How should maintenance personnel validate a dry chemical system's operational readiness?

The operational readiness of a dry chemical system is crucial for ensuring it functions effectively in an emergency situation. Maintenance personnel should utilize a comprehensive approach that includes visual inspections, functional testing, and pressure checks to validate the system's performance.

Visual inspections allow personnel to assess the condition of all system components, looking for any signs of wear, damage, or corrosion that could impair function. Functional testing involves activating the system to ensure that it operates as intended, which confirms that all parts—including nozzles, valves, and pipes—are functioning properly. Pressure checks are vital to verify that the system maintains appropriate pressure levels, which is essential for the effective discharge of the agent.

While the other options include valuable components, they do not provide a complete or appropriate method for validating operational readiness. Drills with personnel and live agents can help in familiarity with procedures but do not assess the actual equipment's state. Comparing inspections against national standards is important for compliance but does not directly verify that the specific system is operational at that moment. Online training assessments are beneficial for knowledge but do not involve hands-on verification of the system’s functionality. Thus, the comprehensive approach described in the correct answer is essential for ensuring that a dry chemical extinguishing system is ready for use when needed.