Class 10-A or better extinguishers are rated only by which test?

Class 10-A or better extinguishers are rated based on their effectiveness in controlling fires involving ordinary combustibles, such as wood and paper. The rating is determined through standardized testing methods that assess how much of a specific fuel type the extinguisher can effectively extinguish.

The wood crib test is a controlled assessment where an extinguisher is used against a standardized wood crib fire, allowing evaluators to determine its performance. This involves measuring the amount of combustible material that the extinguisher can extinguish and ensuring that it meets the necessary criteria for safety and effectiveness.

The significance of the wood crib test is that it provides a reliable measure of an extinguisher's capability, which is crucial for both consumer safety and regulatory compliance. Other potential testing methods, while important for understanding different aspects of extinguisher performance, do not specifically pertain to the Class 10-A rating. For instance, hydrostatic testing is conducted to ensure the structural integrity of the extinguisher itself, rather than its fire suppression capability.