A safety valve functions by automatically releasing pressure when it exceeds a predetermined limit. This limit is set according to the design specifications of the equipment it protects, ensuring that the system can operate within safe parameters. When the pressure within a vessel or pipeline rises beyond this threshold, the safety valve opens, allowing excess pressure to escape, and then closes once the pressure returns to a safe level. This automatic response helps to prevent catastrophic failures, such as explosions or equipment damage, which can have devastating consequences.