Which of the following is NOT a characteristic considered when selecting a dry chemical agent?

When selecting a dry chemical agent for fire extinguishing systems, considerations typically include a variety of technical and practical factors. One of the critical aspects is the effectiveness of the agent against specific fire classes, which ensures the agent can effectively suppress the type of fire anticipated. The chemical composition is equally important, as it determines the agent's reaction to fire and how it interacts with materials, impacting safety and efficiency.

Cost is also a key factor, as budget constraints can drive the choice of agent. However, the manufacturer's warranty period is not generally a characteristic that influences the decision on which dry chemical agent is selected. While a warranty may provide added assurance regarding the product’s reliability and durability after purchase, it does not directly pertain to the agent’s performance or suitability for extinguishing different types of fires. Therefore, the focus of selection criteria is on effectiveness, composition, and cost, making the warranty period a less relevant aspect.