods provide a reliable assessment of the extinguisher's performance and are integral to establishing its rating. The other combinations of tests listed do not align with the standards for assessing Class A fire extinguishers.