Which valve is provided for safety if the pressure becomes too great?

The safety relief valve is specifically designed to protect a system by releasing pressure when it exceeds a predetermined limit. This function is crucial in preventing potential damage to pipes, tanks, and other components that could result from over-pressurization. When pressure builds up beyond a safe threshold, the safety relief valve opens and allows excess pressure to escape, thereby maintaining safety in operation.

In contrast, the main control valve regulates the flow and pressure as part of normal operation but does not directly address safety concerns related to excessive pressure. The back pressure relief valve serves to maintain a certain pressure within a system but is not specifically designed for the safety of relieving excessive pressure. The flow control valve's primary purpose is to manage the flow rate, not pressure levels, and thus does not offer safety measures against high-pressure situations.