What is the required safety valve capacity for a boiler?

The required safety valve capacity for a boiler is designed to ensure that all generated steam can be discharged without exceeding a specific limit above the pressure setting. This limit is typically set at 6% over the valve's set pressure to maintain safe operating conditions within the boiler system.

This function is critical as it prevents dangerous overpressure situations that can lead to catastrophic failures. The capacity to discharge all generated steam effectively ensures that the system can respond to sudden increases in steam production due to operational conditions, thereby maintaining safety and stability. This makes option C the correct choice in describing the fundamental purpose of a safety valve in a boiler system.

In contrast, simply discharging steam slightly below the maximum pressure or maintaining pressure above a certain percentage does not adequately account for the potential variations in steam generation and the need for swift response to prevent overpressure. Continuous release of steam during operation is also not viable as it would disrupt the boiler’s efficiency and operational integrity. Thus, the requirement for safety valve capacity centers on its ability to manage steam discharge effectively while adhering to set pressure limits.