How can excessive pressure in a steam system be mitigated?

Mitigating excessive pressure in a steam system is crucial for safety and operational efficiency. The correct approach is to install pressure relief valves. These valves are specifically designed to open automatically when the pressure exceeds a predetermined level, allowing excess steam to escape safely. This prevents potential damage to the steam system due to overpressure situations, such as explosions or ruptures.

The function of pressure relief valves is vital because they not only help in maintaining the system's pressure within safe limits but also ensure that the steam system can operate effectively without risking structural integrity. This mechanism helps in maintaining a consistent and safe operational environment.

The other options might seem relevant but do not directly address the issue of controlling excessive pressure. Increasing the water level could lead to other complications, sealing joints may help prevent leaks but will not address pressure build-up, and insulating pipes primarily helps with thermal efficiency rather than managing pressure. Pressure relief valves serve a specific and critical role in the safety management of steam systems.