What is required for each cylinder when multiple cylinders are used to pressurize dry chemical agent containers?

To ensure the effective operation of a dry chemical extinguishing system utilizing multiple pressurizing cylinders, it is essential that each cylinder is equipped with a pressure gauge and a manual means of operation. The pressure gauge allows operators to monitor the pressure within each cylinder, ensuring that it is maintained at an optimal level for effective discharging of the agent. A manual means of operation provides the ability to activate the system manually, which is crucial during emergencies when automated systems may fail or be inaccessible. This combination of features helps ensure the reliability and functionality of the extinguishing system in critical situations.

The other options, while they may have their own importance in different contexts, do not specifically apply to the requirements for cylinders in a dry chemical extinguishing system. For instance, a built-in safety valve can be important for preventing overpressure, but it is not a requirement for each cylinder. A digital control panel may enhance system monitoring and control but is not a fundamental necessity for the operation of each cylinder. Similarly, while a backup power supply may be useful for certain systems, it is not specifically required for the operation of multiple pressurizing cylinders in this context.