Which of the following describes an important function of pressure relief valves?

Pressure relief valves serve a critical role in ensuring the safety and functionality of various systems that operate under pressure, such as boilers and pressure vessels. Their primary function is to prevent overpressure conditions, which can lead to catastrophic failures, equipment damage, or even hazards to personnel nearby.

When the pressure within a system exceeds the preset limits, the pressure relief valve opens to release excess pressure, allowing fluid or gas to escape safely. This mechanism is vital for protecting the system from excessive pressure buildup that could result from thermal expansion, a sudden influx of heat, or a malfunction in the system. By venting the excess pressure, these valves maintain operational integrity and safety.

The other choices do not accurately reflect the purpose of pressure relief valves. They do not increase temperature or enhance flow, nor do they directly ensure maximum efficiency; rather, their main function is to maintain safe operational pressure. This function ultimately supports the overall safety and efficiency of the system by preventing scenarios that could lead to pressure-related incidents.